0001708055-23-000003 | 10-K | XBRL Viewer | Ribbon Communications INC

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Cover - USD ($) $ in Thousands	12 Months Ended
Cover - USD ($) $ in Thousands	Dec. 31, 2022	Mar. 28, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38267
Entity Registrant Name	RIBBON COMMUNICATIONS INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1669692
Entity Address, Address Line One	6500 Chase Oaks Boulevard, Suite 100
Entity Address, City or Town	Plano
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75023
City Area Code	978
Local Phone Number	614-8100
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	RBBN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 218,560
Entity Common Stock, Shares Outstanding		169,229,979
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the definitive Proxy Statement to be delivered to stockholders in connection with the Registrant's 2023 Annual Meeting of Stockholders are incorporated by reference into Part III of this report.
Entity Central Index Key	0001708055
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2022
Audit Information [Abstract]
Auditor Firm ID	34
Auditor Name	Deloitte & Touche LLP
Auditor Location	Dallas, Texas

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 67,101	$ 103,915
Restricted cash	161	2,570
Accounts receivable, net	267,244	282,917
Inventory	75,423	54,043
Other current assets	68,057	37,545
Total current assets	477,986	480,990
Property and equipment, net	44,832	47,685
Intangible assets, net	294,728	350,730
Goodwill	300,892	300,892
Investments	0	43,931
Deferred income taxes	53,649	47,287
Operating lease right-of-use assets	44,888	53,147
Other assets	38,589	23,075
Total assets	1,255,564	1,347,737
Current liabilities:
Current portion of term debt	20,058	20,058
Accounts payable	95,810	97,121
Accrued expenses and other	85,270	100,752
Operating lease liabilities	15,416	17,403
Deferred revenue	113,939	109,119
Total current liabilities	330,493	344,453
Long-term debt, net of current	306,270	350,217
Operating lease liabilities, net of current	46,183	55,196
Deferred revenue, net of current	19,254	20,619
Deferred income taxes	3,750	8,116
Other long-term liabilities	31,187	41,970
Total liabilities	737,137	820,571
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value; 10,000,000 shares authorized; none issued and outstanding	0	0
Common stock, 240,000,000 shares authorized, $0.0001 par value, 168,324,995 shares issued and outstanding at December 31, 2022; 148,895,308 shares issued and outstanding at December 31, 2021	17	15
Additional paid-in capital	1,941,569	1,875,234
Accumulated deficit	(1,453,744)	(1,355,661)
Accumulated other comprehensive income	30,585	7,578
Total stockholders' equity	518,427	527,166
Total liabilities and stockholders' equity	$ 1,255,564	$ 1,347,737

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	240,000,000	240,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares issued (in shares)	168,324,995	148,895,308
Common stock, shares outstanding (in shares)	168,324,995	148,895,308

Consolidated Statements of Operations - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue:
Total revenue	$ 819,760,000	$ 844,957,000	$ 843,795,000
Cost of revenue:
Total cost of revenue	418,824,000	400,297,000	392,978,000
Gross profit	400,936,000	444,660,000	450,817,000
Operating expenses:
Research and development	203,676,000	194,948,000	194,525,000
Sales and marketing	147,766,000	150,279,000	139,318,000
General and administrative	51,053,000	53,661,000	63,286,000
Amortization of acquired intangible assets	29,646,000	28,283,000	18,620,000
Impairment of goodwill	0	116,000,000	0
Acquisition-, disposal- and integration-related	6,286,000	7,632,000	17,164,000
Restructuring and related	10,833,000	11,653,000	16,235,000
Total operating expenses	449,260,000	562,456,000	449,148,000
(Loss) income from operations	(48,324,000)	(117,796,000)	1,669,000
Interest expense, net	(19,780,000)	(15,831,000)	(21,042,000)
Other (expense) income, net	(44,495,000)	(74,516,000)	112,690,000
(Loss) income before income taxes	(112,599,000)	(208,143,000)	93,317,000
Income tax benefit (provision)	14,516,000	30,958,000	(4,726,000)
Net (loss) income	$ (98,083,000)	$ (177,185,000)	$ 88,591,000
(Loss) earnings per share:
Basic (in dollars per share)	$ (0.63)	$ (1.20)	$ 0.64
Diluted (in dollars per share)	$ (0.63)	$ (1.20)	$ 0.61
Shares used to compute (loss) earnings per share:
Basic (in shares)	156,668	147,575	138,967
Diluted (in shares)	156,668	147,575	144,650
Product
Revenue:
Total revenue	$ 442,680,000	$ 453,042,000	$ 467,912,000
Cost of revenue:
Total cost of revenue	245,145,000	214,745,000	204,772,000
Service
Revenue:
Total revenue	377,080,000	391,915,000	375,883,000
Cost of revenue:
Total cost of revenue	142,137,000	147,209,000	145,916,000
Amortization of acquired technology
Cost of revenue:
Total cost of revenue	$ 31,542,000	$ 38,343,000	$ 42,290,000

Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (98,083)	$ (177,185)	$ 88,591
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on interest rate swap, net of reclassifications and amortization into earnings	19,321	12,759	(10,948)
Foreign currency translation adjustments	(792)	(239)	894
Employee retirement benefits	4,478	0	2,585
Other comprehensive income (loss), net of tax	23,007	12,520	(7,469)
Comprehensive (loss) income, net of tax	$ (75,076)	$ (164,665)	$ 81,122

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional Paid-in Capital	Accumulated deficit	Accumulated other comprehensive (loss) income	Edgewater Networks, Inc.	Edgewater Networks, Inc. Common stock	Edgewater Networks, Inc. Additional Paid-in Capital	Anova Data, Inc.	Anova Data, Inc. Common stock	Anova Data, Inc. Additional Paid-in Capital
Beginning balance (in shares) at Dec. 31, 2019		110,471,995
Beginning balance at Dec. 31, 2019	$ 483,255	$ 11	$ 1,747,784	$ (1,267,067)	$ 2,527
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)		38,288
Exercise of stock options	70		70
Vesting of restricted stock awards and units (in shares)		2,246,690
Vesting of restricted stock awards and units	1	$ 1
Vesting of performance-based stock units (in shares)		323,752
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations (in shares)		(472,028)
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations	(1,674)		(1,674)
Shares issued as consideration in connection with the acquisition of ECI Telecom Group Ltd. (in shares)							32,500,000
Shares issued as consideration in connection with the acquisition of ECI Telecom Group Ltd.						$ 108,550	$ 3	$ 108,547
Shares issued as consideration in connection with acquisition of Anova Data, Inc. (in shares)										316,551
Shares issued as consideration in connection with acquisition of Anova Data, Inc.									$ 1,630		$ 1,630
Stock-based compensation expense	13,899		13,899
Other comprehensive income (loss)	(7,469)				(7,469)
Net loss (income)	88,591			88,591
Ending balance (in shares) at Dec. 31, 2020		145,425,248
Ending balance at Dec. 31, 2020	686,853	$ 15	1,870,256	(1,178,476)	(4,942)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)		13,815
Exercise of stock options	24		24
Vesting of restricted stock awards and units (in shares)		3,653,552
Vesting of restricted stock awards and units	0
Vesting of performance-based stock units (in shares)		1,557,656
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations (in shares)		(1,754,963)
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations	(14,464)		(14,464)
Stock-based compensation expense	19,418		19,418
Other comprehensive income (loss)	12,520				12,520
Net loss (income)	$ (177,185)			(177,185)
Ending balance (in shares) at Dec. 31, 2021	148,895,308	148,895,308
Ending balance at Dec. 31, 2021	$ 527,166	$ 15	1,875,234	(1,355,661)	7,578
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)		708
Exercise of stock options	1		1
Vesting of restricted stock awards and units (in shares)		3,075,543
Vesting of restricted stock awards and units	0
Vesting of performance-based stock units (in shares)		179,184
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations (in shares)		(897,059)
Shares of restricted stock returned to the Company under net share settlements to satisfy tax withholding obligations	(2,784)		(2,784)
Common stock issued in equity offering (in shares)		17,071,311
Common stock issued in equity offering	52,067	$ 2	52,065
Issuance costs related to equity offering	(1,654)		(1,654)
Stock-based compensation expense	18,707		18,707
Other comprehensive income (loss)	23,007				23,007
Net loss (income)	$ (98,083)			(98,083)
Ending balance (in shares) at Dec. 31, 2022	168,324,995	168,324,995
Ending balance at Dec. 31, 2022	$ 518,427	$ 17	$ 1,941,569	$ (1,453,744)	$ 30,585

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net (loss) income	$ (98,083)	$ (177,185)	$ 88,591
Adjustments to reconcile net (loss) income to cash flows (used in) provided by operating activities:
Depreciation and amortization of property and equipment	15,295	16,962	17,188
Amortization of intangible assets	61,188	66,626	60,910
Amortization of debt issuance costs	2,308	4,763	5,673
Stock-based compensation	18,707	19,418	13,899
Impairment of goodwill	0	116,000	0
Deferred income taxes	(18,251)	(45,596)	(4,616)
Gain on sale of business	(62)	(2,772)	(83,552)
Decrease (increase) in fair value of investments	41,291	71,252	(30,296)
Reduction to deferred purchase consideration	0	0	(70)
Foreign currency exchange losses	1,576	5,002	2,961
Changes in operating assets and liabilities:
Accounts receivable	14,285	(47,279)	9,578
Inventory	(32,099)	(9,029)	11,842
Other operating assets	2,109	9,958	44,343
Accounts payable	(448)	34,482	(49,561)
Accrued expenses and other long-term liabilities	(37,635)	(50,324)	20,629
Deferred revenue	3,455	6,904	(5,955)
Net cash (used in) provided by operating activities	(26,364)	19,182	101,564
Cash flows from investing activities:
Purchases of property and equipment	(10,254)	(17,132)	(26,721)
Purchases of software licenses	(3,300)	0	0
Business acquisitions, net of cash acquired	0	0	(346,852)
Proceeds from sale of business	1,418	2,944	0
Proceeds from the sale of fixed assets	0	0	43,500
Net cash used in investing activities	(12,136)	(14,188)	(330,073)
Cash flows from financing activities:
Borrowings under revolving line of credit	73,625	0	615
Principal payments on revolving line of credit	(73,625)	0	(8,615)
Proceeds from issuance of long-term debt	0	74,625	478,500
Principal payments of term debt	(45,058)	(92,176)	(134,188)
Principal payments of finance leases	(595)	(903)	(1,258)
Payment of debt issuance costs	(1,046)	(789)	(14,147)
Proceeds from equity offering	52,067	0	0
Payment of equity offering issuance costs	(1,654)	0	0
Proceeds from the exercise of stock options	1	24	70
Payment of tax withholding obligations related to net share settlements of restricted stock awards	(2,784)	(14,464)	(1,674)
Net cash provided by (used in) financing activities	931	(33,683)	319,303
Effect of exchange rate changes on cash and cash equivalents	(1,654)	(523)	260
Net (decrease) increase in cash and cash equivalents	(39,223)	(29,212)	91,054
Cash, cash equivalents and restricted cash, beginning of year	106,485	135,697	44,643
Cash, cash equivalents and restricted cash, end of year	67,262	106,485	135,697
Supplemental disclosure of cash flow information:
Interest paid	19,336	14,867	15,546
Income taxes paid	16,988	14,447	9,293
Income tax refunds received	1,251	1,488	1,163
Supplemental disclosure of non-cash investing activities:
Capital expenditures incurred, but not yet paid	2,559	2,269	3,749
Inventory transfers to property and equipment	2,896	676	818
Software license acquired through investment disposal	1,886	0	0
Business acquisition purchase consideration - common stock issued	0	0	108,550
Business acquisition purchase consideration - deferred payments	0	0	1,630
Supplemental disclosure of non-cash financing activities:
Total fair value of restricted stock awards, restricted stock units, performance-based stock awards and performance-based stock units on date vested	$ 9,858	$ 40,751	$ 7,927

NATURE OF THE BUSINESS	12 Months Ended
NATURE OF THE BUSINESS	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF THE BUSINESS	NATURE OF THE BUSINESSRibbon Communications Inc. ("Ribbon" or the "Company") is a leading global provider of communications technology to service providers and enterprises. The Company provides a broad range of software and high-performance hardware products, network solutions, and services that enable the secure delivery of data and voice communications, and high-bandwidth networking and connectivity for residential consumers and for small, medium, and large enterprises and industry verticals such as finance, education, government, utilities, and transportation. Ribbon's mission is to create a recognized global technology leader providing cloud-centric solutions that enable the secure exchange of information, with unparalleled scale, performance, and elasticity. The Company is headquartered in Plano, Texas, and has a global presence with research and development, or sales and support locations in over thirty countries around the world.

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The consolidated financial statements have been prepared in United States dollars, in accordance with accounting principles generally accepted in the United States ("GAAP"). On December 1, 2020 (the "Kandy Sale Date"), American Virtual Cloud Technologies, Inc. ("AVCT") completed the purchase of the Company's cloud-based enterprise service business (the "Kandy Communications Business"). The revenue and expenses of the Kandy Communications Business are excluded from the Company's consolidated financial statements for the period subsequent to the Kandy Sale Date. On March 3, 2020 (the "ECI Acquisition Date"), the Company merged with ECI Telecom Group Ltd ("ECI") (the "ECI Acquisition"). The financial results of ECI are included in the Company's consolidated financial statements for the period subsequent to the ECI Acquisition Date. Equity Offering On August 12, 2022, the Company entered into a Securities Purchase Agreement with certain investors for the sale (the "Equity Offering") in a private placement by the Company of 17,071,311 shares (the "Shares") of the Company’s common stock, par value $0.0001 per share, at a price of $3.05 per share. The aggregate gross proceeds from the Equity Offering were approximately $52.1 million, including $10.0 million from existing related party shareholders, before deducting offering expenses paid by the Company of approximately $1.7 million. The Company intends to continue to use the net proceeds from the Equity Offering to fund general corporate purposes, including capital expenditures, working capital and repayment of debt. The original issuance of the Shares in the Equity Offering was exempt from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). The Company subsequently filed a registration statement on Form S-3 (the “Registration Statement”) with the SEC registering the Shares, which Registration Statement was declared effective by the SEC on September 23, 2022. Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of Ribbon and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Use of Estimates and Judgments The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and judgments relied upon in preparing these consolidated financial statements include accounting for business combinations, revenue recognition for multiple element arrangements, inventory valuations, assumptions used to determine the fair value of stock-based compensation, intangible assets, goodwill, debentures and warrants, legal contingencies and recoverability of Ribbon's net deferred tax assets and the related valuation allowances. Ribbon regularly assesses these estimates and records changes in estimates in the period in which they become known. Ribbon bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results could differ from those estimates. Reclassifications Certain reclassifications, not affecting previously reported net income (loss), have been made to the previously issued financial statements to conform to the current year presentation. Business Combinations The Company recognizes identifiable assets acquired and liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred over the net of the acquisition date fair values of the assets acquired and the liabilities assumed and represents the expected future economic benefits arising from other assets acquired in the business combination that are not individually identified and separately recognized. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill to the extent that it identifies adjustments to the preliminary purchase price allocation. Upon the conclusion of the measurement period or final determination of the values of assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of operations. Revenue Recognition The Company derives revenue from two primary sources: products and services. Product revenue includes the Company's hardware and software that function together to deliver the products' essential functionality. Software and hardware are also sold on a standalone basis. Services include customer support (software updates, upgrades and technical support), consulting, design services, installation services and training. Generally, contracts with customers contain multiple performance obligations, consisting of products and services. For these contracts, the Company accounts for individual performance obligations separately if they are considered distinct. When an arrangement contains more than one performance obligation, the Company will allocate the transaction price to each performance obligation on a relative standalone selling price basis. The Company utilizes the observable price of goods and services, including when they are sold separately to similar customers, in order to estimate standalone selling price. The Company's software licenses typically provide a perpetual right to use the Company's software. The Company also sells term-based software licenses that expire and Software-as-a-Service ("SaaS")-based software which are referred to as subscription arrangements. The Company does not customize its software nor are installation services required, as the customer has a right to utilize internal resources or a third-party service company. The software and hardware are delivered before related services are provided and are functional without professional services or customer support. The Company has concluded that its software licenses are functional intellectual property that are distinct, as the user can benefit from the software on its own. Product revenue is typically recognized upon transfer of control or when the software is made available for download, as this is the point the user of the software can direct the use of, and obtain substantially all of the remaining benefits from, the functional intellectual property. The Company begins to recognize software revenue related to the renewal of subscription software licenses at the start of the subscription period. The Company offers warranties on its products. Certain of the Company's warranties are considered to be assurance-type in nature, ensuring the product is functioning as intended. Assurance-type warranties do not represent separate performance obligations. The Company also sells separately-priced maintenance service contracts which qualify as service-type warranties and represent separate performance obligations. The Company does not allow and has no history of accepting product returns. Services revenue includes revenue from customer support and other professional services. Customer support includes software updates on a when-and-if-available basis, telephone support, integrated web-based support and bug fixes or patches. The Company sells its customer support contracts at a percentage of list or net product price. Customer support revenue is recognized ratably over the term of the customer support agreement, which is typically one year. The Company's professional services include consulting, technical support, resident engineer services, design services and installation services. Because control transfers over time, revenue is recognized based on progress toward completion of the performance obligation. The method to measure progress toward completion requires judgment and is based on the nature of the products or services to be provided. The Company generally uses the input method to measure progress for its contracts because it believes such method best depicts the transfer of assets to the customer, which occurs as the Company incurs costs for the contracts. However, in some instances, the Company uses the output method because it best depicts the transfer of asset to the customer. Under the cost-to-cost measure of progress, the progress toward completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. When the measure of progress is based upon expended labor, progress toward completion is measured as the ratio of labor time expended to date versus the total estimated labor time required to complete the performance obligation. Revenue is recorded proportionally as costs are incurred or as labor is expended. Costs to fulfill these obligations include internal labor as well as subcontractor costs. Customer training includes courses offered by the Company. The related revenue is typically recognized as the training services are performed. Operating Segments The Company's chief operating decision maker (the "CODM") is its president and chief executive officer. Effective in the fourth quarter of 2020 and in connection with the ECI Acquisition, the CODM began to assess the Company's performance based on the performance of two separate lines of business within Ribbon: the Cloud and Edge segment ("Cloud and Edge") and the IP Optical Networks segment ("IP Optical Networks"). Financial Instruments The carrying amounts of Ribbon's financial instruments that approximate their fair values include accounts receivable, equity securities and convertible warrants received as sale consideration, accounts payable and borrowings under a revolving credit facility. Ribbon's term debt balance as of December 31, 2022 of $330.4 million had a fair value of approximately $323.0 million. Financial instruments with remaining maturities or that are due within one year from the balance sheet date are classified as current. Financial instruments with maturities or that are payable more than one year from the balance sheet date are classified as noncurrent. Fair Value Option - Investment in AVCT The Company received debentures and warrants as sale consideration in connection with the sale of the Kandy Communications Business. On September 8, 2021 (the "Debenture Conversion Date"), the debentures were converted into 13,700,421 shares of AVCT common stock (the "Debenture Shares") (see Note 4 for a discussion of the valuation of the debentures, warrants and Debenture Shares). In connection with the conversion of the debentures to the Debenture Shares, the Company elected to use the fair value option to account for its equity investment in AVCT as permitted under Accounting Standards Codification ("ASC") 825, Financial Instruments ("ASC 825"), which then refers to ASC 820, Fair Value Measurement ("ASC 820") to provide the fair value framework for valuing such investments. In accordance with ASC 820, the Company recorded the investment in AVCT at fair value, with changes in fair value recorded as a component of Other (expense) income, net, in the consolidated statements of operations. On August 29, 2022, the Company and AVCT entered into a settlement agreement which provided for, amongst other things, the cancellation of the Company's investment in the Debenture Shares and the Warrants with an aggregate fair value of $2.6 million. Pursuant to the settlement agreements, the Company and AVCT also entered into a Wind Down Agreement, pursuant to which a Reseller Agreement between the parties, as previously amended, was terminated, and the Company was granted a non-exclusive perpetual license to use and modify certain intellectual property owned by AVCT comprising WebRTC gateway technology that is integrated with Ribbon’s SBCs and Application Servers. As consideration, the Company paid AVCT $2.5 million in cash, the Debenture Shares were redeemed and canceled, and the Warrants were terminated and canceled. The perpetual license granted by AVCT is classified as Intangible assets, net in the Company's consolidated balance sheet as of December 31, 2022 in the amount of $3.9 million. Restricted Cash The Company classifies as restricted cash all cash pledged as collateral to secure long-term obligations and all cash whose use is otherwise limited by contractual provisions. At December 31, 2022, the Company had $0.2 million of restricted cash, representing restricted short-term bank deposits pledged to secure certain performance and financial bonds as security for the Company's obligations under tenders, and contracts. At December 31, 2021, the Company had $2.6 million of restricted cash, representing restricted short-term bank deposits pledged to secure certain performance and financial bonds as security for the Company's obligations under tenders, contracts and to one of its main subcontractors. Transfers of Financial Assets The Company's IP Optical Networks segment maintains customer receivables factoring agreements with a number of financial institutions. Under the terms of these agreements, the Company may transfer receivables to the financial institutions, on a non-recourse basis, provided that the financial institutions approve the receivables in advance. The Company maintains credit insurance policies from major insurance providers or obtains letters of credit from the customers for a majority of its factored trade receivables. The Company accounts for the factoring of its financial assets as a sale of the assets and records the factoring fees, when incurred, as a component of interest expense in the consolidated statements of operations, and the proceeds from the sales of receivables are included in cash from operating activities in the consolidated statements of cash flows. During the year ended December 31, 2022, the Company received $73.4 million of cash from the sale of certain accounts receivable and recorded $1.1 million of interest expense in connection with these transactions. During the year ended December 31, 2021, the Company received $118.5 million of cash from the sale of certain accounts receivable and recorded $0.8 million of interest expense in connection with these transactions. Foreign Currency Translation For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Accumulated other comprehensive income. For foreign subsidiaries where the functional currency is the U.S. dollar, monetary assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Nonmonetary assets and liabilities are remeasured into U.S. dollars at historical exchange rates. Revenue and expense items are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Other expense (income), net. Realized and unrealized foreign currency exchange gains and losses arising from transactions denominated in currencies other than the subsidiary's functional currency are reflected in earnings. The Company records its foreign currency gains (losses) as a component of Other (expense) income, net. The Company recognized net foreign currency losses of $1.6 million, $5.0 million and $3.0 million for the years ended December 31, 2022, 2021 and 2020, respectively. Inventory Inventory is recorded at the lower of cost or market value using the first-in, first-out convention. The Company reduces the carrying value of inventory for those items that are potentially excess, obsolete or slow-moving based on changes in customer demand, technology developments or other economic factors. Ribbon writes down evaluation equipment (equipment at customer sites for testing and evaluation) at the time of shipment to its customers, as it is probable that the inventory value will not be realized. Deferred product costs represent deferred cost of revenue for product shipments to customers prior to satisfaction of Ribbon's revenue recognition criteria. The Company classifies inventory that is not expected to be consumed within one year from the balance sheet date as noncurrent and includes such inventory as a component of Other assets. Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, which range from two to five years. Leasehold improvements are amortized over the lesser of the lease term or five years. When an asset is sold or retired, the cost and related accumulated depreciation or amortization are eliminated, and the resulting gain or loss, if any, is recognized in (Loss) income from operations in the consolidated statement of operations. The Company reviews property and equipment for impairment in the same manner as intangible assets discussed below. Software development costs associated with internal use software are incurred in three stages of development: the preliminary project stage, the application development stage and the post-implementation stage. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Certain qualifying costs incurred during the application development stage are capitalized as property and equipment. Internal use software is amortized on a straight-line basis over its estimated useful life of three years, beginning when the software is ready for its intended use. Intangible Assets and Goodwill The Company's intangible assets are comprised of in-process research and development, developed technology, customer relationships, trade names, and internal use software. Intangible assets are reviewed for impairment when events or changes in circumstances indicate that their carrying amounts may not be recoverable based upon the estimated undiscounted cash flows. Recoverability of intangible assets with estimated lives and other long-lived assets is measured by a comparison of the carrying amount of an asset or asset group to future net undiscounted cash flows expected to be generated by the asset or asset group. If these comparisons indicate that an asset is not recoverable, the Company will recognize an impairment loss for the amount by which the carrying value of the asset or asset group exceeds the related estimated fair value. Estimated fair value is based on either discounted future operating cash flows or appraised values, depending on the nature of the asset. The Company amortizes its intangible assets over their respective useful lives, with the exception of in-process research and development, which has an indefinite life until the product is generally available, at which time such asset is typically reclassified to developed technology, and the Company begins to amortize this asset. See Note 10 for additional information regarding the Company's intangible assets. Goodwill is recorded when the consideration for an acquisition exceeds the fair value of net tangible and identifiable intangible assets acquired. Goodwill is not amortized, but instead is tested for impairment at least annually, or more frequently if indicators of potential impairment exist, by comparing the fair value of the Company's reporting unit to its carrying value. The Company's annual test for impairment of goodwill is completed as of October 1. As described above, effective in the fourth quarter of 2020, the Company determined that it has two operating segments: Cloud and Edge, and IP Optical Networks. For the purpose of testing goodwill for impairment, all goodwill is assigned to a reporting unit, which may be either an operating segment or a portion of an operating segment. The Company's reporting units are its operating segments. The Company performs a fair value analysis using both an income and market approach, which encompasses a discounted cash flow analysis and a guideline public company analysis using selected multiples. The Company assesses each valuation methodology based upon the relevance and availability of the data at the time the valuation is performed and the methodologies are weighted appropriately. Any impairment charges are reported separately in the Company's consolidated statements of operations. Stock-Based Compensation The Company's stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which generally represents the vesting period, and includes an estimate of the awards that will be forfeited. The Company uses the Black-Scholes valuation model for estimating the fair value of stock options on the grant date. The fair value of stock option awards is affected by the Company's stock price as well as valuation assumptions, including the volatility of Ribbon's stock price, expected term of the option, risk-free interest rate and expected dividends. The Company may grant to certain of its executives and certain other employees performance-based stock units ("PSUs") that include a market condition. The Company uses a Monte Carlo simulation approach to model future stock price movements based upon the risk-free rate of return, the volatility of each entity and the pair-wise covariance between each entity. These results are then used to calculate the grant date fair values of the PSUs. The Company is required to record expense for the PSUs with market conditions through their respective final vesting dates regardless of the number of shares that are ultimately earned. Once the grant date criteria have been met for a fiscal year performance period, the Company records stock-based compensation expense based on its assessment of the probability that the respective performance condition will be achieved and the level, if any, of such achievement. The Compensation Committee determines the number of shares earned, if any, after the Company's financial results for each fiscal year performance period are finalized. Upon the determination by the Compensation Committee of the number of shares that will be received upon vesting, such number of shares becomes fixed and the unamortized expense is recorded through the remainder of the service period, at which time any Performance PSUs earned, will vest pending each executive's continued employment with the Company through that date. Concentration of Risk The financial instruments that potentially subject Ribbon to concentrations of credit risk are cash, restricted cash and accounts receivable. The Company's cash equivalents and investments were managed by one financial institution at December 31, 2022. Historically, the Company has not experienced significant losses due to such bank depository concentration. The Company's investments at December 31, 2021 consisted of securities of AVCT (see Note 4). Certain components and software licenses from third parties used in Ribbon's products are procured from single sources of supply. The failure of a supplier, including a subcontractor, to deliver on schedule could delay or interrupt Ribbon's delivery of products and thereby materially adversely affect Ribbon's revenue and operating results. Advertising Costs Advertising costs are expensed as incurred and included as a component of Sales and marketing expense in the Company's consolidated statements of operations. Advertising expenses were $1.5 million, $1.6 million and $0.8 million for the years ended December 31, 2022, 2021 and 2020, respectively. Loss Contingencies and Reserves Ribbon is subject to ongoing business risks arising in the ordinary course of business, including legal claims, that affect the estimation process of the carrying value of assets, the recording of liabilities and the possibility of various loss contingencies. An estimated loss contingency is accrued when it is probable that a liability has been incurred or an asset has been impaired and the amount of loss can be reasonably estimated. Ribbon regularly evaluates current information available to determine whether such amounts should be adjusted and records changes in estimates in the period they become known. An allowance for doubtful accounts is estimated based on the Company's assessment of the collectability of specific customer accounts. Ribbon accrues for royalties for technology that it licenses from vendors based on established royalty rates and usage. Ribbon is periodically contacted by third parties who claim that Ribbon's products infringe on certain intellectual property of a third party. Ribbon evaluates these claims and accrues amounts when it is probable that the obligation has been incurred and the amounts are reasonably estimable. Warranty The Company records warranty liabilities for estimated costs of fulfilling its obligations under standard limited hardware and software warranties at the time of sale. The specific warranty terms and conditions vary depending upon the country in which the Company does business, but generally includes material costs, technical support, labor and associated overhead over a period ranging from one to three years. At December 31, 2022, the Company's liability for product warranties was $11.9 million of which $5.3 million was current and included in Accrued expenses and other and $6.6 million was long-term and included in Other long-term liabilities in the Company's consolidated balance sheet. At December 31, 2021, the Company's liability for product warranties was $13.1 million, of which $5.9 million was current and included in Accrued expenses and other, and $7.2 million was long-term and included in Other long-term liabilities in the Company's consolidated balance sheet. Research and Development Grants The Company records grants received from the Office of the Innovation Authority of the Israeli Ministry of Economics (the "IIA") as a reduction to Research and development expense. Royalties payable to the IIA are recognized pursuant to sales of related products and are included in Cost of revenue - product (see Note 25). Accounting for Leases The Company accounts for its leases in accordance with Accounting Standards Codification ("ASC") 842, Leases ("ASC 842") (see Note 20). The Company has operating and finance leases for corporate offices, research and development facilities, and certain equipment. Operating leases are reported separately in the Company's consolidated balance sheets at December 31, 2022 and 2021. The Company has no finance leases as of December 31, 2022. Assets acquired under finance leases are included in Property and equipment, net, in the consolidated balance sheets at December 31, 2021. The Company determines if an arrangement is a lease at inception. A contract is determined to contain a lease component if the arrangement provides the Company with a right to control the use of an identified asset. Lease agreements may include lease and non-lease components. In such instances for all classes of underlying assets, the Company does not separate lease and non-lease components but rather, accounts for the entire arrangement under leasing guidance. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term. For operating leases, lease expense for minimum fixed lease payments is recognized on a straight-line basis over the lease term. The expense for finance leases includes both interest and amortization expense components, with the interest component calculated based on the effective interest method and the amortization component calculated based on straight-line amortization of the right-of-use asset over the lease term. Lease contracts may contain variable lease costs, such as common area maintenance, utilities and tax reimbursements that vary over the term of the contract. Variable lease costs are not included in minimum fixed lease payments and as a result, are excluded from the measurement of the right-of-use assets and lease liabilities. The Company expenses all variable lease costs as incurred. Accounting for Income Taxes Deferred tax assets and liabilities are recognized for the expected future consequences of events that have been reflected in the consolidated financial statements. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and operating loss carryforwards, using tax rates expected to be in effect for the years in which the differences are expected to reverse. The Company records valuation allowances to reduce deferred income tax assets to the amount that is more likely than not to be realized. The Company has provided for income taxes on the undistributed earnings of its non-U.S. subsidiaries as of December 31, 2022, excluding Ireland and Israel, which are indefinitely reinvested. Accordingly, the Company is required to recognize and record deferred taxes for 2022 on the entire outside basis differences related to the foreign subsidiaries, the largest of these differences being undistributed earnings. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, no amount of the benefit attributable to the position is recognized. The tax benefit to be recognized of any tax position that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. Defined Benefit Plans The Company has defined benefit plans for some of its employees at various international locations. The Company recognizes retirement benefit assets or liabilities in the consolidated balance sheets reflecting the funded status of pension and other retirement benefit plans. Retirement benefit assets and liabilities are adjusted for the difference between the benefit obligations and the plan assets at fair value (measured at year-end), with the offset recorded directly to stockholders' equity through accumulated other comprehensive income (loss), net of tax. The amount recorded in stockholders' equity represents the after-tax unamortized actuarial gains or losses, unamortized transition obligations and unamortized prior service costs. Recent Accounting Pronouncements In March 2022, the Financial Accounting Standards Board (the "FASB") issued ASU 2022-02, Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures (“ASU 2022-02”), which eliminates the accounting guidance on troubled debt restructurings ("TDRs") for creditors in ASC 310, Receivables (Topic 310), and requires entities to provide disclosures about current period gross write-offs by year of origination. Also, ASU 2022-02 updates the requirements related to accounting for credit losses under ASC 326, Financial Instruments – Credit Losses (Topic 326), and adds enhanced disclosures for creditors with respect to loan refinancings and restructurings for borrowers experiencing financial difficulty. ASU 2022-02 is effective for the Company January 1, 2023. The Company believes that the adoption of ASU 2022-02 will not have a material impact on its consolidated financial statements upon adoption. In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers ("ASU 2021-08"), which amends ASC 805, Business Combinations (Topic 805), to add contract assets and contract liabilities to the list of exceptions to the recognition and measurement principles that apply to business combinations and to require that an acquiring entity recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC 606, Revenue from Contracts with Customers (Topic 606) ("ASC 606"). Under current GAAP, an acquirer generally recognizes such items at fair value on the acquisition date. While primarily related to contract assets and contract liabilities that were accounted for by the acquiree in accordance with ASC 606, ASU 2021-08 also applies to contract assets and contract liabilities from other contracts to which the provisions of ASC 606 apply, such as contract liabilities from the sale of nonfinancial assets within the scope of ASU 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20). ASU 2021-08 is effective for the Company January 1, 2023. The Company believes that the adoption of ASU 2021-08 could have a material impact on its consolidated financial statements for periods including and subsequent to significant business acquisitions. In January 2021 the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope ("ASU 2021-01"), which refines the scope of ASC 848, Reference Rate Reform, and clarifies some of its guidance as part of the FASB's monitoring of global reference rate reform activities. ASU 2021-01 permits entities to elect certain optional expedients and exceptions when accounting for derivative contracts and certain hedging relationships affected by changes in the interest rates used for discounting cash flows, for computing variation margin settlements, and for calculating price alignment interest in connection with reference rate reform activities under way in global financial markets (the "discounting transition"). In December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 ("ASU 2022-06") which extends the date through which companies can utilize optional expedients and exceptions allowed in Topic 848 from December 31, 2022 to December 31, 2024. The adoption of ASU 2021-01 and ASU 2022-06 did not have a material impact on the Company's consolidated financial statements.

BUSINESS ACQUISITIONS

12 Months Ended

Dec. 31, 2022

Business Combinations [Abstract]

BUSINESS ACQUISITIONS

ECI

On the ECI Acquisition Date, Ribbon completed its merger transaction with ECI in accordance with the terms of the Agreement and Plan of Merger, dated as of November 14, 2019, by and among Ribbon, ECI, an indirect wholly-owned

subsidiary of Ribbon ("Merger Sub"), Ribbon Communications Israel Ltd. and ECI Holding (Hungary) Kft pursuant to which Merger Sub merged with and into ECI, with ECI surviving such merger as a wholly-owned subsidiary of Ribbon. Prior to the ECI Acquisition Date, ECI was a privately-held global provider of end-to-end packet optical transport and software-defined networking ("SDN") and network function virtualization ("NFV") solutions for service providers, enterprises and data center operators.

As consideration for ECI, Ribbon issued the ECI shareholders and certain others 32.5 million shares of Ribbon common stock with a fair value of $108.6 million (the "Stock Consideration") and paid $322.5 million of cash (the "Cash Consideration"), comprised of $183.3 million to repay ECI's outstanding debt, including both principal and interest, and $139.2 million paid to ECI's selling shareholders. In addition, ECI shareholders received $33.4 million from the sale of certain of ECI's real estate assets. Cash Consideration was financed through cash on hand and committed debt financing consisting of a new $400 million term loan facility and $100 million revolving credit facility, which was undrawn at the ECI Acquisition Date.

The ECI Acquisition has been accounted for as a business combination and the financial results of ECI have been included in the Company's consolidated financial statements for the period subsequent to the ECI Acquisition. The Company's financial results for the year ended December 31, 2020 included $260.5 million of revenue and $52.9 million of net loss attributable to ECI.

The Company finalized the valuation of acquired assets, identifiable intangible assets and certain assumed liabilities in the fourth quarter of 2020. A summary of the allocation of the purchase consideration for ECI is as follows (in thousands):


Fair value of consideration transferred:
Cash consideration:
Repayment of ECI outstanding debt obligations	$	183,266
Cash paid to selling shareholders	139,244
Payment to selling shareholders from sale of ECI real estate assets	33,400
Less cash and restricted cash acquired	(9,058)
Net cash consideration	346,852
Fair value of Ribbon stock issued	108,550
Fair value of total consideration	$	455,402

Fair value of assets acquired and liabilities assumed:
Current assets, net of cash and restricted cash acquired	$	120,203
Property and equipment	54,913
Intangible assets:
In-process research and development	34,000
Developed technology	111,900
Customer relationships	116,000
Trade names	3,000
Goodwill	191,996
Other noncurrent assets	37,528
Deferred revenue	(4,369)
Other current liabilities	(146,618)
Deferred revenue, net of current	(3,726)
Deferred tax liability	(13,308)
Other long-term liabilities	(46,117)
	$	455,402

The valuation of the acquired intangible assets is inherently subjective and relies on significant unobservable inputs. The Company used an income approach to value the acquired in-process research and development, developed technology, customer relationships and trade name intangible assets. The valuation for each of these intangible assets was based on estimated projections of expected cash flows to be generated by the assets, discounted to the present value at discount rates

commensurate with perceived risk. The valuation assumptions take into consideration the Company's estimates of customer attrition, technology obsolescence and revenue growth projections. The Company is amortizing the identifiable intangible assets arising from the ECI Acquisition in relation to the expected cash flows from the individual intangible assets over their respective useful lives, which have a weighted average life of 12.38 years (see Note 10). Goodwill results from assets that are not separately identifiable as part of the transaction and is not deductible for tax purposes.

Pro Forma Results

The following unaudited pro forma information presents the combined results of operations of Ribbon and ECI for the years ended December 31, 2020 as if the ECI Acquisition had been completed on January 1, 2019, with adjustments to give effect to pro forma events that are directly attributable to the ECI Acquisition. These pro forma adjustments include an increase in research and development expense related to the conformance of ECI's cost capitalization policy to Ribbon's, additional amortization expense for the acquired identifiable intangible assets, a decrease in historical ECI interest expense reflecting the extinguishment of certain of ECI's debt as a result of the ECI Acquisition, and an increase in interest expense reflecting the new debt entered into by the Company in connection with the ECI Acquisition. Pro forma adjustments also include the elimination of acquisition- and integration-related costs directly attributable to the acquisition from the year ended December 31, 2020.

The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings that may result from the consolidation of the operations of Ribbon and ECI. Accordingly, these unaudited pro forma results are presented for illustrative purposes and are not intended to represent or be indicative of the actual results of operations of the combined company that would have been achieved had the ECI Acquisition occurred at January 1, 2019, nor are they intended to represent or be indicative of future results of operations (in thousands, except per share amounts):


	Year ended December 31,
	2020
	(unaudited)
Revenue	$	869,002
Net income	$	97,036
Diluted earnings per share	$	0.65

Acquisition-, Disposal- and Integration-Related Expenses

Acquisition-related expenses include those expenses related to acquisitions that would otherwise not have been incurred by the Company, including professional and services fees, such as legal, audit, consulting, paying agent and other fees, and expenses related to cash payments to certain former executives of the acquired businesses in connection with their employment agreements. Disposal-related expenses are professional and services fees related to disposals of subsidiaries or portions of the business. Integration-related expenses represent incremental costs related to combining the Company and its business acquisitions, such as third-party consulting and other third-party services related to merging the previously separate companies' systems and processes.

The disposal-related expenses in the year ended December 31, 2022 primarily relate to costs incurred from the sale of one of our foreign subsidiaries. The disposal-related expenses in the year ended December 31, 2021 relate to the Kandy Sale (as defined below). The acquisition-related professional and services fees recorded in the year ended December 31, 2020 primarily related to the ECI Acquisition and the disposal-related expenses related to the Company's sale of the Kandy Communications Business.

The components of Acquisition-, disposal- and integration-related expenses incurred in the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Professional and services fees (acquisition-related)	$	—	$	165	$	13,441
Professional and services fees (disposal-related)	414		329		1,890
Integration-related expenses	5,872		7,138		1,833
	$	6,286	$	7,632	$	17,164

SALE OF KANDY COMMUNICATIONS BUSINESS	12 Months Ended
SALE OF KANDY COMMUNICATIONS BUSINESS	Dec. 31, 2022
Discontinued Operations and Disposal Groups [Abstract]
SALE OF KANDY COMMUNICATIONS BUSINESS	SALE OF KANDY COMMUNICATIONS BUSINESS On August 5, 2020, the Company announced that it had entered into a definitive agreement (the "Kandy Purchase Agreement") with American Virtual Cloud Technologies, Inc. ("AVCT") to sell the Kandy Communications Business. Under the Kandy Purchase Agreement, AVCT would purchase the assets and assume certain liabilities associated with the Kandy Communications Business, as well as all of the outstanding interests in Kandy Communications LLC, a subsidiary of the Company (the "Kandy Sale"). On December 1, 2020, the Company completed the Kandy Sale. The assets acquired and liabilities assumed by AVCT in connection with the Kandy Sale were primarily comprised of accounts receivable, property and equipment, trade accounts payable and employee-related accruals. As consideration, AVCT paid Ribbon $45.0 million, subject to certain adjustments, in the form of units of AVCT’s securities (the “AVCT Units”), with each AVCT Unit consisting of: (i) $1,000 in principal amount of AVCT’s Series A-1 convertible debentures (the “Debentures”); and (ii) one warrant to purchase 100 shares of AVCT common stock, $0.0001 par value (the “Warrants”). The Company received 43,778 AVCT Units as sale consideration on the Kandy Sale Date (the "Kandy Sale Consideration"). The Debentures bore interest at a rate of 10% per annum, which was added to the principal amount of the Debenture. The entire principal amount of each Debenture, together with accrued and unpaid interest thereon, was due and payable on the earlier of the May 1, 2023 maturity date or the occurrence of a Change in Control as defined in the Kandy Purchase Agreement. Each Debenture was convertible, in whole or in part, at any time at the Company's option into that number of shares of AVCT common stock, calculated by dividing the principal amount being converted, together with all accrued and unpaid interest thereon, by the applicable conversion price, initially $3.45. The Debentures were subject to mandatory conversion if the AVCT stock price was at or above $6.00 per share for 40 trading days in any 60 consecutive trading day period, subject to the satisfaction of certain other conditions. The conversion price was subject to customary adjustments including, but not limited to, stock dividends, stock splits and reclassifications. As of February 19, 2021, the stock price had traded above $6.00 for 40 days within a 60 consecutive trading day period, and accordingly, on September 8, 2021 (the "Debenture Conversion Date"), upon the completion of customary regulatory filings by AVCT, the Debentures were converted into 13,700,421 shares of AVCT common stock (the "Debenture Shares"). The Warrants were independent of the Debentures and entitled the Company to purchase 4,377,800 shares of AVCT common stock at an exercise price of $0.01 per share. The Warrants expire on December 1, 2025, and were immediately exercisable on the Kandy Sale Date. The Company had not exercised any of the Warrants as of December 31, 2021. The Company was also subject to a lock-up provision which limited the Company's ability to sell any shares of the AVCT common stock underlying the AVCT Units prior to June 1, 2021 (the "Lock-Up Period"), except in certain transactions. The Company determined that the AVCT Units had a fair value of $84.9 million at the Kandy Sale Date, comprised of the Debentures with a fair value of $66.3 million and the Warrants with a fair value of $18.6 million. The value of the net assets sold to AVCT totaled $1.3 million, resulting in a gain on the sale of $83.6 million. The gain on the Kandy Sale is included as a component of Other (expense) income, net, in the consolidated statement of operations for the year ended December 31, 2020. The Company calculated the fair value of the Debentures using a Lattice-based valuation approach, which utilizes a binomial tree to model the different paths the price of AVCT's common stock might take over the Debentures' life by using assumptions regarding the stock price volatility and risk-free interest rate. These results were then used to calculate the fair value of the Debentures at each measurement date. The Company used the Black-Scholes valuation model for estimating the fair value of the Warrants at each measurement date. The fair value of the Warrants is affected by AVCT's stock price as well as valuation assumptions, including the volatility of AVCT's stock price, expected term of the option, risk-free interest rate and expected dividends. Both the Lattice and Black-Scholes valuation models are based on available market data, giving consideration to all of the rights and obligations of each instrument and precluding the use of "blockage" discounts or premiums in determining the fair value of a large block of financial instruments. After the expiration of the Lock-Up Period and prior to the Debenture Conversion Date, the Company valued the AVCT Units at each measurement date by multiplying the closing stock price of AVCT common stock by the number of shares upon conversion of the Debentures and Warrants. At December 31, 2021, the Company valued the Debenture Shares and Warrants (collectively, the "AVCT Investment") by multiplying the closing stock price of AVCT common stock by the number of Debenture Shares and Warrants it held. At December 31, 2021, the fair value of the AVCT Investment was $43.9 million. The Company recorded a loss of $74.8 million in the year ended December 31, 2021 arising from the change in the fair value of the AVCT Investment, and recorded a gain of $30.3 million in the year ended December 31, 2020 arising from the change in the fair value of the AVCT Units. These amounts are included as components of Other (expense) income, net, in the Company's consolidated statements of operations. The Company recorded $3.5 million of interest income in the year ended December 31, 2021, which was added to the principal amount of the Debentures prior to the Debenture Conversion Date, and which is included in Interest expense, net, in the consolidated statement of operations. The fair value of the AVCT Investment at December 31, 2021 is reported as Investments in the Company's consolidated balance sheets. The AVCT Investment is classified as a Level 1 fair value measurement at December 31, 2021 (see Note 6). The Company evaluated the nature of the AVCT Investment at December 31, 2021, and determined that it represented an equity interest on a diluted basis of approximately 15%. The Company determined that it was not the primary beneficiary of AVCT as it did not have the power to direct the activities that most significantly impact the AVCT Investment's economic performance, and therefore concluded that the Company had neither significant influence nor a controlling interest arising from the AVCT Investment that would require consolidation as of December 31, 2021. On August 29, 2022, the Company and AVCT entered into a settlement agreement which provided for, amongst other things, the cancellation of the Company's investment in the Debenture Shares and the Warrants with an aggregate fair value of $2.6 million. Pursuant to the settlement agreements, the Company and AVCT also entered into a Wind Down Agreement, pursuant to which a Reseller Agreement between the parties, as previously amended, was terminated, and the Company was granted a non-exclusive perpetual license to use and modify certain intellectual property owned by AVCT comprising WebRTC gateway technology that is integrated with Ribbon’s SBCs and Application Servers. As consideration, the Company paid AVCT $2.5 million in cash, the Debenture Shares were redeemed and canceled, and the Warrants were terminated and canceled. The perpetual license granted by AVCT is classified as Intangible assets, net in the Company's consolidated balance sheet as of December 31, 2022 in the amount of $3.9 million. The Company had no investment in AVCT as of December 31, 2022 due to the settlement agreement entered into on August 29, 2022. The Company recorded losses of $41.3 million in the year ended December 31, 2022, representing the change in the fair value of the AVCT Investment. The results of the Kandy Communications Business are excluded from the Company's consolidated results for the period subsequent to the Kandy Sale Date.

EARNINGS (LOSS) PER SHARE

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

EARNINGS (LOSS) PER SHARE

Basic earnings (loss) per share is computed by dividing net income (loss) by the weighted average number of shares outstanding during the period. For periods in which the Company reports net income, diluted net income per share is determined by using the weighted average number of common and dilutive common equivalent shares outstanding during the period unless the effect is antidilutive.

The calculations of shares used to compute basic and diluted earnings (loss) per share are as follows (in thousands):


	Year ended December 31,
	2022	2021	2020
Weighted average shares outstanding—basic	156,668	147,575	138,967
Potential dilutive common shares	—	—	5,683
Weighted average shares outstanding—diluted	156,668	147,575	144,650

Options to purchase the Company's common stock and unvested restricted and performance-based stock units aggregating 14.5 million shares and 10.6 million shares were excluded from the computation of diluted loss per share for the years ended December 31, 2022 and 2021, respectively, because their effect would have been antidilutive. Options to purchase the Company's common stock aggregating 0.2 million shares were excluded from the computation of diluted earnings per share for the year ended December 31, 2020 because their effect would have been antidilutive.

INVESTMENTS AND FAIR VALUE HIERARCHY

12 Months Ended

Dec. 31, 2022

Investments, All Other Investments [Abstract]

INVESTMENTS AND FAIR VALUE HIERARCHY

The Company's policy and historical practice has been to invest in debt instruments, primarily U.S. government-backed, municipal and corporate obligations, which management believes to be high quality (investment grade) credit instruments.

At December 31, 2021, the Company's investments were comprised of the AVCT Investment (see Note 4).

On a quarterly basis, the Company reviews its investments, if any, to determine if there have been any events that could create a credit impairment.

Fair Value Hierarchy

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The three-tier fair value hierarchy is based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument's categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The fair value hierarchy is as follows:

Level 1. Level 1 applies to assets or liabilities for which there are quoted prices in active markets for identical assets or liabilities.

Level 2. Level 2 applies to assets or liabilities for which there are inputs that are directly or indirectly observable in the marketplace, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets with insufficient volume or infrequent transactions (less active markets).

Level 3. Level 3 applies to assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value of the assets or liabilities.

The classification of each asset or liability fair value measurement within the fair value hierarchy is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Market activity is presumed to be orderly in the absence of evidence of forced or disorderly sales, although such sales may still be indicative of fair value. Applicable accounting guidance precludes the use of blockage factors or liquidity adjustments due to the quantity of securities held by an entity.

ACCOUNTS RECEIVABLE, NET

12 Months Ended

Dec. 31, 2022

Receivables [Abstract]

ACCOUNTS RECEIVABLE, NET

Accounts receivable, net, consisted of the following (in thousands):


	December 31,
	2022		2021
Accounts receivable	$	268,671	$	284,187
Allowance for doubtful accounts	(1,427)		(1,270)
Accounts receivable, net	$	267,244	$	282,917

The Company's allowance for doubtful accounts activity was as follows (in thousands):


Year ended December 31,	Balance at beginning of year		Charges to expense		Charges (credits) to other accounts		Write-offs		Balance at end of year
2022	$	1,270	$	100	$	159	$	(102)	$	1,427
2021	$	776	$	553	$	85	$	(144)	$	1,270
2020	$	913	$	686	$	94	$	(917)	$	776

INVENTORY

12 Months Ended

Dec. 31, 2022

Inventory Disclosure [Abstract]

INVENTORY

Inventory consisted of the following (in thousands):


	December 31,
	2022		2021
On-hand final assemblies and finished goods inventories	$	85,888	$	57,360
Deferred cost of goods sold	1,449		1,474
	87,337		58,834
Less noncurrent portion (included in Other assets)	(11,914)		(4,791)
Current portion	$	75,423	$	54,043

PROPERTY AND EQUIPMENT

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT

Property and equipment consisted of the following (in thousands):


		December 31,
	Useful Life	2022		2021
Equipment	2-5 years	$	76,674	$	74,769
Software	2-5 years	33,639		32,804
Furniture and fixtures	3-5 years	3,168		3,188
Leasehold improvements	Shorter of the estimated lease term or useful life	35,448		34,640
		148,929		145,401
Less accumulated depreciation and amortization		(104,097)		(97,716)
Property and equipment, net		$	44,832	$	47,685

The Company recorded depreciation and amortization expense related to property and equipment of $15.3 million for the year ended December 31, 2022, $17.0 million for the year ended December 31, 2021 and $17.2 million for the year ended December 31, 2020. During each of these years, the Company disposed of certain property and equipment that was fully depreciated at the time of disposal, which resulted in reductions in both Cost and Accumulated depreciation.

Property and equipment under finance leases included in the amounts above were as follows (in thousands):


	December 31,
	2022		2021
Cost	$	—	$	2,050
Less accumulated depreciation	—		(1,763)
Property and equipment under finance leases, net	$	—	$	287

The net book values of the Company's property and equipment by geographic area were as follows (in thousands):


	December 31,
	2022		2021
United States	$	23,143	$	24,683
Canada	3,471		5,184
Asia/Pacific	8,152		8,174
Europe	833		1,157
Israel	8,860		7,859
Other	373		628
	$	44,832	$	47,685

INTANGIBLE ASSETS AND GOODWILL

12 Months Ended

Dec. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

INTANGIBLE ASSETS AND GOODWILL

The Company's intangible assets at December 31, 2022 and 2021 consisted of the following (in thousands):


December 31, 2022	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
Developed technology	7.84	$	340,380	$	212,448	$	127,932
Customer relationships	11.86	268,140		106,385		161,755
Trade names	3.88	5,000		4,658		342
Software licenses	3.00	5,186		487		4,699
	9.51	$	618,706	$	323,978	$	294,728


December 31, 2021	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
In-process research and development	*	$	34,000	$	—	$	34,000

Developed technology	7.93	306,380		181,393		124,987
Customer relationships	11.86	268,140		77,653		190,487
Trade names	3.88	5,000		3,744		1,256

Internal use software	3.00	730		730		—
	9.17	$	614,250	$	263,520	$	350,730

* An in-process research and development intangible asset has an indefinite life until the product is generally available, at which time such asset is typically reclassified to developed technology and the Company begins to amortize the asset. In the fourth quarter of 2022, the Company reclassified an in-process research and development intangible asset to developed technology, as the associated products and features related to 5G technology became generally available.

Estimated future amortization expense for the Company's intangible assets at December 31, 2022 was as follows (in thousands):


Years ending December 31,
2023	$	56,882
2024	50,717
2025	44,006
2026	38,965
2027	33,936
Thereafter	70,222
	$	294,728

Goodwill is recorded when the consideration for an acquisition exceeds the fair value of net tangible and identifiable

intangible assets acquired. For the purpose of testing goodwill for impairment, all goodwill is assigned to a reporting unit, which may be either an operating segment or a portion of an operating segment. The Company determined in the fourth quarter of 2020 that it had two operating segments: Cloud and Edge, and IP Optical Networks, at which time it was determined that the goodwill assigned to these two segments was $224.9 million and $192.0 million, respectively. The Company's reporting units are its operating segments. Our annual testing for impairment of goodwill is completed as of October 1.

Upon completion of the 2022 annual test for goodwill impairment, the Company determined that there was no impairment of goodwill in either of its reporting units. Based on the results of the 2021 impairment test, the Company determined that the carrying value of its IP Optical Networks segment exceeded its fair value and the amount of the impairment was $116.0 million. This impairment charge was recorded in the fourth quarter of 2021 and is reported separately in the Company's consolidated statement of operations. In the 2021 impairment test, the Company determined that there was no impairment of its Cloud and Edge segment.

The changes in the carrying value of the Company's goodwill in the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Cloud and Edge		IP Optical Networks		Total
Balance at January 1, 2021 (1)	$	224,896	$	191,996	$	416,892
Impairment of goodwill	—		(116,000)		(116,000)
Balance at December 31, 2021 (1)(2)	224,896		75,996		300,892
Activity	—		—		—
Balance at December 31, 2022 (1)(2)	$	224,896	$	75,996	$	300,892

(1) Balance is presented net of accumulated impairment losses of $167.4 million for the Cloud and Edge segment.

(2) Balance is presented net of an impairment loss of $116.0 million for the IP Optical Networks segment.

The components of goodwill at December 31, 2021 and 2022 were as follows (in thousands):


	Cloud and Edge		IP Optical Networks		Total
Balance at December 31, 2021
Goodwill	$	392,302	$	191,996	$	584,298
Accumulated impairment losses	(167,406)		(116,000)		(283,406)
	224,896		75,996		300,892
Balance at December 31, 2022
Goodwill	$	392,302	$	191,996	$	584,298
Accumulated impairment losses	(167,406)		(116,000)		(283,406)
	$	224,896	$	75,996	$	300,892

ACCRUED EXPENSES AND OTHER

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

ACCRUED EXPENSES AND OTHER

Accrued expenses and other consisted of the following (in thousands):


	December 31,
	2022		2021
Employee compensation and related costs	$	25,994	$	38,040
Professional fees	17,195		14,365
Other	42,081		48,347
	$	85,270	$	100,752

WARRANTY

12 Months Ended

Dec. 31, 2022

Guarantees and Product Warranties [Abstract]

WARRANTY

The changes in the Company's warranty accrual balance in the years ended December 31, 2022 and 2021 were as follows (in thousands):


Year ended December 31,	Balance at beginning of year		Provision		Settlements		Balance at end of year
2022	$	13,120	$	4,605	$	(5,868)	$	11,857
2021	$	14,855	$	3,777	$	(5,512)	$	13,120

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES

12 Months Ended

Dec. 31, 2022

Restructuring and Related Activities [Abstract]

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES

The Company recorded restructuring and related expense aggregating $10.8 million, $11.7 million and $16.2 million in the years ended December 31, 2022, 2021 and 2020, respectively. Restructuring and related expense includes restructuring expense (primarily severance and related costs), estimated future variable lease costs for vacated properties with no intent or ability of sublease, and accelerated rent amortization expense.

For restructuring events that involve lease assets and liabilities, the Company applies lease reassessment and modification guidance and evaluates the right-of-use assets for potential impairment. If the Company plans to exit all or distinct portions of a facility and does not have the ability or intent to sublease, the Company will accelerate the amortization of each of those lease components through the vacate date. The accelerated amortization is recorded as a component of Restructuring and related expense in the Company's consolidated statements of operations. Related variable lease expenses will continue to be expensed as incurred through the vacate date, at which time the Company will reassess the liability balance to ensure it appropriately reflects the remaining liability associated with the premises and record a liability for the estimated future variable lease costs.

Accelerated amortization of lease assets is recognized from the date that the Company commences the plan to fully or partially vacate a facility, for which there is no intent or ability to enter into a sublease, through the final vacate date. Amounts of accelerated rent amortization that are included as a component of restructuring and related expense are not included in the tables below, as the liability for the total lease payments for each respective facility is included as a component of Operating lease liabilities in the Company's consolidated balance sheets at December 31, 2022 and 2021, both current and noncurrent (see Note 20). The Company may incur additional future expense if it is unable to sublease other locations included in the Facilities Initiative.

The components of restructuring and related expense for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Severance and related costs	$	5,230	$	4,618	$	12,025
Variable and other facilities-related costs	3,992		5,710		3,605
Accelerated amortization of lease assets due to cease-use	1,611		1,325		605
	$	10,833	$	11,653	$	16,235

Accelerated Rent Amortization

Accelerated amortization of lease assets is recognized from the date that the Company commences the plan to fully or partially vacate a facility, for which there is no intent or ability to enter into a sublease, through the final vacate date. The liability for the total lease payments for each respective facility is included as a component of Operating lease liabilities in the Company's consolidated balance sheets at December 31, 2022 and 2021, both current and noncurrent (see Note 20). The Company may incur additional future expense if it is unable to sublease other locations included in its restructuring initiatives.

2022 Restructuring Plan

On February 14, 2022, the Company's Board of Directors approved a strategic restructuring program (the "2022 Restructuring Plan") to streamline the Company's operations in order to support the Company's investment in critical growth areas. The 2022 Restructuring Plan is expected to include, among other things, charges related to a consolidation of facilities and a workforce reduction. Any positions eliminated in countries outside the United States are subject to local law and consultation requirements.

The Company recorded restructuring and related expense of $10.2 million in connection with the 2022 Restructuring Initiative in the year ended December 31, 2022. The amount for the year ended December 31, 2022 was comprised of $5.3 million for severance and related costs for approximately 70 employees, $3.3 million for variable and other facilities-related costs and $1.6 million for accelerated amortization of lease assets no longer being used with no ability or intent to sublease. The Company estimates that it will record approximately $8.0 million of future expense under the 2022 Restructuring Plan. A summary of the 2022 Restructuring Plan accrual activity for the year ended December 31, 2022 is as follows (in thousands):


	Balance at January 1, 2022		Initiatives charged to expense		Cash payments		Net transfer to operating lease accounts		Balance at December 31, 2022
Severance	$	—	$	5,287	$	(4,123)	$	—	$	1,164
Variable and other facilities-related costs	—		3,299		(2,409)		—		890
Accelerated amortization of lease assets due to cease-use	—		1,611		—		(1,611)		—
	$	—	$	10,197	$	(6,532)	$	(1,611)	$	2,054

2020 Restructuring Initiative

In 2020, the Company implemented a restructuring plan to eliminate certain positions and redundant facilities, primarily in connection with the ECI Acquisition, to further streamline the Company's global footprint and improve its operations (the "2020 Restructuring Initiative"). The 2020 Restructuring Initiative includes facility consolidations and a reduction in workforce. In connection with this initiative, the Company is eliminating functions arising from the ECI Acquisition and supporting its efforts to integrate the two companies.

The Company recorded restructuring and related expense of less than $0.1 million and $4.7 million in connection with the 2020 Restructuring Initiative in the years ended December 31, 2022 and 2021, respectively. The 2021 amount was comprised of $4.6 million for severance and related costs for approximately 60 employees and $0.1 million for variable and other facilities-related costs. The Company expects these amounts will be fully paid in 2023. The Company estimates that it will record nominal, if any, future expense under the 2020 Restructuring Initiative. Summaries of the 2020 Restructuring Initiative accrual activity for the years ended December 31, 2022 and 2021 are as follows (in thousands):


Year ended December 31, 2022	Balance at January 1, 2022		Initiatives charged to expense		Adjustments for changes in estimate		Cash payments		Balance at December 31, 2022
Severance	$	1,895	$	—	$	(57)	$	(1,782)	56
Facilities	60		34		—		(94)		—
	$	1,955	$	34	$	(57)	$	(1,876)	$	56


Year ended December 31, 2021	Balance at January 1, 2021		Initiatives charged to expense		Adjustments for changes in estimate		Cash payments		Balance at December 31, 2021
Severance	$	5,237	$	4,618	$	—	$	(7,960)	1,895
Facilities	1,256		742		(670)		(1,268)		60
	$	6,493	$	5,360	$	(670)	$	(9,228)	$	1,955

2019 Restructuring and Facilities Consolidation Initiative

In June 2019, the Company implemented a restructuring plan to further streamline the Company's global footprint, improve its operations and enhance its customer delivery (the "2019 Restructuring Initiative"). The 2019 Restructuring Initiative includes facility consolidations, refinement of the Company's research and development activities, and a reduction in workforce. The facility consolidations under the 2019 Restructuring Initiative (the "Facilities Initiative") include a consolidation of the Company's North Texas sites into a single campus, housing engineering, customer training and support, and administrative functions, as well as a reduction or elimination of certain excess and duplicative facilities worldwide. In addition, the Company is substantially consolidating its global software laboratories and server farms into two lower cost North American sites. The Company continues to evaluate its properties included in the Facilities Initiative for accelerated amortization and/or right-of-use asset impairment. The Company expects that the actions under the Facilities Initiative will be completed in 2023.

In connection with the 2019 Restructuring Initiative, the Company recorded restructuring and related expense of $0.7 million, $7.0 million, and $2.3 million in the years ended December 31, 2022, 2021 and 2020, respectively. The amount recorded in 2022 was for facilities related costs. The amount recorded in 2021 was comprised of $5.7 million for variable and other facilities-related costs and $1.3 million of net expense for accelerated amortization of lease assets. The amount for accelerated amortization of lease assets includes income of $2.1 million related to a lease modification for one of the Company's restructured facilities. The amount recorded in 2020 was comprised of $0.5 million for severance and related costs for approximately 5 employees, $1.7 million for variable and other facilities-related costs and $0.1 million for accelerated amortization of lease assets. The Company estimates that it will record nominal, if any, future expense under the 2019 Restructuring Initiative.

Summaries of the 2019 Restructuring Initiative accrual activity for the years ended December 31, 2022 and 2021 are as follows (in thousands):


Year ended December 31, 2022	Balance at January 1, 2022		Initiatives charged to expense		Net transfer to operating lease liability accounts				Cash payments				Balance at December 31, 2022
Severance	$	—	$	—	$	—			$	—			$	—
Facilities	1,594		658		—				(1,004)				1,248
	$	1,594	$	658	$	—	$	—	$	(1,004)	$	—	$	1,248


Year ended December 31, 2021	Balance at January 1, 2021		Initiatives charged to expense		Adjustments for changes in estimate		Net transfer to operating lease liability accounts		Cash payments		Balance at December 31, 2021
Severance	$	173	$	—	$	—	$	—	$	(173)	$	—
Facilities	766		9,006		(2,043)		(1,325)		(4,810)		1,594
	$	939	$	9,006	$	(2,043)	$	(1,325)	$	(4,983)	$	1,594

Balance Sheet Classification

The current portions of accrued restructuring were $1.3 million and $1.9 million at December 31, 2022 and 2021, respectively, and are included as components of Accrued expenses in the consolidated balance sheets. The long-term portions of accrued restructuring are included as components of Other long-term liabilities in the consolidated balance sheets. The long-term portions of accrued restructuring were $2.0 million and $1.6 million at December 31, 2022 and 2021, respectively.

DEBT	12 Months Ended
DEBT	Dec. 31, 2022
Debt Disclosure [Abstract]
DEBT	DEBT 2019 Credit Facility On April 29, 2019, the Company, as guarantor, and Ribbon Communications Operating Company, Inc., as borrower, entered into a syndicated, amended and restated credit facility (the "2019 Credit Facility"), which provided for a $50 million term loan facility that was advanced in full on April 29, 2019, and a $100 million revolving line of credit. Revolving loans under the 2019 Credit Facility bore interest at the Borrower’s option at either the Eurodollar (LIBOR) rate plus a margin ranging from 1.50% to 3.00% per year or the base rate plus a margin ranging from 0.50% to 2.00% per year. The 2019 Credit Facility was superseded by the 2020 Credit Facility, which was entered into on March 3, 2020, and which is discussed below. 2020 Credit Facility On March 3, 2020, the Company entered into a Senior Secured Credit Facilities Credit Agreement (as amended, the "2020 Credit Facility"), by and among the Company, as a guarantor, Ribbon Communications Operating Company, Inc., as the borrower ("Borrower"), Citizens Bank, N.A. ("Citizens"), Santander Bank, N.A., and others as lenders, ("Lenders"). The proceeds of the Credit Agreement were used, in part, to pay off in full all obligations of the Company under the 2019 Credit Facility. The 2020 Credit Facility provides for $500 million of commitments from the Lenders to the Borrower, comprised of $400 million in term loans (the "2020 Term Loan Facility") and a $100 million facility available for revolving loans (the "2020 Revolving Credit Facility"). Under the 2020 Revolving Credit Facility, a $30 million sublimit is available for letters of credit and a $20 million submit is available for swingline loans. The indebtedness and other obligations under the 2020 Credit Facility are unconditionally guaranteed on a senior secured basis by the Company, Edgewater Networks, Inc., a wholly-owned subsidiary of the Company, and GENBAND Inc., wholly-owned subsidiary of the Company (together, the "Guarantors"). The 2020 Credit Facility is secured by first-priority liens on substantially all of the assets of the Borrower and the Guarantors, including substantially all of the assets of the Company. The 2020 Credit Facility requires compliance with certain financial covenants, including a minimum Consolidated Fixed Charge Coverage Ratio and a maximum Consolidated Net Leverage Ratio (each as defined in the 2020 Credit Facility, and each tested on a quarterly basis). On August 18, 2020, the Company entered into the First Amendment to the 2020 Credit Facility in which $75 million of the 2020 Term Loan Facility was assigned from Citizens to a new lender and designated as the Term B Loan. The remaining $325 million of the 2020 Term Loan Facility was deemed the Term A Loan. The Term A Loan and the 2020 Revolving Credit Facility mature in March 2025 and bore interest at the Borrower's option at either the LIBOR rate plus a margin ranging from 1.50% to 3.50% per year, or the base rate plus 0.50%, or the prime rate plus a margin ranging from 0.50% to 2.50% per year (the "Applicable Margin"). The Applicable Margin varies depending on the Company's Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility). The Term B Loan was scheduled to mature in March 2026 and bore interest, at the Borrower's option, at either the LIBOR rate plus a margin of 7.50% per year, or the base rate (the highest of the Federal Funds Effective Rate (as defined in the First Amendment) plus 0.50%, or the prime rate. On December 1, 2020, the Company entered into the Second Amendment to the 2020 Credit Facility to obtain consent for an equity exchange with AVCT in connection with the Kandy Sale, as well as to amend certain other provisions of the 2020 Credit Facility. On March 3, 2021, the Company entered into the Third Amendment to the 2020 Credit Facility which provided for an incremental term loan facility in the principal amount of $74.6 million, the proceeds of which were used to consummate an open market purchase of all outstanding amounts under the Term B Loan, resulting in the assignment and immediate cancellation of the Term B Loan, such that the outstanding amount under the Term A Loan and incremental term loan facility were combined and held by the Lenders (the "2020 Term Loan") with the same terms as the Term A Loan. The Company wrote off $2.5 million of capitalized debt issuance costs in connection with the Third Amendment, which is included in Interest expense, net, in the Company's consolidated statement of operations for the year ended December 31, 2021. On March 10, 2022, the Company entered into the Fourth Amendment to the 2020 Credit Facility to increase the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility) and in conjunction the Company made a $15.0 million prepayment that was applied to the final payment due on the maturity date. On June 30, 2022, the Company entered into the Fifth Amendment to the 2020 Credit Facility (the "Fifth Amendment") to increase the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility) for 2022, with the fourth quarter of 2022 increased to 4.75:1.00. In the 1st and 2nd quarters of 2023, the Maximum Consolidated Net Leverage Ratio allowed declines to 3.25:1.00 and in all subsequent quarters the ratio will be fixed at 3.00:1.00. Also, the Fifth Amendment reduced the minimum Consolidated Fixed Charge Coverage Ratio (as defined in the 2020 Credit Facility) in 2022, with the fourth quarter of 2022 reduced to 1.10:1.00 and in all subsequent quarters the ratio will be fixed at 1.25:1.00. In addition, the Fifth Amendment increased the maximum rate at which loans bear interest if the Company's Consolidated Net Leverage Ratio for any quarter is greater than 4.50:1.00. Specifically, loans incurred bear interest, at the Borrower’s option, at either LIBOR plus a margin ranging from 1.50% to 4.50% per year, or the base rate plus 0.50%, or the prime rate plus a margin ranging from 0.50% to 3.50% per year. In addition, the Fifth Amendment allows the Company to incur junior secured or unsecured debt in an amount no less than $50 million, subject to certain conditions, including the requirement that 50% of the aggregate amount of such incurred debt (net of certain costs, fees and other amounts) must be applied to prepay the 2020 Credit Facility, and compliance with certain leverage ratio-based covenant exceptions. In connection with the Fifth Amendment, the Company made a $10.0 million voluntary prepayment that was applied to the final payment due on the maturity date. Subsequent to the Fifth Amendment, the Company is required to make quarterly principal payments on the 2020 Term Loan aggregating approximately $5.0 million per quarter through March 31, 2024 and $10.0 million in each of the three quarters thereafter, with the final payment approximating $275 million due on the maturity date in March 2025. At December 31, 2022, the Company had an outstanding balance under the 2020 Term Loan of $330.4 million at an average interest rate of 5.4% and $3.3 million of letters of credit outstanding with an interest rate of 4.5%. At December 31, 2021, the Company had an outstanding balance under the 2020 Term Loan of $375.5 million at an average interest rate of 3.4% and $4.3 million of letters of credit outstanding with an interest rate of 2.5%. The Company was in compliance with all covenants of the 2020 Credit Facility at both December 31, 2022 and 2021. Letters of Credit and Performance and Bid Bonds The Company uses letters of credit and performance and bid bonds in the course of its business. At December 31, 2022, the Company had $8.3 million of letters of credit, bank guarantees, and performance and bid bonds outstanding (collectively, "Guarantees"), comprised of the $3.3 million of letters of credit under the 2020 Credit Agreement described above (the "Letters of Credit") and $5.0 million of bank guarantees and performance and bid bonds (collectively, the "Other Guarantees") under various uncommitted facilities. At December 31, 2021, the Company had Guarantees aggregating $30.1 million, comprised of the $4.3 million of Letters of Credit and $25.8 million of Other Guarantees. At December 31, 2022 and 2021, the Company had cash collateral of $0.2 million and $2.6 million, respectively, supporting the Guarantees, which are reported in Restricted cash in the consolidated balance sheets.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI https://asc.fasb.org/topic&trid=2208564

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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-Subparagraph (h)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Paragraph 1I
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-Publisher FASB
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-Paragraph 1I
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 1C
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Section 50
-Paragraph 1E
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495348-112611

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

12 Months Ended

Dec. 31, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

The Company is exposed to financial market risk related to foreign currency fluctuations and changes in interest rates. These exposures are actively monitored by management. To manage the volatility related to the exposure to changes in interest rates, the Company has entered into a derivative financial instrument. Management's objective is to reduce, where it is deemed appropriate to do so, fluctuations in earnings and cash flows associated with changes in interest rates. Ribbon's policies and practices are to use derivative financial instruments only to the extent necessary to manage exposures. Ribbon does not hold or issue derivative financial instruments for trading or speculative purposes.

The Company records derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a specific risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Derivatives may also be designated as hedges of the foreign currency exposure of a net investment in a foreign operation. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge, or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk even though hedge accounting does not apply or the Company elects not to apply hedge accounting.

Cash Flow Hedge of Interest Rate Risk

The 2020 Term Loan Facility had outstanding balances of $330.4 million and $375.5 million at December 31, 2022 and 2021, respectively. The 2020 Revolving Credit Facility was undrawn at both December 31, 2022 and 2021. Borrowings under the 2020 Credit Agreement have variable interest rates based on LIBOR (see Note 14). As a result of exposure to interest rate movements, during March 2020, the Company entered into an interest rate swap arrangement, which effectively converted its $400 million term loan with its variable interest rate based upon one-month LIBOR to an aggregate fixed rate of 0.904%, plus a leverage-based margin as defined in the 2020 Credit Facility.

On July 22, 2022, the Company sold $30 million of the notional amount of its interest rate swap back to its counterparty for $1.5 million, reducing the notional amount of this swap to $370 million. On August 16, 2022 the Company sold another $30 million of the notional amount of its interest rate swap back to its counterparty for $1.6 million, reducing the notional amount to $340 million, which approximates the current level of our term loan debt outstanding. The gain in accumulated other comprehensive (loss) income related to the $60 million notional amount sold of $3.1 million is being released into earnings on a straight line basis over the remaining term of the 2020 Credit Facility as a decrease to interest expense, the amortization of which totaled $0.5 million for the year ended December 31, 2022. The notional amount of this swap at December 31, 2022 and 2021 was $340 million and $400 million, respectively. The swap matures on March 3, 2025, the same date the 2020 Credit Facility matures.

The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company is using an interest rate swap as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.

The effective portion of changes in the fair value of designated derivatives that qualify as cash flow hedges is recorded in accumulated other comprehensive income (loss) in the consolidated balance sheet and is subsequently reclassified into earnings in the period that the hedged forecasted transactions affect earnings. During the years ended December 31, 2022 and 2021, such a derivative was used to hedge the variable cash flows associated with the credit facilities under the 2020 Credit Facility,

and the Company has accounted for this derivative as an effective hedge. Any ineffective portion of the change in the fair value of the derivative would be recognized directly in earnings.

Amounts reported in accumulated other comprehensive income (loss) related to the Company's derivative are reclassified to interest expense as interest is accrued on the Company’s variable-rate debt. Based upon projected forward rates, the Company estimates that as of December 31, 2022, $13.2 million may be reclassified as a decrease to interest expense over the next twelve months.

The impact of the Company’s derivative financial instrument on its consolidated statement of comprehensive income (loss) for the years ended December 31, 2022 and 2021 was as follows, net of tax (in thousands):


		Year ended December 31,
	2022			2021
Gain recognized in other comprehensive income (loss) on interest rate swap, net of tax		$	22,456		$	9,505
Amount reclassified from accumulated other comprehensive income (loss) to interest expense		(3,135)			3,254
Unrealized gain (loss) on interest rate swap, net of reclassifications and amortization		$	19,321		$	12,759

The fair values and locations in the consolidated balance sheet at December 31, 2022 and 2021 of the Company's derivative assets (liabilities) designated as a hedging instrument were as follows (in thousands):


		December 31,
	Balance sheet location	2022		2021
Interest rate derivative - asset derivative	Other current assets	$	13,212	$	—
Interest rate derivative - asset derivative	Other assets	12,216		3,865
Interest rate derivative - liability derivative	Accrued expenses and other	—		(2,054)
Interest rate derivative - liability derivative	Other long-term liabilities	—		—
		$	25,428	$	1,811

The Company has classified the interest rate derivative net asset of $25.4 million and $1.8 million at December 31, 2022 and 2021, respectively, as Level 2 fair value measurements within the fair value hierarchy (see Note 6).

REVENUE RECOGNITION

12 Months Ended

Dec. 31, 2022

Revenue from Contract with Customer [Abstract]

REVENUE RECOGNITION

The Company's typical performance obligations include the following:

Performance Obligation

When Performance Obligation is Typically Satisfied

When Payment is Typically Due

Software and Product Revenue

Software licenses (perpetual or term)

Upon transfer of control; typically, when made available for download (point in time)

Generally, within 30 days of invoicing except for term licenses, which may be paid for over time

Software licenses (subscription)

Upon activation of hosted site (over time)

Generally, within 30 days of invoicing

Hardware

When control of the hardware passes to the customer; typically, upon delivery (point in time)

Generally, within 30 days of invoicing

Software upgrades

Upon transfer of control; typically, when made available for download (point in time)

Generally, within 30 days of invoicing

Customer Support Revenue

Customer support

Ratably over the course of the support contract (over time)

Generally, within 30 days of invoicing

Professional Services

Other professional services (excluding training services)

As work is performed (over time)

Generally, within 30 days of invoicing (upon completion of services)

Training

When the class is taught (point in time)

Generally, within 30 days of services being performed

Significant Judgments

The Company's contracts with customers often include promises to transfer multiple products and services to the customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment.

Judgment is required to determine the standalone selling price for each distinct performance obligation. The Company typically has more than one standalone selling price ("SSP") for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, the Company may use information such as the size of the customer and geographic region in determining the SSP.

Deferred Revenue

Deferred revenue is a contract liability representing amounts collected from or invoiced to customers in excess of revenue recognized. This results primarily from the billing of annual customer support agreements where the revenue is recognized over the term of the agreement. The value of deferred revenue will increase or decrease based on the timing of invoices and recognition of revenue.

Disaggregation of Revenue

The Company disaggregates its revenue from contracts with customers based on the nature of the products and services and the geographic regions in which each customer is domiciled. The Company's total revenue for the years ended December 31, 2022, 2021 and 2020 was disaggregated geographically as follows:


Year ended December 31, 2022	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	175,189	$	132,655	$	44,819	$	352,663
Europe, Middle East and Africa	147,523		75,948		29,310		252,781

Asia Pacific	95,828		41,677		13,594		151,099
Other	24,140		31,815		7,262		63,217
	$	442,680	$	282,095	$	94,985	$	819,760


Year ended December 31, 2021	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	196,058	$	132,683	$	47,296	$	376,037
Europe, Middle East and Africa	138,203		79,475		30,349		248,027

Asia Pacific	92,803		41,945		18,183		152,931
Other	25,978		32,218		9,766		67,962
	$	453,042	$	286,321	$	105,594	$	844,957


Year ended December 31, 2020	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	201,347	$	132,661	$	48,611	$	382,619
Europe, Middle East and Africa	149,567		73,475		25,226		248,268

Asia Pacific	90,201		36,628		19,627		146,456
Other	26,797		32,052		7,603		66,452
	$	467,912	$	274,816	$	101,067	$	843,795

The Company's product revenue from its direct sales program and from indirect sales through its channel partner program for the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Indirect sales through channel program	$	131,998	$	117,065	$	134,876
Direct sales	310,682		335,977		333,036
	$	442,680	$	453,042	$	467,912

The Company's product revenue from sales to enterprise customers and from sales to service provider customers for the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Sales to enterprise customers	$	125,664	$	111,494	$	138,469
Sales to service provider customers	317,016		341,548		329,443
	$	442,680	$	453,042	$	467,912

The Company's product revenue and service revenue components by segment for the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2022	2021	2020
Product revenue
Cloud and Edge	215,770	248,570	275,445
IP Optical Networks	226,910	204,472	192,467
Total product revenue	442,680	453,042	467,912

Service revenue
Maintenance
Cloud and Edge	222,238	228,321	229,035
IP Optical Networks	59,857	58,000	45,781
Total maintenance revenue	282,095	286,321	274,816
Professional services
Cloud and Edge	70,130	79,765	78,790
IP Optical Networks	24,855	25,829	22,277
Total professional services revenue	94,985	105,594	101,067
Total service revenue	377,080	391,915	375,883

Revenue Contract Balances

The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables, which are contract assets, and customer advances and deposits, which are contract liabilities, in the Company's consolidated balance sheets. Amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Completion of services and billing may occur subsequent to revenue recognition, resulting in contract assets. The Company may receive advances or deposits from its customers before revenue is recognized, resulting in contract liabilities which are classified as deferred revenue. These assets and liabilities are reported in the Company's consolidated balance sheets on a contract-by-contract basis as of the end of each reporting period. Changes in the contract asset and liability balances during the years ended December 31, 2022 and 2021 were not materially impacted by any factors other than billing and revenue recognition. Nearly all of the Company's deferred revenue balance is related to services revenue, primarily customer support contracts. Unbilled receivables stem primarily from engagements where services have been performed; however, billing cannot occur until services are completed.

In some arrangements, the Company allows customers to pay for term-based software licenses and products over the term of the software license. The Company also sells SaaS-based software under subscription arrangements, with payment terms over the term of the SaaS agreement. Amounts recognized as revenue in excess of amounts billed are recorded as unbilled receivables. Unbilled receivables that are anticipated to be invoiced in the next twelve months are included in Accounts receivable on the Company's consolidated balance sheets. The changes in the Company's accounts receivable, unbilled receivables and deferred revenue balances for the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Accounts receivable		Unbilled accounts receivable		Deferred revenue (current)		Deferred revenue (long-term)
Balance at January 1, 2022	$	208,972	$	73,945	$	109,119	$	20,619
Increase (decrease), net	(38,003)		22,330		4,820		(1,365)
Balance at December 31, 2022	$	170,969	$	96,275	$	113,939	$	19,254


	Accounts receivable		Unbilled accounts receivable		Deferred revenue (current)		Deferred revenue (long-term)
Balance at January 1, 2021	$	179,331	$	58,407	$	96,824	$	26,010
Increase (decrease), net	29,641		15,538		12,295		(5,391)
Balance at December 31, 2021	$	208,972	$	73,945	$	109,119	$	20,619

The Company recognized approximately $103 million of revenue in the year ended December 31, 2022 that was recorded as deferred revenue at December 31, 2021 and approximately $94 million of revenue in the year ended December 31, 2021 that was recorded as deferred revenue at December 31, 2020. Of the Company's deferred revenue reported as long-term in its

consolidated balance sheet at December 31, 2022, the Company expects that approximately $12 million will be recognized as revenue in 2024, approximately $5 million will be recognized as revenue in 2025 and approximately $2 million will be recognized as revenue in 2026 and beyond.

All freight-related customer invoicing is recorded as revenue, while the shipping and handling costs that occur after control of the promised goods or services transfer to the customer are reported as fulfillment costs, a component of Cost of revenue - product in the Company's consolidated statements of operations.

Deferred Commissions Cost

Sales commissions earned by the Company's employees are considered incremental and recoverable costs of obtaining a contract with a customer. The payments related to these costs have been deferred on our consolidated balance sheet and are being amortized over the expected life of the customer contract, which is generally five years. At December 31, 2022 and 2021, the Company had $3.6 million and $3.8 million, respectively, of deferred sales commissions capitalized.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI https://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

OPERATING SEGMENT INFORMATION

12 Months Ended

Dec. 31, 2022

Segment Reporting [Abstract]

OPERATING SEGMENT INFORMATION

The Company has two reportable segments, which are intended to align with the manner in which the business is managed: Cloud and Edge, and IP Optical Networks.

The Cloud and Edge segment provides secure and reliable software and hardware products, solutions and services for enabling Voice over Internet Protocol ("VoIP") communications, Voice over Long-Term Evolution ("VoLTE") and Voice Over 5G ("VoNR") communications and Unified Communications and Collaboration ("UC&C") within service provider and enterprise networks and from the cloud. The Cloud and Edge products are increasingly software-centric and cloud-native for deployment on private, public or hybrid cloud infrastructures, in data centers, on enterprise premises and within service provider networks. Ribbon's Cloud and Edge product portfolio consists of our Session Border Controller ("SBC") products and our Network Transformation ("NTR") products.

The IP Optical Networks segment provides high-performance, secure solutions for IP networking and optical transport, supporting wireless networks including 5G, metro and edge aggregation, core networking, data center interconnect, legacy network transformation and transport solutions for wholesale carriers. This portfolio is offered to service provider, enterprise and industry verticals with critical transport network infrastructures including utilities, government, defense, transportation, and education and research.

The Company has not provided segment asset information as such information is not provided to the CODM and accordingly, asset information is not used in assessing segment performance. Segment revenue and expense included in the tables below represent direct revenue and expense attributable to each segment. Please see Note 10 for information regarding the allocation of goodwill between segments.

The CODM utilizes revenue and adjusted gross profit to measure and assess each segment's performance. The Company calculates adjusted gross profit by excluding from cost of revenue: amortization of acquired technology, stock-based compensation, acquisition-related inventory adjustments and acquisition-related facilities adjustments, and may also exclude other items in future periods that the Company believes are not part of the Company's core business. Adjusted gross profit is not a financial measure determined in accordance with U.S. GAAP, may not be comparable to similarly titled measures used by other companies, and should not be considered a substitute for gross profit or other results reported in accordance with U.S. GAAP. See below for a reconciliation of adjusted gross profit to gross profit which is the most directly comparable U.S. GAAP measure.

The tables below provide revenue, adjusted gross profit and depreciation expense by reportable segment for the years ended December 31, 2022, 2021 and 2020 (in thousands):


	Year ended December 31,
Revenue	2022		2021		2020
Segment revenue:
Cloud and Edge	$	508,137	$	556,656	$	583,270
IP Optical Networks	311,623		288,301		260,525
Total revenue	$	819,760	$	844,957	$	843,795



	Year ended December 31,
Adjusted gross profit	2022		2021		2020
Segment adjusted gross profit:
Cloud and Edge	$	330,395	$	370,504	$	385,137
IP Optical Networks	104,711		114,496		110,845
Total segment adjusted gross profit	435,106		485,000		495,982


Stock-based compensation expense	(2,628)		(1,997)		(875)
Amortization of acquired technology	(31,542)		(38,343)		(42,290)
Acquisition-related inventory and facilities adjustments	—		—		(2,000)


Gross profit	$	400,936	$	444,660	$	450,817

























	Year ended December 31,
Depreciation expense	2022		2021		2020
Segment depreciation expense:
Cloud and Edge	$	10,758	$	12,269	$	12,111
IP Optical Networks	4,537		4,693		5,077
Total depreciation expense	$	15,295	$	16,962	$	17,188

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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+ Details

MAJOR CUSTOMERS

12 Months Ended

Dec. 31, 2022

Risks and Uncertainties [Abstract]

MAJOR CUSTOMERS

The following customers contributed 10% or more of the Company's revenue in at least one of the years ended December 31, 2022, 2021 and 2020:


	Year ended December 31,
	2022	2021	2020
Verizon Communications Inc.	15%	16%	15%

At December 31, 2022, no customer accounted for 10% or more of the Company's accounts receivable balance. At December 31, 2021, one customer accounted for 10% or more of the Company's accounts receivable balance, representing approximately 15% of total accounts receivable. The Company performs ongoing credit evaluations of its customers and generally does not require collateral on accounts receivable. The Company maintains an allowance for doubtful accounts and such losses have historically been within management's expectations.

STOCK-BASED COMPENSATION PLANS

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

STOCK-BASED COMPENSATION PLANS

The Company grants stock-based compensation to employees, officers and non-employee directors, as well as consultants and advisors of the Company and its subsidiaries under its Amended and Restated 2019 Incentive Award Plan (the "2019 Plan") which provides for the award of stock options, stock appreciation rights ("SARs"), restricted stock awards ("RSAs"), performance-based stock awards ("PSAs"), restricted stock units ("RSUs"), performance-based stock units ("PSUs") and other stock- or cash-based awards.

At the Company's annual meeting of stockholders held on May 25, 2022, the Company's stockholders approved an amendment to the 2019 Plan to increase the number of shares of the Company's common stock authorized for issuance under

the 2019 Plan by 10.0 million shares.

Executive Equity Arrangements

Inducement Awards

In connection with his appointment as President and Chief Executive Officer of Ribbon on March 16, 2020, the Company awarded Bruce McClelland sign-on equity grants, comprised of RSUs and a PSU grant with both market and service conditions (the "Inducement PSUs").

Performance-Based Stock Grants

In addition to granting RSAs and RSUs to its executives and certain of its employees, the Company also grants PSUs to certain of its executives and certain other employees. Vesting periods for RSAs, RSUs, and PSUs granted range from one to three years. PSUs granted consist of 60% that have both performance and service conditions (the "Performance PSUs") and 40% that have both market and service conditions (the "Market PSUs"). Each Performance PSU is comprised of three consecutive fiscal year performance periods beginning in the year of grant, with one-third of the Performance PSUs attributable to each fiscal year performance period. The Market PSUs have one three-year performance period, beginning January 1 in the year of grant and ending on December 31, three years thereafter. The number of shares of common stock underlying the PSUs that can be earned will not exceed 200% of the Performance or Market PSUs. Shares subject to PSUs that fail to be earned will be forfeited.

Restricted Stock Units

The activity related to the Company's RSUs for the year ended December 31, 2022 was as follows:


	Shares	Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2022	5,389,611	$	6.19
Granted	6,096,248	$	3.09

Vested	(3,075,543)	$	5.87
Forfeited	(760,569)	$	5.05
Unvested balance at December 31, 2022	7,649,747	$	3.96

The total grant date fair value of restricted stock underlying RSUs that vested was $18.1 million in the year ended December 31, 2022, $12.5 million in the year ended December 31, 2021 and $11.2 million in the year ended December 31, 2020.

Performance-Based Stock Units

The activity related to the Company's PSUs for the year ended December 31, 2022 was as follows:


	Shares	Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2022	4,987,876	$	2.87
Granted	2,228,073	$	3.27

Vested	(179,184)	$	5.02
Forfeited	(383,262)	$	7.82
Unvested balance at December 31, 2022	6,653,503	$	2.52

The total grant date fair value of restricted stock underlying PSUs that vested was $0.9 million in the year ended December 31, 2022, $1.7 million in the year ended December 31, 2021 and $1.8 million in the year ended December 31, 2020.

Stock-Based Compensation

The consolidated statements of operations included stock-based compensation for the years ended December 31, 2022, 2021 and 2020 as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Product cost of revenue	$	471	$	313	$	174
Service cost of revenue	2,157		1,684		701
Research and development	5,108		4,253		2,968
Sales and marketing	6,074		7,218		4,129
General and administrative	4,897		5,950		5,927
	$	18,707	$	19,418	$	13,899

There was an income tax benefit for employee stock-based compensation expense for the years ended December 31, 2022, 2021 and 2020. At December 31, 2022, there was $23.0 million, net of expected forfeitures, of unrecognized stock-based compensation expense related to unvested RSUs and PSUs. This expense is expected to be recognized over a weighted average period of approximately two years. The Company issues authorized and unissued shares under its equity plans and at December 31, 2022, there were 5,027,305 total shares of common stock reserved for that purpose with 105,495 of those shares authorized only for issuance of shares upon exercise of stock options.

LEASES

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

LEASES

The Company has operating and finance leases for corporate offices, research and development facilities, and certain equipment. Operating leases are reported separately in the Company's consolidated balance sheet at December 31, 2022 and 2021. Assets acquired under finance leases are included in Property and equipment, net, in the consolidated balance sheets at December 31, 2022 and 2021.

The Company determines if an arrangement is a lease at inception. A contract is determined to contain a lease component if the arrangement provides the Company with a right to control the use of an identified asset. Lease agreements may include lease and non-lease components. In such instances for all classes of underlying assets, the Company does not separate lease and non-lease components but rather, accounts for the entire arrangement under leasing guidance. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term.

Right-of-use assets and lease liabilities are initially measured based on the present value of the future minimum fixed lease payments (i.e., fixed payments in the lease contract) over the lease term at the commencement date. As the Company's existing leases do not have a readily determinable implicit rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of future minimum fixed lease payments. The Company calculates its incremental borrowing rate to reflect the interest rate that it would have to pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment over a similar term and considers its historical borrowing activities and market data from entities with comparable credit ratings in this determination. The measurement of the right-of-use asset also includes any lease payments made prior to the commencement date (excluding any lease incentives) and initial direct costs incurred. The Company assessed its right-of-use assets for impairment as of December 31, 2022 and 2021 and determined no impairment had occurred.

Lease terms may include options to extend or terminate the lease and the Company incorporates such options in the lease term when it has the unilateral right to make such an election and it is reasonably certain that the Company will exercise that option. In making this determination, the Company considers its prior renewal and termination history and planned usage of the assets under lease, incorporating expected market conditions.

For operating leases, lease expense for minimum fixed lease payments is recognized on a straight-line basis over the lease term. The expense for finance leases includes both interest and amortization expense components, with the interest component calculated based on the effective interest method and the amortization component calculated based on straight-line amortization

of the right-of-use asset over the lease term. Lease contracts may contain variable lease costs, such as common area maintenance, utilities and tax reimbursements that vary over the term of the contract. Variable lease costs are not included in minimum fixed lease payments and as a result, are excluded from the measurement of the right-of-use assets and lease liabilities. The Company expenses all variable lease costs as incurred.

Certain leased facilities are being partially or fully vacated as part of the 2022 Restructuring Plan and for some of those facilities, the Company has no plans to enter into sublease agreements. Accordingly, the Company accelerated the amortization of those lease assets through the planned cease-use date of each facility, resulting in additional amortization expense of $1.6 million in the year ended December 31, 2022. The Company also recorded expense of $1.0 million in the year ended December 31, 2022 for all estimated future variable lease costs related to those facilities.

In connection with the 2020 Restructuring Plan, the Company accelerated amortization totaling $0.8 million in the year ended December 31, 2021 for leased facilities that were vacated in 2021 as part of the consolidation of certain sites following the ECI Acquisition. The Company did not record estimated future variable lease costs in the year ended December 31, 2021 related to the 2020 Restructuring Plan. The Company did not record any accelerated amortization or estimated future variable lease costs in the year ended December 31, 2022 or 2022 related to the 2020 Restructuring Plan.

In connection with the 2019 Restructuring Initiative, certain lease assets related to facilities are being partially or fully vacated as the Company consolidates its facilities. The Company has no plans to enter into sublease agreements for certain facilities. The Company accelerated amortization of $3.4 million and $0.6 million in the years ended December 31, 2021 and 2020, respectively, for leased facilities that were vacated in the respective years. The Company also recorded liabilities aggregating $1.4 million in the year ended December 31, 2021 for all future estimated variable lease costs related to these facilities. The Company did not record liabilities for future estimated variable lease costs in the year ended December 31, 2020. The Company did not accelerate amortization or record liabilities for future estimated variable lease costs in the year ended December 31, 2022.

All incremental accelerated amortization and accrual for all estimated future variable lease costs are included in Restructuring and related expense in the Company's consolidated statements of operations for the years ended December 31, 2022, 2021 and 2020. At December 31, 2022 and 2021, the Company had accruals of $2.0 million and $1.6 million, respectively, for all future anticipated variable lease costs related to these facilities. The Company may incur additional future expense if it is unable to sublease other locations included in the Facilities Initiative. In addition, in the year ended December 31, 2021, this accelerated amortization and provision for future estimated variable lease costs was partially offset by the recognition of $2.1 million of income in conjunction with lease amendments that modified the Company's obligation and rentable square footage at a site in North Carolina.

The Company leases its corporate offices and other facilities under operating leases, which expire at various times through 2032.

The Company's right-of-use lease assets and lease liabilities at December 31, 2022 and 2021 were as follows (in thousands):


		December 31,
	Classification	2022		2021
Assets:
Operating lease assets	Operating lease right-of-use assets	$	44,888	$	53,147
Finance lease assets*	Property and equipment, net	—		287
Total leased assets		$	44,888	$	53,434

Liabilities:
Current:
Operating	Operating lease liabilities	$	15,416	$	17,403
Finance	Accrued expenses and other	—		503
Noncurrent:
Operating	Operating lease liabilities, net of current	46,183		55,196
Finance	Other long-term liabilities	—		64
Total lease liabilities		$	61,599	$	73,166

* Finance lease assets were fully depreciated at December 31, 2022 and were recorded net of accumulated depreciation of $1.8 million at December 31, 2021.

The components of lease expense for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020

Operating lease cost*	$	21,121	$	21,828	$	19,582
Finance lease cost:
Amortization of leased assets	287		695		1,200
Interest on lease liabilities	13		67		173
Short-term lease cost	14,209		13,250		20,687
Variable lease costs (costs excluded from minimum fixed lease payments)**	4,007		4,030		2,713
Sublease income	(1,647)		(1,496)		(1,087)
Net lease cost	$	37,990	$	38,374	$	43,268

* Operating lease costs for the years ended December 31, 2022, 2021 and 2020 include $1.6 million, $3.4 million, and $0.6 million, respectively, of accelerated amortization for certain assets partially or fully vacated with no intent or ability to sublease. Operating lease cost for the year ended December 31, 2021 also includes $2.1 million of income related to a lease modification for one of these assets.

** Variable lease costs for the years ended December 31, 2022 and 2021 included accruals of $1.0 million and $1.4 million, respectively, for all future estimated variable expenses related to certain assets partially or fully vacated with no intent or ability to sublease. No such variable costs were accrued in the year ended December 31, 2020.

Cash flow information related to the Company's leases for the years ended December 31, 2022 and 2021 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	20,363	$	22,365	19,161
Operating cash flows from finance leases	$	13	$	67	173
Financing cash flows from finance leases	$	595	$	903	1,279

Other information related to the Company's leases as of December 31, 2022 and 2021 was as follows (in thousands):


	December 31,
	2022		2021


Weighted average remaining lease term (years):
Operating leases	5.90		6.25
Finance leases	—		1.00
Weighted average discount rate:
Operating leases	5.79	%	5.61	%
Finance leases	—		4.15	%

Future minimum fixed lease payments under noncancelable leases at December 31, 2022 were as follows (in thousands):


	December 31, 2022
	Operating		Finance
	leases		leases
2023	$	18,384	$	—
2024	15,380		—
2025	8,249		—
2026	7,110		—
2027	6,429		—
2028 and beyond	18,210		—
Total lease payments	73,762		—
Less: interest	(12,163)		—
Present value of lease liabilities	$	61,599	$	—

LEASES

The Company leases its corporate offices and other facilities under operating leases, which expire at various times through 2032.

The Company's right-of-use lease assets and lease liabilities at December 31, 2022 and 2021 were as follows (in thousands):


		December 31,
	Classification	2022		2021
Assets:
Operating lease assets	Operating lease right-of-use assets	$	44,888	$	53,147
Finance lease assets*	Property and equipment, net	—		287
Total leased assets		$	44,888	$	53,434

Liabilities:
Current:
Operating	Operating lease liabilities	$	15,416	$	17,403
Finance	Accrued expenses and other	—		503
Noncurrent:
Operating	Operating lease liabilities, net of current	46,183		55,196
Finance	Other long-term liabilities	—		64
Total lease liabilities		$	61,599	$	73,166

* Finance lease assets were fully depreciated at December 31, 2022 and were recorded net of accumulated depreciation of $1.8 million at December 31, 2021.

The components of lease expense for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020

Operating lease cost*	$	21,121	$	21,828	$	19,582
Finance lease cost:
Amortization of leased assets	287		695		1,200
Interest on lease liabilities	13		67		173
Short-term lease cost	14,209		13,250		20,687
Variable lease costs (costs excluded from minimum fixed lease payments)**	4,007		4,030		2,713
Sublease income	(1,647)		(1,496)		(1,087)
Net lease cost	$	37,990	$	38,374	$	43,268

Cash flow information related to the Company's leases for the years ended December 31, 2022 and 2021 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	20,363	$	22,365	19,161
Operating cash flows from finance leases	$	13	$	67	173
Financing cash flows from finance leases	$	595	$	903	1,279

Other information related to the Company's leases as of December 31, 2022 and 2021 was as follows (in thousands):


	December 31,
	2022		2021


Weighted average remaining lease term (years):
Operating leases	5.90		6.25
Finance leases	—		1.00
Weighted average discount rate:
Operating leases	5.79	%	5.61	%
Finance leases	—		4.15	%

Future minimum fixed lease payments under noncancelable leases at December 31, 2022 were as follows (in thousands):


	December 31, 2022
	Operating		Finance
	leases		leases
2023	$	18,384	$	—
2024	15,380		—
2025	8,249		—
2026	7,110		—
2027	6,429		—
2028 and beyond	18,210		—
Total lease payments	73,762		—
Less: interest	(12,163)		—
Present value of lease liabilities	$	61,599	$	—

EMPLOYEE DEFINED CONTRIBUTION PLANS

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

EMPLOYEE DEFINED CONTRIBUTION PLANS

The Company offers 401(k) savings plans to eligible employees. The Company matches 50% of each employee's contributions to the 401(k) program up to 4% of the employee's eligible earnings, for a maximum match of 2% of eligible earnings.

The Company recorded expense related to its employee defined contribution plans aggregating $3.3 million, $3.5 million and $3.4 million in the years ended December 31, 2022, 2021 and 2020, respectively.

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS

The Company has defined benefit retirement plans that cover certain employees at various international locations. The Company's policy is to contribute amounts at least sufficient to satisfy the minimum amount required by applicable law and regulations or to directly pay benefits where appropriate. Benefits under the defined benefit plans are typically based either on years of service and the employee's compensation (generally during a fixed number of years immediately before retirement) or on annual credits. The range of assumptions that are used for these non-U.S. defined benefit plans reflect the different economic environments within the various countries.

In the year ended December 31, 2020, the Company assumed ECI's defined benefit plans in connection with the ECI Acquisition. These plans exist in several international locations where severance pay is either required by law for voluntary or involuntary terminations or upon reaching a statutory retirement age. The Company adopted ECI's policy to fund notional accounts each month in the name of each employee to satisfy not only the severance amounts required by the applicable laws and regulations in certain countries, but also to satisfy severance for other types of terminations not necessarily required by law, but paid in accordance with company policy. Benefits funded and paid under these plans are based upon years of service and the employees' current compensation. At the ECI Acquisition Date, ECI accounted for these plans under the shutdown approach allowed under ASC 715, Compensation - Retirement Benefits (Topic 715) ("ASC 715"). Beginning December 31, 2020, in order to be consistent with the accounting methodology utilized for Ribbon's other defined benefit plans, the Company began to account for the ECI assumed plans using the actuarial cost approach, which is also allowed under ASC 715 for these types of plans. The range of assumptions that are utilized for these plans reflects the different economic environments within each country where such severance indemnities are required.

The Company expanded its actuarial valuation of defined benefit plans beginning with the year ended December 31, 2021 to include the severance plan for employees in India that are unaffiliated with the 2020 acquisition of ECI, thereby increasing the projected benefit obligation by $1.5 million as of December 31, 2021. In addition, the Company aligned the benefits for all employees in India in the year 2021 for consistency, including those employees assumed in the ECI Acquisition in 2020. This benefit alignment was considered a plan amendment for those former ECI employees, resulting in the establishment of a $(3.8) million prior service credit in the year ended December 31, 2021.

In 2020, regulatory changes occurred in the Netherlands that changed the Company's defined benefit pension plan there from a participating plan to a non-participating plan. This plan amendment triggered settlement accounting, resulting in a gain

of $1.6 million, which is included in Other (expense) income, net, in the Company's consolidated statement of operations for the year ended December 31, 2020. Prior to the amendment, the Company's Netherlands pension plan provided defined benefit accruals which were financed by insurance contracts that had a profit sharing feature. The pension benefits accrued were subject to future increases based on final earnings at the end of employment (the final average earnings formula). With the amendment in 2020, the final average earnings formula was frozen and the insurance contracts were converted to fully paid contracts. Following the amendment, pension accruals are now based upon a new formula that only considers current earnings (the career earnings formula) with the benefits still financed through insurance contracts. Ribbon has no further liability for pension benefits earned prior to the amendment as they are fully paid contracts. In addition, the insurance contract for the new benefit accruals has no profit sharing feature. Therefore, Ribbon has no current or future obligation to pay pension benefits promised in the Netherlands beyond the payment of premiums to the insurance company.

A reconciliation of the changes in the benefit obligations and fair value of the assets of the defined benefit plans for the years ended December 31, 2022 and 2021, the funded status of the plans, and the amounts recognized in the consolidated balance sheets as of December 31, 2022 and 2021 were as follows (in thousands):


	Year ended December 31,
	2022		2021
Changes in projected benefit obligations:
Projected benefit obligation, beginning of year	$	26,938	$	25,067
Service cost	1,355		1,321
Interest cost	563		523
Participant contributions	—		—
Plan amendments	—		(3,801)

Net actuarial (gain) loss on obligation	(5,604)		4,868
Settlement	(1,063)		—
Benefits and expenses paid	(932)		(1,040)
Projected benefit obligation, end of year	$	21,257	$	26,938

Changes in plan assets:
Fair value of plan assets, beginning of year	$	15,303	$	14,350

Actual return on plan assets	(672)		981

Employer contributions	1,954		989
Participant contributions	39		23
Benefits paid	(1,995)		(1,040)
Fair value of plan assets, end of year	$	14,629	$	15,303

Funded status at end of year	$	(6,628)	$	(11,635)

Amounts recognized in accumulated other comprehensive income consist of:
Prior service (credit) cost	$	(3,481)	$	(3,801)
Net actuarial (gain) loss	(1,704)		4,045
	$	(5,185)	$	244

Amounts recognized in the consolidated balance sheets consist of:
Other assets (non-current pension asset)	$	552	$	—
Accrued expenses and other (current pension liability)	(803)		(461)
Other long-term liabilities (non-current pension liability)	(6,377)		(11,174)
Net amount recognized	$	(6,628)	$	(11,635)

The decrease in the underfunded status of the Company's defined benefit plans at December 31, 2022 compared to December 31, 2021 was primarily the result of the increase in the discount rates in the various countries, partially offset by continued benefit accruals. The source of the projected benefit obligation ("PBO") actuarial (gain) loss differed in each country. However, in aggregate, the effect of discount rate changes in 2022 represented the most significant contributor to the PBO actuarial (gain) loss.

Plans with underfunded or non-funded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	9,450	$	26,938
Aggregate accumulated benefit obligation	$	7,418	$	20,695
Aggregate fair value of plan assets	$	2,270	$	15,303

Plans with overfunded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	11,807	$	—
Aggregate accumulated benefit obligation	$	9,547	$	—
Aggregate fair value of plan assets	$	12,359	$	—

Net periodic benefit costs for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Service cost	$	1,355	$	1,321	$	1,459
Interest cost	563		523		46
Expected return on plan assets	(266)		(314)		(343)
Plan asset expenses	—		—		—


Settlement charge (credit)	808		—		(1,557)
Amortization of prior service cost	(320)		—		—
Amortization of net loss	275		81		20
Net periodic benefit costs	$	2,415	$	1,611	$	(375)

Expected benefit payments for the next ten years are as follows (in thousands):


Years ending December 31,
2023	$	2,863
2024	1,314
2025	1,562
2026	1,315
2027	1,584
2028 to 2032	11,326
	$	19,964

The changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before tax for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Net (gain) loss	$	(4,666)	$	4,201	$	(503)


Prior service (credit) cost	—		(3,801)		—
Amortization of net gain (loss)	(275)		(81)		(20)
Amortization of prior service credit (cost)	320		—		—
Settlement (charge) credit	(808)		—		(1,557)
Total recognized in other comprehensive income (loss)	$	(5,429)	$	319	$	(2,080)

The Company defers all actuarial gains and losses resulting from variances between actual results and economic estimates or actuarial assumptions. The unrecognized actuarial gains and losses are recorded as unrealized pension actuarial gains (losses) in the Company's consolidated balance sheets as a component of Accumulated other comprehensive income (loss).

These unrecognized gains and losses are amortized as a component of net periodic benefit cost when the net gains and losses exceed 10% of the greater of the market value of plan assets or the projected benefit obligation at the beginning of the year.

The principal weighted average assumptions used to determine the benefit obligation at December 31, 2022 and 2021 were as follows:


	December 31,
	2022		2021
Discount rate	4.74	%	2.24	%
Rate of compensation increase	4.02	%	3.90	%

The principal weighted average assumptions used to determine net period benefit cost for the years ended December 31, 2022, 2021 and 2020 were as follows:


	Year ended December 31,
	2022		2021		2020
Discount rate	2.24	%	2.16	%	0.68	%
Expected long-term return on plan assets	1.79	%	2.06	%	0.21	%
Rate of compensation increase	3.90	%	2.41	%	2.88	%

Assumed discount rates are used in the measurement of the projected and accumulated benefit obligations, as well as the service and interest cost components of net periodic pension cost. Estimated discount rates reflect the rates at which the pension benefits could be effectively settled. For each defined benefit plan, the Company chooses an estimated discount rate from a readily available market index rate, based upon high-quality fixed income investments, specific to the country or economic zone in which the benefits are paid and taking into account the duration of the plan and the number of participants.

The Company's plans in both the Netherlands and Switzerland are funded through insurance contracts, which have historically provided guaranteed interest credit. The fair value of these contracts is derived from the insurance companies' assessment of the minimum value of the benefits provided by the insurance contracts. The methodology used to value these plan assets has always assumed that the value of the plan assets equals the guaranteed insured benefits. For consistency, the same discount rate used in the valuation of the benefit obligations is used to place a value on the plan assets. The assets are assumed to grow each year in line with the discount rate, and therefore, the expected return on the assets is set equal to the discount rate. The fair value of the plan assets in Switzerland was $2.3 million at December 31, 2022 and $1.7 million at December 31, 2021. Due to the plan amendment in 2020 that changed the benefit structure of the Netherlands plan, the Company no longer has any obligation related to this plan beyond the payment of insurance premiums. Therefore, there is no projected benefit obligation and no plan assets in the Netherlands as of December 31, 2022, 2021 or 2020. The Company classifies the fair value of its plan assets as Level 2 in the fair value hierarchy as discussed in Note 6.

During the years ended December 31, 2022 and 2021, employees in Switzerland made contributions to their pension plan aggregating $39,000 and $23,000, respectively. Employee contributions to this plan are based on a fixed 5% of the relevant pensionable earnings. The Company funds this plan by contributing at least the minimum amount required by applicable regulations and as recommended by an independent actuary.

During the years ended December 31, 2022, 2021 and 2020, the Company contributed $2.0 million, $1.0 million and $0.8 million, respectively, to all of its pension plans. The Company expects to contribute $1.5 million to all of its defined benefit plans in 2023.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section S99
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=21916913&loc=d3e273930-122802

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (o)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (p)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
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-Section 50
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-URI https://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/topic&trid=2235017

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 3
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=6414203&loc=d3e39689-114964

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (r)(2)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

+ Details

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS

EMPLOYEE DEFINED CONTRIBUTION PLANS

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS


	Year ended December 31,
	2022		2021
Changes in projected benefit obligations:
Projected benefit obligation, beginning of year	$	26,938	$	25,067
Service cost	1,355		1,321
Interest cost	563		523
Participant contributions	—		—
Plan amendments	—		(3,801)

Net actuarial (gain) loss on obligation	(5,604)		4,868
Settlement	(1,063)		—
Benefits and expenses paid	(932)		(1,040)
Projected benefit obligation, end of year	$	21,257	$	26,938

Changes in plan assets:
Fair value of plan assets, beginning of year	$	15,303	$	14,350

Actual return on plan assets	(672)		981

Employer contributions	1,954		989
Participant contributions	39		23
Benefits paid	(1,995)		(1,040)
Fair value of plan assets, end of year	$	14,629	$	15,303

Funded status at end of year	$	(6,628)	$	(11,635)

Amounts recognized in accumulated other comprehensive income consist of:
Prior service (credit) cost	$	(3,481)	$	(3,801)
Net actuarial (gain) loss	(1,704)		4,045
	$	(5,185)	$	244

Amounts recognized in the consolidated balance sheets consist of:
Other assets (non-current pension asset)	$	552	$	—
Accrued expenses and other (current pension liability)	(803)		(461)
Other long-term liabilities (non-current pension liability)	(6,377)		(11,174)
Net amount recognized	$	(6,628)	$	(11,635)

Plans with underfunded or non-funded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	9,450	$	26,938
Aggregate accumulated benefit obligation	$	7,418	$	20,695
Aggregate fair value of plan assets	$	2,270	$	15,303

Plans with overfunded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	11,807	$	—
Aggregate accumulated benefit obligation	$	9,547	$	—
Aggregate fair value of plan assets	$	12,359	$	—

Net periodic benefit costs for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Service cost	$	1,355	$	1,321	$	1,459
Interest cost	563		523		46
Expected return on plan assets	(266)		(314)		(343)
Plan asset expenses	—		—		—


Settlement charge (credit)	808		—		(1,557)
Amortization of prior service cost	(320)		—		—
Amortization of net loss	275		81		20
Net periodic benefit costs	$	2,415	$	1,611	$	(375)

Expected benefit payments for the next ten years are as follows (in thousands):


Years ending December 31,
2023	$	2,863
2024	1,314
2025	1,562
2026	1,315
2027	1,584
2028 to 2032	11,326
	$	19,964

The changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before tax for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Net (gain) loss	$	(4,666)	$	4,201	$	(503)


Prior service (credit) cost	—		(3,801)		—
Amortization of net gain (loss)	(275)		(81)		(20)
Amortization of prior service credit (cost)	320		—		—
Settlement (charge) credit	(808)		—		(1,557)
Total recognized in other comprehensive income (loss)	$	(5,429)	$	319	$	(2,080)

The principal weighted average assumptions used to determine the benefit obligation at December 31, 2022 and 2021 were as follows:


	December 31,
	2022		2021
Discount rate	4.74	%	2.24	%
Rate of compensation increase	4.02	%	3.90	%

The principal weighted average assumptions used to determine net period benefit cost for the years ended December 31, 2022, 2021 and 2020 were as follows:


	Year ended December 31,
	2022		2021		2020
Discount rate	2.24	%	2.16	%	0.68	%
Expected long-term return on plan assets	1.79	%	2.06	%	0.21	%
Rate of compensation increase	3.90	%	2.41	%	2.88	%

- Definition

The entire disclosure for retirement benefits.

+ References

+ Details

INCOME TAXES

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

INCOME TAXES

The components of (loss) income from continuing operations before income taxes consisted of the following (in thousands):


	Year ended December 31,
	2022		2021		2020
(Loss) income before income taxes:
United States	$	(84,784)	$	(29,985)	$	123,817
Foreign	(27,815)		(178,158)		(30,500)
	$	(112,599)	$	(208,143)	$	93,317

The (benefit) provision for income taxes from continuing operations consisted of the following (in thousands):


	Year ended December 31,
	2022		2021		2020
(Benefit) provision for income taxes:
Current:
Federal	$	(3,582)	$	5,033	$	677
State	2,573		1,836		1,310
Foreign	4,744		7,661		7,355
Total current	3,735		14,530		9,342
Deferred:
Federal	(10,333)		(38,027)		1,957
State	(4,045)		97		(15)
Foreign	(3,873)		(7,558)		(6,558)
Total deferred	(18,251)		(45,488)		(4,616)
Total	$	(14,516)	$	(30,958)	$	4,726

A reconciliation of the Company's effective tax rate for continuing operations to the U.S. statutory federal rate is as follows:


	Year ended December 31,
	2022		2021		2020
U.S. statutory income tax rate	21.0	%	21.0	%	21.0	%
State income taxes, net of federal benefit	1.8		(0.7)		1.1
Foreign income taxes	(1.4)		0.5		0.2
Stock-based compensation	(2.4)		(0.1)		1.0
Tax credits	2.2		1.6		(2.8)
Uncertain tax positions	1.3		0.5		0.5
Valuation allowance	(3.8)		2.5		(20.3)
Non-deductible goodwill impairment	—		(11.7)		—
Other permanent adjustments	(2.6)		0.9		1.8
Permanent foreign exchange adjustments	(1.4)		0.5		1.8
Other, net	(1.8)		(0.1)		0.8
Effective income tax rate	12.9	%	14.9	%	5.1	%

The following is a summary of the significant components of deferred income tax assets and liabilities (in thousands):


	December 31,
	2022		2021
Assets:
Net operating loss carryforwards	$	413,773	$	437,669
Capital loss carryforwards	99,505		79,716
Tax credit carryforwards	28,902		23,450
Capitalized research and development expenses	40,668		18,106
Deferred revenue	3,510		3,472
Accrued expenses	9,068		7,505
Inventory	2,820		3,102
Stock-based compensation	1,709		1,689
Fixed assets	2,506		2,710
Lease liabilities	12,829		15,250
Mark-to-market investments	—		1,714
Other temporary differences	1,324		3,839
	616,614		598,222
Valuation allowance	(488,550)		(471,515)
Total deferred tax assets	128,064		126,707
Liabilities:
Intangible assets	(55,037)		(65,647)
Operating lease right-of-use assets	(8,519)		(10,370)
Interest rate swap	(6,168)		—
Unremitted foreign income	(8,441)		(11,519)
Total deferred tax liabilities	(78,165)		(87,536)
Total net deferred tax assets	$	49,899	$	39,171

The deferred tax assets and liabilities based on tax jurisdictions are presented in the Company's consolidated balance sheets as follows:


	December 31,
	2022		2021
Deferred income taxes - net noncurrent assets	$	53,649	$	47,287
Deferred income taxes - net noncurrent liabilities	(3,750)		(8,116)
	$	49,899	$	39,171

At December 31, 2022, the Company had U.S. federal net operating losses ("NOLs") of $152.5 million. The Company also had U.S. state NOLs of $18.8 million. In addition, the Company had $1.6 billion of Israel NOLs through the ECI Acquisition. The U.S. federal NOL carryforwards expire between 2023 and 2037. The U.S. state NOLs begin to expire in 2023, and the Company also has indefinite-lived state NOLs. The Israel NOLs do not expire.

The Company also has available federal, state and foreign income tax credit carryforwards of $28.9 million. The federal foreign tax credit carryforwards expire between 2030 and 2032. The state tax credits, which are primarily research and development credits, begin to expire in 2023, while others can be carried forward until exhausted. The foreign income tax credits expire in various periods.

The Company has provided for income taxes on the undistributed earnings of its non-U.S. subsidiaries as of December 31, 2022, excluding Ireland and Israel. These subsidiaries, excluding Ireland and Israel, are cost-plus or limited risk distributors that are not anticipated to need to use excess funds locally. Accordingly, the Company is required to recognize and record deferred taxes in 2022. The deferred taxes, which are primarily future withholding taxes, are recorded on the entire outside basis differences related to the foreign subsidiaries, the largest of these differences being undistributed earnings. Undistributed profits of Ireland and Israel, as well as other outside basis differences in foreign subsidiaries, were indefinitely reinvested in foreign operations. Quantification of the deferred tax liability, if any, associated with indefinitely reinvested earnings and outside basis differences was not practicable.

Under the provisions of the Internal Revenue Code, the net operating losses and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service. Net operating losses and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership of significant shareholders over a three-year period in excess of 50%, as defined under sections 382 and 383 of the Internal Revenue Code, as well as similar state provisions. As a result of the Sonus and GENBAND merger in 2017, the Company has $112.3 million of U.S. federal net operating loss carryforwards remaining as of December 31, 2022 with an annual section 382 limitation of $9.7 million. The Company believes these NOLs are fully realizable. As a result of the ECI Acquisition, the Company has $41.9 million of U.S. federal NOLs remaining as of December 31, 2022 with an annual section 382 limitation of $1.1 million. The Company does not believe all of these NOLs are realizable and, therefore, have recorded a partial valuation allowance against these NOLs.

The Company performed an analysis to determine if, based on all available evidence, it considered it more likely than not that some portion or all of the recorded deferred tax assets will not be realized in a future period. Accordingly, the Company has recorded a valuation allowance against its U.S. deferred tax assets of $25.5 million at December 31, 2022 and $30.5 million at December 31, 2021. The Company also maintains a valuation allowance against certain of its foreign deferred tax assets, predominantly Israel, amounting to approximately $463 million at December 31, 2022 and $441 million at December 31, 2021. The deferred tax assets recognized with no valuation allowance at December 31, 2022 and 2021 primarily relate to other foreign subsidiaries where recoverability is concluded to be more likely than not based on the Company's cost-plus compensation policy, as well as NOLs and tax credits in the U.S. that are expected to be utilized prior to expiration.

A reconciliation of the Company's unrecognized tax benefits is as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Unrecognized tax benefits at January 1	$	17,813	$	14,054	$	2,932
Increases related to current year tax positions	156		4,017		485
Increases related to prior period tax positions	40		3,168		11,209
Decreases related to the lapse of the applicable statute of limitations	(560)		(3,087)		(122)
Decreases related to prior period tax positions	$	(5,448)	$	(339)	$	(450)
Unrecognized tax benefits at December 31	$	12,001	$	17,813	$	14,054

The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. The Company had $14.9 million, $21.0 million and $15.3 million of unrecognized tax benefits, including penalties and interest, at December 31, 2022, 2021 and 2020, respectively. Of these amounts, $11.2 million, $12.7 million and $13.9 million represent the amount of unrecognized tax benefits that, if recognized, would impact the effective income tax rate for the years ended December 31, 2022, 2021 and 2020, respectively. The Company recorded income tax expense (benefit) for potential penalties and interest of $(0.3) million, $1.9 million and $0.5 million for the years ended December 31, 2022, 2021 and 2020, respectively. The Company had $2.9 million and $3.2 million accrued in Other long-term liabilities for penalties and interest at December 31, 2022 and 2021, respectively. The Company believes that it is reasonably possible that $(0.6) million in tax positions related to its unrecognized tax benefits will be recognized within the next twelve months.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various state and foreign jurisdictions. Generally, the tax years 2018 through 2021 remain open to examination by the major taxing jurisdictions in which the Company operates. The Company's federal and state NOLs generated prior to 2018 could be adjusted on examination even though the year in which the loss was generated is otherwise closed by the statute of limitations.

As of December 31, 2022, the Company had ongoing income tax audits in certain foreign countries. Management believes that an adequate provision has been recorded for any adjustments that may result from tax examinations.

Under the Tax Cuts and Jobs Act of 2017, research and development costs are no longer fully deductible and are required to be capitalized and amortized for U.S. tax purposes effective January 1, 2022. The mandatory capitalization requirement increases our deferred tax assets and cash tax liabilities.

On August 16, 2022, Congress passed the Inflation Reduction Act of 2022 which introduced the 15% corporate alternative minimum tax on book income and a 1% excise tax on stock repurchases which are both effective January 1, 2023. We do not currently anticipate these new laws to have a material effect on the Company's financial position in the near term.

A change in tax laws is one of many factors that impact the Company’s effective tax rate. The U.S. and other jurisdictions where the Company does business have had an extended focus on issues related to the taxation of multinational corporations. As a result, the tax laws in the U.S. and other countries in which the Company does business could change, and any such changes could adversely impact our effective tax rate, financial condition and results of operations. The Organization for Economic Co-operation and Development ("OECD"), an international association of 38 countries including the United States, has proposed changes to numerous long-standing tax principles (e.g. Pillar 1 and Pillar 2). These proposals, if finalized and adopted by the associated countries, will likely increase tax uncertainty and may adversely affect our provision for income taxes.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI https://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI https://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

RELATED PARTIES	12 Months Ended
RELATED PARTIES	Dec. 31, 2022
Related Party Transactions [Abstract]
RELATED PARTIES	RELATED PARTIESThe Company recognized revenue in the years ended December 31, 2022, 2021 and 2020 of $6.6 million, $4.5 million and $3.3 million, respectively, from its largest shareholder. Additionally, as discussed in Note 2, certain related party shareholders participated in the Equity Offering on August 12, 2022.

COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Litigation Settlement As previously disclosed, the Company was involved in six lawsuits (together, the "Lawsuits") with Metaswitch Networks Ltd., Metaswitch Networks Corp. and Metaswitch Inc. (collectively, "Metaswitch"). In five of the Lawsuits, the Company was the plaintiff, and in three of those five lawsuits, the Company was also a counterclaim defendant. In the sixth case, the Company was the defendant. On April 22, 2019, the Company and Metaswitch agreed to a binding mediator's proposal that resolved the six Lawsuits between the Company and Metaswitch (the "Lawsuits"). The Company and Metaswitch signed a Settlement and Cross-License Agreement on May 29, 2019 (the "Royalty Agreement"). Pursuant to the terms of the Royalty Agreement, Metaswitch agreed to pay the Company an aggregate amount of $63.0 million, which included cash payments of $37.5 million during the second quarter of 2019 and $25.5 million payable in three installments annually, beginning June 26, 2020, with such installment payments accruing interest at a rate of 4% per year. As part of the Royalty Agreement, the Company and Metaswitch (i) have released the other from all claims and liabilities; (ii) have licensed each party's existing patent portfolio to the other party; and (iii) have requested the applicable courts to dismiss the Lawsuits. The $63.0 million gain from the settlement is included in Other (expense) income, net, in the Company's consolidated statement of operations for the year ended December 31, 2019, and had notes receivable for future payments of $25.5 million, comprised of $8.5 million in Other current assets and $17.0 million in Other assets in the consolidated balance sheet. The Company received $37.5 million of aggregate payments from Metaswitch in the second quarter of 2019 and $9.5 million, including $1.0 million of interest, in the second quarter of 2020. On July 6, 2020, the Company and Metaswitch signed a First Supplemental Agreement to the Settlement and Cross-License Agreement (the "Supplemental Agreement") under which Metaswitch could elect to repay the outstanding amounts under the Royalty Agreement early in exchange for a reduction of $0.25 million to the outstanding principal, from $17.0 million to $16.75 million, and the payment of no further interest by Metaswitch effective June 26, 2020. The Company recorded the reduction to the outstanding principal as a reduction to interest income. On July 14, 2020, Metaswitch paid the Company the remaining outstanding balance of $16.75 million. Contingencies Liabilities for Royalty Payments to the IIA Prior to the ECI Acquisition, ECI had received research and development grants from the IIA. The Company assumed ECI's contract with the IIA, which requires the Company to pay royalties to the IIA on proceeds from the sale of products which the Israeli government has supported by way of research and development grants. The royalties for grants prior to 2017 were calculated at the rates of 1.3% to 5.0% of the aggregated proceeds from the sale of such products developed at certain of the Company's R&D centers, up to an amount not exceeding 100% of such grants plus interest at LIBOR. Effective for grants approved in 2017 and thereafter, interest was calculated at the higher of LIBOR plus 1.5% to 2.75%. At December 31, 2022, the Company's maximum possible future royalties commitment, including $3.8 million of unpaid royalties accrued at December 31, 2022, was $28.4 million, including interest of $1.4 million, based on estimates of future product sales, grants received from the IIA and not yet repaid, and management's estimation of products still to be sold. Litigation Miller Complaint. On November 8, 2018, Ron Miller, a purported stockholder of the Company, filed a Class Action Complaint (the "Miller Complaint") in the United States District Court for the District of Massachusetts (the "Massachusetts District Court") against the Company and three of its former officers (collectively, the "Defendants"), claiming to represent a class of purchasers of Sonus common stock during the period from January 8, 2015 through March 24, 2015 and alleging violations of the federal securities laws. Similar to a previous complaint entitled Sousa et al. vs. Sonus Networks, Inc. et al., which was dismissed with prejudice by an order dated June 6, 2017, the Miller Complaint claims that the Defendants made misleading forward-looking statements concerning Sonus' expected fiscal first quarter of 2015 financial performance, which statements were also the subject of an August 7, 2018 Securities and Exchange Commission Cease and Desist Order, whose findings the Company neither admitted nor denied. The Miller plaintiffs are seeking monetary damages. After the Miller Complaint was filed, several parties filed and briefed motions seeking to be selected by the Massachusetts District Court to serve as a Lead Plaintiff in the action. On June 21, 2019, the Massachusetts District Court appointed a group as Lead Plaintiffs and the Lead Plaintiffs filed an amended complaint on July 19, 2019. On August 30, 2019, the Defendants filed a motion to dismiss the Miller Complaint and, on October 4, 2019, the Lead Plaintiffs filed an opposition to the motion to dismiss. There was an oral argument on the motion to dismiss on February 12, 2020, and on October 20, 2022 the court denied the motion to dismiss. Discovery and class certification determination are on-going. Charter Complaints. On September 19, 2022, Charter Communications Operating, LLC (“Charter”) filed two complaints against two of the Company’s subsidiaries (Sonus Networks, Inc. and Ribbon Communications Operating Company, Inc.) alleging breach of contract with respect to indemnification obligations purportedly owed to Charter in connection with Charter’s legal dispute with Sprint Communications Company L.P., which was settled by Charter in March 2022. One complaint was filed in the Supreme Court of the State of New York, New York County; the other was filed by Charter as well as co-Plaintiffs Charter Communications Holding Company, LLC and Bright House Networks, LLC, in the Superior Court of the State of Delaware in and for New Castle County. In both suits, Charter is seeking monetary damages. The Company filed its answer in the New York Case on December 7, 2022 and in the Delaware case on January 9, 2023. Discovery is on-going and the court in the Delaware case has set a preliminary trial date of January 2025. In addition, the Company is often a party to disputes and legal proceedings that it considers routine and incidental to its business. Management does not expect the results of any of these actions to have a material effect on the Company's business or consolidated financial statements.

SUBSEQUENT EVENT	12 Months Ended
SUBSEQUENT EVENT	Dec. 31, 2022
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENTS 2023 Restructuring On February 22, 2023, the Company's Board of Directors approved a strategic restructuring program (the "2023 Restructuring Plan") to streamline the Company's operations in order to support the Company's investment in critical growth areas. The 2023 Restructuring Plan is expected to include, among other things, charges related to a consolidation of facilities and a workforce reduction. Any potential positions eliminated in countries outside the United States will be subject to local law and consultation requirements. The Company currently expects to record approximately $10 million of restructuring and related expense associated with the 2023 Restructuring Plan, almost entirely related to employee severance arrangements. The Company expects the 2023 Restructuring Plan will be substantially completed in 2023. Issuance of Preferred Stock and Warrants, Sale of Interest Rate Swap, and Amendment of the 2020 Credit Facility On March 28, 2023, the Company issued 55,000 shares of newly designated Series A Preferred Stock (the "Preferred Stock") to investors in a private placement offering at a price of $970 per share, along with 4.9 million warrants to purchase shares of the Company's common stock, par value $0.0001 per share (the "Private Placement"). The proceeds from the Private Placement were approximately $53.4 million, including approximately $10 million from existing related party shareholders. On March 24, 2023, the Company sold $170 million of its $340 million notional amount interest rate swap back to its counterparty for $9.4 million, reducing the notional amount to $170 million. On March 27, 2023, the Company sold the remaining $170 million of its interest rate swap back to its counterparty for $9.8 million. On March 24, 2023, the Company also entered into an amendment to its 2020 Credit Facility (the “Sixth Amendment”) effective March 30, 2023. The Sixth Amendment, among other things, increased the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility), with the first, second and third quarters of 2023 increasing to 4.50:1.00. In the fourth quarter of 2023 and the first quarter of 2024, the Maximum Consolidated Net Leverage Ratio allowed then declines to 4.25:1.00 and 4.00:1.00, respectively. In all subsequent quarters, the Maximum Consolidated Senior Net Leverage Ratio will be fixed at 3.00:1.00 and the Maximum Consolidated Net Leverage Ratio will be fixed at 4.00:1.00. Also, the Sixth Amendment reduced the minimum Consolidated Fixed Charge Coverage Ratio (as defined in the 2020 Credit Facility) to 1.10:1.00 through the first quarter of 2024 and in all subsequent quarters the ratio will be fixed at 1.25:1.00. The Sixth Amendment reduced the maximum borrowings allowed under the 2020 Revolving Credit Facility from $100 million to $75 million. In addition, the Sixth Amendment replaced LIBOR with the Secured Overnight Financing Rate, or SOFR, as the alternative rate that may be used by the Company for calculating interest owed under the 2020 Credit Facility. In conjunction with the Sixth Amendment, the Company made a $75 million prepayment that was applied to the final payment due on the maturity date. The prepayment was almost entirely funded with the net proceeds from the Private Placement and the sales of our interest rate swap.

QUARTERLY RESULTS (UNAUDITED)

12 Months Ended

Dec. 31, 2022

Quarterly Financial Information Disclosure [Abstract]

QUARTERLY RESULTS (UNAUDITED)

The following tables present the Company's quarterly operating results for the years ended December 31, 2022 and 2021. The information for each of these quarters is unaudited and has been prepared on the same basis as the audited consolidated financial statements. In the opinion of management, all necessary adjustments, consisting only of normal recurring adjustments, have been included to present fairly the unaudited consolidated quarterly results when read in conjunction with the Company's audited consolidated financial statements and related notes.


	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(In thousands, except per share data)
Year ended December 31, 2022
Revenue	$	173,198	$	205,796	$	207,127	$	233,639
Cost of revenue	95,143		101,246		102,809		119,626
Gross profit	$	78,055	$	104,550	$	104,318	$	114,013
(Loss) income from operations	$	(39,054)	$	(7,239)	$	(3,296)	$	1,265
Net (loss) income	$	(69,975)	$	(30,180)	$	(18,416)	$	20,488
(Loss) earnings per share (2):
Basic	$	(0.47)	$	(0.20)	$	(0.12)	$	0.12
Diluted	$	(0.47)	$	(0.20)	$	(0.12)	$	0.12
Shares used in computing (loss) earnings per share:
Basic	149,167		150,190		158,921		168,163
Diluted	149,167		150,190		158,921		172,213


	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(In thousands, except per share data)
Year ended December 31, 2021
Revenue	$	192,772	$	211,210	$	210,398	$	230,577
Cost of revenue (1)	92,286		92,483		99,744		115,784
Gross profit (1)	$	100,486	$	118,727	$	110,654	$	114,793
Loss (income) from operations	$	(12,604)	$	12,952	$	1,992	$	(120,136)
Net (loss) income	$	(44,687)	$	23,241	$	(59,431)	$	(96,308)
Loss (earnings) per share (2):
Basic	$	(0.31)	$	0.16	$	(0.40)	$	(0.65)
Diluted	$	(0.31)	$	0.15	$	(0.40)	$	(0.65)
Shares used in computing loss (earnings) per share:
Basic	145,936		147,467		148,184		148,675
Diluted	145,936		154,160		148,184		148,675

__________________________________

(1)Reflects the increases to Cost of revenue arising from the reclassification of amortization of acquired technology from amortization of acquired intangible assets within operating expenses in 2021 of $10.1 million in the first quarter, $9.7 million in the second quarter and $9.7 million in the third quarter. See Note 2 for a discussion of the reclassification.

(2)(Loss) earnings per share is calculated independently for each of the quarters presented; accordingly, the sum of the quarterly (loss) earnings per share amounts may not equal the total calculated for the year.

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in United States dollars, in accordance with accounting principles generally accepted in the United States ("GAAP"). On December 1, 2020 (the "Kandy Sale Date"), American Virtual Cloud Technologies, Inc. ("AVCT") completed the purchase of the Company's cloud-based enterprise service business (the "Kandy Communications Business"). The revenue and expenses of the Kandy Communications Business are excluded from the Company's consolidated financial statements for the period subsequent to the Kandy Sale Date. On March 3, 2020 (the "ECI Acquisition Date"), the Company merged with ECI Telecom Group Ltd ("ECI") (the "ECI Acquisition"). The financial results of ECI are included in the Company's consolidated financial statements for the period subsequent to the ECI Acquisition Date.
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Ribbon and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates and Judgments	Use of Estimates and Judgments The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and judgments relied upon in preparing these consolidated financial statements include accounting for business combinations, revenue recognition for multiple element arrangements, inventory valuations, assumptions used to determine the fair value of stock-based compensation, intangible assets, goodwill, debentures and warrants, legal contingencies and recoverability of Ribbon's net deferred tax assets and the related valuation allowances. Ribbon regularly assesses these estimates and records changes in estimates in the period in which they become known. Ribbon bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Reclassifications	Reclassifications Certain reclassifications, not affecting previously reported net income (loss), have been made to the previously issued financial statements to conform to the current year presentation.
Business Combinations	Business Combinations The Company recognizes identifiable assets acquired and liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred over the net of the acquisition date fair values of the assets acquired and the liabilities assumed and represents the expected future economic benefits arising from other assets acquired in the business combination that are not individually identified and separately recognized. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill to the extent that it identifies adjustments to the preliminary purchase price allocation. Upon the conclusion of the measurement period or final determination of the values of assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of operations.
Revenue Recognition	Revenue Recognition The Company derives revenue from two primary sources: products and services. Product revenue includes the Company's hardware and software that function together to deliver the products' essential functionality. Software and hardware are also sold on a standalone basis. Services include customer support (software updates, upgrades and technical support), consulting, design services, installation services and training. Generally, contracts with customers contain multiple performance obligations, consisting of products and services. For these contracts, the Company accounts for individual performance obligations separately if they are considered distinct. When an arrangement contains more than one performance obligation, the Company will allocate the transaction price to each performance obligation on a relative standalone selling price basis. The Company utilizes the observable price of goods and services, including when they are sold separately to similar customers, in order to estimate standalone selling price. The Company's software licenses typically provide a perpetual right to use the Company's software. The Company also sells term-based software licenses that expire and Software-as-a-Service ("SaaS")-based software which are referred to as subscription arrangements. The Company does not customize its software nor are installation services required, as the customer has a right to utilize internal resources or a third-party service company. The software and hardware are delivered before related services are provided and are functional without professional services or customer support. The Company has concluded that its software licenses are functional intellectual property that are distinct, as the user can benefit from the software on its own. Product revenue is typically recognized upon transfer of control or when the software is made available for download, as this is the point the user of the software can direct the use of, and obtain substantially all of the remaining benefits from, the functional intellectual property. The Company begins to recognize software revenue related to the renewal of subscription software licenses at the start of the subscription period. The Company offers warranties on its products. Certain of the Company's warranties are considered to be assurance-type in nature, ensuring the product is functioning as intended. Assurance-type warranties do not represent separate performance obligations. The Company also sells separately-priced maintenance service contracts which qualify as service-type warranties and represent separate performance obligations. The Company does not allow and has no history of accepting product returns. Services revenue includes revenue from customer support and other professional services. Customer support includes software updates on a when-and-if-available basis, telephone support, integrated web-based support and bug fixes or patches. The Company sells its customer support contracts at a percentage of list or net product price. Customer support revenue is recognized ratably over the term of the customer support agreement, which is typically one year. The Company's professional services include consulting, technical support, resident engineer services, design services and installation services. Because control transfers over time, revenue is recognized based on progress toward completion of the performance obligation. The method to measure progress toward completion requires judgment and is based on the nature of the products or services to be provided. The Company generally uses the input method to measure progress for its contracts because it believes such method best depicts the transfer of assets to the customer, which occurs as the Company incurs costs for the contracts. However, in some instances, the Company uses the output method because it best depicts the transfer of asset to the customer. Under the cost-to-cost measure of progress, the progress toward completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. When the measure of progress is based upon expended labor, progress toward completion is measured as the ratio of labor time expended to date versus the total estimated labor time required to complete the performance obligation. Revenue is recorded proportionally as costs are incurred or as labor is expended. Costs to fulfill these obligations include internal labor as well as subcontractor costs. Customer training includes courses offered by the Company. The related revenue is typically recognized as the training services are performed.
Operating Segments	Operating SegmentsThe Company's chief operating decision maker (the "CODM") is its president and chief executive officer. Effective in the fourth quarter of 2020 and in connection with the ECI Acquisition, the CODM began to assess the Company's performance based on the performance of two separate lines of business within Ribbon: the Cloud and Edge segment ("Cloud and Edge") and the IP Optical Networks segment ("IP Optical Networks").
Financial Instruments	Financial Instruments The carrying amounts of Ribbon's financial instruments that approximate their fair values include accounts receivable, equity securities and convertible warrants received as sale consideration, accounts payable and borrowings under a revolving credit facility. Ribbon's term debt balance as of December 31, 2022 of $330.4 million had a fair value of approximately $323.0 million. Financial instruments with remaining maturities or that are due within one year from the balance sheet date are classified as current. Financial instruments with maturities or that are payable more than one year from the balance sheet date are classified as noncurrent.
Fair Value Option - Investment in AVCT	Fair Value Option - Investment in AVCT The Company received debentures and warrants as sale consideration in connection with the sale of the Kandy Communications Business. On September 8, 2021 (the "Debenture Conversion Date"), the debentures were converted into 13,700,421 shares of AVCT common stock (the "Debenture Shares") (see Note 4 for a discussion of the valuation of the debentures, warrants and Debenture Shares). In connection with the conversion of the debentures to the Debenture Shares, the Company elected to use the fair value option to account for its equity investment in AVCT as permitted under Accounting Standards Codification ("ASC") 825, Financial Instruments ("ASC 825"), which then refers to ASC 820, Fair Value Measurement ("ASC 820") to provide the fair value framework for valuing such investments. In accordance with ASC 820, the Company recorded the investment in AVCT at fair value, with changes in fair value recorded as a component of Other (expense) income, net, in the consolidated statements of operations. On August 29, 2022, the Company and AVCT entered into a settlement agreement which provided for, amongst other things, the cancellation of the Company's investment in the Debenture Shares and the Warrants with an aggregate fair value of $2.6 million. Pursuant to the settlement agreements, the Company and AVCT also entered into a Wind Down Agreement, pursuant to which a Reseller Agreement between the parties, as previously amended, was terminated, and the Company was granted a non-exclusive perpetual license to use and modify certain intellectual property owned by AVCT comprising WebRTC gateway technology that is integrated with Ribbon’s SBCs and Application Servers. As consideration, the Company paid AVCT $2.5 million in cash, the Debenture Shares were redeemed and canceled, and the Warrants were terminated and canceled. The perpetual license granted by AVCT is classified as Intangible assets, net in the Company's consolidated balance sheet as of December 31, 2022 in the amount of $3.9 million.
Restricted Cash	Restricted CashThe Company classifies as restricted cash all cash pledged as collateral to secure long-term obligations and all cash whose use is otherwise limited by contractual provisions.
Transfers of Financial Assets	Transfers of Financial AssetsThe Company's IP Optical Networks segment maintains customer receivables factoring agreements with a number of financial institutions. Under the terms of these agreements, the Company may transfer receivables to the financial institutions, on a non-recourse basis, provided that the financial institutions approve the receivables in advance. The Company maintains credit insurance policies from major insurance providers or obtains letters of credit from the customers for a majority of its factored trade receivables. The Company accounts for the factoring of its financial assets as a sale of the assets and records the factoring fees, when incurred, as a component of interest expense in the consolidated statements of operations, and the proceeds from the sales of receivables are included in cash from operating activities in the consolidated statements of cash flows.
Foreign Currency Translation	Foreign Currency Translation For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Accumulated other comprehensive income. For foreign subsidiaries where the functional currency is the U.S. dollar, monetary assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Nonmonetary assets and liabilities are remeasured into U.S. dollars at historical exchange rates. Revenue and expense items are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Other expense (income), net. Realized and unrealized foreign currency exchange gains and losses arising from transactions denominated in currencies other than the subsidiary's functional currency are reflected in earnings. The Company records its foreign currency gains (losses) as a component of Other (expense) income, net.
Inventory	Inventory Inventory is recorded at the lower of cost or market value using the first-in, first-out convention. The Company reduces the carrying value of inventory for those items that are potentially excess, obsolete or slow-moving based on changes in customer demand, technology developments or other economic factors. Ribbon writes down evaluation equipment (equipment at customer sites for testing and evaluation) at the time of shipment to its customers, as it is probable that the inventory value will not be realized. Deferred product costs represent deferred cost of revenue for product shipments to customers prior to satisfaction of Ribbon's revenue recognition criteria. The Company classifies inventory that is not expected to be consumed within one year from the balance sheet date as noncurrent and includes such inventory as a component of Other assets.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, net of accumulated depreciation. Expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, which range from two to five years. Leasehold improvements are amortized over the lesser of the lease term or five years. When an asset is sold or retired, the cost and related accumulated depreciation or amortization are eliminated, and the resulting gain or loss, if any, is recognized in (Loss) income from operations in the consolidated statement of operations. The Company reviews property and equipment for impairment in the same manner as intangible assets discussed below. Software development costs associated with internal use software are incurred in three stages of development: the preliminary project stage, the application development stage and the post-implementation stage. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Certain qualifying costs incurred during the application development stage are capitalized as property and equipment. Internal use software is amortized on a straight-line basis over its estimated useful life of three years, beginning when the software is ready for its intended use.
Intangible Assets and Goodwill	Intangible Assets and Goodwill The Company's intangible assets are comprised of in-process research and development, developed technology, customer relationships, trade names, and internal use software. Intangible assets are reviewed for impairment when events or changes in circumstances indicate that their carrying amounts may not be recoverable based upon the estimated undiscounted cash flows. Recoverability of intangible assets with estimated lives and other long-lived assets is measured by a comparison of the carrying amount of an asset or asset group to future net undiscounted cash flows expected to be generated by the asset or asset group. If these comparisons indicate that an asset is not recoverable, the Company will recognize an impairment loss for the amount by which the carrying value of the asset or asset group exceeds the related estimated fair value. Estimated fair value is based on either discounted future operating cash flows or appraised values, depending on the nature of the asset. The Company amortizes its intangible assets over their respective useful lives, with the exception of in-process research and development, which has an indefinite life until the product is generally available, at which time such asset is typically reclassified to developed technology, and the Company begins to amortize this asset. See Note 10 for additional information regarding the Company's intangible assets. Goodwill is recorded when the consideration for an acquisition exceeds the fair value of net tangible and identifiable intangible assets acquired. Goodwill is not amortized, but instead is tested for impairment at least annually, or more frequently if indicators of potential impairment exist, by comparing the fair value of the Company's reporting unit to its carrying value. The Company's annual test for impairment of goodwill is completed as of October 1. As described above, effective in the fourth quarter of 2020, the Company determined that it has two operating segments: Cloud and Edge, and IP Optical Networks. For the purpose of testing goodwill for impairment, all goodwill is assigned to a reporting unit, which may be either an operating segment or a portion of an operating segment. The Company's reporting units are its operating segments. The Company performs a fair value analysis using both an income and market approach, which encompasses a discounted cash flow analysis and a guideline public company analysis using selected multiples. The Company assesses each valuation methodology based upon the relevance and availability of the data at the time the valuation is performed and the methodologies are weighted appropriately. Any impairment charges are reported separately in the Company's consolidated statements of operations.
Stock-Based Compensation	Stock-Based Compensation The Company's stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which generally represents the vesting period, and includes an estimate of the awards that will be forfeited. The Company uses the Black-Scholes valuation model for estimating the fair value of stock options on the grant date. The fair value of stock option awards is affected by the Company's stock price as well as valuation assumptions, including the volatility of Ribbon's stock price, expected term of the option, risk-free interest rate and expected dividends. The Company may grant to certain of its executives and certain other employees performance-based stock units ("PSUs") that include a market condition. The Company uses a Monte Carlo simulation approach to model future stock price movements based upon the risk-free rate of return, the volatility of each entity and the pair-wise covariance between each entity. These results are then used to calculate the grant date fair values of the PSUs. The Company is required to record expense for the PSUs with market conditions through their respective final vesting dates regardless of the number of shares that are ultimately earned. Once the grant date criteria have been met for a fiscal year performance period, the Company records stock-based compensation expense based on its assessment of the probability that the respective performance condition will be achieved and the level, if any, of such achievement. The Compensation Committee determines the number of shares earned, if any, after the Company's financial results for each fiscal year performance period are finalized. Upon the determination by the Compensation Committee of the number of shares that will be received upon vesting, such number of shares becomes fixed and the unamortized expense is recorded through the remainder of the service period, at which time any Performance PSUs earned, will vest pending each executive's continued employment with the Company through that date.
Concentration of Risk	Concentration of Risk The financial instruments that potentially subject Ribbon to concentrations of credit risk are cash, restricted cash and accounts receivable. The Company's cash equivalents and investments were managed by one financial institution at December 31, 2022. Historically, the Company has not experienced significant losses due to such bank depository concentration. The Company's investments at December 31, 2021 consisted of securities of AVCT (see Note 4). Certain components and software licenses from third parties used in Ribbon's products are procured from single sources of supply. The failure of a supplier, including a subcontractor, to deliver on schedule could delay or interrupt Ribbon's delivery of products and thereby materially adversely affect Ribbon's revenue and operating results.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and included as a component of Sales and marketing expense in the Company's consolidated statements of operations. Advertising expenses were $1.5 million, $1.6 million and $0.8 million for the years ended December 31, 2022, 2021 and 2020, respectively.
Loss Contingencies and Reserves	Loss Contingencies and Reserves Ribbon is subject to ongoing business risks arising in the ordinary course of business, including legal claims, that affect the estimation process of the carrying value of assets, the recording of liabilities and the possibility of various loss contingencies. An estimated loss contingency is accrued when it is probable that a liability has been incurred or an asset has been impaired and the amount of loss can be reasonably estimated. Ribbon regularly evaluates current information available to determine whether such amounts should be adjusted and records changes in estimates in the period they become known. An allowance for doubtful accounts is estimated based on the Company's assessment of the collectability of specific customer accounts. Ribbon accrues for royalties for technology that it licenses from vendors based on established royalty rates and usage. Ribbon is periodically contacted by third parties who claim that Ribbon's products infringe on certain intellectual property of a third party. Ribbon evaluates these claims and accrues amounts when it is probable that the obligation has been incurred and the amounts are reasonably estimable.
Warranty	WarrantyThe Company records warranty liabilities for estimated costs of fulfilling its obligations under standard limited hardware and software warranties at the time of sale. The specific warranty terms and conditions vary depending upon the country in which the Company does business, but generally includes material costs, technical support, labor and associated overhead over a period ranging from one to three years.
Research and Development Grants	Research and Development Grants The Company records grants received from the Office of the Innovation Authority of the Israeli Ministry of Economics (the "IIA") as a reduction to Research and development expense. Royalties payable to the IIA are recognized pursuant to sales of related products and are included in Cost of revenue - product (see Note 25).
Accounting for Leases	Accounting for Leases The Company accounts for its leases in accordance with Accounting Standards Codification ("ASC") 842, Leases ("ASC 842") (see Note 20). The Company has operating and finance leases for corporate offices, research and development facilities, and certain equipment. Operating leases are reported separately in the Company's consolidated balance sheets at December 31, 2022 and 2021. The Company has no finance leases as of December 31, 2022. Assets acquired under finance leases are included in Property and equipment, net, in the consolidated balance sheets at December 31, 2021. The Company determines if an arrangement is a lease at inception. A contract is determined to contain a lease component if the arrangement provides the Company with a right to control the use of an identified asset. Lease agreements may include lease and non-lease components. In such instances for all classes of underlying assets, the Company does not separate lease and non-lease components but rather, accounts for the entire arrangement under leasing guidance. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term. For operating leases, lease expense for minimum fixed lease payments is recognized on a straight-line basis over the lease term. The expense for finance leases includes both interest and amortization expense components, with the interest component calculated based on the effective interest method and the amortization component calculated based on straight-line amortization of the right-of-use asset over the lease term. Lease contracts may contain variable lease costs, such as common area maintenance, utilities and tax reimbursements that vary over the term of the contract. Variable lease costs are not included in minimum fixed lease payments and as a result, are excluded from the measurement of the right-of-use assets and lease liabilities. The Company expenses all variable lease costs as incurred.
Accounting for Income Taxes	Accounting for Income Taxes Deferred tax assets and liabilities are recognized for the expected future consequences of events that have been reflected in the consolidated financial statements. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and operating loss carryforwards, using tax rates expected to be in effect for the years in which the differences are expected to reverse. The Company records valuation allowances to reduce deferred income tax assets to the amount that is more likely than not to be realized. The Company has provided for income taxes on the undistributed earnings of its non-U.S. subsidiaries as of December 31, 2022, excluding Ireland and Israel, which are indefinitely reinvested. Accordingly, the Company is required to recognize and record deferred taxes for 2022 on the entire outside basis differences related to the foreign subsidiaries, the largest of these differences being undistributed earnings. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, no amount of the benefit attributable to the position is recognized. The tax benefit to be recognized of any tax position that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes.
Defined Benefit Plans	Defined Benefit Plans The Company has defined benefit plans for some of its employees at various international locations. The Company recognizes retirement benefit assets or liabilities in the consolidated balance sheets reflecting the funded status of pension and other retirement benefit plans. Retirement benefit assets and liabilities are adjusted for the difference between the benefit obligations and the plan assets at fair value (measured at year-end), with the offset recorded directly to stockholders' equity through accumulated other comprehensive income (loss), net of tax. The amount recorded in stockholders' equity represents the after-tax unamortized actuarial gains or losses, unamortized transition obligations and unamortized prior service costs.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2022, the Financial Accounting Standards Board (the "FASB") issued ASU 2022-02, Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures (“ASU 2022-02”), which eliminates the accounting guidance on troubled debt restructurings ("TDRs") for creditors in ASC 310, Receivables (Topic 310), and requires entities to provide disclosures about current period gross write-offs by year of origination. Also, ASU 2022-02 updates the requirements related to accounting for credit losses under ASC 326, Financial Instruments – Credit Losses (Topic 326), and adds enhanced disclosures for creditors with respect to loan refinancings and restructurings for borrowers experiencing financial difficulty. ASU 2022-02 is effective for the Company January 1, 2023. The Company believes that the adoption of ASU 2022-02 will not have a material impact on its consolidated financial statements upon adoption. In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers ("ASU 2021-08"), which amends ASC 805, Business Combinations (Topic 805), to add contract assets and contract liabilities to the list of exceptions to the recognition and measurement principles that apply to business combinations and to require that an acquiring entity recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC 606, Revenue from Contracts with Customers (Topic 606) ("ASC 606"). Under current GAAP, an acquirer generally recognizes such items at fair value on the acquisition date. While primarily related to contract assets and contract liabilities that were accounted for by the acquiree in accordance with ASC 606, ASU 2021-08 also applies to contract assets and contract liabilities from other contracts to which the provisions of ASC 606 apply, such as contract liabilities from the sale of nonfinancial assets within the scope of ASU 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20). ASU 2021-08 is effective for the Company January 1, 2023. The Company believes that the adoption of ASU 2021-08 could have a material impact on its consolidated financial statements for periods including and subsequent to significant business acquisitions. In January 2021 the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope ("ASU 2021-01"), which refines the scope of ASC 848, Reference Rate Reform, and clarifies some of its guidance as part of the FASB's monitoring of global reference rate reform activities. ASU 2021-01 permits entities to elect certain optional expedients and exceptions when accounting for derivative contracts and certain hedging relationships affected by changes in the interest rates used for discounting cash flows, for computing variation margin settlements, and for calculating price alignment interest in connection with reference rate reform activities under way in global financial markets (the "discounting transition"). In December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 ("ASU 2022-06") which extends the date through which companies can utilize optional expedients and exceptions allowed in Topic 848 from December 31, 2022 to December 31, 2024. The adoption of ASU 2021-01 and ASU 2022-06 did not have a material impact on the Company's consolidated financial statements.

BUSINESS ACQUISITIONS (Tables)

12 Months Ended

Dec. 31, 2022

Business Combinations [Abstract]

Schedule of preliminary allocation of purchase consideration

A summary of the allocation of the purchase consideration for ECI is as follows (in thousands):


Fair value of consideration transferred:
Cash consideration:
Repayment of ECI outstanding debt obligations	$	183,266
Cash paid to selling shareholders	139,244
Payment to selling shareholders from sale of ECI real estate assets	33,400
Less cash and restricted cash acquired	(9,058)
Net cash consideration	346,852
Fair value of Ribbon stock issued	108,550
Fair value of total consideration	$	455,402

Fair value of assets acquired and liabilities assumed:
Current assets, net of cash and restricted cash acquired	$	120,203
Property and equipment	54,913
Intangible assets:
In-process research and development	34,000
Developed technology	111,900
Customer relationships	116,000
Trade names	3,000
Goodwill	191,996
Other noncurrent assets	37,528
Deferred revenue	(4,369)
Other current liabilities	(146,618)
Deferred revenue, net of current	(3,726)
Deferred tax liability	(13,308)
Other long-term liabilities	(46,117)
	$	455,402

Schedule of Unaudited pro forma results


	Year ended December 31,
	2020
	(unaudited)
Revenue	$	869,002
Net income	$	97,036
Diluted earnings per share	$	0.65

Schedule of components of acquisition related costs

The components of Acquisition-, disposal- and integration-related expenses incurred in the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Professional and services fees (acquisition-related)	$	—	$	165	$	13,441
Professional and services fees (disposal-related)	414		329		1,890
Integration-related expenses	5,872		7,138		1,833
	$	6,286	$	7,632	$	17,164

EARNINGS (LOSS) PER SHARE (Tables)

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Abstract]

Schedule of calculations of shares used to compute basic and diluted earnings (loss) per share

The calculations of shares used to compute basic and diluted earnings (loss) per share are as follows (in thousands):


	Year ended December 31,
	2022	2021	2020
Weighted average shares outstanding—basic	156,668	147,575	138,967
Potential dilutive common shares	—	—	5,683
Weighted average shares outstanding—diluted	156,668	147,575	144,650

ACCOUNTS RECEIVABLE, NET (Tables)

12 Months Ended

Dec. 31, 2022

Receivables [Abstract]

Schedule of accounts receivable, net

Accounts receivable, net, consisted of the following (in thousands):


	December 31,
	2022		2021
Accounts receivable	$	268,671	$	284,187
Allowance for doubtful accounts	(1,427)		(1,270)
Accounts receivable, net	$	267,244	$	282,917

Schedule of allowance for doubtful accounts

The Company's allowance for doubtful accounts activity was as follows (in thousands):


Year ended December 31,	Balance at beginning of year		Charges to expense		Charges (credits) to other accounts		Write-offs		Balance at end of year
2022	$	1,270	$	100	$	159	$	(102)	$	1,427
2021	$	776	$	553	$	85	$	(144)	$	1,270
2020	$	913	$	686	$	94	$	(917)	$	776

INVENTORY (Tables)

12 Months Ended

Dec. 31, 2022

Inventory Disclosure [Abstract]

Schedule of inventory

Inventory consisted of the following (in thousands):


	December 31,
	2022		2021
On-hand final assemblies and finished goods inventories	$	85,888	$	57,360
Deferred cost of goods sold	1,449		1,474
	87,337		58,834
Less noncurrent portion (included in Other assets)	(11,914)		(4,791)
Current portion	$	75,423	$	54,043

PROPERTY AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2022

Property, Plant and Equipment [Abstract]

Schedule of property and equipment

Property and equipment consisted of the following (in thousands):


		December 31,
	Useful Life	2022		2021
Equipment	2-5 years	$	76,674	$	74,769
Software	2-5 years	33,639		32,804
Furniture and fixtures	3-5 years	3,168		3,188
Leasehold improvements	Shorter of the estimated lease term or useful life	35,448		34,640
		148,929		145,401
Less accumulated depreciation and amortization		(104,097)		(97,716)
Property and equipment, net		$	44,832	$	47,685

Property and equipment under finance leases included in the amounts above were as follows (in thousands):


	December 31,
	2022		2021
Cost	$	—	$	2,050
Less accumulated depreciation	—		(1,763)
Property and equipment under finance leases, net	$	—	$	287

The net book values of the Company's property and equipment by geographic area were as follows (in thousands):


	December 31,
	2022		2021
United States	$	23,143	$	24,683
Canada	3,471		5,184
Asia/Pacific	8,152		8,174
Europe	833		1,157
Israel	8,860		7,859
Other	373		628
	$	44,832	$	47,685

INTANGIBLE ASSETS AND GOODWILL (Tables)

12 Months Ended

Dec. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of intangible assets

The Company's intangible assets at December 31, 2022 and 2021 consisted of the following (in thousands):


December 31, 2022	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
Developed technology	7.84	$	340,380	$	212,448	$	127,932
Customer relationships	11.86	268,140		106,385		161,755
Trade names	3.88	5,000		4,658		342
Software licenses	3.00	5,186		487		4,699
	9.51	$	618,706	$	323,978	$	294,728


December 31, 2021	Weighted average amortization period (years)	Cost		Accumulated amortization		Net carrying value
In-process research and development	*	$	34,000	$	—	$	34,000

Developed technology	7.93	306,380		181,393		124,987
Customer relationships	11.86	268,140		77,653		190,487
Trade names	3.88	5,000		3,744		1,256

Internal use software	3.00	730		730		—
	9.17	$	614,250	$	263,520	$	350,730

Schedule of estimated future amortization expense for intangible assets

Estimated future amortization expense for the Company's intangible assets at December 31, 2022 was as follows (in thousands):


Years ending December 31,
2023	$	56,882
2024	50,717
2025	44,006
2026	38,965
2027	33,936
Thereafter	70,222
	$	294,728

Schedule of goodwill

The changes in the carrying value of the Company's goodwill in the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Cloud and Edge		IP Optical Networks		Total
Balance at January 1, 2021 (1)	$	224,896	$	191,996	$	416,892
Impairment of goodwill	—		(116,000)		(116,000)
Balance at December 31, 2021 (1)(2)	224,896		75,996		300,892
Activity	—		—		—
Balance at December 31, 2022 (1)(2)	$	224,896	$	75,996	$	300,892

(1) Balance is presented net of accumulated impairment losses of $167.4 million for the Cloud and Edge segment.

(2) Balance is presented net of an impairment loss of $116.0 million for the IP Optical Networks segment.

The components of goodwill at December 31, 2021 and 2022 were as follows (in thousands):


	Cloud and Edge		IP Optical Networks		Total
Balance at December 31, 2021
Goodwill	$	392,302	$	191,996	$	584,298
Accumulated impairment losses	(167,406)		(116,000)		(283,406)
	224,896		75,996		300,892
Balance at December 31, 2022
Goodwill	$	392,302	$	191,996	$	584,298
Accumulated impairment losses	(167,406)		(116,000)		(283,406)
	$	224,896	$	75,996	$	300,892

- Definition

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

+ Details

ACCRUED EXPENSES AND OTHER (Tables)

12 Months Ended

Dec. 31, 2022

Payables and Accruals [Abstract]

Schedule of accrued expenses

Accrued expenses and other consisted of the following (in thousands):


	December 31,
	2022		2021
Employee compensation and related costs	$	25,994	$	38,040
Professional fees	17,195		14,365
Other	42,081		48,347
	$	85,270	$	100,752

WARRANTY (Tables)

12 Months Ended

Dec. 31, 2022

Guarantees and Product Warranties [Abstract]

Schedule of changes in accrual balance

The changes in the Company's warranty accrual balance in the years ended December 31, 2022 and 2021 were as follows (in thousands):


Year ended December 31,	Balance at beginning of year		Provision		Settlements		Balance at end of year
2022	$	13,120	$	4,605	$	(5,868)	$	11,857
2021	$	14,855	$	3,777	$	(5,512)	$	13,120

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES (Tables)

12 Months Ended

Dec. 31, 2022

Restructuring and Related Activities [Abstract]

Schedule of restructuring accrual activity

The components of restructuring and related expense for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Severance and related costs	$	5,230	$	4,618	$	12,025
Variable and other facilities-related costs	3,992		5,710		3,605
Accelerated amortization of lease assets due to cease-use	1,611		1,325		605
	$	10,833	$	11,653	$	16,235

A summary of the 2022 Restructuring Plan accrual activity for the year ended December 31, 2022 is as follows (in thousands):


	Balance at January 1, 2022		Initiatives charged to expense		Cash payments		Net transfer to operating lease accounts		Balance at December 31, 2022
Severance	$	—	$	5,287	$	(4,123)	$	—	$	1,164
Variable and other facilities-related costs	—		3,299		(2,409)		—		890
Accelerated amortization of lease assets due to cease-use	—		1,611		—		(1,611)		—
	$	—	$	10,197	$	(6,532)	$	(1,611)	$	2,054

Summaries of the 2020 Restructuring Initiative accrual activity for the years ended December 31, 2022 and 2021 are as follows (in thousands):


Year ended December 31, 2022	Balance at January 1, 2022		Initiatives charged to expense		Adjustments for changes in estimate		Cash payments		Balance at December 31, 2022
Severance	$	1,895	$	—	$	(57)	$	(1,782)	56
Facilities	60		34		—		(94)		—
	$	1,955	$	34	$	(57)	$	(1,876)	$	56


Year ended December 31, 2021	Balance at January 1, 2021		Initiatives charged to expense		Adjustments for changes in estimate		Cash payments		Balance at December 31, 2021
Severance	$	5,237	$	4,618	$	—	$	(7,960)	1,895
Facilities	1,256		742		(670)		(1,268)		60
	$	6,493	$	5,360	$	(670)	$	(9,228)	$	1,955

Summaries of the 2019 Restructuring Initiative accrual activity for the years ended December 31, 2022 and 2021 are as follows (in thousands):


Year ended December 31, 2022	Balance at January 1, 2022		Initiatives charged to expense		Net transfer to operating lease liability accounts				Cash payments				Balance at December 31, 2022
Severance	$	—	$	—	$	—			$	—			$	—
Facilities	1,594		658		—				(1,004)				1,248
	$	1,594	$	658	$	—	$	—	$	(1,004)	$	—	$	1,248


Year ended December 31, 2021	Balance at January 1, 2021		Initiatives charged to expense		Adjustments for changes in estimate		Net transfer to operating lease liability accounts		Cash payments		Balance at December 31, 2021
Severance	$	173	$	—	$	—	$	—	$	(173)	$	—
Facilities	766		9,006		(2,043)		(1,325)		(4,810)		1,594
	$	939	$	9,006	$	(2,043)	$	(1,325)	$	(4,983)	$	1,594

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Tables)

12 Months Ended

Dec. 31, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of impact of derivative financial instrument on condensed consolidated statement of operations


		Year ended December 31,
	2022			2021
Gain recognized in other comprehensive income (loss) on interest rate swap, net of tax		$	22,456		$	9,505
Amount reclassified from accumulated other comprehensive income (loss) to interest expense		(3,135)			3,254
Unrealized gain (loss) on interest rate swap, net of reclassifications and amortization		$	19,321		$	12,759

Schedule of derivative liability designed as a hedging instrument


		December 31,
	Balance sheet location	2022		2021
Interest rate derivative - asset derivative	Other current assets	$	13,212	$	—
Interest rate derivative - asset derivative	Other assets	12,216		3,865
Interest rate derivative - liability derivative	Accrued expenses and other	—		(2,054)
Interest rate derivative - liability derivative	Other long-term liabilities	—		—
		$	25,428	$	1,811

REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2022

Revenue from Contract with Customer [Abstract]

Schedule of timing of performance obligation

The Company's typical performance obligations include the following:

Performance Obligation

When Performance Obligation is Typically Satisfied

When Payment is Typically Due

Software and Product Revenue

Software licenses (perpetual or term)

Upon transfer of control; typically, when made available for download (point in time)

Generally, within 30 days of invoicing except for term licenses, which may be paid for over time

Software licenses (subscription)

Upon activation of hosted site (over time)

Generally, within 30 days of invoicing

Hardware

When control of the hardware passes to the customer; typically, upon delivery (point in time)

Generally, within 30 days of invoicing

Software upgrades

Upon transfer of control; typically, when made available for download (point in time)

Generally, within 30 days of invoicing

Customer Support Revenue

Customer support

Ratably over the course of the support contract (over time)

Generally, within 30 days of invoicing

Professional Services

Other professional services (excluding training services)

As work is performed (over time)

Generally, within 30 days of invoicing (upon completion of services)

Training

When the class is taught (point in time)

Generally, within 30 days of services being performed

Schedule of Disaggregation of revenue

The Company's total revenue for the years ended December 31, 2022, 2021 and 2020 was disaggregated geographically as follows:


Year ended December 31, 2022	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	175,189	$	132,655	$	44,819	$	352,663
Europe, Middle East and Africa	147,523		75,948		29,310		252,781

Asia Pacific	95,828		41,677		13,594		151,099
Other	24,140		31,815		7,262		63,217
	$	442,680	$	282,095	$	94,985	$	819,760


Year ended December 31, 2021	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	196,058	$	132,683	$	47,296	$	376,037
Europe, Middle East and Africa	138,203		79,475		30,349		248,027

Asia Pacific	92,803		41,945		18,183		152,931
Other	25,978		32,218		9,766		67,962
	$	453,042	$	286,321	$	105,594	$	844,957


Year ended December 31, 2020	Product revenue		Service revenue (maintenance)		Service revenue (professional services)		Total revenue
United States	$	201,347	$	132,661	$	48,611	$	382,619
Europe, Middle East and Africa	149,567		73,475		25,226		248,268

Asia Pacific	90,201		36,628		19,627		146,456
Other	26,797		32,052		7,603		66,452
	$	467,912	$	274,816	$	101,067	$	843,795


	Year ended December 31,
	2022		2021		2020
Indirect sales through channel program	$	131,998	$	117,065	$	134,876
Direct sales	310,682		335,977		333,036
	$	442,680	$	453,042	$	467,912

The Company's product revenue from sales to enterprise customers and from sales to service provider customers for the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Sales to enterprise customers	$	125,664	$	111,494	$	138,469
Sales to service provider customers	317,016		341,548		329,443
	$	442,680	$	453,042	$	467,912

The Company's product revenue and service revenue components by segment for the years ended December 31, 2022, 2021 and 2020 was as follows (in thousands):


	Year ended December 31,
	2022	2021	2020
Product revenue
Cloud and Edge	215,770	248,570	275,445
IP Optical Networks	226,910	204,472	192,467
Total product revenue	442,680	453,042	467,912

Service revenue
Maintenance
Cloud and Edge	222,238	228,321	229,035
IP Optical Networks	59,857	58,000	45,781
Total maintenance revenue	282,095	286,321	274,816
Professional services
Cloud and Edge	70,130	79,765	78,790
IP Optical Networks	24,855	25,829	22,277
Total professional services revenue	94,985	105,594	101,067
Total service revenue	377,080	391,915	375,883

Schedule of customer assets and liabilities

The changes in the Company's accounts receivable, unbilled receivables and deferred revenue balances for the years ended December 31, 2022 and 2021 were as follows (in thousands):


	Accounts receivable		Unbilled accounts receivable		Deferred revenue (current)		Deferred revenue (long-term)
Balance at January 1, 2022	$	208,972	$	73,945	$	109,119	$	20,619
Increase (decrease), net	(38,003)		22,330		4,820		(1,365)
Balance at December 31, 2022	$	170,969	$	96,275	$	113,939	$	19,254


	Accounts receivable		Unbilled accounts receivable		Deferred revenue (current)		Deferred revenue (long-term)
Balance at January 1, 2021	$	179,331	$	58,407	$	96,824	$	26,010
Increase (decrease), net	29,641		15,538		12,295		(5,391)
Balance at December 31, 2021	$	208,972	$	73,945	$	109,119	$	20,619

OPERATING SEGMENT INFORMATION (Tables)

12 Months Ended

Dec. 31, 2022

Segment Reporting [Abstract]

Schedule of Segment Reporting Information

The tables below provide revenue, adjusted gross profit and depreciation expense by reportable segment for the years ended December 31, 2022, 2021 and 2020 (in thousands):


	Year ended December 31,
Revenue	2022		2021		2020
Segment revenue:
Cloud and Edge	$	508,137	$	556,656	$	583,270
IP Optical Networks	311,623		288,301		260,525
Total revenue	$	819,760	$	844,957	$	843,795



	Year ended December 31,
Adjusted gross profit	2022		2021		2020
Segment adjusted gross profit:
Cloud and Edge	$	330,395	$	370,504	$	385,137
IP Optical Networks	104,711		114,496		110,845
Total segment adjusted gross profit	435,106		485,000		495,982


Stock-based compensation expense	(2,628)		(1,997)		(875)
Amortization of acquired technology	(31,542)		(38,343)		(42,290)
Acquisition-related inventory and facilities adjustments	—		—		(2,000)


Gross profit	$	400,936	$	444,660	$	450,817

























	Year ended December 31,
Depreciation expense	2022		2021		2020
Segment depreciation expense:
Cloud and Edge	$	10,758	$	12,269	$	12,111
IP Optical Networks	4,537		4,693		5,077
Total depreciation expense	$	15,295	$	16,962	$	17,188

MAJOR CUSTOMERS (Tables)

12 Months Ended

Dec. 31, 2022

Risks and Uncertainties [Abstract]

Schedule of customers contributing 10% or more of the revenue

The following customers contributed 10% or more of the Company's revenue in at least one of the years ended December 31, 2022, 2021 and 2020:


	Year ended December 31,
	2022	2021	2020
Verizon Communications Inc.	15%	16%	15%

STOCK-BASED COMPENSATION PLANS (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Schedule of activity related to unvested restricted stock grants

The activity related to the Company's RSUs for the year ended December 31, 2022 was as follows:


	Shares	Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2022	5,389,611	$	6.19
Granted	6,096,248	$	3.09

Vested	(3,075,543)	$	5.87
Forfeited	(760,569)	$	5.05
Unvested balance at December 31, 2022	7,649,747	$	3.96

Schedule of activity related to performance stock awards

The activity related to the Company's PSUs for the year ended December 31, 2022 was as follows:


	Shares	Weighted Average Grant Date Fair Value
Unvested balance at January 1, 2022	4,987,876	$	2.87
Granted	2,228,073	$	3.27

Vested	(179,184)	$	5.02
Forfeited	(383,262)	$	7.82
Unvested balance at December 31, 2022	6,653,503	$	2.52

Schedule of stock-based compensation expenses which are included in condensed consolidated statement of operations

The consolidated statements of operations included stock-based compensation for the years ended December 31, 2022, 2021 and 2020 as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Product cost of revenue	$	471	$	313	$	174
Service cost of revenue	2,157		1,684		701
Research and development	5,108		4,253		2,968
Sales and marketing	6,074		7,218		4,129
General and administrative	4,897		5,950		5,927
	$	18,707	$	19,418	$	13,899

LEASES (Tables)

12 Months Ended

Dec. 31, 2022

Leases [Abstract]

Schedule of right-of-use lease assets and lease liabilities

The Company's right-of-use lease assets and lease liabilities at December 31, 2022 and 2021 were as follows (in thousands):


		December 31,
	Classification	2022		2021
Assets:
Operating lease assets	Operating lease right-of-use assets	$	44,888	$	53,147
Finance lease assets*	Property and equipment, net	—		287
Total leased assets		$	44,888	$	53,434

Liabilities:
Current:
Operating	Operating lease liabilities	$	15,416	$	17,403
Finance	Accrued expenses and other	—		503
Noncurrent:
Operating	Operating lease liabilities, net of current	46,183		55,196
Finance	Other long-term liabilities	—		64
Total lease liabilities		$	61,599	$	73,166

* Finance lease assets were fully depreciated at December 31, 2022 and were recorded net of accumulated depreciation of $1.8 million at December 31, 2021.

Schedule of components of lease expense

The components of lease expense for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020

Operating lease cost*	$	21,121	$	21,828	$	19,582
Finance lease cost:
Amortization of leased assets	287		695		1,200
Interest on lease liabilities	13		67		173
Short-term lease cost	14,209		13,250		20,687
Variable lease costs (costs excluded from minimum fixed lease payments)**	4,007		4,030		2,713
Sublease income	(1,647)		(1,496)		(1,087)
Net lease cost	$	37,990	$	38,374	$	43,268

Cash flow information related to the Company's leases for the years ended December 31, 2022 and 2021 was as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	20,363	$	22,365	19,161
Operating cash flows from finance leases	$	13	$	67	173
Financing cash flows from finance leases	$	595	$	903	1,279

Other information related to the Company's leases as of December 31, 2022 and 2021 was as follows (in thousands):


	December 31,
	2022		2021


Weighted average remaining lease term (years):
Operating leases	5.90		6.25
Finance leases	—		1.00
Weighted average discount rate:
Operating leases	5.79	%	5.61	%
Finance leases	—		4.15	%

Schedule of future minimum fixed operating lease payments

Future minimum fixed lease payments under noncancelable leases at December 31, 2022 were as follows (in thousands):


	December 31, 2022
	Operating		Finance
	leases		leases
2023	$	18,384	$	—
2024	15,380		—
2025	8,249		—
2026	7,110		—
2027	6,429		—
2028 and beyond	18,210		—
Total lease payments	73,762		—
Less: interest	(12,163)		—
Present value of lease liabilities	$	61,599	$	—

Schedule of future minimum fixed finance lease payments

Future minimum fixed lease payments under noncancelable leases at December 31, 2022 were as follows (in thousands):


	December 31, 2022
	Operating		Finance
	leases		leases
2023	$	18,384	$	—
2024	15,380		—
2025	8,249		—
2026	7,110		—
2027	6,429		—
2028 and beyond	18,210		—
Total lease payments	73,762		—
Less: interest	(12,163)		—
Present value of lease liabilities	$	61,599	$	—

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

Schedule of changes in projected benefit obligations, fair value of plan assets, and funded status of plan


	Year ended December 31,
	2022		2021
Changes in projected benefit obligations:
Projected benefit obligation, beginning of year	$	26,938	$	25,067
Service cost	1,355		1,321
Interest cost	563		523
Participant contributions	—		—
Plan amendments	—		(3,801)

Net actuarial (gain) loss on obligation	(5,604)		4,868
Settlement	(1,063)		—
Benefits and expenses paid	(932)		(1,040)
Projected benefit obligation, end of year	$	21,257	$	26,938

Changes in plan assets:
Fair value of plan assets, beginning of year	$	15,303	$	14,350

Actual return on plan assets	(672)		981

Employer contributions	1,954		989
Participant contributions	39		23
Benefits paid	(1,995)		(1,040)
Fair value of plan assets, end of year	$	14,629	$	15,303

Funded status at end of year	$	(6,628)	$	(11,635)

Amounts recognized in accumulated other comprehensive income consist of:
Prior service (credit) cost	$	(3,481)	$	(3,801)
Net actuarial (gain) loss	(1,704)		4,045
	$	(5,185)	$	244

Amounts recognized in the consolidated balance sheets consist of:
Other assets (non-current pension asset)	$	552	$	—
Accrued expenses and other (current pension liability)	(803)		(461)
Other long-term liabilities (non-current pension liability)	(6,377)		(11,174)
Net amount recognized	$	(6,628)	$	(11,635)

Schedule of accumulated benefit obligations

Plans with underfunded or non-funded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	9,450	$	26,938
Aggregate accumulated benefit obligation	$	7,418	$	20,695
Aggregate fair value of plan assets	$	2,270	$	15,303

Plans with overfunded accumulated benefit obligations at December 31, 2022 and 2021 were as follows (in thousands):


	December 31,
	2022		2021
Aggregate projected benefit obligation	$	11,807	$	—
Aggregate accumulated benefit obligation	$	9,547	$	—
Aggregate fair value of plan assets	$	12,359	$	—

Schedule of net benefit costs

Net periodic benefit costs for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Service cost	$	1,355	$	1,321	$	1,459
Interest cost	563		523		46
Expected return on plan assets	(266)		(314)		(343)
Plan asset expenses	—		—		—


Settlement charge (credit)	808		—		(1,557)
Amortization of prior service cost	(320)		—		—
Amortization of net loss	275		81		20
Net periodic benefit costs	$	2,415	$	1,611	$	(375)

Schedule of expected benefit payments

Expected benefit payments for the next ten years are as follows (in thousands):


Years ending December 31,
2023	$	2,863
2024	1,314
2025	1,562
2026	1,315
2027	1,584
2028 to 2032	11,326
	$	19,964

Schedule of defined benefit plan amounts recognized in other comprehensive income (loss)

The changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before tax for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Net (gain) loss	$	(4,666)	$	4,201	$	(503)


Prior service (credit) cost	—		(3,801)		—
Amortization of net gain (loss)	(275)		(81)		(20)
Amortization of prior service credit (cost)	320		—		—
Settlement (charge) credit	(808)		—		(1,557)
Total recognized in other comprehensive income (loss)	$	(5,429)	$	319	$	(2,080)

Schedule of assumptions used

The principal weighted average assumptions used to determine the benefit obligation at December 31, 2022 and 2021 were as follows:


	December 31,
	2022		2021
Discount rate	4.74	%	2.24	%
Rate of compensation increase	4.02	%	3.90	%

The principal weighted average assumptions used to determine net period benefit cost for the years ended December 31, 2022, 2021 and 2020 were as follows:


	Year ended December 31,
	2022		2021		2020
Discount rate	2.24	%	2.16	%	0.68	%
Expected long-term return on plan assets	1.79	%	2.06	%	0.21	%
Rate of compensation increase	3.90	%	2.41	%	2.88	%

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of income (loss) before taxes

The components of (loss) income from continuing operations before income taxes consisted of the following (in thousands):


	Year ended December 31,
	2022		2021		2020
(Loss) income before income taxes:
United States	$	(84,784)	$	(29,985)	$	123,817
Foreign	(27,815)		(178,158)		(30,500)
	$	(112,599)	$	(208,143)	$	93,317

Schedule of income tax expense (benefit)

The (benefit) provision for income taxes from continuing operations consisted of the following (in thousands):


	Year ended December 31,
	2022		2021		2020
(Benefit) provision for income taxes:
Current:
Federal	$	(3,582)	$	5,033	$	677
State	2,573		1,836		1,310
Foreign	4,744		7,661		7,355
Total current	3,735		14,530		9,342
Deferred:
Federal	(10,333)		(38,027)		1,957
State	(4,045)		97		(15)
Foreign	(3,873)		(7,558)		(6,558)
Total deferred	(18,251)		(45,488)		(4,616)
Total	$	(14,516)	$	(30,958)	$	4,726

Schedule of effective income tax rate reconciliation

A reconciliation of the Company's effective tax rate for continuing operations to the U.S. statutory federal rate is as follows:


	Year ended December 31,
	2022		2021		2020
U.S. statutory income tax rate	21.0	%	21.0	%	21.0	%
State income taxes, net of federal benefit	1.8		(0.7)		1.1
Foreign income taxes	(1.4)		0.5		0.2
Stock-based compensation	(2.4)		(0.1)		1.0
Tax credits	2.2		1.6		(2.8)
Uncertain tax positions	1.3		0.5		0.5
Valuation allowance	(3.8)		2.5		(20.3)
Non-deductible goodwill impairment	—		(11.7)		—
Other permanent adjustments	(2.6)		0.9		1.8
Permanent foreign exchange adjustments	(1.4)		0.5		1.8
Other, net	(1.8)		(0.1)		0.8
Effective income tax rate	12.9	%	14.9	%	5.1	%

Summary of deferred tax assets and liabilities

The following is a summary of the significant components of deferred income tax assets and liabilities (in thousands):


	December 31,
	2022		2021
Assets:
Net operating loss carryforwards	$	413,773	$	437,669
Capital loss carryforwards	99,505		79,716
Tax credit carryforwards	28,902		23,450
Capitalized research and development expenses	40,668		18,106
Deferred revenue	3,510		3,472
Accrued expenses	9,068		7,505
Inventory	2,820		3,102
Stock-based compensation	1,709		1,689
Fixed assets	2,506		2,710
Lease liabilities	12,829		15,250
Mark-to-market investments	—		1,714
Other temporary differences	1,324		3,839
	616,614		598,222
Valuation allowance	(488,550)		(471,515)
Total deferred tax assets	128,064		126,707
Liabilities:
Intangible assets	(55,037)		(65,647)
Operating lease right-of-use assets	(8,519)		(10,370)
Interest rate swap	(6,168)		—
Unremitted foreign income	(8,441)		(11,519)
Total deferred tax liabilities	(78,165)		(87,536)
Total net deferred tax assets	$	49,899	$	39,171

The deferred tax assets and liabilities based on tax jurisdictions are presented in the Company's consolidated balance sheets as follows:


	December 31,
	2022		2021
Deferred income taxes - net noncurrent assets	$	53,649	$	47,287
Deferred income taxes - net noncurrent liabilities	(3,750)		(8,116)
	$	49,899	$	39,171

Schedule of unrecognized tax benefits

A reconciliation of the Company's unrecognized tax benefits is as follows (in thousands):


	Year ended December 31,
	2022		2021		2020
Unrecognized tax benefits at January 1	$	17,813	$	14,054	$	2,932
Increases related to current year tax positions	156		4,017		485
Increases related to prior period tax positions	40		3,168		11,209
Decreases related to the lapse of the applicable statute of limitations	(560)		(3,087)		(122)
Decreases related to prior period tax positions	$	(5,448)	$	(339)	$	(450)
Unrecognized tax benefits at December 31	$	12,001	$	17,813	$	14,054

QUARTERLY RESULTS (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2022

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information

In the opinion of management, all necessary adjustments, consisting only of normal recurring adjustments, have been included to present fairly the unaudited consolidated quarterly results when read in conjunction with the Company's audited consolidated financial statements and related notes.


	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(In thousands, except per share data)
Year ended December 31, 2022
Revenue	$	173,198	$	205,796	$	207,127	$	233,639
Cost of revenue	95,143		101,246		102,809		119,626
Gross profit	$	78,055	$	104,550	$	104,318	$	114,013
(Loss) income from operations	$	(39,054)	$	(7,239)	$	(3,296)	$	1,265
Net (loss) income	$	(69,975)	$	(30,180)	$	(18,416)	$	20,488
(Loss) earnings per share (2):
Basic	$	(0.47)	$	(0.20)	$	(0.12)	$	0.12
Diluted	$	(0.47)	$	(0.20)	$	(0.12)	$	0.12
Shares used in computing (loss) earnings per share:
Basic	149,167		150,190		158,921		168,163
Diluted	149,167		150,190		158,921		172,213


	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
	(In thousands, except per share data)
Year ended December 31, 2021
Revenue	$	192,772	$	211,210	$	210,398	$	230,577
Cost of revenue (1)	92,286		92,483		99,744		115,784
Gross profit (1)	$	100,486	$	118,727	$	110,654	$	114,793
Loss (income) from operations	$	(12,604)	$	12,952	$	1,992	$	(120,136)
Net (loss) income	$	(44,687)	$	23,241	$	(59,431)	$	(96,308)
Loss (earnings) per share (2):
Basic	$	(0.31)	$	0.16	$	(0.40)	$	(0.65)
Diluted	$	(0.31)	$	0.15	$	(0.40)	$	(0.65)
Shares used in computing loss (earnings) per share:
Basic	145,936		147,467		148,184		148,675
Diluted	145,936		154,160		148,184		148,675

__________________________________

NATURE OF THE BUSINESS (Details)	Dec. 31, 2022 country
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of countries (over)	30

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Aug. 12, 2022 USD ($) $ / shares shares	Sep. 08, 2021 shares	Dec. 31, 2022 USD ($) segment $ / shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($)	Aug. 29, 2022 USD ($)	Dec. 01, 2020 USD ($)
Property, Plant and Equipment [Line Items]
Common stock, par value (in dollars per share) \| $ / shares			$ 0.0001	$ 0.0001
Offering expenses paid			$ 1,654	$ 0	$ 0
Maximum measurement period from the acquisition date within which company records adjustments to the assets acquired and liabilities assumed (in years)			1 year
Revenue agreement term (in years)			1 year
Number of operating segments \| segment			2
Term debt balance			$ 330,493	344,453
Fair value of debt			323,000
Intangible assets, net			294,728	350,730
Restricted cash			161	2,570
Cash received from the sale of certain accounts receivable			73,400	118,500
Interest expense			1,100	800
Foreign currency exchange losses			1,576	5,002	2,961
Advertising expense			1,500	1,600	800
Accrued expenses and other			5,300	5,900
Other long-term liabilities			6,600	7,200
Warranty			$ 11,857	13,120	14,855
Percent threshold (as a percent)			50.00%
General and Administrative Expense
Property, Plant and Equipment [Line Items]
Foreign currency exchange losses			$ 1,600	5,000	$ 3,000
Restricted Short-term Bank Deposits
Property, Plant and Equipment [Line Items]
Restricted cash			$ 200
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			5 years
Internal use software
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			3 years
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			2 years
Standard product warranty period (in years)			1 year
Minimum \| Internal use software
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			5 years
Standard product warranty period (in years)			3 years
Maximum \| Internal use software
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)			5 years
Licensing Agreements
Property, Plant and Equipment [Line Items]
Intangible assets, net			$ 4,699
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Property, Plant and Equipment [Line Items]
Fair value of AVCT units			0			$ 2,600
Payments for settlement agreement						$ 2,500
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Licensing Agreements
Property, Plant and Equipment [Line Items]
Intangible assets, net			$ 3,900
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Kandy Communications Business
Property, Plant and Equipment [Line Items]
Debt conversion, converted instrument, shares issued (in shares) \| shares		13,700,421
Fair value of AVCT units				$ 43,900			$ 84,900
Operating Segments
Property, Plant and Equipment [Line Items]
Number of operating segments \| segment			2
Private Placement
Property, Plant and Equipment [Line Items]
Sale of stock, number of shares issued in transaction (in shares) \| shares	17,071,311
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001
Sale of stock (in dollars per share) \| $ / shares	$ 3.05
Sale of stock, consideration received on transaction	$ 52,100
Offering expenses paid	1,700
Private Placement \| Majority Shareholder
Property, Plant and Equipment [Line Items]
Sale of stock, consideration received on transaction	$ 10,000

BUSINESS ACQUISITIONS - ECI Narrative (Details) - USD ($) shares in Millions		12 Months Ended
	Nov. 14, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Net cash consideration		$ 0	$ 0	$ 346,852,000
Term Loan Facility
Business Acquisition [Line Items]
Commitments from lender	$ 400,000,000
Revolving Credit Facility
Business Acquisition [Line Items]
Commitments from lender	100,000,000
ECI
Business Acquisition [Line Items]
Proceeds from sale of real estate assets	$ 33,400,000
Revenue				260,500,000
Net loss				$ 52,900,000
ECI
Business Acquisition [Line Items]
Common stock to be issued (in shares)	32.5
Fair value of Ribbon stock issued	$ 108,600,000	108,550,000
Net cash consideration	322,500,000	346,852,000
Repayment of ECI outstanding debt obligations	183,300,000
Payment to selling shareholders	$ 139,200,000	$ 139,244,000
Weighted average useful life of intangible assets (in years)		12 years 4 months 17 days

BUSINESS ACQUISITIONS - Schedule of Preliminary Allocation of Purchase Consideration (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 14, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash consideration:
Net cash consideration		$ 0	$ 0	$ 346,852
Fair value of assets acquired and liabilities assumed:
Goodwill		300,892	$ 300,892	$ 416,892
ECI
Cash consideration:
Repayment of ECI outstanding debt obligations		183,266
Cash paid to selling shareholders	$ 139,200	139,244
Payment to selling shareholders from sale of ECI real estate assets		33,400
Less cash and restricted cash acquired		(9,058)
Net cash consideration	322,500	346,852
Fair value of Ribbon stock issued	$ 108,600	108,550
Fair value of total consideration		455,402
Fair value of assets acquired and liabilities assumed:
Current assets, net of cash and restricted cash acquired		120,203
Property and equipment		54,913
Goodwill		191,996
Other noncurrent assets		37,528
Deferred revenue		(4,369)
Other current liabilities		(146,618)
Deferred revenue, net of current		(3,726)
Deferred tax liability		(13,308)
Other long-term liabilities		(46,117)
Assets acquired and liabilities assumed		455,402
ECI \| In-process research and development
Fair value of assets acquired and liabilities assumed:
Intangible assets		34,000
ECI \| Developed technology
Fair value of assets acquired and liabilities assumed:
Intangible assets		111,900
ECI \| Customer relationships
Fair value of assets acquired and liabilities assumed:
Intangible assets		116,000
ECI \| Trade names
Fair value of assets acquired and liabilities assumed:
Intangible assets		$ 3,000

BUSINESS ACQUISITIONS - Schedule of Unaudited Pro Forma Results (Details) - ECI $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares
Business Acquisition [Line Items]
Revenue	$ 869,002
Net income	$ 97,036
Diluted earnings per share (in dollars per share) \| $ / shares	$ 0.65

BUSINESS ACQUISITIONS - Schedule of Acquisition- and Integration-related Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Professional and services fees (acquisition-related)	$ 0	$ 165	$ 13,441
Professional and services fees (disposal-related)	414	329	1,890
Integration-related expenses	5,872	7,138	1,833
Acquisition- and integration-related	$ 6,286	$ 7,632	$ 17,164

SALE OF KANDY COMMUNICATIONS BUSINESS (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Sep. 08, 2021 shares	Feb. 19, 2021 day $ / shares	Dec. 01, 2020 USD ($) day $ / shares shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 29, 2022 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Decrease (increase) in fair value of investments				$ (41,291)	$ (71,252)	$ 30,296
Intangible assets, net				294,728	$ 350,730
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]						Other (expense) income, net
Variable Interest Entity, Not Primary Beneficiary \| AVCT Investment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity interest (as a percent)					15.00%
Licensing Agreements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Intangible assets, net				4,699
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Fair value of AVCT units				0			$ 2,600
Decrease (increase) in fair value of investments				(41,300)
Payments for settlement agreement							$ 2,500
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Licensing Agreements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Intangible assets, net				$ 3,900
Kandy Communications Business \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale			$ 45,000
Principal amount of debentures			$ 1
Number of warrants acquired (in shares) \| shares			1
Number of shares entitled from warrant (in shares) \| shares			100
Par value of common stock (in dollars per share) \| $ / shares			$ 0.0001
Number of AVCT Units acquired (in shares) \| shares			43,778
Interest rate (as a percent)			10.00%
Debenture, conversion price (in dollars per share) \| $ / shares			$ 3.45
Debenture, stock price trigger (in dollars per share) \| $ / shares		$ 6.00	$ 6.00
Debenture, number of trading days \| day		40	40
Debenture, number of consecutive trading days \| day		60	60
Debt conversion, converted instrument, shares issued (in shares) \| shares	13,700,421
Number of shares of common stock entitled from warrants (in shares) \| shares			4,377,800
Exercise price of warrants (in dollars per share) \| $ / shares			$ 0.01
Fair value of AVCT units			$ 84,900		$ 43,900
Fair value of debentures			66,300
Fair value of warrants			18,600
Net assets sold			$ 1,300
Gain on sale						$ 83,600
Decrease (increase) in fair value of investments					(74,800)	$ 30,300
Loss partially offset principal of the debentures					$ 3,500

EARNINGS (LOSS) PER SHARE (Details) - shares shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of weighted average shares outstanding from basic to diluted
Weighted average shares outstanding - basic (in shares)	168,163	158,921	150,190	149,167	148,675	148,184	147,467	145,936	156,668	147,575	138,967
Potential dilutive common shares (in shares)									0	0	5,683
Weighted average shares outstanding - diluted (in shares)	172,213	158,921	150,190	149,167	148,675	148,184	154,160	145,936	156,668	147,575	144,650
Options, restricted and performance-based stock and stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities not included in computation of diluted loss per share (in shares)									14,500	10,600	200

ACCOUNTS RECEIVABLE, NET - Schedule of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Accounts receivable	$ 268,671	$ 284,187
Allowance for doubtful accounts	(1,427)	(1,270)	$ (776)	$ (913)
Accounts receivable, net	$ 267,244	$ 282,917

ACCOUNTS RECEIVABLE, NET - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 1,270	$ 776	$ 913
Charges to expense	100	553	686
Charges (credits) to other accounts	159	85	94
Write-offs	(102)	(144)	(917)
Balance at end of year	$ 1,427	$ 1,270	$ 776

INVENTORY (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
On-hand final assemblies and finished goods inventories	$ 85,888	$ 57,360
Deferred cost of goods sold	1,449	1,474
Gross inventory	87,337	58,834
Less noncurrent portion (included in Other assets)	(11,914)	(4,791)
Current portion	$ 75,423	$ 54,043

PROPERTY AND EQUIPMENT - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 148,929	$ 145,401
Less accumulated depreciation and amortization	(104,097)	(97,716)
Property and equipment, net	$ 44,832	47,685
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 76,674	74,769
Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	2 years
Equipment \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Software
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	3 years
Property and equipment, gross	$ 33,639	32,804
Software \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	2 years
Software \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,168	3,188
Furniture and fixtures \| Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	3 years
Furniture and fixtures \| Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Property and equipment, gross	$ 35,448	$ 34,640

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation and amortization of property and equipment	$ 15,295	$ 16,962	$ 17,188

PROPERTY AND EQUIPMENT - Property and Equipment Under Finance Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Cost	$ 0	$ 2,050
Less accumulated depreciation	0	(1,763)
Property and equipment under finance leases, net	$ 0	$ 287

PROPERTY AND EQUIPMENT - Property and Equipment by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 44,832	$ 47,685
United States
Property, Plant and Equipment [Line Items]
Property and equipment, net	23,143	24,683
Canada
Property, Plant and Equipment [Line Items]
Property and equipment, net	3,471	5,184
Asia/Pacific
Property, Plant and Equipment [Line Items]
Property and equipment, net	8,152	8,174
Europe
Property, Plant and Equipment [Line Items]
Property and equipment, net	833	1,157
Israel
Property, Plant and Equipment [Line Items]
Property and equipment, net	8,860	7,859
Other
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 373	$ 628

INTANGIBLE ASSETS AND GOODWILL -Schedule of Intangible Assets and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	9 years 6 months 3 days	9 years 2 months 1 day
Cost	$ 618,706	$ 614,250
Accumulated amortization	323,978	263,520
Net carrying value	294,728	350,730
Estimated future amortization expense for intangible assets
2023	56,882
2024	50,717
2025	44,006
2026	38,965
2027	33,936
Thereafter	70,222
Total	$ 294,728
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Cost		34,000
Accumulated amortization		0
Net carrying value		$ 34,000
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	7 years 10 months 2 days	7 years 11 months 4 days
Cost	$ 340,380	$ 306,380
Accumulated amortization	212,448	181,393
Net carrying value	$ 127,932	$ 124,987
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	11 years 10 months 9 days	11 years 10 months 9 days
Cost	$ 268,140	$ 268,140
Accumulated amortization	106,385	77,653
Net carrying value	$ 161,755	$ 190,487
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	3 years 10 months 17 days	3 years 10 months 17 days
Cost	$ 5,000	$ 5,000
Accumulated amortization	4,658	3,744
Net carrying value	$ 342	$ 1,256
Software licenses
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)	3 years
Cost	$ 5,186
Accumulated amortization	487
Net carrying value	$ 4,699
Internal use software
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period (years)		3 years
Cost		$ 730
Accumulated amortization		730
Net carrying value		$ 0

INTANGIBLE ASSETS AND GOODWILL - Narrative (Details)	3 Months Ended	12 Months Ended
INTANGIBLE ASSETS AND GOODWILL - Narrative (Details)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Goodwill [Line Items]
Number of operating segments \| segment		2
Goodwill	$ 300,892,000	$ 300,892,000	$ 300,892,000	$ 416,892,000
Impairment of goodwill		$ 0	116,000,000	0
Number of reportable operating segments \| segment		2
Cloud and Edge
Goodwill [Line Items]
Goodwill	224,896,000	$ 224,896,000	224,896,000	224,896,000
Impairment of goodwill	0
IP Optical Networks
Goodwill [Line Items]
Goodwill	75,996,000	$ 75,996,000	$ 75,996,000	$ 191,996,000
Impairment of goodwill	$ 116,000,000

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

INTANGIBLE ASSETS AND GOODWILL - Schedule of Changes in Carrying Value of Goodwill (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Goodwill at the beginning of the period		$ 300,892,000	$ 416,892,000
Impairment of goodwill		0	(116,000,000)	$ 0
Goodwill, Ending Balance	$ 300,892,000	300,892,000	300,892,000	416,892,000
Accumulated impairment losses	(283,406,000)	(283,406,000)	(283,406,000)
Cloud and Edge
Goodwill [Roll Forward]
Goodwill at the beginning of the period		224,896,000	224,896,000
Impairment of goodwill	0
Goodwill, Ending Balance	224,896,000	224,896,000	224,896,000	224,896,000
Accumulated impairment losses	(167,406,000)	(167,406,000)	(167,406,000)
IP Optical Networks
Goodwill [Roll Forward]
Goodwill at the beginning of the period		75,996,000	191,996,000
Impairment of goodwill	(116,000,000)
Goodwill, Ending Balance	75,996,000	75,996,000	75,996,000	$ 191,996,000
Accumulated impairment losses	$ (116,000,000)	(116,000,000)	(116,000,000)
ECI
Goodwill [Roll Forward]
Impairment of goodwill		0	(116,000,000)
Goodwill, Ending Balance		191,996,000
ECI \| Cloud and Edge
Goodwill [Roll Forward]
Impairment of goodwill		0	0
ECI \| IP Optical Networks
Goodwill [Roll Forward]
Impairment of goodwill		$ 0	$ (116,000,000)

- Definition

+ References + Details

INTANGIBLE ASSETS AND GOODWILL - Schedule of Components of Goodwill (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill, gross	$ 584,298	$ 584,298
Accumulated impairment losses	(283,406)	(283,406)
Goodwill	300,892	300,892	$ 416,892
Cloud and Edge
Goodwill [Line Items]
Goodwill, gross	392,302	392,302
Accumulated impairment losses	(167,406)	(167,406)
Goodwill	224,896	224,896	224,896
IP Optical Networks
Goodwill [Line Items]
Goodwill, gross	191,996	191,996
Accumulated impairment losses	(116,000)	(116,000)
Goodwill	$ 75,996	$ 75,996	$ 191,996

- Definition

+ References + Details

ACCRUED EXPENSES AND OTHER (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Employee compensation and related costs	$ 25,994	$ 38,040
Professional fees	17,195	14,365
Other	42,081	48,347
Total	$ 85,270	$ 100,752

WARRANTY (Details) - USD ($) $ in Thousands	12 Months Ended
WARRANTY (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of year	$ 13,120	$ 14,855
Provision	4,605	3,777
Settlements	(5,868)	(5,512)
Balance at end of year	$ 11,857	$ 13,120

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) employee	Dec. 31, 2021 USD ($) employee	Dec. 31, 2020 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring and related	$ 10,833	$ 11,653	$ 16,235
Accelerated amortization of lease assets due to cease-use	1,611	1,325	$ 605
Restructuring reserve current	1,300	1,900
Long-term portions of accrued restructuring	2,000	1,600
2022 Restructuring Initiative
Restructuring Cost and Reserve [Line Items]
Restructuring and related	10,197
Restructuring and related expense	8,000
Net transfer to operating lease accounts	(1,611)
2022 Restructuring Initiative \| Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and related	$ 5,287
Number of positions eliminated \| employee	70
Net transfer to operating lease accounts	$ 0
2022 Restructuring Initiative \| Variable and other facilities-related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and related	3,299
Net transfer to operating lease accounts	0
2022 Restructuring Initiative \| Accelerated amortization of lease assets due to cease-use
Restructuring Cost and Reserve [Line Items]
Restructuring and related	1,611
Net transfer to operating lease accounts	(1,611)
2022 Restructuring Initiative \| Facilities
Restructuring Cost and Reserve [Line Items]
Accelerated amortization of lease assets due to cease-use	1,600
2020 Restructuring Initiative
Restructuring Cost and Reserve [Line Items]
Restructuring and related	34	5,360
Net transfer to operating lease accounts	57	670
Restructuring charges, net of adjustments	100	4,700
2020 Restructuring Initiative \| Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and related	0	$ 4,618
Number of positions eliminated \| employee		60
Net transfer to operating lease accounts	57	$ 0
2020 Restructuring Initiative \| Variable and other facilities-related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and related		100
2020 Restructuring Initiative \| Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring and related	34	742
Accelerated amortization of lease assets due to cease-use		800
Net transfer to operating lease accounts	0	670
2019 Restructuring Initiative
Restructuring Cost and Reserve [Line Items]
Restructuring and related	658	9,006
Number of positions eliminated \| employee			5
Accelerated amortization of lease assets due to cease-use		1,300	$ 100
Net transfer to operating lease accounts	0	1,325
Restructuring charges, net of adjustments	700	7,000	2,300
2019 Restructuring Initiative \| North Carolina Amended Lease
Restructuring Cost and Reserve [Line Items]
Net transfer to operating lease accounts		2,100
2019 Restructuring Initiative \| Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and related	0	0
Net transfer to operating lease accounts	0	0
Restructuring charges, net of adjustments			500
2019 Restructuring Initiative \| Facilities
Restructuring Cost and Reserve [Line Items]
Restructuring and related	658	9,006
Accelerated amortization of lease assets due to cease-use		3,400	600
Net transfer to operating lease accounts	$ 0	1,325
Restructuring charges, net of adjustments		$ 5,700	$ 1,700

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES - Components of Restructuring Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Severance and related costs	$ 5,230	$ 4,618	$ 12,025
Variable and other facilities-related costs	3,992	5,710	3,605
Accelerated amortization of lease assets due to cease-use	1,611	1,325	605
Restructuring and related	$ 10,833	$ 11,653	$ 16,235

RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES - Restructuring Initiatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restructuring Reserve [Roll Forward]
Initiatives charged to expense	$ 10,833	$ 11,653	$ 16,235
2022 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	0
Initiatives charged to expense	10,197
Net transfer to operating lease liability accounts	1,611
Cash payments	(6,532)
Balance at the end of the period	2,054	0
2020 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	1,955	6,493
Initiatives charged to expense	34	5,360
Net transfer to operating lease liability accounts	(57)	(670)
Cash payments	(1,876)	(9,228)
Balance at the end of the period	56	1,955	6,493
2019 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	1,594	939
Initiatives charged to expense	658	9,006
Restructuring Reserve, Translation and Other Adjustment		(2,043)
Net transfer to operating lease liability accounts	0	(1,325)
Cash payments	(1,004)	(4,983)
Balance at the end of the period	1,248	1,594	939
Severance \| 2022 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	0
Initiatives charged to expense	5,287
Net transfer to operating lease liability accounts	0
Cash payments	(4,123)
Balance at the end of the period	1,164	0
Severance \| 2020 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	1,895	5,237
Initiatives charged to expense	0	4,618
Net transfer to operating lease liability accounts	(57)	0
Cash payments	(1,782)	(7,960)
Balance at the end of the period	56	1,895	5,237
Severance \| 2019 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	0	173
Initiatives charged to expense	0	0
Restructuring Reserve, Translation and Other Adjustment		0
Net transfer to operating lease liability accounts	0	0
Cash payments	0	(173)
Balance at the end of the period	0	0	173
Variable and other facilities-related costs \| 2022 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	0
Initiatives charged to expense	3,299
Net transfer to operating lease liability accounts	0
Cash payments	(2,409)
Balance at the end of the period	890	0
Variable and other facilities-related costs \| 2020 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Initiatives charged to expense		100
Accelerated amortization of lease assets due to cease-use \| 2022 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	0
Initiatives charged to expense	1,611
Net transfer to operating lease liability accounts	1,611
Cash payments	0
Balance at the end of the period	0	0
Facilities
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	1,600
Balance at the end of the period	2,000	1,600
Facilities \| 2020 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	60	1,256
Initiatives charged to expense	34	742
Net transfer to operating lease liability accounts	0	(670)
Cash payments	(94)	(1,268)
Balance at the end of the period	0	60	1,256
Facilities \| 2019 Restructuring Initiative
Restructuring Reserve [Roll Forward]
Balance at the beginning of the period	1,594	766
Initiatives charged to expense	658	9,006
Restructuring Reserve, Translation and Other Adjustment		(2,043)
Net transfer to operating lease liability accounts	0	(1,325)
Cash payments	(1,004)	(4,810)
Balance at the end of the period	$ 1,248	$ 1,594	$ 766

DEBT - Naratives (Details)					12 Months Ended
DEBT - Naratives (Details)	Jun. 30, 2022 USD ($)	Mar. 10, 2022 USD ($)	Mar. 03, 2021 USD ($)	Aug. 18, 2020 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Mar. 03, 2020 USD ($)	Nov. 14, 2019 USD ($)	Apr. 29, 2019 USD ($)
Debt Instrument [Line Items]
Repayment of principal					$ 73,625,000	$ 0	$ 8,615,000
Letters of credit outstanding					8,300,000	30,100,000
Restricted cash					161,000	2,570,000
Restricted Short-term Bank Deposits
Debt Instrument [Line Items]
Restricted cash					$ 200,000
2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender									$ 500,000,000
Repayment of principal	$ 10,000,000	$ 15,000,000
Accordion feature	$ 50,000,000
Percent of aggregate amount applied for repayment	50.00%
2020 Credit Facility \| Debt Instrument, Period Five
Debt Instrument [Line Items]
Consolidated net leverage ratio	1.25
2020 Credit Facility \| Debt Instrument, Period Four
Debt Instrument [Line Items]
Consolidated net leverage ratio	1.10
2020 Credit Facility \| Maximum \| Debt Instrument, Period Five
Debt Instrument [Line Items]
Consolidated net leverage ratio	4.50
2020 Credit Facility \| Maximum \| Debt Instrument, Period One
Debt Instrument [Line Items]
Consolidated net leverage ratio	4.75
2020 Credit Facility \| Maximum \| Debt Instrument, Period Two
Debt Instrument [Line Items]
Consolidated net leverage ratio	3.25
2020 Credit Facility \| Maximum \| Debt Instrument, Period Three
Debt Instrument [Line Items]
Consolidated net leverage ratio	3.00
Revolving Credit Facility
Debt Instrument [Line Items]
Commitments from lender										$ 100,000,000
Revolving Credit Facility \| 2019 Credit Facility
Debt Instrument [Line Items]
Principal amount											$ 50,000,000
Revolving Credit Facility \| 2019 Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Commitments from lender											$ 100,000,000
Revolving Credit Facility \| 2019 Credit Facility \| Line of Credit \| Minimum \| Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate					1.50%
Revolving Credit Facility \| 2019 Credit Facility \| Line of Credit \| Minimum \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate					0.50%
Revolving Credit Facility \| 2019 Credit Facility \| Line of Credit \| Maximum \| Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate					3.00%
Revolving Credit Facility \| 2019 Credit Facility \| Line of Credit \| Maximum \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate					2.00%
Revolving Credit Facility \| 2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender									100,000,000
Term Loan Facility
Debt Instrument [Line Items]
Commitments from lender										$ 400,000,000
Term Loan Facility \| 2020 Credit Facility
Debt Instrument [Line Items]
Principal amount								$ 400,000,000
Commitments from lender									400,000,000
Outstanding balance					$ 330,400,000	$ 375,500,000
Letter of Credit \| 2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender									30,000,000
Debt average interest rate					4.50%	2.50%
Letters of credit outstanding					$ 3,300,000	$ 4,300,000
Swingline Loan \| 2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender									$ 20,000,000
Term Loan Facility, Term B Loan \| Minimum \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Term Loan Facility, Term B Loan \| Maximum \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	3.50%
Term Loan Facility, Term B Loan \| 2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender				$ 75,000,000
Term Loan Facility, Term B Loan \| 2020 Credit Facility \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				7.50%
Term Loan Facility, Term B Loan \| 2020 Credit Facility \| Minimum \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
Term Loan Facility, Term B Loan \| 2020 Credit Facility \| Maximum \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	4.50%
Term Loan Facility, Term B Loan \| 2020 Credit Facility \| Maximum \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate				0.50%
Term Loan Facility, Term B Loan \| 2020 Credit Facility \| Maximum \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Term Loan Facility, Term A Loan \| 2020 Credit Facility
Debt Instrument [Line Items]
Commitments from lender				$ 325,000,000
Outstanding balance						$ 375,500,000
Debt average interest rate					5.40%	3.40%
Term Loan Facility, Term A Loan \| 2020 Credit Facility \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate				0.50%
Term Loan Facility, Term A Loan \| 2020 Credit Facility \| Minimum \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				1.50%
Term Loan Facility, Term A Loan \| 2020 Credit Facility \| Minimum \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate				0.50%
Term Loan Facility, Term A Loan \| 2020 Credit Facility \| Maximum \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate				3.50%
Term Loan Facility, Term A Loan \| 2020 Credit Facility \| Maximum \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate				2.50%
2020 Term Loan
Debt Instrument [Line Items]
Quarterly principal payment amount			$ 74,600,000
Write off of capitalized debt issuance costs					$ 2,500,000
Repayment of debt per quarter through March 31, 2024	$ 5,000,000
Repayment of debt for three quarters, thereafter	10,000,000
Repayment of debt, final payment	$ 275,000,000
Various Uncommitted Facilities
Debt Instrument [Line Items]
Letters of credit outstanding					$ 5,000,000	$ 25,800,000

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Narrative (Details) - USD ($)			1 Months Ended	12 Months Ended
	Aug. 16, 2022	Jul. 22, 2022	Aug. 16, 2022	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2020
Derivative [Line Items]
Amount reclassified from accumulated other comprehensive income (loss) to interest expense				$ 3,135,000	$ (3,254,000)
Reclassified as an increase to interest expense over the next twelve months				13,200,000
Interest Rate Swap
Derivative [Line Items]
Derivative instrument sold	$ 30,000,000	$ 30,000,000	$ 60,000,000
Proceeds from sale	1,600,000	1,500,000
Notional amount	$ 340,000,000	$ 370,000,000	340,000,000	340,000,000	400,000,000
Amount reclassified from accumulated other comprehensive income (loss) to interest expense			$ 3,100,000
Amortization of derivative instrument				500,000
Interest rate derivative				25,428,000	1,811,000
Interest Rate Swap \| Level Two
Derivative [Line Items]
Interest rate derivative				25,400,000	1,800,000
Term Loan Facility \| 2020 Credit Facility
Derivative [Line Items]
Outstanding balance				$ 330,400,000	$ 375,500,000
Principal amount						$ 400,000,000
Fixed rate				0.904%

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Impact of Derivative Financial Instrument on Condensed Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain recognized in other comprehensive income (loss) on interest rate swap, net of tax	$ 22,456	$ 9,505
Amount reclassified from accumulated other comprehensive income (loss) to interest expense	(3,135)	3,254
Unrealized gain (loss) on interest rate swap, net of reclassifications and amortization	$ 19,321	$ 12,759	$ (10,948)

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Fair Values and Locations in the Condensed Consolidated Balance Sheet (Details) - Interest Rate Swap - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Interest rate derivative - asset derivative	$ 13,212	$ 0
Interest rate derivative - asset derivative	12,216	3,865
Interest rate derivative - liability derivative	0	(2,054)
Interest rate derivative - liability derivative	0	0
Interest rate derivative	$ 25,428	$ 1,811

REVENUE RECOGNITION - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 819,760	$ 844,957	$ 843,795
Cloud and Edge
Disaggregation of Revenue [Line Items]
Total revenue	508,137	556,656	583,270
IP Optical Networks
Disaggregation of Revenue [Line Items]
Total revenue	311,623	288,301	260,525
Product revenue
Disaggregation of Revenue [Line Items]
Total revenue	442,680	453,042	467,912
Product revenue \| Cloud and Edge
Disaggregation of Revenue [Line Items]
Total revenue	215,770	248,570	275,445
Product revenue \| IP Optical Networks
Disaggregation of Revenue [Line Items]
Total revenue	226,910	204,472	192,467
Product revenue \| Sales to enterprise customers
Disaggregation of Revenue [Line Items]
Total revenue	125,664	111,494	138,469
Product revenue \| Sales to service provider customers
Disaggregation of Revenue [Line Items]
Total revenue	317,016	341,548	329,443
Product revenue \| Indirect sales through channel program
Disaggregation of Revenue [Line Items]
Total revenue	131,998	117,065	134,876
Product revenue \| Direct sales
Disaggregation of Revenue [Line Items]
Total revenue	310,682	335,977	333,036
Service
Disaggregation of Revenue [Line Items]
Total revenue	377,080	391,915	375,883
Service revenue (maintenance)
Disaggregation of Revenue [Line Items]
Total revenue	282,095	286,321	274,816
Service revenue (maintenance) \| Cloud and Edge
Disaggregation of Revenue [Line Items]
Total revenue	222,238	228,321	229,035
Service revenue (maintenance) \| IP Optical Networks
Disaggregation of Revenue [Line Items]
Total revenue	59,857	58,000	45,781
Service revenue (professional services)
Disaggregation of Revenue [Line Items]
Total revenue	94,985	105,594	101,067
Service revenue (professional services) \| Cloud and Edge
Disaggregation of Revenue [Line Items]
Total revenue	70,130	79,765	78,790
Service revenue (professional services) \| IP Optical Networks
Disaggregation of Revenue [Line Items]
Total revenue	24,855	25,829	22,277
United States
Disaggregation of Revenue [Line Items]
Total revenue	352,663	376,037	382,619
United States \| Product revenue
Disaggregation of Revenue [Line Items]
Total revenue	175,189	196,058	201,347
United States \| Service revenue (maintenance)
Disaggregation of Revenue [Line Items]
Total revenue	132,655	132,683	132,661
United States \| Service revenue (professional services)
Disaggregation of Revenue [Line Items]
Total revenue	44,819	47,296	48,611
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	252,781	248,027	248,268
Europe, Middle East and Africa \| Product revenue
Disaggregation of Revenue [Line Items]
Total revenue	147,523	138,203	149,567
Europe, Middle East and Africa \| Service revenue (maintenance)
Disaggregation of Revenue [Line Items]
Total revenue	75,948	79,475	73,475
Europe, Middle East and Africa \| Service revenue (professional services)
Disaggregation of Revenue [Line Items]
Total revenue	29,310	30,349	25,226
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenue	151,099	152,931	146,456
Asia Pacific \| Product revenue
Disaggregation of Revenue [Line Items]
Total revenue	95,828	92,803	90,201
Asia Pacific \| Service revenue (maintenance)
Disaggregation of Revenue [Line Items]
Total revenue	41,677	41,945	36,628
Asia Pacific \| Service revenue (professional services)
Disaggregation of Revenue [Line Items]
Total revenue	13,594	18,183	19,627
Other
Disaggregation of Revenue [Line Items]
Total revenue	63,217	67,962	66,452
Other \| Product revenue
Disaggregation of Revenue [Line Items]
Total revenue	24,140	25,978	26,797
Other \| Service revenue (maintenance)
Disaggregation of Revenue [Line Items]
Total revenue	31,815	32,218	32,052
Other \| Service revenue (professional services)
Disaggregation of Revenue [Line Items]
Total revenue	$ 7,262	$ 9,766	$ 7,603

REVENUE RECOGNITION - Schedule of Customer Assets & Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accounts receivable
Beginning balance	$ 208,972	$ 179,331
Increase (decrease), net	(38,003)	29,641
Ending balance	170,969	208,972
Unbilled accounts receivable
Beginning balance	73,945	58,407
Increase (decrease), net	22,330	15,538
Ending balance	96,275	73,945
Deferred revenue (current)
Beginning balance	109,119	96,824
Increase (decrease), net	4,820	12,295
Ending balance	113,939	109,119
Deferred revenue (long-term)
Beginning balance	20,619	26,010
Increase (decrease), net	(1,365)	(5,391)
Ending balance	$ 19,254	$ 20,619

REVENUE RECOGNITION - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized	$ 103.0	$ 94.0
Customer contract expected life (in years)	5 years
Deferred sales commissions capitalized	$ 3.6	$ 3.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue to be recognized	$ 12.0
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue to be recognized	$ 5.0
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue to be recognized	$ 2.0
Revenue, remaining performance obligation, period	1 year

OPERATING SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended								12 Months Ended
OPERATING SEGMENT INFORMATION (Details) $ in Thousands	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting [Abstract]
Number of reportable operating segments \| segment									2
Segment Reporting Information [Line Items]
Total revenue									$ 819,760	$ 844,957	$ 843,795
Total segment adjusted gross profit									435,106	485,000	495,982
Stock-based compensation expense									(2,628)	(1,997)	(875)
Amortization of acquired technology									(31,542)	(38,343)	(42,290)
Acquisition-related inventory and facilities adjustments									0	0	(2,000)
Gross profit	$ 114,013	$ 104,318	$ 104,550	$ 78,055	$ 114,793	$ 110,654	$ 118,727	$ 100,486	400,936	444,660	450,817
Segment depreciation expense:
Total depreciation expense									15,295	16,962	17,188
Cloud and Edge
Segment Reporting Information [Line Items]
Total revenue									508,137	556,656	583,270
Total segment adjusted gross profit									330,395	370,504	385,137
Segment depreciation expense:
Total depreciation expense									10,758	12,269	12,111
IP Optical Networks
Segment Reporting Information [Line Items]
Total revenue									311,623	288,301	260,525
Total segment adjusted gross profit									104,711	114,496	110,845
Segment depreciation expense:
Total depreciation expense									$ 4,537	$ 4,693	$ 5,077

MAJOR CUSTOMERS (Details) - Customer	12 Months Ended
MAJOR CUSTOMERS (Details) - Customer	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue \| Verizon Communications Inc.
Concentration Risk [Line Items]
Concentration risk (as a percent)	15.00%	16.00%	15.00%
Accounts Receivable \| One Customer
Concentration Risk [Line Items]
Concentration risk (as a percent)		15.00%

STOCK-BASED COMPENSATION PLANS - Narratives (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) performance_period shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	May 25, 2022 shares
Stock-based compensation
Authorized for issuance of common stock under the 2022 plan (in shares) \| shares				10,000,000
Total fair value of restricted stock awards, restricted stock units, performance-based stock awards and performance-based stock units on date vested	$ 9,858	$ 40,751	$ 7,927
Fair value of the assumed awards attributable to future stock-based compensation expense	$ 23,000
Expected period for unrecognized expense	2 years
Shares available for future issuance (in shares) \| shares	5,027,305
PSUs
Stock-based compensation
Total fair value of restricted stock awards, restricted stock units, performance-based stock awards and performance-based stock units on date vested	$ 900	$ 1,700	$ 1,800
PSUs, Performance Based
Stock-based compensation
Granted percentage		60.00%
Number of performance periods \| performance_period	3
PSUs, Market Based
Stock-based compensation
Granted percentage			40.00%
Number of performance periods \| performance_period	1
Performance period (in years)	3 years
Percent of performance metrics achieved	200.00%
RSAs
Stock-based compensation
Total fair value of restricted stock awards, restricted stock units, performance-based stock awards and performance-based stock units on date vested	$ 18,100	$ 12,500	$ 11,200
Stock Options
Stock-based compensation
Shares available for future issuance (in shares) \| shares	105,495

STOCK-BASED COMPENSATION PLANS - Restricted Stock Awards and Units and Performance-Based Stock Units (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Weighted Average Grant Date Fair Value
Total grant date fair value of shares that vested during the period	$ 9,858	$ 40,751	$ 7,927
RSUs
Shares
Unvested balance at the beginning of the period (in shares)	5,389,611
Granted (in shares)	6,096,248
Vested (in shares)	(3,075,543)
Forfeited (in shares)	(760,569)
Unvested balance at the end of the period (in shares)	7,649,747	5,389,611
Weighted Average Grant Date Fair Value
Unvested balance at the beginning of the period (in dollars per share)	$ 6.19
Granted (in dollars per share)	3.09
Vested (in dollars per share)	5.87
Forfeited (in dollars per share)	5.05
Unvested balance at end of the period (in dollars per share)	$ 3.96	$ 6.19
RSAs
Weighted Average Grant Date Fair Value
Total grant date fair value of shares that vested during the period	$ 18,100	$ 12,500	11,200
PSUs
Shares
Unvested balance at the beginning of the period (in shares)	4,987,876
Granted (in shares)	2,228,073
Vested (in shares)	(179,184)
Forfeited (in shares)	(383,262)
Unvested balance at the end of the period (in shares)	6,653,503	4,987,876
Weighted Average Grant Date Fair Value
Unvested balance at the beginning of the period (in dollars per share)	$ 2.87
Granted (in dollars per share)	3.27
Vested (in dollars per share)	5.02
Forfeited (in dollars per share)	7.82
Unvested balance at end of the period (in dollars per share)	$ 2.52	$ 2.87
Total grant date fair value of shares that vested during the period	$ 900	$ 1,700	$ 1,800

STOCK-BASED COMPENSATION PLANS - Schedule of Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation
Stock-based compensation	$ 18,707	$ 19,418	$ 13,899
Product cost of revenue
Stock-based compensation
Stock-based compensation	471	313	174
Service cost of revenue
Stock-based compensation
Stock-based compensation	2,157	1,684	701
Research and development
Stock-based compensation
Stock-based compensation	5,108	4,253	2,968
Sales and marketing
Stock-based compensation
Stock-based compensation	6,074	7,218	4,129
General and administrative
Stock-based compensation
Stock-based compensation	$ 4,897	$ 5,950	$ 5,927

LEASES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
LEASES - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease impairment	$ 0	$ 0
Finance lease impairment	0	0
Additional amortization expense	1,611	$ 1,325	$ 605
Variable lease, payment			0
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other (expense) income, net
Facilities
Lessee, Lease, Description [Line Items]
Accrual for future anticipated variable lease costs	2,000	$ 1,600
2022 Restructuring Initiative
Lessee, Lease, Description [Line Items]
Accrual for future anticipated variable lease costs	2,054	0
Net transfer to operating lease accounts	(1,611)
2022 Restructuring Initiative \| Facilities
Lessee, Lease, Description [Line Items]
Additional amortization expense	1,600
Expense recorded for estimated future variable lease costs	1,000
2020 Restructuring Initiative
Lessee, Lease, Description [Line Items]
Accrual for future anticipated variable lease costs	56	1,955	6,493
Net transfer to operating lease accounts	57	670
2020 Restructuring Initiative \| Facilities
Lessee, Lease, Description [Line Items]
Additional amortization expense		800
Accrual for future anticipated variable lease costs	0	60	1,256
Net transfer to operating lease accounts	0	670
2019 Restructuring Initiative
Lessee, Lease, Description [Line Items]
Additional amortization expense		1,300	100
Accrual for future anticipated variable lease costs	1,248	1,594	939
Net transfer to operating lease accounts	0	1,325
2019 Restructuring Initiative \| North Carolina Amended Lease
Lessee, Lease, Description [Line Items]
Net transfer to operating lease accounts		2,100
2019 Restructuring Initiative \| Facilities
Lessee, Lease, Description [Line Items]
Additional amortization expense		3,400	600
Expense recorded for estimated future variable lease costs		1,400
Accrual for future anticipated variable lease costs	1,248	1,594	$ 766
Net transfer to operating lease accounts	$ 0	$ 1,325

LEASES - Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Operating lease assets	$ 44,888	$ 53,147
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property and equipment, net	Property and equipment, net
Finance lease assets	$ 0	$ 287
Total leased assets	44,888	53,434
Current:
Operating	$ 15,416	$ 17,403
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other	Accrued expenses and other
Finance	$ 0	$ 503
Noncurrent:
Operating	$ 46,183	$ 55,196
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities
Finance	$ 0	$ 64
Total lease liabilities	61,599	73,166
Finance lease, accumulated deprecation	$ 0	$ 1,763

LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease cost	$ 21,121	$ 21,828	$ 19,582
Finance lease cost:
Amortization of leased assets	287	695	1,200
Interest on lease liabilities	13	67	173
Short-term lease cost	14,209	13,250	20,687
Variable lease costs (costs excluded from minimum fixed lease payments)	4,007	4,030	2,713
Sublease income	(1,647)	(1,496)	(1,087)
Net lease cost	37,990	38,374	43,268
Accelerated amortization	1,600	3,400	600
Operating lease, lease income		2,100
Variable lease cost accrued	$ 1,000	$ 1,400
Variable lease, payment			$ 0

LEASES - Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 20,363	$ 22,365	$ 19,161
Operating cash flows from finance leases	13	67	173
Financing cash flows from finance leases	$ 595	$ 903	$ 1,279
Weighted average remaining lease term (years):
Operating leases	5 years 10 months 24 days	6 years 3 months
Finance leases		1 year
Weighted average discount rate:
Operating leases	5.79%	5.61%
Finance leases	0.00%	4.15%

LEASES - Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Operating leases
2023	$ 18,384
2024	15,380
2025	8,249
2026	7,110
2027	6,429
2028 and beyond	18,210
Total lease payments	73,762
Less: interest	(12,163)
Present value of lease liabilities	61,599
Finance leases
2023	0
2024	0
2025	0
2026	0
2027	0
2028 and beyond	0
Total lease payments	0
Less: interest	0
Present value of lease liabilities	$ 0

EMPLOYEE DEFINED CONTRIBUTION PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Employer matching percent of employees' contribution	50.00%
Employer matching contribution percentage of employees' gross pay	4.00%
Maximum employer match percentage per employee	2.00%
Defined contribution expense	$ 3.3	$ 3.5	$ 3.4

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost	$ (320)	$ 0	$ 0
Settlement gain	$ (808)	0	1,557
Net gains and losses amortization threshold	10.00%
Fair value of combined plan assets	$ 14,629	15,303	14,350
Participant contributions	$ 39	23
Fixed contributions per employee, percent	5.00%
Employer pension plan contributions	$ 1,954	989	800
Expected future employer contributions to pension plans in 2020	1,500
Switzerland
Defined Benefit Plan Disclosure [Line Items]
Fair value of combined plan assets	2,300	1,700
Netherlands
Defined Benefit Plan Disclosure [Line Items]
Fair value of combined plan assets	$ 0	0	$ 0
INDIA
Defined Benefit Plan Disclosure [Line Items]
Increase in plan assets		1,500
Amortization of prior service cost		$ (3,800)

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Changes in Benefit Obligations and Fair Value of Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in projected benefit obligations:
Projected benefit obligation, beginning of year	$ 26,938	$ 25,067
Service cost	1,355	1,321	$ 1,459
Interest cost	563	523	46
Participant contributions	0	0
Plan amendments	0	(3,801)
Net actuarial (gain) loss on obligation	(5,604)	4,868
Settlement	(1,063)	0
Benefits and expenses paid	(932)	(1,040)
Projected benefit obligation, end of year	21,257	26,938	25,067
Changes in plan assets:
Fair value of plan assets, beginning of year	15,303	14,350
Actual return on plan assets	(672)	981
Employer contributions	1,954	989	800
Participant contributions	39	23
Benefits paid	(1,995)	(1,040)
Fair value of plan assets, end of year	14,629	15,303	$ 14,350
Funded status at end of year	(6,628)	(11,635)
Prior service (credit) cost	(3,481)	(3,801)
Net actuarial (gain) loss	(1,704)	4,045
Accumulated other comprehensive income	(5,185)	244
Amounts recognized in the consolidated balance sheets consist of:
Other assets (non-current pension asset)	552	0
Accrued expenses and other (current pension liability)	(803)	(461)
Other long-term liabilities (non-current pension liability)	(6,377)	(11,174)
Net amount recognized	$ (6,628)	$ (11,635)

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Accumulated Benefit Obligation (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Aggregate fair value of plan assets	$ 14,629	$ 15,303	$ 14,350
Defined Benefit Plan, Underfunded or Non-funded Plan
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligation	9,450	26,938
Aggregate accumulated benefit obligation	7,418	20,695
Aggregate fair value of plan assets	2,270	15,303
Defined Benefit Plan, Overfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligation	11,807	0
Aggregate accumulated benefit obligation	9,547	0
Aggregate fair value of plan assets	$ 12,359	$ 0

- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References + Details

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Service cost	$ 1,355	$ 1,321	$ 1,459
Interest cost	563	523	46
Expected return on plan assets	(266)	(314)	(343)
Plan asset expenses	0	0	0
Settlement charge (credit)	808	0	(1,557)
Amortization of prior service cost	$ (320)	$ 0	$ 0
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent
Amortization of net loss	$ 275	$ 81	$ 20
Net periodic benefit costs	$ 2,415	$ 1,611	$ (375)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Expected Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Retirement Benefits [Abstract]
2023	$ 2,863
2024	1,314
2025	1,562
2026	1,315
2027	1,584
2028 to 2032	11,326
Expected future benefit payments	$ 19,964

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Change Recognized in Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Net (gain) loss	$ (4,666)	$ 4,201	$ (503)
Prior service (credit) cost	0	(3,801)	0
Amortization of net gain (loss)	(275)	(81)	(20)
Amortization of prior service credit (cost)	320	0	0
Settlement (charge) credit	(808)	0	(1,557)
Total recognized in other comprehensive income (loss)	$ (5,429)	$ 319	$ (2,080)

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Assumptions for Benefit Obligation (Details)	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Discount rate	4.74%	2.24%
Rate of compensation increase	4.02%	3.90%

NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS - Assumption for Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Benefits [Abstract]
Discount rate	2.24%	2.16%	0.68%
Expected long-term return on plan assets	1.79%	2.06%	0.21%
Rate of compensation increase	3.90%	2.41%	2.88%

INCOME TAXES - Schedule of Income (Loss) Before Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
(Loss) income before income taxes:
United States	$ (84,784)	$ (29,985)	$ 123,817
Foreign	(27,815)	(178,158)	(30,500)
(Loss) income before income taxes	$ (112,599)	$ (208,143)	$ 93,317

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126941158&loc=d3e41242-110953

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(8))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI https://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8924-108599

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

INCOME TAXES - Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current:
Federal	$ (3,582)	$ 5,033	$ 677
State	2,573	1,836	1,310
Foreign	4,744	7,661	7,355
Total current	3,735	14,530	9,342
Deferred:
Federal	(10,333)	(38,027)	1,957
State	(4,045)	97	(15)
Foreign	(3,873)	(7,558)	(6,558)
Total deferred	(18,251)	(45,488)	(4,616)
Total	$ (14,516)	$ (30,958)	$ 4,726

INCOME TAXES - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
U.S. statutory income tax rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	1.80%	(0.70%)	1.10%
Foreign income taxes	(1.40%)	0.50%	0.20%
Stock-based compensation	(2.40%)	(0.10%)	1.00%
Tax credits	2.20%	1.60%	(2.80%)
Uncertain tax positions	1.30%	0.50%	0.50%
Valuation allowance	(3.80%)	2.50%	(20.30%)
Non-deductible goodwill impairment	0.00%	(11.70%)	0.00%
Other permanent adjustments	(2.60%)	0.90%	1.80%
Permanent foreign exchange adjustments	(1.40%)	0.50%	1.80%
Other, net	(1.80%)	(0.10%)	0.80%
Effective income tax rate	12.90%	14.90%	5.10%

INCOME TAXES - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Net operating loss carryforwards	$ 413,773	$ 437,669
Capital loss carryforwards	99,505	79,716
Tax credit carryforwards	28,902	23,450
Capitalized research and development expenses	40,668	18,106
Deferred revenue	3,510	3,472
Accrued expenses	9,068	7,505
Inventory	2,820	3,102
Stock-based compensation	1,709	1,689
Fixed assets	2,506	2,710
Lease liabilities	12,829	15,250
Mark-to-market investments	0	1,714
Other temporary differences	1,324	3,839
Deferred tax assets, gross	616,614	598,222
Valuation allowance	(488,550)	(471,515)
Total deferred tax assets	128,064	126,707
Liabilities:
Intangible assets	(55,037)	(65,647)
Operating lease right-of-use assets	(8,519)	(10,370)
Interest rate swap	6,168	0
Unremitted foreign income	(8,441)	(11,519)
Total deferred tax liabilities	(78,165)	(87,536)
Deferred income taxes - net noncurrent assets	53,649	47,287
Deferred income taxes - net noncurrent liabilities	(3,750)	(8,116)
Total net deferred tax assets	$ 49,899	$ 39,171

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 24, 2018
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 28,900
Significant change in shareholder ownership, period of change	3 years
Significant change in shareholder ownership, benchmark percentage	50.00%
Deferred tax assets, valuation allowance	$ 488,550	$ 471,515
Unrecognized tax benefits, income tax penalties and interest accrued	14,900	21,000	$ 15,300
Unrecognized tax benefits that would impact effective tax rate	11,200	12,700	13,900
Unrecognized tax benefits, income tax penalties and interest expense	(300)	1,900	$ 500
Accrued expenses and other
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits, income tax penalties and interest accrued	2,900	3,200
Edgewater
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards acquired				$ 112,300
Annual limitation	9,700
ECI
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards acquired				$ 41,900
Annual limitation	1,100
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	152,500
Deferred tax assets, valuation allowance	25,500	30,500
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	18,800
Israel
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,600,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	$ 463,000	$ 441,000

INCOME TAXES - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at January 1	$ 17,813	$ 14,054	$ 2,932
Increases related to current year tax positions	156	4,017	485
Increases related to prior period tax positions	40	3,168	11,209
Decreases related to the lapse of the applicable statute of limitations	(560)	(3,087)	(122)
Decreases related to prior period tax positions	(5,448)	(339)	(450)
Unrecognized tax benefits at December 31	$ 12,001	$ 17,813	$ 14,054

RELATED PARTIES (Details) - USD ($) $ in Millions	12 Months Ended
RELATED PARTIES (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Majority Shareholder
Related Party Transaction [Line Items]
Revenue from related party	$ 6.6	$ 4.5	$ 3.3

COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands				3 Months Ended		12 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) $ in Thousands	Jul. 14, 2020 USD ($)	Jun. 26, 2020 USD ($)	Apr. 22, 2019 USD ($) country	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2022 USD ($) segment case	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Jun. 25, 2020 USD ($)	May 29, 2019 USD ($) installment	Dec. 31, 2017
Loss Contingencies [Line Items]
Ongoing lawsuits			6			6
Damages awarded from other party			$ 63,000
Cash payments from settlement	$ 16,750			$ 9,500	$ 37,500
Annual installment receivable							$ 25,500			$ 25,500
Number of installments \| installment										3
Installment payments interest rate (as a percentage)										4.00%
Gain from settlement							$ 63,000
Cash payments from settlement, interest				$ 1,000
Reduction to annual installment receivable		$ 250
Sale of stock grant interest											100.00%
Maximum future unpaid royalty commitment						$ 3,800
Maximum future royalty commitment						28,400
Maximum future royalty commitment, interest						$ 1,400
Litigation Case, Plaintiff
Loss Contingencies [Line Items]
Ongoing lawsuits \| segment						5
Litigation Case, Counterclaim Defendant
Loss Contingencies [Line Items]
Ongoing lawsuits \| segment						3
Minimum
Loss Contingencies [Line Items]
Annual installment receivable									$ 16,750
Royalties rates											1.30%
Maximum
Loss Contingencies [Line Items]
Annual installment receivable									$ 17,000
Royalties rates											5.00%
LIBOR \| Minimum
Loss Contingencies [Line Items]
Basis spread on variable rate						1.50%
LIBOR \| Maximum
Loss Contingencies [Line Items]
Basis spread on variable rate						2.75%
Other Current Assets
Loss Contingencies [Line Items]
Annual installment receivable								$ 8,500
Other Noncurrent Assets
Loss Contingencies [Line Items]
Annual installment receivable								$ 17,000

SUBSEQUENT EVENT (Details)						1 Months Ended
SUBSEQUENT EVENT (Details)	Mar. 28, 2023 USD ($) $ / shares shares	Mar. 27, 2023 USD ($)	Mar. 24, 2023 USD ($)	Aug. 16, 2022 USD ($)	Jul. 22, 2022 USD ($)	Aug. 16, 2022 USD ($)	Feb. 28, 2023 USD ($)	Dec. 31, 2022 USD ($) $ / shares	Aug. 12, 2022 $ / shares	Jun. 30, 2022	Dec. 31, 2021 USD ($) $ / shares	Mar. 03, 2020 USD ($)	Nov. 14, 2019 USD ($)
Subsequent Event [Line Items]
Common stock, par value (in dollars per share) \| $ / shares								$ 0.0001			$ 0.0001
Revolving Credit Facility
Subsequent Event [Line Items]
Commitments from lender													$ 100,000,000
2020 Credit Facility
Subsequent Event [Line Items]
Commitments from lender												$ 500,000,000
2020 Credit Facility \| Revolving Credit Facility
Subsequent Event [Line Items]
Commitments from lender												$ 100,000,000
Debt Instrument, Period One \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										4.75
Debt Instrument, Period Two \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										3.25
Debt Instrument, Period Three \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										3.00
Debt Instrument, Period Four \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										1.10
Debt Instrument, Period Five \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										1.25
Debt Instrument, Period Five \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio										4.50
Interest Rate Swap
Subsequent Event [Line Items]
Derivative instrument sold				$ 30,000,000	$ 30,000,000	$ 60,000,000
Notional amount				340,000,000	370,000,000	$ 340,000,000		$ 340,000,000			$ 400,000,000
Proceeds from sale				$ 1,600,000	$ 1,500,000
Private Placement
Subsequent Event [Line Items]
Common stock, par value (in dollars per share) \| $ / shares									$ 0.0001
Subsequent Event \| 2020 Credit Facility \| Revolving Credit Facility
Subsequent Event [Line Items]
Commitments from lender			$ 75,000,000
Repayments of debt			$ 75,000,000
Subsequent Event \| Debt Instrument, Period One \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			4.50
Subsequent Event \| Debt Instrument, Period Two \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			4.25
Subsequent Event \| Debt Instrument, Period Three \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			4.00
Subsequent Event \| Debt Instrument, Period Four \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			3.00
Subsequent Event \| Debt Instrument, Period Five \| Maximum \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			4.00
Subsequent Event \| Debt Instrument, Period Six \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			1.10
Subsequent Event \| Debt Instrument, Period Seven \| 2020 Credit Facility
Subsequent Event [Line Items]
Consolidated net leverage ratio			1.25
Subsequent Event \| Interest Rate Swap
Subsequent Event [Line Items]
Derivative instrument sold		$ 170,000,000	$ 170,000,000
Notional amount			170,000,000
Proceeds from sale		$ 9,800,000	$ 9,400,000
Subsequent Event \| Series A Preferred Stock
Subsequent Event [Line Items]
Preferred stock, liquidation preference per share (in dollar per share) \| $ / shares	$ 970
Subsequent Event \| Series A Preferred Stock \| Warrant
Subsequent Event [Line Items]
Number of shares of common stock entitled from warrants (in shares) \| shares	4,900,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.0001
Proceeds from Issuance of Common Stock	$ 53,400,000
Subsequent Event \| Series A Preferred Stock \| Warrant \| Existing Related Party Shareholders
Subsequent Event [Line Items]
Proceeds from Issuance of Common Stock	$ 10,000,000
Subsequent Event \| Series A Preferred Stock \| Private Placement
Subsequent Event [Line Items]
Shares issued (in shares) \| shares	55,000
2023 Restructuring Plan \| Subsequent Event
Subsequent Event [Line Items]
Expected cost							$ 10,000,000

QUARTERLY RESULTS (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 233,639	$ 207,127	$ 205,796	$ 173,198	$ 230,577	$ 210,398	$ 211,210	$ 192,772
Cost of revenue	119,626	102,809	101,246	95,143	115,784	99,744	92,483	92,286
Gross profit	114,013	104,318	104,550	78,055	114,793	110,654	118,727	100,486	$ 400,936	$ 444,660	$ 450,817
(Loss) income from operations	1,265	(3,296)	(7,239)	(39,054)	(120,136)	1,992	12,952	(12,604)	(48,324)	(117,796)	1,669
Net (loss) income	$ 20,488	$ (18,416)	$ (30,180)	$ (69,975)	$ (96,308)	$ (59,431)	$ 23,241	$ (44,687)	$ (98,083)	$ (177,185)	$ 88,591
Loss (earnings) per share:
Basic (in dollars per share)	$ 0.12	$ (0.12)	$ (0.20)	$ (0.47)	$ (0.65)	$ (0.40)	$ 0.16	$ (0.31)	$ (0.63)	$ (1.20)	$ 0.64
Diluted (in dollars per share)	$ 0.12	$ (0.12)	$ (0.20)	$ (0.47)	$ (0.65)	$ (0.40)	$ 0.15	$ (0.31)	$ (0.63)	$ (1.20)	$ 0.61
Shares used in computing (loss) earnings per share:
Basic (in shares)	168,163	158,921	150,190	149,167	148,675	148,184	147,467	145,936	156,668	147,575	138,967
Diluted (in shares)	172,213	158,921	150,190	149,167	148,675	148,184	154,160	145,936	156,668	147,575	144,650
Amortization of acquired intangible assets to operating expenses						$ 9,700	$ 9,700	$ 10,100