ADTRAN (ADTN) 10-Q 5 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 03, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Entity Registrant Name	ADTRAN Holdings, Inc.
Trading Symbol	ADTN
Entity Central Index Key	0000926282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		77,420,133
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-41446
Entity Tax Identification Number	87-2164282
Entity Address, Address Line One	901 Explorer Boulevard
Entity Address, City or Town	Huntsville
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	35806-2807
City Area Code	256
Local Phone Number	963-8000
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, Par Value $0.01 per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current Assets
Cash and cash equivalents	$ 43,368	$ 56,603
Restricted cash		215
Short-term investments (includes $1,773 and $350 of available-for-sale securities as of June 30, 2022 and December 31, 2021, respectively, reported at fair value)	1,773	350
Accounts receivable, less allowance for credit losses of $0 as of June 30, 2022 and December 31, 2021	172,088	158,742
Other receivables	8,413	11,228
Inventory, net	196,916	139,891
Prepaid expenses and other current assets	9,306	9,296
Total Current Assets	431,864	376,325
Property, plant and equipment, net	53,432	55,766
Deferred tax assets, net	8,508	9,079
Goodwill	6,968	6,968
Intangibles, net	17,473	19,293
Other non-current assets	29,637	30,971
Long-term investments (includes $27,499 and $29,717 of available-for-sale securities as of June 30, 2022 and December 31, 2021, respectively, reported at fair value)	52,297	70,615
Total Assets	600,179	569,017
Current Liabilities
Accounts payable	144,432	102,489
Unearned revenue	22,705	17,737
Accrued expenses and other liabilities	16,759	13,673
Accrued wages and benefits	13,276	14,900
Income tax payable, net	4,541	6,560
Total Current Liabilities	201,713	155,359
Non-current unearned revenue	10,133	9,271
Pension liability	9,889	11,402
Deferred compensation liability	26,014	31,383
Other non-current liabilities	3,893	4,500
Total Liabilities	251,642	211,915
Commitments and contingencies (see Note 17)
Stockholders’ Equity
Common stock, par value $0.01 per share; 200,000 shares authorized; 79,652 shares issued and 49,126 shares outstanding as of June 30, 2022 and 79,652 shares issued and 49,063 shares outstanding as of December 31, 2021	797	797
Additional paid-in capital	292,727	288,946
Accumulated other comprehensive loss	(16,696)	(11,914)
Retained earnings	731,821	740,820
Treasury stock at cost: 30,526 and 30,590 shares at June 30, 2022 and December 31, 2021, respectively	(660,112)	(661,547)
Total Stockholders’ Equity	348,537	357,102
Total Liabilities and Stockholders’ Equity	$ 600,179	$ 569,017

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Short term investments, available-for-sale securities at fair value	$ 1,773	$ 350
Accounts receivable, allowance for expected credit losses	0	0
Long Term Investments, available-for-sale securities Fair Value	$ 27,499	$ 29,717
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	79,652,000	79,652,000
Common stock, shares outstanding	49,126,000	49,063,000
Treasury stock, shares	30,526,000	30,590,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue
Total Revenue	$ 172,038	$ 143,232	$ 326,556	$ 270,765
Cost of Revenue
Total Cost of Revenue	109,532	80,564	209,734	154,496
Gross Profit	62,506	62,668	116,822	116,269
Selling, general and administrative expenses	27,873	30,866	55,766	58,301
Research and development expenses	26,500	27,871	52,991	55,372
Operating Income	8,133	3,931	8,065	2,596
Interest and dividend income	217	253	421	543
Interest expense	(94)	(6)	(124)	(12)
Net investment (loss) gain	(4,646)	2,009	(8,061)	3,005
Other income, net	681	26	455	2,025
Income Before Income Taxes	4,291	6,213	756	8,157
Income tax (expense) benefit	(2,148)	(1,127)	260	(2,175)
Net Income	$ 2,143	$ 5,086	$ 1,016	$ 5,982
Weighted average shares outstanding – basic	49,123	48,449	49,110	48,393
Weighted average shares outstanding – diluted	49,809	49,426	49,813	49,225
Earnings per common share - basic	$ 0.04	$ 0.10	$ 0.02	$ 0.12
Earnings per common share - diluted	$ 0.04	$ 0.10	$ 0.02	$ 0.12
Network Solutions [Member]
Revenue
Total Revenue	$ 155,992	$ 125,449	$ 294,366	$ 239,258
Cost of Revenue
Total Cost of Revenue	99,921	70,014	190,575	135,015
Gross Profit	56,071	55,435	103,791	104,243
Services & Support [Member]
Revenue
Total Revenue	16,046	17,783	32,190	31,507
Cost of Revenue
Total Cost of Revenue	9,611	10,550	19,159	19,481
Gross Profit	$ 6,435	$ 7,233	$ 13,031	$ 12,026

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 2,143	$ 5,086	$ 1,016	$ 5,982
Other Comprehensive (Loss) Income, net of tax
Net unrealized loss on available-for-sale securities	(200)	(95)	(924)	(287)
Defined benefit plan adjustments	(87)	212	(100)	311
Foreign currency translation (loss) gain	(2,853)	338	(3,758)	(1,525)
Other Comprehensive (Loss) Income, net of tax	(3,140)	455	(4,782)	(1,501)
Comprehensive (Loss) Income, net of tax	$ (997)	$ 5,541	$ (3,766)	$ 4,481

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2020	$ 372,944	$ 797	$ 281,466	$ 781,813	$ (679,493)	$ (11,639)
Beginning Balance, Shares at Dec. 31, 2020		79,652
Net Income (Loss)	896			896
Other comprehensive income (loss), net of tax	(1,956)					(1,956)
Dividend payments ($0.09 per share)	(4,361)			(4,361)
Dividends accrued on unvested RSUs	(68)			(68)
Deferred compensation adjustments, net of tax	(50)				(50)
PSUs, RSUs and restricted stock vested	(81)			(1,683)	1,602
Stock options exercised	1,244			(476)	1,720
Stock-based compensation expense	1,807		1,807
Ending Balance at Mar. 31, 2021	370,375	$ 797	283,273	776,121	(676,221)	(13,595)
Ending Balance, Shares at Mar. 31, 2021		79,652
Beginning Balance at Dec. 31, 2020	372,944	$ 797	281,466	781,813	(679,493)	(11,639)
Beginning Balance, Shares at Dec. 31, 2020		79,652
Net Income (Loss)	5,982
Other comprehensive income (loss), net of tax	(1,501)
Ending Balance at Jun. 30, 2021	375,515	$ 797	285,081	776,054	(673,277)	(13,140)
Ending Balance, Shares at Jun. 30, 2021		79,652
Beginning Balance at Mar. 31, 2021	370,375	$ 797	283,273	776,121	(676,221)	(13,595)
Beginning Balance, Shares at Mar. 31, 2021		79,652
Net Income (Loss)	5,086			5,086
Other comprehensive income (loss), net of tax	455					455
Dividend payments ($0.09 per share)	(4,374)			(4,374)
Dividends accrued on unvested RSUs	(128)			(128)
Deferred compensation adjustments, net of tax	(12)				(12)
PSUs, RSUs and restricted stock vested	(3)			(32)	29
Stock options exercised	2,308			(619)	2,927
Stock-based compensation expense	1,808		1,808
Ending Balance at Jun. 30, 2021	375,515	$ 797	285,081	776,054	(673,277)	(13,140)
Ending Balance, Shares at Jun. 30, 2021		79,652
Beginning Balance at Dec. 31, 2021	$ 357,102	$ 797	288,946	740,820	(661,547)	(11,914)
Beginning Balance, Shares at Dec. 31, 2021	79,652	79,652
Net Income (Loss)	$ (1,127)			(1,127)
Other comprehensive income (loss), net of tax	(1,642)					(1,642)
Dividend payments ($0.09 per share)	(4,438)			(4,438)
Dividends accrued on unvested RSUs	32			32
Deferred compensation adjustments, net of tax	(18)				(18)
PSUs, RSUs and restricted stock vested	(54)			(895)	841
Stock options exercised	568			(143)	711
Stock-based compensation expense	1,893		1,893
Ending Balance at Mar. 31, 2022	352,316	$ 797	290,839	734,249	(660,013)	(13,556)
Ending Balance, Shares at Mar. 31, 2022		79,652
Beginning Balance at Dec. 31, 2021	$ 357,102	$ 797	288,946	740,820	(661,547)	(11,914)
Beginning Balance, Shares at Dec. 31, 2021	79,652	79,652
Net Income (Loss)	$ 1,016
Other comprehensive income (loss), net of tax	(4,782)
Ending Balance at Jun. 30, 2022	$ 348,537	$ 797	292,727	731,821	(660,112)	(16,696)
Ending Balance, Shares at Jun. 30, 2022	79,652	79,652
Beginning Balance at Mar. 31, 2022	$ 352,316	$ 797	290,839	734,249	(660,013)	(13,556)
Beginning Balance, Shares at Mar. 31, 2022		79,652
Net Income (Loss)	2,143			2,143
Other comprehensive income (loss), net of tax	(3,140)					(3,140)
Dividend payments ($0.09 per share)	(4,439)			(4,439)
Dividends accrued on unvested RSUs	(23)			(23)
Deferred compensation adjustments, net of tax	24				24
PSUs, RSUs and restricted stock vested	(300)			(90)	(210)
Stock options exercised	68			(19)	87
Stock-based compensation expense	1,888		1,888
Ending Balance at Jun. 30, 2022	$ 348,537	$ 797	$ 292,727	$ 731,821	$ (660,112)	$ (16,696)
Ending Balance, Shares at Jun. 30, 2022	79,652	79,652

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021
Statement of Stockholders' Equity [Abstract]
Dividend payments	$ 0.09	$ 0.09	$ 0.09	$ 0.09

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net income	$ 1,016	$ 5,982
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	7,235	8,232
Loss (gain) on investments	7,882	(3,255)
Stock-based compensation expense	3,781	3,615
Deferred income taxes	(93)	441
Other, net	27	53
Inventory reserves	(4,296)	(3,167)
Changes in operating assets and liabilities:
Accounts receivable, net	(14,315)	(24,322)
Other receivables	2,606	1,412
Inventory	(53,982)	9,107
Prepaid expenses, other current assets and other assets	671	(4,767)
Accounts payable	42,968	16,814
Accrued expenses and other liabilities	2,179	6,999
Income taxes payable, net	(1,597)	1,069
Net cash (used in) provided by operating activities	(5,918)	18,213
Cash flows from investing activities:
Purchases of property, plant and equipment	(3,285)	(2,210)
Proceeds from sales and maturities of available-for-sale investments	25,071	20,597
Purchases of available-for-sale investments	(17,002)	(20,121)
Net cash provided by (used in) investing activities	4,784	(1,734)
Cash flows from financing activities:
Tax withholdings related to stock-based compensation settlements	(333)	(113)
Proceeds from stock option exercises	636	3,552
Dividend payments	(8,877)	(8,735)
Proceeds from draw on line of credit	28,000
Repayment of line of credit	(28,000)
Net cash used in financing activities	(8,574)	(5,296)
Net (decrease) increase in cash, cash equivalents and restricted cash	(9,708)	11,183
Effect of exchange rate changes	(3,742)	(1,381)
Cash, cash equivalents and restricted cash, beginning of period	56,818	60,179
Cash, cash equivalents and restricted cash, end of period	43,368	69,981
Supplemental disclosure of non-cash investing activities:
Right-of-use assets obtained in exchange for lease obligations	552	275
Purchases of property, plant and equipment included in accounts payable	$ 818	$ 144

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	On July 8, 2022, Acorn MergeCo, Inc. (“Merger Sub”), a Delaware corporation and wholly-owned direct subsidiary of ADTRAN Holdings, Inc. (formerly known as Acorn HoldCo), merged with and into ADTRAN, Inc., with ADTRAN, Inc. surviving the merger as a wholly-owned direct subsidiary of ADTRAN Holdings, Inc. (the “Merger”). The Merger was consummated pursuant to the Business Combination Agreement, dated as of August 30, 2021 (the “Business Combination Agreement”), by and among ADTRAN Holdings, Inc., ADTRAN, Inc., ADVA Optical Networking SE, a company organized and existing under the laws of Germany (“ADVA”), and Merger Sub. In accordance with the Business Combination Agreement, ADTRAN Holdings, Inc. made a public offer to exchange each issued and outstanding no-par value bearer share of ADVA for 0.8244 shares of common stock, par value $ 0.01 per share (the “Company Common Stock”), of ADTRAN Holdings, Inc. (the “Exchange Offer” and, together with the Merger, the “Business Combination”). On July 15, 2022 (the “Exchange Offer Settlement Date”), ADTRAN Holdings, Inc. completed the Exchange Offer, in which ADTRAN Holdings, Inc. acquired 33,957,538 bearer shares of ADVA, or 65.43 % of ADVA’s outstanding bearer shares as of the Exchange Offer Settlement Date, in exchange for the issuance of an aggregate of 27,994,595 shares of common stock of ADTRAN Holdings, Inc. Except as otherwise indicated, references in these notes to “ADTRAN,” the “Company,” “we,” “us” and “our” for time periods at and before the effectiveness of the Merger, including all fiscal periods ended on or prior to June 30, 2022, shall be deemed to refer to ADTRAN, Inc. as the predecessor registrant to ADTRAN Holdings, Inc. 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited condensed consolidated financial statements of ADTRAN and its subsidiaries have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) applicable to interim financial information presented in Quarterly Reports on Form 10-Q. Accordingly, certain information and notes required by generally accepted accounting principles in the United States of America (“U.S. GAAP”) for complete financial statements are not included herein. Certain prior year amounts have been reclassified to conform to the current period presentation. The December 31, 2021 Condensed Consolidated Balance Sheet is derived from audited financial statements but does not include all disclosures required by U.S. GAAP. In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in ADTRAN, Inc. Annual Report on Form 10-K for the year ended December 31, 2021 , filed with the SEC on February 25, 2022. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Significant estimates include excess and obsolete inventory reserves, warranty reserves, customer rebates, determination and accrual of the deferred revenue related to performance obligations under contracts with customers, estimated costs to complete obligations associated with deferred and accrued revenues and network installations, estimated income tax provision and income tax contingencies, fair value of stock-based compensation, assessment of goodwill and other intangibles for impairment, estimated lives of intangible assets, estimated pension liability and fair value of investments. Actual amounts could differ significantly from these estimates. We assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to us and the unknown future impacts of the SARS-CoV-2 coronavirus/COVID-19 global pandemic (or variants of the SARS-CoV-2 coronavirus) as well as supply chain constraints as of June 30, 2022 and through the date of this report. The accounting matters assessed included, but were not limited to, the allowance for credit losses, stock-based compensation, carrying value of goodwill, intangibles and other long-lived assets, financial assets, valuation allowances for tax assets, revenue recognition and costs of revenue. Future conditions related to the magnitude and duration of the COVID-19 pandemic, as well as other factors, including supply chain constraints, could result in further impacts to our consolidated financial statements in future reporting periods. Recently Adopted Accounting Pronouncements There are currently no recently adopted accounting pronouncements that had a material effect on the condensed consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In October 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2021-08, Business Combinations (Topic 805) Accounting for Contract Assets and Contract Liabilities from Contracts with Customers, which would require an acquirer to recognize and measure acquired contract assets and contract liabilities in a manner consistent with how the acquiree recognized and measured them in its pre-acquisition financial statements in accordance with Topic 606, Revenue Recognition. ASU 2021-08 is effective for annual periods beginning after December 15, 2022, including interim periods within those fiscal years. Adoption of the AS U should be applied prospectively. Early adoption is also permitted, including adoption in an interim period. If early adopted, the amendments are applied retrospectively to all business combinations for which the acquisition date occurred during the fiscal year of adoption. Given that the Business Combination with ADVA was finalized in July 2022, the Company plans to early adopt ASU 2021-08 during the third quarter of 2022. ASU 2021-08 will be effective as of January 1, 2022 and will be applied on a prospective basis. However, we are unable to estimate the effect on our Condensed Consolidated Financial Statements as of the date of this report.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	6 Months Ended
	Jun. 30, 2022
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	2. CASH, CASH EQUIVALENTS AND RESTRICTED CASH The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statements of Cash Flows: As of As of (In thousands) June 30, 2022 December 31, 2021 Cash and cash equivalents $ 43,368 $ 56,603 Restricted cash — 215 Cash, cash equivalents and restricted cash $ 43,368 $ 56,818

Revenue

Revenue	6 Months Ended
	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
Revenue	3. REVENUE The following is a description of the principal activities from which revenue is generated by reportable segment: Network Solutions Segment - Includes hardware products and software-defined next-generation virtualized solutions used in service provider or business networks, as well as prior generation products. Services & Support Segment - Includes maintenance, network implementation, solutions integration and managed services, which include hosted cloud services and subscription services. Revenue by Category In addition to our reportable segments, revenue is also reported for the following three categories – Access & Aggregation, Subscriber Solutions & Experience and Traditional & Other Products. The following tables disaggregate revenue by reportable segment and revenue category: Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 78,852 $ 10,909 $ 89,761 $ 78,307 $ 12,657 $ 90,964 Subscriber Solutions & Experience 75,186 2,958 78,144 45,097 2,713 47,810 Traditional & Other Products 1,954 2,179 4,133 2,045 2,413 4,458 Total $ 155,992 $ 16,046 $ 172,038 $ 125,449 $ 17,783 $ 143,232 Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 163,141 $ 22,080 $ 185,221 $ 138,360 $ 21,678 $ 160,038 Subscriber Solutions & Experience 127,009 5,741 132,750 97,366 5,013 102,379 Traditional & Other Products 4,216 4,369 8,585 3,532 4,816 8,348 Total $ 294,366 $ 32,190 $ 326,556 $ 239,258 $ 31,507 $ 270,765 The aggregate amount of transaction price allocated to remaining performance obligations that have not been satisfied as of June 30, 2022 and December 31, 2021 related to contractual maintenance agreements, contractual SaaS and subscription services, and hardware contracts that exceed one year in duration amounted to $ 164.5 milli on and $ 101.1 million, respectively. As of June 30, 2022, approximately 84 % is expected to be recognized over the next 12 months and the remainder recognized thereafter. The majority of the Company's remaining performance obligations at June 30, 2022 are related to contracts or orders that have an original expected duration of one year or less, for which the Company is electing to utilize the practical expedient available within the guidance, and are excluded from the transaction price related to these future obligations. The Company will generally satisfy the remaining performance obligations as we transfer control of the products ordered or services to our customers, excluding maintenance services, which are satisfied over time. The following table provides information about receivables, contract assets and unearned revenue from contracts with customers: As of As of (In thousands) June 30, 2022 December 31, 2021 Accounts receivable, net $ 172,088 $ 158,742 Contract assets (1) $ 1,749 $ 464 Unearned revenue $ 22,705 $ 17,737 Non-current unearned revenue $ 10,133 $ 9,271 (1) Included in other receivables on the Condensed Consolidated Balance Sheets. Of the outstanding unearned revenue balances as of December 31, 2021, $ 4.1 million and $ 9.5 m illion was recognized as revenue during the three and six months ended June 30, 2022, respective ly. Of the $ 14.1 million of outstanding unearned revenue balances as of December 31, 2020, $ 2.9 million and $ 7.9 million was recognized as revenue during the three and six months ended June 30, 2021, respectively.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	4. INCOME TAXES Our effective tax rate changed from an expense of 18.1 % of pre-tax income for the three months ended June 30, 2021, to an expense of 50.1 % of pre-tax income for the three months ended June 30, 2022 and changed from an expense of 26.7 % of pre-tax income for the six months ended June 30, 2021, to a benefit of 34.3 % of pre-tax income for the six months ended June 30, 2022. The change in the effective tax rate for the three and six months ended June 30, 2022, was driven primarily by a change in our annual estimated tax rate as a result of the requirement to begin capitalizing research and development expenses for U.S. tax purposes beginning in 2022 as previously passed as part of the Tax Cuts and Jobs Act in December 2017 and the associated impact of those changes on our previously established valuation allowance. The Company continually reviews the adequacy of its valuation allowance and recognizes the benefits of deferred tax assets only as the assessment indicates that it is more likely than not that the deferred tax assets will be recognized in accordance with ASC 740, Income Taxes. As of June 30, 2022, the Company had deferred tax assets totaling $ 71.4 million, and a valuation allowance totaling $ 62.9 million against those deferred tax assets. The remaining $ 8.5 million in deferred tax assets not offset by a valuation allowance are located in various foreign jurisdictions where the Company believes it is more likely than not we will realize these deferred tax assets. During the six months ended June 30, 2022, the total change in the valuation allowance against our domestic and international deferred tax assets was recorded in the amount of an $ 12.6 million increase and a $ 0.2 million decrease, respectively. Our assessment of the realizability of our deferred tax assets includes the evaluation of historical operating results as well as the evaluation of evidence which requires significant judgment, including the evaluation of our three-year cumulative income position, future taxable income projections and tax planning strategies. Should management’s conclusion change in the future and an additional valuation allowance or a partial or full release of the valuation allowance becomes necessary, it may have a material effect on our consolidated financial statements. Supplemental balance sheet information related to deferred tax assets is as follows: As of June 30, 2022 (In thousands) Deferred Tax Assets Valuation Allowance Deferred Tax Assets, net Domestic $ 60,873 $ ( 60,873 ) $ — International 10,568 ( 2,060 ) 8,508 Total $ 71,441 $ ( 62,933 ) $ 8,508 As of December 31, 2021 (In thousands) Deferred Tax Assets Valuation Allowance Deferred Tax Assets, net Domestic $ 48,265 $ ( 48,265 ) $ — International 11,378 ( 2,299 ) 9,079 Total $ 59,643 $ ( 50,564 ) $ 9,079

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	5. STOCK-BASED COMPENSATION The following table summarizes stock-based compensation expense related to stock options, performance stock units (“PSUs”), restricted stock units (“RSUs”) and restricted stock: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Stock-based compensation expense included in cost of revenue $ 162 $ 125 $ 321 $ 256 Selling, general and administrative expense 1,135 1,098 2,259 2,196 Research and development expense 591 585 1,201 1,163 Stock-based compensation expense included in operating expenses 1,726 1,683 3,460 3,359 Total stock-based compensation expense 1,888 1,808 3,781 3,615 Tax benefit for expense associated with stock options, PSUs, RSUs and restricted stock ( 472 ) ( 452 ) ( 945 ) ( 883 ) Total stock-based compensation expense, net of tax $ 1,416 $ 1,356 $ 2,836 $ 2,732 PSUs, RSUs and Restricted Stock The following table summarizes PSUs, RSUs and restricted stock outstanding as of December 31, 2021 and June 30, 2022 and the changes that occurred during the six months ended June 30, 2022: Number of Weighted Avg. Grant Date Fair Value Unvested PSUs, RSUs and restricted stock outstanding, December 31, 2021 1,930 $ 14.11 PSUs, RSUs and restricted stock granted 336 $ 20.14 PSUs, RSUs and restricted stock vested ( 15 ) $ 13.26 PSUs, RSUs and restricted stock forfeited ( 41 ) $ 14.08 Unvested PSUs, RSUs and restricted stock outstanding, June 30, 2022 2,210 $ 15.04 During each of the six months ended June 30, 2022 and 2021, the Company granted 0.3 million performance-based PSUs to its executive officers and certain employees. The grant-date fair value of these performance-based awards was based on the closing price of the Company’s stock on the date of grant. These awards vest over one-year , two-year and three-year periods, respectively, subject to the grantee’s continued employment, with the ability to earn shares in a range of 0 % to 142.8 % of the awarded number of PSUs based on the achievement of defined performance targets. Equity-based compensation expense with respect to these awards may be adjusted over the vesting period to reflect the probability of achievement of performance targets defined in the award agreements. The fair value of RSUs and restricted stock is equal to the closing price of our stock on the date of grant. The fair value of PSUs with market conditions is calculated using a Monte Carlo simulation valuation method. As of June 30, 2022 , total unrecognized compensation expense related to non-vested market-based PSUs, RSUs and restricted stock was approximately $ 13.9 million, which will be recognized over the remaining weighted-average period of 2.5 years. Pursuant to the Business Combination, which was closed on July 15, 2022, 0.3 million of market-based PSUs were converted to time-based RSUs which will be treated as an award modification under U.S. GAAP in the third quarter of 2022. This will result in incremental compensation expense of $ 1.6 million which will be recognized over the remaining weighted-average period of 1.1 years. In addition, there was $ 13.2 million of unrecognized compensation expense related to unvested 2020, 2021 and 2022 performance-based PSUs, which will be recognized over the remaining requisite service period of 0.5 years if achievement of the performance obligation becomes probable. Pursuant to the Business Combination, which was closed on July 15, 2022, the unearned performance-based PSUs were converted to time-based RSUs which will be treated as an award modification under U.S. GAAP in the third quarter of 2022. This will result in incremental compensation and unrecognized compensation expense totaling $ 17.8 million, which will be recognized over the remaining service period of 0.5 years. Unrecognized compensation expense will be adjusted for actual forfeitures. As of June 30, 2022, 3.5 million shares were available for issuance under stockholder-approved equity plans. Stock Options The following table summarizes stock options outstanding as of December 31, 2021 and June 30, 2022 and the changes that occurred during the six months ended June 30, 2022: Number of Weighted Avg. Weighted Avg. Aggregate Stock options outstanding, December 31, 2021 1,721 $ 19.37 2.4 $ 6,669 Stock options exercised ( 37 ) $ 17.24 $ 110 Stock options expired ( 23 ) $ 23.67 $ 5 Stock options outstanding, June 30, 2022 1,661 $ 19.36 1.9 $ 1,127 Stock options exercisable, June 30, 2022 1,661 $ 19.36 1.9 $ 1,127 As of June 30, 2022 , there was no unrecognized compensation expense related to stock options as all awards vested in prior periods. There were no stock options granted during the six months ended June 30, 2022 and 2021. All of the options were previously issued at exercise prices that approximated fair market value at the date of grant. The aggregate intrinsic value of stock options represents the total pre-tax intrinsic value (the difference between ADTRAN’s closing stock price on the last trading day of the quarter and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on June 30, 2022 . The amount of aggregate intrinsic value was $ 1.1 million as of June 30, 2022 and will change based on the fair market value of ADTRAN’s stock. The total pre-tax intrinsic value of options exercised during the six months ended June 30, 2022 was $ 0.1 million.

Investments

Investments	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Investments	6. INVESTMENTS Debt Securities and Other Investments The following debt securities and other investments were included on the Condensed Consolidated Balance Sheet and recorded at fair value: As of June 30, 2022 Amortized Gross Unrealized Fair (In thousands) Cost Gains Losses Value Corporate bonds $ 10,854 $ 1 $ ( 286 ) $ 10,569 Municipal fixed-rate bonds 1,563 — ( 49 ) 1,514 Asset-backed bonds 1,018 1 ( 16 ) 1,003 Mortgage/Agency-backed bonds 4,199 — ( 185 ) 4,014 U.S. government bonds 12,287 — ( 503 ) 11,784 Foreign government bonds 410 — ( 22 ) 388 Available-for-sale debt securities held at fair value $ 30,331 $ 2 $ ( 1,061 ) $ 29,272 As of December 31, 2021 Amortized Gross Unrealized Fair (In thousands) Cost Gains Losses Value Corporate bonds $ 10,776 $ 6 $ ( 35 ) $ 10,747 Municipal fixed-rate bonds 1,553 2 ( 4 ) 1,551 Asset-backed bonds 322 3 ( 3 ) 322 Mortgage/Agency-backed bonds 4,754 15 ( 33 ) 4,736 U.S. government bonds 12,251 12 ( 92 ) 12,171 Foreign government bonds 543 — ( 4 ) 539 Available-for-sale debt securities held at fair value $ 30,199 $ 38 $ ( 171 ) $ 30,066 The contractual maturities related to debt securities and other investments were as follows: As of June 30, 2022 (In thousands) Corporate Municipal Asset- Mortgage/ U.S. government Foreign government bonds Less than one year $ 621 $ 148 $ — $ 637 $ 367 $ — One to two years 6,484 1,254 — 472 8,315 279 Two to three years 3,339 112 248 621 3,102 109 Three to five years 125 — 313 189 — — Five to ten years — — 215 925 — — More than ten years — — 227 1,170 — — Total $ 10,569 $ 1,514 $ 1,003 $ 4,014 $ 11,784 $ 388 Actual maturities may differ from contractual maturities as some borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Realized gains and losses on sales of debt securities are computed under the specific identification method. The following table presents the gross realized gains and losses related to our debt securities: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Gross realized gain on debt securities $ — $ 97 $ 12 $ 184 Gross realized loss on debt securities ( 85 ) ( 20 ) ( 125 ) ( 36 ) Total (loss) gain recognized, net $ ( 85 ) $ 77 $ ( 113 ) $ 148 Income generated from available-for-sale debt securities was recorded as interest and dividend income in the Condensed Consolidated Statements of Income. No allowance for credit losses was recorded for the six months ended June 30, 2022 and 2021 related to available-for-sale debt securities. The Company’s investment policy provides limitations for issuer concentration, which limits, at the time of purchase, the concentration in any one issuer to 5 % of the market value of our total investment portfolio. The Company did no t purchase any available-for-sale debt security with credit deterioration during the six months ended June 30, 2022. Marketable Equity Securities Our marketable equity securities consist of publicly traded stock, interests in funds and certain other investments measured at fair value or cost (where appropriate). The Company has an equity investment which does not have a readily determinable fair value and is recorded using the measurement alternative. Under the measurement alternative, equity investments that do not have a readily determinable fair value can be recorded at cost less impairment, if any, adjusted for observable price changes for an identical or similar investment. The carrying value of the equity investment as of June 30, 2022 and December 31, 2021 was $ 1.0 million. During the year ended December 31, 2021, impairment charges totaling $ 0.4 million, were recorded related to the equity investment. As of June 30 2022, cumulative impairment charges totaling $ 2.4 million were recorded related to the equity investment. There were no impairment charges during the three and six months ended June 30, 2022 and 2021. During the year ended December 31, 2021, an unsecured loan totaling $ 0.5 million was converted to equity which increased the Company's carrying value of the equity investment. The Company has a secured note receivable as of June 30, 2022 and December 31, 2021 which totaled $ 0.4 million and is included in long term investments on the Consolidated Balance Sheets. During the year ended December 31, 2021, an impairment charge of $ 0.5 million was recognized against the secured note receivable. There were no impairment charges during the three and six months ended June 30, 2022 and 2021. Realized and unrealized gains and losses related to marketable equity securities were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Realized (loss) gain on equity securities sold $ ( 293 ) $ ( 79 ) $ ( 318 ) $ ( 55 ) Unrealized (loss) gain on equity securities held ( 4,268 ) 2,011 ( 7,630 ) 2,912 Total (loss) gain recognized, net $ ( 4,561 ) $ 1,932 $ ( 7,948 ) $ 2,857 Income generated from marketable equity securities was recorded as interest and dividend income in the Condensed Consolidated Statements of Income. U.S. GAAP establishes a three-level valuation hierarchy based upon observable and unobservable inputs for fair value measurement of financial instruments: • Level 2 – Significant inputs that are observable; values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly; • Level 3 – Significant unobservable inputs; values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs could include information supplied by investees. T he Company’s cash equivalents and investments held at fair value are categorized into this hierarchy as follows: Fair Value Measurements as of June 30, 2022 Using (In thousands) Fair Value Quoted Prices Significant Significant Unobservable Inputs Cash equivalents Money market funds $ 409 $ 409 $ — $ — Available-for-sale debt securities Corporate bonds 10,569 — 10,569 — Municipal fixed-rate bonds 1,514 — 1,514 — Asset-backed bonds 1,003 — 1,003 — Mortgage/Agency-backed bonds 4,014 — 4,014 — U.S. government bonds 11,784 11,784 — — Foreign government securities 388 — 388 — Marketable equity securities Marketable equity securities – various industries 873 873 — — Deferred compensation plan assets 22,567 22,567 — — Total $ 53,121 $ 35,633 $ 17,488 $ — Fair Value Measurements as of December 31, 2021 Using (In thousands) Fair Value Quoted Prices Significant Significant Unobservable Inputs Cash equivalents Money market funds $ 652 $ 652 $ — $ — Available-for-sale debt securities Corporate bonds 10,747 — 10,747 — Municipal fixed-rate bonds 1,551 — 1,551 — Asset-backed bonds 322 — 322 — Mortgage/Agency-backed bonds 4,736 — 4,736 — U.S. government bonds 12,171 12,171 — — Foreign government bonds 539 — 539 — Marketable equity securities Marketable equity securities – various industries 12,606 12,606 — — Deferred compensation plan assets 26,935 26,935 — — Total $ 70,259 $ 52,364 $ 17,895 $ — The fair value of our Level 2 securities is calculated using a weighted average market price for each security. Market prices are obtained from a variety of industry standard data providers, large financial institutions and other third-party sources. These multiple market prices are used as inputs into a distribution-curve-based algorithm to determine the daily market value of each security.

Inventory

Inventory	6 Months Ended
	Jun. 30, 2022
Inventory Disclosure [Abstract]
Inventory	7. INVENTORY Inventory consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Raw materials $ 116,307 $ 74,709 Work in process 2,258 2,143 Finished goods 78,351 63,039 Total inventory, net $ 196,916 $ 139,891 Inventory reserves are established for estimated excess and obsolete inventory equal to the difference between the cost of the inventory and the estimated net realizable value of the inventory based on estimated reserve percentages, which considers historical usage, known trends, inventory age and market conditions. As of June 30, 2022 and December 31, 2021 , inventory reserves were $ 48.9 million and $ 44.6 million, respectively.

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	8. PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Engineering and other equipment $ 134,748 $ 134,771 Computer hardware and software 74,141 72,274 Building 68,151 68,157 Building and land improvements 35,719 35,578 Furniture and fixtures 19,967 19,917 Land $ 4,575 $ 4,575 Total property, plant and equipment 337,301 335,272 Less: accumulated depreciation ( 283,869 ) ( 279,506 ) Total property, plant and equipment, net $ 53,432 $ 55,766 Long-lived assets used in operations are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and the undiscounted cash flows estimated to be generated by the asset are less than the asset’s carrying value. No impairment charges were recognized during the three and six months ended June 30, 2022 and 2021. Depreciation expense was $ 2.7 million and $ 3.0 million for the three months ended June 30, 2022 and 2021 and $ 5.5 million and $ 6.1 million for the six months ended June 30, 2022 and 2021, respectively, which is recorded in cost of revenue, selling, general and administrative expenses and research and development expenses in the Condensed Consolidated Statements of Income.

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2022
Goodwill Disclosure [Abstract]
Goodwill	9. GOODWILL Goodwill was $ 7.0 million as of June 30, 2022 and December 31, 2021 , of which $ 6.6 million and $ 0.4 million was allocated to our Network Solutions and Services & Support reportable segments, respectively. Goodwill represents the excess purchase price over the fair value of net assets acquired. We qualitatively assess the carrying value of goodwill each reporting period for events or circumstance changes that would more likely than not reduce the fair value of the reporting unit below its carrying amount. Based on our assessment of certain qualitative factors such as macro-economic conditions, industry and market considerations, costs factors and overall financial performance, management concluded that no such events or circumstance changes were identified that would suggest that the fair value of the goodwill was more likely than not greater than its carrying amount as of June 30, 2022. No impairment of goodwill was recorded during the three and six months ended June 30, 2022 and 2021.

Intangible Assets

Intangible Assets	6 Months Ended
	Jun. 30, 2022
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible Assets	10. INTANGIBLE ASSETS Intangible assets consisted of the following: As of June 30, 2022 As of December 31, 2021 (In thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer relationships $ 20,451 $ ( 10,415 ) $ 10,036 $ 20,796 $ ( 9,906 ) $ 10,890 Developed technology 8,200 ( 4,251 ) 3,949 8,200 ( 3,683 ) 4,517 Licensed technology 5,900 ( 2,813 ) 3,087 5,900 ( 2,486 ) 3,414 Licensing agreements 560 ( 262 ) 298 560 ( 225 ) 335 Patents 500 ( 397 ) 103 500 ( 363 ) 137 Trade names 210 ( 210 ) — 210 ( 210 ) — Total $ 35,821 $ ( 18,348 ) $ 17,473 $ 36,166 $ ( 16,873 ) $ 19,293 The Company evaluates the carrying value of intangible assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and the undiscounted cash flows estimated to be generated by the asset are less than the asset’s carrying value. Due to the current economic environment, particularly related to COVID-19, the Company assessed impairment triggers related to intangible assets during the first and second quarters of 2022 and 2021. As a result, no quantitative impairment test of long-lived assets was performed as of June 30, 2022 and 2021 , and no impairment losses of intangible assets were recorded during the three and six months ended June 30, 2022 and 2021. Amortization expense was $ 0.9 million and $ 1.0 million in the three months ended June 30, 2022 and 2021 and $ 1.8 million and $ 2.1 million in the six months ended June 30, 2022 and 2021, respectively, and was included in cost of revenue, selling, general and administrative expenses and research and development expenses in the Condensed Consolidated Statements of Income. Estimated future amortization expense of intangible assets was as follows: As of (In thousands) June 30, 2022 2022 $ 1,696 2023 3,305 2024 3,213 2025 3,019 2026 1,985 Thereafter 4,255 Total $ 17,473

Leases

Leases	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Leases	11. LEASES Net Investment in Sales-Type Leases We are the lessor in sales-type lease arrangements for network equipment, which consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Current minimum lease payments receivable (1) $ 33 $ 92 Non-current minimum lease payments receivable (2) — 4 Total minimum lease payments receivable 33 96 Less: Current unearned revenue (1) 23 70 Less: Non-current unearned revenue (2) — 1 Net investment in sales-type leases $ 10 $ 25 (1) Included in other receivables on the Condensed Consolidated Balance Sheets. (2) Included in other assets on the Condensed Consolidated Balance Sheets.

Revolving Credit Agreements

Revolving Credit Agreements	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Revolving Credit Agreements	12. REVOLVING CREDIT AGREEMENTS Cadence Revolving Credit Agreement On May 19, 2022, the Company, as borrower, modified its Revolving Credit and Security Agreement and related Promissory Note (together, the “Cadence Revolving Credit Agreement”) with Cadence Bank, N.A., as lender (the “Cadence Lender”). The modified Cadence Revolving Credit Agreement provides the Company with a $ 25.0 million secured revolving credit facility. Loans under the Cadence Revolving Credit Agreement will bear interest at a rate equal to 1.50 % over the screen rate as obtained by Reuter’s, Bloomberg or another commercially available source as may be designated by the Cadence Lender from time to time; provided, however, that in no event shall the applicable rate of interest under the Cadence Revolving Credit Agreement be less than 1.50 % per annum. Such loans are secured by all of the cash, securities, securities entitlements and investment property in a certain bank account, as outlined in the Cadence Revolving Credit Agreement, at a maximum loan-to-value ratio of 85 % determined by dividing the full commitment amount under the Cadence Revolving Credit Agreement on the date of testing, determined by the Cadence Lender each fiscal quarter, by the market value of the collateral. The Cadence Revolving C redit Agreement matures on November 3, 2022 , subject to earlier termination upon the concurrence of certain events of default. The Company entered into the Cadence Revolving Credit Agreement in order to increase the flexibility and management of its short-term liquidity. During the first half of 2022, the Company made draws totaling $ 18.0 million under the Cadence Revolving Credit Agreement all of which had been repaid as of June 30, 2022. The Company agreed to certain negative covenants that are customary for credit arrangements of this type, including, among other things, r estrictions on the Company’s ability to enter into mergers, acquisitions or other business combination transactions, grant liens or suffer a material adverse change in the condition or affairs (financial or otherwise) of the Company. As of June 30, 2022, the Company was in compliance with all contractual requirements under the Cadence Revolving Credit Agreement. Wells Fargo Revolving Credit Agreement On April 1, 2022, the Company entered into a Credit Agreement and related Revolving Line of Credit Note (together, the “Wells Revolving Credit Agreement”) in favor of Wells Fargo Bank, National Association, as lender (the “Wells Lender”). The Wells Revolving Credit Agreement provides the Company with a new $ 25.0 million secured revolving credit facility. The Wells Revolving Credit Agreement matures on April 1, 2023 , subject to earlier termination upon the occurrence of certain events of default as set forth in the Wells Revolving Credit Agreement. Loans under the Wells Revolving Credit Agreement will bear interest at a fluctuating rate per annum equal to: (i) the Daily Simple SOFR (as defined herein) plus (ii) an applicable margin, which will equal 1.00 %, 1.25 %, 1.5 % or 2.0 % per annum depending on the Company’s senior funded debt to EBITDA ratio. The “Daily Simple SOFR” is calculated based upon the greater of (x) a floor of 0.00 % and (b) the Secured Overnight Financing Rate, as established by the Federal Reserve Bank of New York (or a successor thereto) from time to time. Accrued interest is payable on the last day of each quarter, commencing June 30, 2022. Borrowings under the Wells Revolving Credit Agreement may be used solely for issuing letters of credit, financing capital expenditures, and working capital and general corporate purposes. Loans under the Wells Revolving Credit Agreement are secured by a first priority security interest in all of the accounts receivable of the Company and its subsidiary, ADTRAN International, Inc. Specifically, in connection with the Wells Revolving Credit Agreement, the Company entered into a security agreement, dated April 1, 2022, pursuant to which the Company pledged to the Wells Lender all of the rights to payment, accounts, deposit accounts, chattel paper (whether electronic or tangible), instruments, promissory notes, documents, licenses, general intangibles, payment intangibles, software, letter of credit rights and healthcare insurance receivables existing as of the date of execution or arising at any time thereafter. During the first half of 2022, the Company made draws totaling $ 10.0 million under the Wells Revolving Credit Agreement all of which had been repaid as of June 30, 2022. As of June 30, 2022, the Company was in compliance with all contractual requirements under the Wells Fargo Credit Agreement.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Stockholders' Equity	13. STOCKHOLDERS’ EQUITY Stock Repurchase Program During the six months ended June 30, 2022 , we did no t repurchase any shares of our common stock. As of June 30, 2022 , we had the authority to purchase an additional 2.5 million shares of our common stock under the current authorization of up to 5.0 million shares. Subsequent to the Business Combination in July 2022, there is no current authorization to repurchase common stock. Accumulated Other Comprehensive Loss The following tables present the changes in accumulated other comprehensive loss, net of tax, by component: Three Months Ended June 30, 2022 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total Balance as of March 31, 2022 $ ( 1,276 ) $ ( 5,626 ) $ ( 7,039 ) $ 385 $ ( 13,556 ) Other comprehensive loss before ( 589 ) — ( 2,853 ) — ( 3,442 ) Amounts reclassified from accumulated other 389 ( 87 ) — — 302 Net current period other comprehensive loss ( 200 ) ( 87 ) ( 2,853 ) — ( 3,140 ) Balance as of June 30, 2022 $ ( 1,476 ) $ ( 5,713 ) $ ( 9,892 ) $ 385 $ ( 16,696 ) Three Months Ended June 30, 2021 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total Balance as of March 31, 2021 $ ( 160 ) $ ( 9,522 ) $ ( 4,298 ) $ 385 $ ( 13,595 ) Other comprehensive (loss) income before ( 272 ) — 338 — 66 Amounts reclassified from accumulated other 177 212 — — 389 Net current period other comprehensive (loss) income ( 95 ) 212 338 — 455 Balance as of June 30, 2021 $ ( 255 ) $ ( 9,310 ) $ ( 3,960 ) $ 385 $ ( 13,140 ) Six Months Ended June 30, 2022 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total As of December 31, 2021 $ ( 552 ) $ ( 5,613 ) $ ( 6,134 ) $ 385 $ ( 11,914 ) Other comprehensive loss before ( 1,564 ) — ( 3,758 ) — ( 5,322 ) Amounts reclassified from accumulated other 640 ( 100 ) — — 540 Net current period other comprehensive loss ( 924 ) ( 100 ) ( 3,758 ) — ( 4,782 ) As of June 30, 2022 $ ( 1,476 ) $ ( 5,713 ) $ ( 9,892 ) $ 385 $ ( 16,696 ) Six Months Ended June 30, 2021 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total As of December 31, 2020 $ 32 $ ( 9,621 ) $ ( 2,435 ) $ 385 $ ( 11,639 ) Other comprehensive loss before ( 329 ) — ( 1,525 ) — ( 1,854 ) Amounts reclassified from accumulated other 42 311 — — 353 Net current period other comprehensive (loss) income ( 287 ) 311 ( 1,525 ) — ( 1,501 ) As of June 30, 2021 $ ( 255 ) $ ( 9,310 ) $ ( 3,960 ) $ 385 $ ( 13,140 ) The following tables present the details of reclassifications out of accumulated other comprehensive loss: Three Months Ended June 30, 2022 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 512 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain 126 (1) Total reclassifications for the period, before tax ( 386 ) Tax benefit 84 Total reclassifications for the period, net of tax $ ( 302 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Three Months Ended June 30, 2021 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 233 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial losses ( 307 ) (1) Total reclassifications for the period, before tax ( 540 ) Tax benefit 151 Total reclassifications for the period, net of tax $ ( 389 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Six Months Ended June 30, 2022 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 842 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain 145 (1) Total reclassifications for the period, before tax ( 697 ) Tax benefit 157 Total reclassifications for the period, net of tax $ ( 540 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Six Months Ended June 30, 2021 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 55 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain ( 451 ) (1) Total reclassifications for the period, before tax ( 506 ) Tax benefit 153 Total reclassifications for the period, net of tax $ ( 353 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. The following tables present the tax effects related to the change in each component of other comprehensive (loss) income: Three Months Ended Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Net-of-Tax Unrealized loss on available-for-sale $ ( 775 ) $ 186 $ ( 589 ) $ ( 358 ) $ 86 $ ( 272 ) Reclassification adjustment for amounts related to 512 ( 123 ) 389 233 ( 56 ) 177 Reclassification adjustment for amounts related to ( 126 ) 39 ( 87 ) 307 ( 95 ) 212 Foreign currency translation adjustment ( 2,853 ) — ( 2,853 ) 338 — 338 Total Other Comprehensive (Loss) Income $ ( 3,242 ) $ 102 $ ( 3,140 ) $ 520 $ ( 65 ) $ 455 Six Months Ended Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Net-of-Tax Unrealized loss on available-for-sale $ ( 2,058 ) $ 494 $ ( 1,564 ) $ ( 433 ) $ 104 $ ( 329 ) Reclassification adjustment for amounts related to 842 ( 202 ) 640 55 ( 13 ) 42 Reclassification adjustment for amounts related to ( 145 ) 45 ( 100 ) 451 ( 140 ) 311 Foreign currency translation adjustment ( 3,758 ) — ( 3,758 ) ( 1,525 ) — ( 1,525 ) Total Other Comprehensive Loss $ ( 5,119 ) $ 337 $ ( 4,782 ) $ ( 1,452 ) $ ( 49 ) $ ( 1,501 )

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Earnings Per Share	14. EARNINGS PER SHARE The calculation of basic and diluted earnings per share is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands, except per share amounts) 2022 2021 2022 2021 Numerator Net income $ 2,143 $ 5,086 $ 1,016 $ 5,982 Denominator Weighted average number of shares – basic 49,123 48,449 49,110 48,393 Effect of dilutive securities Stock options 84 816 111 722 PSUs, RSUs and restricted stock 602 161 592 110 Weighted average number of shares – diluted 49,809 49,426 49,813 49,225 Earnings per share – basic $ 0.04 $ 0.10 $ 0.02 $ 0.12 Earnings per share – diluted $ 0.04 $ 0.10 $ 0.02 $ 0.12 For the three months ended June 30, 2022 and 2021, 33 thousand and one thousand shares, respectively, and for the six months ended June 30, 2022 and 2021, eight thousand and three thousand, respectively, of unvested PSUs, RSUs and restricted stock were excluded from the calculation of diluted earnings per share due to their anti-dilutive effect. For the three months ended June 30, 2022 and 2021, 0.2 million and 0.4 million stock options, respectively, and for the six months ended June 30, 2022 and 2021, 0.1 million and 0.6 million stock options, respectively, were outstanding but were not included in the computation of diluted earnings per share. These stock options were excluded because their exercise prices were greater than the average market price of the common shares during the applicable period, making them anti-dilutive under the treasury stock method.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2022
Segment Reporting [Abstract]
Segment Information	15. SEGMENT INFORMATION The chief operating decision maker regularly reviews the Company’s financial performance based on two reportable segments: (1) Network Solutions and (2) Services & Support. Network Solutions includes hardware and software products and next-generation virtualized solutions used in service provider or business networks, as well as prior-generation products. Services & Support includes a portfolio of maintenance, network installation and solution integration services, which include hosted cloud services and subscription services. The performance of these segments is evaluated based on gross profit; therefore, selling, general and administrative expenses, research and development expenses, interest and dividend income, interest expense, net investment gain (loss), other income (expense), net and income tax benefit (expense) are reported on a Company-wide basis only. There is no inter-segment revenue. Asset information by reportable segment is not produced and, therefore, is not reported. The following tables present information about the revenue and gross profit of our reportable segments: Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Revenue Gross Profit Revenue Gross Profit Network Solutions $ 155,992 $ 56,071 $ 125,449 $ 55,435 Services & Support 16,046 6,435 17,783 7,233 Total $ 172,038 $ 62,506 $ 143,232 $ 62,668 Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Revenue Gross Profit Revenue Gross Profit Network Solutions $ 294,366 $ 103,791 $ 239,258 $ 104,243 Services & Support 32,190 13,031 31,507 12,026 Total $ 326,556 $ 116,822 $ 270,765 $ 116,269 Revenue by Category In addition to our reportable segments, revenue is also reported for the following three categories – Access & Aggregation, Subscriber Solutions & Experience and Traditional & Other Products. The table below presents revenue information by category: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Access & Aggregation $ 89,761 $ 90,964 $ 185,221 $ 160,038 Subscriber Solutions & Experience 78,144 47,810 132,750 102,379 Traditional & Other Products 4,133 4,458 8,585 8,348 Total $ 172,038 $ 143,232 $ 326,556 $ 270,765 Revenue by Geographic Area The following table presents revenue information by geographic area: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 United States $ 105,752 $ 94,656 $ 204,801 $ 181,141 United Kingdom 28,838 13,566 59,243 21,501 Germany 14,859 18,750 25,376 32,955 Other international 22,589 16,260 37,136 35,168 Total $ 172,038 $ 143,232 $ 326,556 $ 270,765

Liability for Warranty Returns

Liability for Warranty Returns	6 Months Ended
	Jun. 30, 2022
Product Warranties Disclosures [Abstract]
Liability for Warranty Returns	16. LIABILITY FOR WARRANTY RETURNS Our products generally include warranties of 90 days to five years for product defects. We accrue for warranty returns at the time of product shipment based on our historical return rate and estimate of the cost to repair or replace the defective products. We engage in extensive product quality programs and processes, including actively monitoring and evaluating the quality of our component suppliers. The increasing complexity of our products may cause warranty incidences, when they arise, to be more costly. Estimates regarding future warranty obligations may change due to product failure rates, material usage and other rework costs incurred in correcting a product failure. In addition, from time to time, specific warranty accruals may be recorded if unforeseen problems arise. Should our actual experience relative to these factors be worse than our estimates, we will be required to record additional warranty expense. The liability for warranty obligations totaled $ 4.8 million and $ 5.4 million as of June 30, 2022 and December 31, 2021 , respectively, and is included in accrued expenses and other liabilities in the Condensed Consolidated Balance Sheets. During the three months ended June 30, 2021, we had a net reversal of prior provisions related to warranty expirations the impact of which is reflected in the table below. The warranty expense and write-off activity for the three and six months ended June 30, 2022 and 2021 is summarized as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Balance at beginning of period $ 5,143 $ 6,472 $ 5,403 $ 7,146 Plus: Amounts charged to cost and expenses 814 11 1,111 ( 220 ) Less: Deductions ( 1,115 ) ( 486 ) ( 1,672 ) ( 929 ) Balance at end of period $ 4,842 $ 5,997 $ 4,842 $ 5,997

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. COMMITMENTS AND CONTINGENCIES Shareholder Derivative Lawsuit On March 31, 2020, a shareholder derivative suit, captioned Johnson (Derivatively on behalf of ADTRAN) v. Stanton, et al., Case No. 5:20-cv-00447, was filed in the U.S. District Court for the Northern District of Alabama against two of the Company’s current executive officers, one of its former executive officers, and certain current and former members of its Board of Directors, alleging, among other things, that the defendants made or caused the Company to make materially false and misleading statements regarding, and/or failed to disclose material adverse facts about, the Company’s business, operations and prospects, specifically relating to the Company’s internal control over financial reporting, excess and obsolete inventory reserves, financial results and demand from certain customers. The plaintiff in the shareholder derivative suit sent a demand letter dated June 29, 2021 to ADTRAN’s Board of Directors. The letter contains similar allegations to those made in the plaintiff’s filed complaint and in the now dismissed securities class action, and it demands, among other things, that the Board of Directors commence an investigation into the alleged wrongdoing. On December 10, 2021, after investigating the allegations in the plaintiff’s demand with the assistance of independent counsel, the independent members of the Board of Directors concluded that pursuing the claims asserted in the demand would not be in the Company's best interests and exercised their business judgment to refuse the demand. The plaintiff subsequently dismissed the case. On February 25, 2022, the Court entered an order on the parties’ joint stipulation dismissing the case without prejudice. Other Legal Matters In addition to the litigation described above, from time to time we are subject to or otherwise involved in various lawsuits, claims, investigations and legal proceedings that arise out of or are incidental to the conduct of our business (collectively, “Legal Matters”), including those relating to employment matters, patent rights, regulatory compliance matters, stockholder claims, and contractual and other commercial disputes. Such Legal Matters, even if not meritorious, could result in the expenditure of significant financial and managerial resources. Additionally, an unfavorable outcome in a legal matter, including in a patent dispute, could require the Company to pay damages, entitle claimants to other relief, such as royalties, or could prevent the Company from selling some of its products in certain jurisdictions. At this time, we are unable to predict the outcome of or estimate the possible loss or range of loss, if any, associated with such legal matters. Performance Bonds C ertain contracts, customers and jurisdictions in which we do business require us to provide various guarantees of performance such as bid bonds, performance bonds and customs bonds. As of June 30, 2022 and December 31, 2021, we had commitments related to these bonds totaling $ 21.8 million and $ 22.9 million, respectively, which expire at various dates through April 2025 . In general we would only be liable for the amount of these guarantees in the event of default under each contract, the probability of which we believe is remote. In June 2020, the Company entered into a letter of credit with a bank to guarantee performance obligations under a contract with a certain customer. The obligations under this customer contract will be performed over multiple years. We reached the maximum value of our minimum collateral requirement of $ 15.0 million during the three months ended March 31, 2021 as the Company reached certain milestones through the first quarter of 2021 as outlined in the customer contract. In conjunction with the Company entering into the revolving credit facility with Wells Fargo during the three months ended June 30, 2022, our obligation to maintain the pledged collateral was released. This pledged collateral value fluctuated as the Company changed the mix of the pledged collateral between restricted cash and investments. Any shortfalls in the minimum collateral value was required to be restored by the Company from available cash and cash equivalents, short-term investments and/or long-term investments. For additional information on the Wells Fargo revolving credit facility see Note 12 of the Notes to Condensed Consolidated Financial Statements, included in Part I, Item 1 of this report. Investment Commitment We have committed to invest up to an aggregate of $ 5.0 million in a private equity fund, of which $ 4.9 million has been invested as of June 30, 2022 .

Restructuring

Restructuring	6 Months Ended
	Jun. 30, 2022
Restructuring and Related Activities [Abstract]
Restructuring	18. RESTRUCTURING During the second half of 2019, the Company initiated a restructuring plan to realign its expense structure with the reduction in revenue experienced in recent years and overall Company objectives. As part of this restructuring plan, the Company announced plans to reduce its overall operating expenses, both in the U.S. and internationally. Management continued to assess the efficiency of operations during 2020 and the first three months of 2021 and, in turn, consolidated locations and personnel, among other things, where possible. In February 2019, the Company announced the restructuring of a certain portion of its workforce predominantly in Germany, which included the closure of the Company’s office location in Munich, Germany accompanied by relocation or severance benefits for the affected employees. Voluntary early retirement was offered to certain other employees and was announced in March 2019 and again in August 2020. The cumulative amount of restructuring expenses incurred as of June 30, 2022 for the restructuring plans was $ 12.7 million. A reconciliation of the beginning and ending restructuring liability, which is included in accrued wages and benefits in the Condensed Consolidated Balance Sheets is as follows: Three Months Ended Six Months Ended (In thousands) June 30, 2022 June 30, 2022 Balance at beginning of period $ 260 $ 1,514 Plus: Amounts charged to cost and expense — 2 Less: Amounts paid ( 13 ) ( 1,269 ) Balance as of June 30, 2022 $ 247 $ 247 For the Year Ended (In thousands) December 31, 2021 Balance as of December 31, 2020 $ 4,186 Plus: Amounts charged to cost and expense 411 Less: Amounts paid ( 3,083 ) Balance as of December 31, 2021 $ 1,514 Restructuring expenses included in the Condensed Consolidated Statements of Income were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Network Solutions - Cost of revenue $ — $ — $ — $ 12 Services & Support - Cost of revenue — — — 3 Cost of revenue $ — $ — $ — $ 15 Selling, general and administrative expenses (1) — 3 2 145 Research and development expenses (1) — 5 — 149 Total restructuring expenses $ — $ 8 $ 2 $ 309 (1) The Company does not allocate selling, general and administrative expense and research and development expense to the segment level. Components of restructuring expense by geographic area were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 United States $ — $ 3 $ 2 $ 212 International — 5 — 97 Total restructuring expenses $ — $ 8 $ 2 $ 309

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	19. SUBSEQUENT EVENTS On August 3, 2022 , we announced that our Board of Directors declared a quarterly cash dividend of $ 0.09 per common share to be paid to the Company’s stockholders of record as of the close of business on August 18, 2022 . The payment date will be September 1, 2022 in the aggregate amount of approximately $ 7.0 million. Closing of the Business Combination with ADVA As previously disclosed, on July 8, 2022, Acorn MergeCo, Inc. (“Merger Sub”), a Delaware corporation and wholly-owned direct subsidiary of ADTRAN Holdings, Inc. (f/k/a Acorn HoldCo, Inc.) (the “Company”), merged with and into ADTRAN, Inc. (“ADTRAN”), with ADTRAN surviving the merger as a wholly-owned direct subsidiary of the Company (the “Merger”). The Merger was consummated pursuant to the Business Combination Agreement (the “Business Combination Agreement”), dated as of August 30, 2021 , by and among the Company, ADTRAN, ADVA Optical Networking SE, a company organized and existing under the laws of Germany (“ADVA”), and Merger Sub. Pursuant to the Business Combination Agreement, the Company made a public offer to exchange each issued and outstanding no-par value bearer share of ADVA for 0.8244 shares of common stock, par value $ 0.01 per share (the “Company Common Stock”), of the Company (the “Exchange Offer” and, together with the Merger, the “Business Combination”). The acceptance period for the Exchange Offer ended on February 14, 2022, and on July 6, 2022, the Company announced that all special offer conditions to the consummation of the Exchange Offer had been satisfied. The Exchange Offer was settled on July 15, 2022 (the “Exchange Offer Settlement Date”) in which the Company acquired 33,957,538 bearer shares of ADVA, or 65.43 % of ADVA’s outstanding bearer shares as of the Exchange Offer Settlement Date, in exchange for the issuance of an aggregate of 27,994,595 shares of Company Common Stock. Based on the Company's closing share price as of July 15, 2022 of $ 20.20 , the value of the Company Common Stock provided in exchange for ADVA common stock was approximately $ 565.5 million. The issuance of shares of Company Common Stock in connection with the Business Combination was registered under the Securities Act of 1933, as amended (the “Securities Act”), pursuant to a registration statement on Form S-4 (the “Registration Statement”) (File No. 333-259251), which was declared effective by the U.S. Securities and Exchange Commission on December 2, 2021, and which included a proxy statement of ADTRAN for the special meeting of the stockholders of ADTRAN at which ADTRAN’s stockholders voted to adopt the Business Combination Agreement and that also constituted a prospectus for the Company (the “Proxy Statement”). The Company Common Stock is listed on the Nasdaq Global Select Market (“Nasdaq”) and trades under the symbol “ADTN”. The Company Common Stock was also approved for listing on the regulated market segment (regulierter Markt) of the Frankfurt Stock Exchange (Frankfurter Wertpapierbörse) with simultaneous admission to the sub-segment thereof with additional post-admission obligations (Prime Standard) on July 13, 2022 and trades there under the symbol “QH9”. For the three and six months ended June 30, 2022, the Company incurred $ 0.9 million and $ 1.8 million of transaction costs and were recognized as selling, general and administrative expense and research and development expense in our Condensed Consolidated Statements of Income, respectively. For the three and six months ended June 30, 2021, the Company incurred $ 2.4 million and $ 3.4 million of transaction costs and were recognized as selling, general and administrative expense and research and development expense in our Condensed Consolidated Statements of Income, respectively. We expect that the business combination will be accounted for using the acquisition method of accounting under ASC 805, with ADTRAN Holdings, Inc. representing the accounting acquirer under this guidance. Due to the timing of the acquisition subsequent to our June 30, 2022 reporting period end, the initial accounting, including the allocation of purchase price and supplemental pro forma information, is incomplete as of the filing date and, therefore, related disclosures are not included herein. Assumed ADVA Options Pursuant to the Business Combination which closed on July 15, 2022, ADVA stock option holders were entitled to have their ADVA stock options assumed by ADTRAN Holdings (applying the exchange ratio in the Business Combination Agreement), thereafter representing options to acquire stock of ADTRAN Holdings. The maximum number of shares of ADTRAN Holdings stock potentially issuable upon such assumption was 2.1 million shares. The period in which such options could be assumed ended July 22, 2022. A total of 2.0 million shares of ADTRAN Holdings stock are subject to assumed ADVA options. The fair value of the stock options assumed by ADTRAN Holdings will be estimated using a Black-Scholes model. Our valuation of this component of consideration is not yet complete. Wells Fargo Credit Agreement On July 18, 2022, ADTRAN Holdings, Inc. and ADTRAN, Inc., as the borrower, entered into a credit agreement with a syndicate of banks, including Wells Fargo Bank, National Association, as administrative agent (“Administrative Agent”), and the other lenders named therein (the “Credit Agreement”). The Credit Agreement allows for borrowings of up to $ 100 million in aggregate principal amount, subject to being increased to up to $ 400 million in aggregate principal amount upon the Company or Borrower’s execution of a domination and profit and loss transfer agreement with ADVA or a parent of ADVA, among other conditions (the “Senior Credit Facilities Increase”). The Credit Agreement replaced the Cadence Revolving Credit Agreement and the Wells Fargo Revolving Credit Agreement. In connection with the entry into the Credit Agreement, all outstanding borrowings under such credit agreements have been repaid and the agreements terminated. As of August 5, 2022, ADTRAN, Inc.’s borrowings under the revolving line of credit were $ 50.0 million. In addition, a $ 17.5 million letter of credit with ADTRAN, Inc. remains outstanding. Any future credit extensions under the Credit Agreement are subject to customary conditions precedent. The proceeds of any loans are expected to be used for general corporate purposes and to pay a portion of the Exchange Offer consideration. All U.S. borrowings under the Credit Agreement (other than swingline loans, which will bear interest at the Base Rate (as defined below)) will bear interest, at the Company’s option, at a rate per annum equal to (A)(i) the highest of (a) the federal funds rate (i.e., for any day, the rate per annum equal to the weighted average of the rates on overnight federal funds transactions with members of the Federal Reserve System, as published by the Federal Reserve Bank of New York on the business day next succeeding such day) plus ½ of 1 %, (b) the prime commercial lending rate of the Administrative Agent, as established from time to time at its principal U.S. office (which such rate is an index or base rate and will not necessarily be its lowest or best rate charged to its customers or other banks), and (c) the daily Adjusted Term SOFR (as defined in the Credit Agreement) for a one-month tenor plus 1 %, plus (ii) the applicable rate, ranging from 0.5 % to 1.25 % (the “Base Rate”), or (B) the sum of the Adjusted Term SOFR (as defined in the Credit Agreement) plus the applicable rate, ranging from 1.4 % to 2.15 %, provided that such sum is subject to a 0.0 % floor (such loans utilizing this interest rate, “SOFR Loans”). All E.U. borrowings under the Credit Agreement (other than swingline loans) will bear interest at a rate per annum equal to the sum of the Euro Interbank Offered Rate as administered by the European Money Markets Institute (or a comparable or successor administrator approved by the Administrative Agent) plus the applicable rate, ranging from 1.5 % to 2.25 %, provided that such sum is subject to a 0.0 % floor (such loans utilizing this interest rate, “EURIBOR Loans”). The applicable rate is based on the consolidated net leverage ratio of the Company and its subsidiaries as determined pursuant to the terms of the Credit Agreement. Default interest is 2.00 % per annum in excess of the rate otherwise applicable in the case of any overdue principal or any other overdue amount. In addition to paying interest on outstanding principal under the Credit Agreement, the Company is required to pay a commitment fee to the lenders under the Credit Agreement in respect of unutilized revolving loan commitments and an additional commitment ticking fee at a rate of 0.25 % on the commitment amounts of each lender until the earliest of (i) the date of the Senior Credit Facilities Increase, (ii) the Company’s voluntary termination of the credit facility commitment, and (iii) December 31, 2023. The Company is also required to pay a participation fee to the Administrative Agent for the account of each lender with respect to the Company’s participations in letters of credit at the then applicable rate for SOFR Loans. The Credit Agreement will mature on July 14, 2027 , with the Company’s option to request extensions subject to customary conditions. The Credit Agreement permits the Company to prepay any or all of the outstanding loans or to reduce the commitments under the Credit Agreement without incurring premiums or penalties (except breakage costs with respect to SOFR Loans and EURIBOR Loans). The Credit Agreement contains customary affirmative and negative covenants, including incurrence covenants and certain other limitations on the ability of the Company and the Company’s subsidiaries to incur additional debt, guarantee other obligations, grant liens on assets, make investments, dispose of assets, pay dividends or other payments on capital stock, make restricted payments, engage in mergers or consolidations, engage in transactions with affiliates, modify its organizational documents, and enter into certain restrictive agreements. It also contains customary events of default (subject to customary cure periods and materiality thresholds). Furthermore, the Credit Agreement requires that the Consolidated Total Net Leverage Ratio (as defined in the Credit Agreement) of the Company and its subsidiaries tested on the last day of each fiscal quarter not to exceed 3.25 to 1.00 through September 30, 2024 and 2.75 to 1.00 from December 31, 2024 and thereafter, subject to certain exceptions. The Credit Agreement also requires that the Consolidated Interest Coverage Ratio (as defined in the Credit Agreement) of the Company and its subsidiaries tested on the last day of each fiscal quarter not fall below 3.00 to 1.00. Finally, pursuant to a Collateral Agreement, dated as of July 18, 2022, among the Company, ADTRAN, Inc. and the Administrative Agent, ADTRAN, Inc.’s obligations under the Credit Agreement are secured by substantially all of the assets of ADTRAN, Inc. and the Company. In addition, the Company has guaranteed ADTRAN, Inc.’s obligations under the Credit Agreement pursuant to a Guaranty Agreement, dated as of July 18, 2022, by ADTRAN, Inc. and the Company in favor of the Administrative Agent.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements of ADTRAN and its subsidiaries have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) applicable to interim financial information presented in Quarterly Reports on Form 10-Q. Accordingly, certain information and notes required by generally accepted accounting principles in the United States of America (“U.S. GAAP”) for complete financial statements are not included herein. Certain prior year amounts have been reclassified to conform to the current period presentation. The December 31, 2021 Condensed Consolidated Balance Sheet is derived from audited financial statements but does not include all disclosures required by U.S. GAAP. In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in ADTRAN, Inc. Annual Report on Form 10-K for the year ended December 31, 2021 , filed with the SEC on February 25, 2022.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Significant estimates include excess and obsolete inventory reserves, warranty reserves, customer rebates, determination and accrual of the deferred revenue related to performance obligations under contracts with customers, estimated costs to complete obligations associated with deferred and accrued revenues and network installations, estimated income tax provision and income tax contingencies, fair value of stock-based compensation, assessment of goodwill and other intangibles for impairment, estimated lives of intangible assets, estimated pension liability and fair value of investments. Actual amounts could differ significantly from these estimates. We assessed certain accounting matters that generally require consideration of forecasted financial information in context with the information reasonably available to us and the unknown future impacts of the SARS-CoV-2 coronavirus/COVID-19 global pandemic (or variants of the SARS-CoV-2 coronavirus) as well as supply chain constraints as of June 30, 2022 and through the date of this report. The accounting matters assessed included, but were not limited to, the allowance for credit losses, stock-based compensation, carrying value of goodwill, intangibles and other long-lived assets, financial assets, valuation allowances for tax assets, revenue recognition and costs of revenue. Future conditions related to the magnitude and duration of the COVID-19 pandemic, as well as other factors, including supply chain constraints, could result in further impacts to our consolidated financial statements in future reporting periods.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements There are currently no recently adopted accounting pronouncements that had a material effect on the condensed consolidated financial statements.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In October 2021, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") 2021-08, Business Combinations (Topic 805) Accounting for Contract Assets and Contract Liabilities from Contracts with Customers, which would require an acquirer to recognize and measure acquired contract assets and contract liabilities in a manner consistent with how the acquiree recognized and measured them in its pre-acquisition financial statements in accordance with Topic 606, Revenue Recognition. ASU 2021-08 is effective for annual periods beginning after December 15, 2022, including interim periods within those fiscal years. Adoption of the AS U should be applied prospectively. Early adoption is also permitted, including adoption in an interim period. If early adopted, the amendments are applied retrospectively to all business combinations for which the acquisition date occurred during the fiscal year of adoption. Given that the Business Combination with ADVA was finalized in July 2022, the Company plans to early adopt ASU 2021-08 during the third quarter of 2022. ASU 2021-08 will be effective as of January 1, 2022 and will be applied on a prospective basis. However, we are unable to estimate the effect on our Condensed Consolidated Financial Statements as of the date of this report.

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2022
Cash and Cash Equivalents [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statements of Cash Flows: As of As of (In thousands) June 30, 2022 December 31, 2021 Cash and cash equivalents $ 43,368 $ 56,603 Restricted cash — 215 Cash, cash equivalents and restricted cash $ 43,368 $ 56,818

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
Disaggregate of Revenue by Reportable Segment and Revenue Category	The following tables disaggregate revenue by reportable segment and revenue category: Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 78,852 $ 10,909 $ 89,761 $ 78,307 $ 12,657 $ 90,964 Subscriber Solutions & Experience 75,186 2,958 78,144 45,097 2,713 47,810 Traditional & Other Products 1,954 2,179 4,133 2,045 2,413 4,458 Total $ 155,992 $ 16,046 $ 172,038 $ 125,449 $ 17,783 $ 143,232 Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 163,141 $ 22,080 $ 185,221 $ 138,360 $ 21,678 $ 160,038 Subscriber Solutions & Experience 127,009 5,741 132,750 97,366 5,013 102,379 Traditional & Other Products 4,216 4,369 8,585 3,532 4,816 8,348 Total $ 294,366 $ 32,190 $ 326,556 $ 239,258 $ 31,507 $ 270,765 The table below presents revenue information by category: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Access & Aggregation $ 89,761 $ 90,964 $ 185,221 $ 160,038 Subscriber Solutions & Experience 78,144 47,810 132,750 102,379 Traditional & Other Products 4,133 4,458 8,585 8,348 Total $ 172,038 $ 143,232 $ 326,556 $ 270,765
Information about Receivables, Contract Assets, and Unearned Revenue from Contracts with Customers	The following table provides information about receivables, contract assets and unearned revenue from contracts with customers: As of As of (In thousands) June 30, 2022 December 31, 2021 Accounts receivable, net $ 172,088 $ 158,742 Contract assets (1) $ 1,749 $ 464 Unearned revenue $ 22,705 $ 17,737 Non-current unearned revenue $ 10,133 $ 9,271

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Summary of Supplemental Balance Sheet Information Related to Deferred Tax Assets	Supplemental balance sheet information related to deferred tax assets is as follows: As of June 30, 2022 (In thousands) Deferred Tax Assets Valuation Allowance Deferred Tax Assets, net Domestic $ 60,873 $ ( 60,873 ) $ — International 10,568 ( 2,060 ) 8,508 Total $ 71,441 $ ( 62,933 ) $ 8,508 As of December 31, 2021 (In thousands) Deferred Tax Assets Valuation Allowance Deferred Tax Assets, net Domestic $ 48,265 $ ( 48,265 ) $ — International 11,378 ( 2,299 ) 9,079 Total $ 59,643 $ ( 50,564 ) $ 9,079

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation Expense Related to Stock Options, PSUs, RSUs and Restricted Stock	The following table summarizes stock-based compensation expense related to stock options, performance stock units (“PSUs”), restricted stock units (“RSUs”) and restricted stock: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Stock-based compensation expense included in cost of revenue $ 162 $ 125 $ 321 $ 256 Selling, general and administrative expense 1,135 1,098 2,259 2,196 Research and development expense 591 585 1,201 1,163 Stock-based compensation expense included in operating expenses 1,726 1,683 3,460 3,359 Total stock-based compensation expense 1,888 1,808 3,781 3,615 Tax benefit for expense associated with stock options, PSUs, RSUs and restricted stock ( 472 ) ( 452 ) ( 945 ) ( 883 ) Total stock-based compensation expense, net of tax $ 1,416 $ 1,356 $ 2,836 $ 2,732
Summary of PSUs, RSUs and Restricted Stock Outstanding	The following table summarizes PSUs, RSUs and restricted stock outstanding as of December 31, 2021 and June 30, 2022 and the changes that occurred during the six months ended June 30, 2022: Number of Weighted Avg. Grant Date Fair Value Unvested PSUs, RSUs and restricted stock outstanding, December 31, 2021 1,930 $ 14.11 PSUs, RSUs and restricted stock granted 336 $ 20.14 PSUs, RSUs and restricted stock vested ( 15 ) $ 13.26 PSUs, RSUs and restricted stock forfeited ( 41 ) $ 14.08 Unvested PSUs, RSUs and restricted stock outstanding, June 30, 2022 2,210 $ 15.04
Summary of Stock Options Outstanding	The following table summarizes stock options outstanding as of December 31, 2021 and June 30, 2022 and the changes that occurred during the six months ended June 30, 2022: Number of Weighted Avg. Weighted Avg. Aggregate Stock options outstanding, December 31, 2021 1,721 $ 19.37 2.4 $ 6,669 Stock options exercised ( 37 ) $ 17.24 $ 110 Stock options expired ( 23 ) $ 23.67 $ 5 Stock options outstanding, June 30, 2022 1,661 $ 19.36 1.9 $ 1,127 Stock options exercisable, June 30, 2022 1,661 $ 19.36 1.9 $ 1,127

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Debt Securities and Other Investments, Included on Condensed Consolidated Balance Sheet and Recorded at Fair Value	The following debt securities and other investments were included on the Condensed Consolidated Balance Sheet and recorded at fair value: As of June 30, 2022 Amortized Gross Unrealized Fair (In thousands) Cost Gains Losses Value Corporate bonds $ 10,854 $ 1 $ ( 286 ) $ 10,569 Municipal fixed-rate bonds 1,563 — ( 49 ) 1,514 Asset-backed bonds 1,018 1 ( 16 ) 1,003 Mortgage/Agency-backed bonds 4,199 — ( 185 ) 4,014 U.S. government bonds 12,287 — ( 503 ) 11,784 Foreign government bonds 410 — ( 22 ) 388 Available-for-sale debt securities held at fair value $ 30,331 $ 2 $ ( 1,061 ) $ 29,272 As of December 31, 2021 Amortized Gross Unrealized Fair (In thousands) Cost Gains Losses Value Corporate bonds $ 10,776 $ 6 $ ( 35 ) $ 10,747 Municipal fixed-rate bonds 1,553 2 ( 4 ) 1,551 Asset-backed bonds 322 3 ( 3 ) 322 Mortgage/Agency-backed bonds 4,754 15 ( 33 ) 4,736 U.S. government bonds 12,251 12 ( 92 ) 12,171 Foreign government bonds 543 — ( 4 ) 539 Available-for-sale debt securities held at fair value $ 30,199 $ 38 $ ( 171 ) $ 30,066
Contractual Maturities of Debt Securities and Other Investments	The contractual maturities related to debt securities and other investments were as follows: As of June 30, 2022 (In thousands) Corporate Municipal Asset- Mortgage/ U.S. government Foreign government bonds Less than one year $ 621 $ 148 $ — $ 637 $ 367 $ — One to two years 6,484 1,254 — 472 8,315 279 Two to three years 3,339 112 248 621 3,102 109 Three to five years 125 — 313 189 — — Five to ten years — — 215 925 — — More than ten years — — 227 1,170 — — Total $ 10,569 $ 1,514 $ 1,003 $ 4,014 $ 11,784 $ 388
Gross Realized Gains and Losses on Sale of Debt Securities	The following table presents the gross realized gains and losses related to our debt securities: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Gross realized gain on debt securities $ — $ 97 $ 12 $ 184 Gross realized loss on debt securities ( 85 ) ( 20 ) ( 125 ) ( 36 ) Total (loss) gain recognized, net $ ( 85 ) $ 77 $ ( 113 ) $ 148
Realized and Unrealized Gains and Losses related to Marketable Equity Securities	Realized and unrealized gains and losses related to marketable equity securities were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Realized (loss) gain on equity securities sold $ ( 293 ) $ ( 79 ) $ ( 318 ) $ ( 55 ) Unrealized (loss) gain on equity securities held ( 4,268 ) 2,011 ( 7,630 ) 2,912 Total (loss) gain recognized, net $ ( 4,561 ) $ 1,932 $ ( 7,948 ) $ 2,857
Cash Equivalents and Investments held at Fair Value	he Company’s cash equivalents and investments held at fair value are categorized into this hierarchy as follows: Fair Value Measurements as of June 30, 2022 Using (In thousands) Fair Value Quoted Prices Significant Significant Unobservable Inputs Cash equivalents Money market funds $ 409 $ 409 $ — $ — Available-for-sale debt securities Corporate bonds 10,569 — 10,569 — Municipal fixed-rate bonds 1,514 — 1,514 — Asset-backed bonds 1,003 — 1,003 — Mortgage/Agency-backed bonds 4,014 — 4,014 — U.S. government bonds 11,784 11,784 — — Foreign government securities 388 — 388 — Marketable equity securities Marketable equity securities – various industries 873 873 — — Deferred compensation plan assets 22,567 22,567 — — Total $ 53,121 $ 35,633 $ 17,488 $ — Fair Value Measurements as of December 31, 2021 Using (In thousands) Fair Value Quoted Prices Significant Significant Unobservable Inputs Cash equivalents Money market funds $ 652 $ 652 $ — $ — Available-for-sale debt securities Corporate bonds 10,747 — 10,747 — Municipal fixed-rate bonds 1,551 — 1,551 — Asset-backed bonds 322 — 322 — Mortgage/Agency-backed bonds 4,736 — 4,736 — U.S. government bonds 12,171 12,171 — — Foreign government bonds 539 — 539 — Marketable equity securities Marketable equity securities – various industries 12,606 12,606 — — Deferred compensation plan assets 26,935 26,935 — — Total $ 70,259 $ 52,364 $ 17,895 $ —

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2022
Inventory Disclosure [Abstract]
Components of Inventory	Inventory consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Raw materials $ 116,307 $ 74,709 Work in process 2,258 2,143 Finished goods 78,351 63,039 Total inventory, net $ 196,916 $ 139,891

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Engineering and other equipment $ 134,748 $ 134,771 Computer hardware and software 74,141 72,274 Building 68,151 68,157 Building and land improvements 35,719 35,578 Furniture and fixtures 19,967 19,917 Land $ 4,575 $ 4,575 Total property, plant and equipment 337,301 335,272 Less: accumulated depreciation ( 283,869 ) ( 279,506 ) Total property, plant and equipment, net $ 53,432 $ 55,766

Intangible Assets (Tables)

Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2022
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Summary of Intangible Assets	Intangible assets consisted of the following: As of June 30, 2022 As of December 31, 2021 (In thousands) Gross Carrying Amount Accumulated Amortization Net Book Value Gross Carrying Amount Accumulated Amortization Net Book Value Customer relationships $ 20,451 $ ( 10,415 ) $ 10,036 $ 20,796 $ ( 9,906 ) $ 10,890 Developed technology 8,200 ( 4,251 ) 3,949 8,200 ( 3,683 ) 4,517 Licensed technology 5,900 ( 2,813 ) 3,087 5,900 ( 2,486 ) 3,414 Licensing agreements 560 ( 262 ) 298 560 ( 225 ) 335 Patents 500 ( 397 ) 103 500 ( 363 ) 137 Trade names 210 ( 210 ) — 210 ( 210 ) — Total $ 35,821 $ ( 18,348 ) $ 17,473 $ 36,166 $ ( 16,873 ) $ 19,293
Estimated Future Amortization Expense Related to Intangible Assets	Estimated future amortization expense of intangible assets was as follows: As of (In thousands) June 30, 2022 2022 $ 1,696 2023 3,305 2024 3,213 2025 3,019 2026 1,985 Thereafter 4,255 Total $ 17,473

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Net Investment in Sales-Type Leases	We are the lessor in sales-type lease arrangements for network equipment, which consisted of the following: As of As of (In thousands) June 30, 2022 December 31, 2021 Current minimum lease payments receivable (1) $ 33 $ 92 Non-current minimum lease payments receivable (2) — 4 Total minimum lease payments receivable 33 96 Less: Current unearned revenue (1) 23 70 Less: Non-current unearned revenue (2) — 1 Net investment in sales-type leases $ 10 $ 25 (1) Included in other receivables on the Condensed Consolidated Balance Sheets. (2) Included in other assets on the Condensed Consolidated Balance Sheets.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Changes in Accumulated Other Comprehensive Loss, Net of Tax, by Component	The following tables present the changes in accumulated other comprehensive loss, net of tax, by component: Three Months Ended June 30, 2022 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total Balance as of March 31, 2022 $ ( 1,276 ) $ ( 5,626 ) $ ( 7,039 ) $ 385 $ ( 13,556 ) Other comprehensive loss before ( 589 ) — ( 2,853 ) — ( 3,442 ) Amounts reclassified from accumulated other 389 ( 87 ) — — 302 Net current period other comprehensive loss ( 200 ) ( 87 ) ( 2,853 ) — ( 3,140 ) Balance as of June 30, 2022 $ ( 1,476 ) $ ( 5,713 ) $ ( 9,892 ) $ 385 $ ( 16,696 ) Three Months Ended June 30, 2021 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total Balance as of March 31, 2021 $ ( 160 ) $ ( 9,522 ) $ ( 4,298 ) $ 385 $ ( 13,595 ) Other comprehensive (loss) income before ( 272 ) — 338 — 66 Amounts reclassified from accumulated other 177 212 — — 389 Net current period other comprehensive (loss) income ( 95 ) 212 338 — 455 Balance as of June 30, 2021 $ ( 255 ) $ ( 9,310 ) $ ( 3,960 ) $ 385 $ ( 13,140 ) Six Months Ended June 30, 2022 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total As of December 31, 2021 $ ( 552 ) $ ( 5,613 ) $ ( 6,134 ) $ 385 $ ( 11,914 ) Other comprehensive loss before ( 1,564 ) — ( 3,758 ) — ( 5,322 ) Amounts reclassified from accumulated other 640 ( 100 ) — — 540 Net current period other comprehensive loss ( 924 ) ( 100 ) ( 3,758 ) — ( 4,782 ) As of June 30, 2022 $ ( 1,476 ) $ ( 5,713 ) $ ( 9,892 ) $ 385 $ ( 16,696 ) Six Months Ended June 30, 2021 (In thousands) Unrealized Defined Foreign ASU 2018-02 Adoption Total As of December 31, 2020 $ 32 $ ( 9,621 ) $ ( 2,435 ) $ 385 $ ( 11,639 ) Other comprehensive loss before ( 329 ) — ( 1,525 ) — ( 1,854 ) Amounts reclassified from accumulated other 42 311 — — 353 Net current period other comprehensive (loss) income ( 287 ) 311 ( 1,525 ) — ( 1,501 ) As of June 30, 2021 $ ( 255 ) $ ( 9,310 ) $ ( 3,960 ) $ 385 $ ( 13,140 )
Reclassifications Out of Accumulated Other Comprehensive Income (Loss)	The following tables present the details of reclassifications out of accumulated other comprehensive loss: Three Months Ended June 30, 2022 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 512 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain 126 (1) Total reclassifications for the period, before tax ( 386 ) Tax benefit 84 Total reclassifications for the period, net of tax $ ( 302 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Three Months Ended June 30, 2021 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 233 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial losses ( 307 ) (1) Total reclassifications for the period, before tax ( 540 ) Tax benefit 151 Total reclassifications for the period, net of tax $ ( 389 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Six Months Ended June 30, 2022 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 842 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain 145 (1) Total reclassifications for the period, before tax ( 697 ) Tax benefit 157 Total reclassifications for the period, net of tax $ ( 540 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income. Six Months Ended June 30, 2021 (In thousands) Amount Affected Line Item in the Unrealized gain (loss) on available-for-sale securities: Net realized loss on sales of securities $ ( 55 ) Net investment gain (loss) Defined benefit plan adjustments – actuarial gain ( 451 ) (1) Total reclassifications for the period, before tax ( 506 ) Tax benefit 153 Total reclassifications for the period, net of tax $ ( 353 ) (1) A part of the computation of net periodic pension cost, which is included in other (expense) income, net in the Condensed Consolidated Statements of Income.
Tax Effects Related to the Change in Each Component of Other Comprehensive Loss	The following tables present the tax effects related to the change in each component of other comprehensive (loss) income: Three Months Ended Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Net-of-Tax Unrealized loss on available-for-sale $ ( 775 ) $ 186 $ ( 589 ) $ ( 358 ) $ 86 $ ( 272 ) Reclassification adjustment for amounts related to 512 ( 123 ) 389 233 ( 56 ) 177 Reclassification adjustment for amounts related to ( 126 ) 39 ( 87 ) 307 ( 95 ) 212 Foreign currency translation adjustment ( 2,853 ) — ( 2,853 ) 338 — 338 Total Other Comprehensive (Loss) Income $ ( 3,242 ) $ 102 $ ( 3,140 ) $ 520 $ ( 65 ) $ 455 Six Months Ended Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Net-of-Tax Unrealized loss on available-for-sale $ ( 2,058 ) $ 494 $ ( 1,564 ) $ ( 433 ) $ 104 $ ( 329 ) Reclassification adjustment for amounts related to 842 ( 202 ) 640 55 ( 13 ) 42 Reclassification adjustment for amounts related to ( 145 ) 45 ( 100 ) 451 ( 140 ) 311 Foreign currency translation adjustment ( 3,758 ) — ( 3,758 ) ( 1,525 ) — ( 1,525 ) Total Other Comprehensive Loss $ ( 5,119 ) $ 337 $ ( 4,782 ) $ ( 1,452 ) $ ( 49 ) $ ( 1,501 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Summary of Calculation of Basic and Diluted Earnings (Loss) Per Share	The calculation of basic and diluted earnings per share is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands, except per share amounts) 2022 2021 2022 2021 Numerator Net income $ 2,143 $ 5,086 $ 1,016 $ 5,982 Denominator Weighted average number of shares – basic 49,123 48,449 49,110 48,393 Effect of dilutive securities Stock options 84 816 111 722 PSUs, RSUs and restricted stock 602 161 592 110 Weighted average number of shares – diluted 49,809 49,426 49,813 49,225 Earnings per share – basic $ 0.04 $ 0.10 $ 0.02 $ 0.12 Earnings per share – diluted $ 0.04 $ 0.10 $ 0.02 $ 0.12

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2022
Segment Reporting [Abstract]
Revenue and Gross Profit of Reportable Segments	The following tables present information about the revenue and gross profit of our reportable segments: Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Revenue Gross Profit Revenue Gross Profit Network Solutions $ 155,992 $ 56,071 $ 125,449 $ 55,435 Services & Support 16,046 6,435 17,783 7,233 Total $ 172,038 $ 62,506 $ 143,232 $ 62,668 Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Revenue Gross Profit Revenue Gross Profit Network Solutions $ 294,366 $ 103,791 $ 239,258 $ 104,243 Services & Support 32,190 13,031 31,507 12,026 Total $ 326,556 $ 116,822 $ 270,765 $ 116,269
Disaggregate of Revenue by Reportable Segment and Revenue Category	The following tables disaggregate revenue by reportable segment and revenue category: Three Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 78,852 $ 10,909 $ 89,761 $ 78,307 $ 12,657 $ 90,964 Subscriber Solutions & Experience 75,186 2,958 78,144 45,097 2,713 47,810 Traditional & Other Products 1,954 2,179 4,133 2,045 2,413 4,458 Total $ 155,992 $ 16,046 $ 172,038 $ 125,449 $ 17,783 $ 143,232 Six Months Ended June 30, 2022 June 30, 2021 (In thousands) Network Solutions Services & Support Total Network Solutions Services & Support Total Access & Aggregation $ 163,141 $ 22,080 $ 185,221 $ 138,360 $ 21,678 $ 160,038 Subscriber Solutions & Experience 127,009 5,741 132,750 97,366 5,013 102,379 Traditional & Other Products 4,216 4,369 8,585 3,532 4,816 8,348 Total $ 294,366 $ 32,190 $ 326,556 $ 239,258 $ 31,507 $ 270,765 The table below presents revenue information by category: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Access & Aggregation $ 89,761 $ 90,964 $ 185,221 $ 160,038 Subscriber Solutions & Experience 78,144 47,810 132,750 102,379 Traditional & Other Products 4,133 4,458 8,585 8,348 Total $ 172,038 $ 143,232 $ 326,556 $ 270,765
Revenue Information by Geographic Area	The following table presents revenue information by geographic area: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 United States $ 105,752 $ 94,656 $ 204,801 $ 181,141 United Kingdom 28,838 13,566 59,243 21,501 Germany 14,859 18,750 25,376 32,955 Other international 22,589 16,260 37,136 35,168 Total $ 172,038 $ 143,232 $ 326,556 $ 270,765

Liability for Warranty Returns

Liability for Warranty Returns (Tables)	6 Months Ended
	Jun. 30, 2022
Product Warranties Disclosures [Abstract]
Summary of Warranty Expense and Write-off Activity	The warranty expense and write-off activity for the three and six months ended June 30, 2022 and 2021 is summarized as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Balance at beginning of period $ 5,143 $ 6,472 $ 5,403 $ 7,146 Plus: Amounts charged to cost and expenses 814 11 1,111 ( 220 ) Less: Deductions ( 1,115 ) ( 486 ) ( 1,672 ) ( 929 ) Balance at end of period $ 4,842 $ 5,997 $ 4,842 $ 5,997

Restructuring (Tables)

Restructuring (Tables)	6 Months Ended
	Jun. 30, 2022
Restructuring and Related Activities [Abstract]
Schedule of Reconciliation of Restructuring Liability	A reconciliation of the beginning and ending restructuring liability, which is included in accrued wages and benefits in the Condensed Consolidated Balance Sheets is as follows: Three Months Ended Six Months Ended (In thousands) June 30, 2022 June 30, 2022 Balance at beginning of period $ 260 $ 1,514 Plus: Amounts charged to cost and expense — 2 Less: Amounts paid ( 13 ) ( 1,269 ) Balance as of June 30, 2022 $ 247 $ 247 For the Year Ended (In thousands) December 31, 2021 Balance as of December 31, 2020 $ 4,186 Plus: Amounts charged to cost and expense 411 Less: Amounts paid ( 3,083 ) Balance as of December 31, 2021 $ 1,514
Schedule of Components of Restructuring Expenses	Restructuring expenses included in the Condensed Consolidated Statements of Income were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 Network Solutions - Cost of revenue $ — $ — $ — $ 12 Services & Support - Cost of revenue — — — 3 Cost of revenue $ — $ — $ — $ 15 Selling, general and administrative expenses (1) — 3 2 145 Research and development expenses (1) — 5 — 149 Total restructuring expenses $ — $ 8 $ 2 $ 309 (1) The Company does not allocate selling, general and administrative expense and research and development expense to the segment level. Components of restructuring expense by geographic area were as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2022 2021 2022 2021 United States $ — $ 3 $ 2 $ 212 International — 5 — 97 Total restructuring expenses $ — $ 8 $ 2 $ 309

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - $ / shares	Jul. 15, 2022	Aug. 30, 2021	Jun. 30, 2022	Dec. 31, 2021
Summary Of Significant Accounting Policy [Line Items]
Common stock, par value		$ 0.01	$ 0.01	$ 0.01
Common stock, shares outstanding			49,126,000	49,063,000
Subsequent Event [Member]
Summary Of Significant Accounting Policy [Line Items]
Issuance of shares of common stock	27,994,595
Acorn HoldCo, Inc., [Member]
Summary Of Significant Accounting Policy [Line Items]
Business combination date of agreement		Aug. 30, 2021
Common stock, par value		$ 0.01
Acorn HoldCo, Inc., [Member] | Subsequent Event [Member]
Summary Of Significant Accounting Policy [Line Items]
Common stock, shares outstanding	33,957,538
Percentage of outstanding bearer shares	65.43%
Acorn HoldCo, Inc., [Member] | ADVA Optical Networking SE, [Member] | Common Stock [Member]
Summary Of Significant Accounting Policy [Line Items]
Number of shares issuable for each share of acquired entity		0.8244

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 43,368	$ 56,603
Restricted cash		215
Cash, cash equivalents and restricted cash	$ 43,368	$ 56,818

Revenue - Additional Informatio

Revenue - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) Category	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Revenue [Line Items]
Number of categories | Category			3
Recognized revenue	$ 4.1	$ 2.9	$ 9.5	$ 7.9
Outstanding unearned revenue						$ 14.1
Contractual Maintenance Agreements, Contractual SaaS and Subscription Services and Hardware Contracts [Member]
Revenue [Line Items]
Remaining performance obligations	$ 164.5		$ 164.5		$ 101.1

Revenue - Disaggregate of Reven

Revenue - Disaggregate of Revenue by Reportable Segment and Revenue Category (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Revenue	$ 172,038	$ 143,232	$ 326,556	$ 270,765
Access & Aggregation [Member]
Disaggregation Of Revenue [Line Items]
Revenue	89,761	90,964	185,221	160,038
Subscriber Solutions & Experience [Member]
Disaggregation Of Revenue [Line Items]
Revenue	78,144	47,810	132,750	102,379
Traditional & Other Products [Member]
Disaggregation Of Revenue [Line Items]
Revenue	4,133	4,458	8,585	8,348
Network Solutions [Member]
Disaggregation Of Revenue [Line Items]
Revenue	155,992	125,449	294,366	239,258
Network Solutions [Member] | Access & Aggregation [Member]
Disaggregation Of Revenue [Line Items]
Revenue	78,852	78,307	163,141	138,360
Network Solutions [Member] | Subscriber Solutions & Experience [Member]
Disaggregation Of Revenue [Line Items]
Revenue	75,186	45,097	127,009	97,366
Network Solutions [Member] | Traditional & Other Products [Member]
Disaggregation Of Revenue [Line Items]
Revenue	1,954	2,045	4,216	3,532
Services & Support [Member]
Disaggregation Of Revenue [Line Items]
Revenue	16,046	17,783	32,190	31,507
Services & Support [Member] | Access & Aggregation [Member]
Disaggregation Of Revenue [Line Items]
Revenue	10,909	12,657	22,080	21,678
Services & Support [Member] | Subscriber Solutions & Experience [Member]
Disaggregation Of Revenue [Line Items]
Revenue	2,958	2,713	5,741	5,013
Services & Support [Member] | Traditional & Other Products [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 2,179	$ 2,413	$ 4,369	$ 4,816

Revenue - Additional Informat_2

Revenue - Additional Information (Detail1) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-07-01	Jun. 30, 2022
Revenue [Line Items]
Remaining performance obligations, percentage	84%
Remaining performance obligations, period	12 months

Revenue - Information about Rec

Revenue - Information about Receivables, Contract Assets, and Unearned Revenue from Contracts with Customers (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 172,088	$ 158,742
Contract assets	1,749	464
Unearned revenue	22,705	17,737
Non-current unearned revenue	$ 10,133	$ 9,271

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Effective tax rate expense (benefit)	50.10%	18.10%	(34.30%)	26.70%
Deferred tax assets, gross	$ 71,441		$ 71,441		$ 59,643
Valuation allowance established against deferred tax assets	62,933		62,933		50,564
Deferred tax assets	8,508		8,508		9,079
Domestic [Member]
Income Tax Disclosure [Line Items]
Deferred tax assets, gross	60,873		60,873		48,265
Valuation allowance established against deferred tax assets	60,873		60,873		48,265
Increase (decrease) in deferred tax asset valuation allowance			12,600
International [Member]
Income Tax Disclosure [Line Items]
Deferred tax assets, gross	10,568		10,568		11,378
Valuation allowance established against deferred tax assets	2,060		2,060		2,299
Deferred tax assets	$ 8,508		8,508		$ 9,079
Increase (decrease) in deferred tax asset valuation allowance			$ (200)

Income Taxes - Summary of Suppl

Income Taxes - Summary of Supplemental Balance Sheet Information Related to Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets	$ 71,441	$ 59,643
Valuation Allowance	(62,933)	(50,564)
Deferred Tax Assets, net	8,508	9,079
Domestic [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets	60,873	48,265
Valuation Allowance	(60,873)	(48,265)
International [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets	10,568	11,378
Valuation Allowance	(2,060)	(2,299)
Deferred Tax Assets, net	$ 8,508	$ 9,079

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense Related to Stock Options, PSUs, RSUs and Restricted Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,888	$ 1,808	$ 3,781	$ 3,615
Tax benefit for expense associated with stock options, PSUs, RSUs and restricted stock	(472)	(452)	(945)	(883)
Total stock-based compensation expense, net of tax	1,416	1,356	2,836	2,732
Stock-based Compensation Expense Included in Cost of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	162	125	321	256
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,135	1,098	2,259	2,196
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	591	585	1,201	1,163
Stock-based Compensation Expense Included in Operating Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,726	$ 1,683	$ 3,460	$ 3,359

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of PSUs, RSUs and Restricted Stock Outstanding (Detail) shares in Thousands	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Shares, Unvested PSUs, RSUs and restricted stock outstanding, beginning balance | shares	1,930
Number of Shares, PSUs, RSUs and restricted stock granted | shares	336
Number of Shares, PSUs, RSUs and restricted stock vested | shares	(15)
Number of Shares, PSUs, RSUs and restricted stock forfeited | shares	(41)
Number of Shares, Unvested PSUs, RSUs and restricted stock outstanding, ending balance | shares	2,210
Weighted Avg. Grant Date Fair Value, Unvested PSUs, RSUs and restricted stock outstanding, Beginning Balance | $ / shares	$ 14.11
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock granted | $ / shares	20.14
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock vested | $ / shares	13.26
Weighted Avg. Grant Date Fair Value, PSUs, RSUs and restricted stock forfeited | $ / shares	14.08
Weighted Avg. Grant Date Fair Value, Unvested PSUs, RSUs and restricted stock outstanding, Ending Balance | $ / shares	$ 15.04

Stock-Based Compensation (PSUs,

Stock-Based Compensation (PSUs, RSUs and Restricted Stock) - Additional Information (Detail) - USD ($) shares in Thousands, $ in Millions		6 Months Ended
	Jul. 15, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share granted		336
Options available for issuance under stockholders-approved equity plan		3,500
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options available for issuance under stockholders-approved equity plan		2,100
Performance Stock Units (PSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share granted		300	300
Vesting period		1 year	2 years	3 years
Performance Stock Units (PSUs) [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of performance stock units granted		0%	0%	0%
Performance Stock Units (PSUs) [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of performance stock units granted		142.80%	142.80%	142.80%
Market-Based PSUs, RSUs and Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to other than options		$ 13.9
Recognition period of unvested compensation expense		2 years 6 months
Market-Based PSUs, RSUs and Restricted Stock [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to other than options	$ 1.6
Recognition period of unvested compensation expense	1 year 1 month 6 days
Restricted Stock Units (RSUs) [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to other than options	$ 0.3
Performance-Based PSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to other than options		$ 13.2
Recognition period of unvested compensation expense		6 months
Performance-Based PSUs [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to other than options	$ 17.8
Recognition period of unvested compensation expense	6 months

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Options Outstanding (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of Stock Options, Stock options outstanding, Beginning Balance	1,721
Number of Stock Options, Stock options exercised	(37)
Number of Stock Options, Stock options expired	(23)
Number of Stock Options, Stock options outstanding, Ending Balance	1,661	1,721
Number of Stock Options, Stock options exercisable	1,661
Weighted Avg. Exercise Price, Stock options outstanding, Beginning Balance	$ 19.37
Weighted Avg. Exercise Price, Stock options exercised	17.24
Weighted Avg. Exercise Price, Stock options expired	23.67
Weighted Avg. Exercise Price, Stock options outstanding, Ending Balance	19.36	$ 19.37
Weighted Avg. Exercise Price, Stock options exercisable	$ 19.36
Weighted Avg. Remaining Contractual Life In Years, Stock options outstanding	1 year 10 months 24 days	2 years 4 months 24 days
Weighted Avg. Remaining Contractual Life in Years, Stock options exercisable	1 year 10 months 24 days
Aggregate Intrinsic Value, Stock options outstanding	$ 6,669
Aggregate Intrinsic Value, Stock options exercised	110
Aggregate Intrinsic Value, Stock options expired	5
Aggregate Intrinsic Value, Stock options outstanding	1,127	$ 6,669
Aggregate Intrinsic Value, Stock options exercisable	$ 1,127

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Options) - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Unrecognized compensation expense related to stock options	$ 0
Number of Stock options, granted	0	0
Aggregate intrinsic value based on fair market value	$ 1,127,000		$ 6,669,000
Total pre-tax intrinsic value of options exercised	$ 110,000

Investments - Debt Securities a

Investments - Debt Securities and Other Investments, Included on Condensed Consolidated Balance Sheet and Recorded at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 30,331	$ 30,199
Gross Unrealized Gains	2	38
Gross Unrealized Losses	(1,061)	(171)
Fair Value	29,272	30,066
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,854	10,776
Gross Unrealized Gains	1	6
Gross Unrealized Losses	(286)	(35)
Fair Value	10,569	10,747
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,563	1,553
Gross Unrealized Gains		2
Gross Unrealized Losses	(49)	(4)
Fair Value	1,514	1,551
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,018	322
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(16)	(3)
Fair Value	1,003	322
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,199	4,754
Gross Unrealized Gains		15
Gross Unrealized Losses	(185)	(33)
Fair Value	4,014	4,736
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,287	12,251
Gross Unrealized Gains		12
Gross Unrealized Losses	(503)	(92)
Fair Value	11,784	12,171
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	410	543
Gross Unrealized Losses	(22)	(4)
Fair Value	$ 388	$ 539

Investments - Contractual Matur

Investments - Contractual Maturities of Debt Securities and Other Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities, Fair Value/Carrying Value	$ 29,272	$ 30,066
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	621
One to two years	6,484
Two to three years	3,339
Three to five years	125
Available-for-sale debt securities, Fair Value/Carrying Value	10,569	10,747
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	148
One to two years	1,254
Two to three years	112
Available-for-sale debt securities, Fair Value/Carrying Value	1,514	1,551
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Two to three years	248
Three to five years	313
Five to ten years	215
More than ten years	227
Available-for-sale debt securities, Fair Value/Carrying Value	1,003	322
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	637
One to two years	472
Two to three years	621
Three to five years	189
Five to ten years	925
More than ten years	1,170
Available-for-sale debt securities, Fair Value/Carrying Value	4,014	4,736
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	367
One to two years	8,315
Two to three years	3,102
Available-for-sale debt securities, Fair Value/Carrying Value	11,784	12,171
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
One to two years	279
Two to three years	109
Available-for-sale debt securities, Fair Value/Carrying Value	$ 388	$ 539

Investments - Gross Realized Ga

Investments - Gross Realized Gains and Losses on Sale of Debt Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Gross realized gain on debt securities		$ 97	$ 12	$ 184
Gross realized loss on debt securities	$ (85)	(20)	(125)	(36)
Total (loss) gain recognized, net	$ (85)	$ 77	$ (113)	$ 148

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Schedule of Investments [Line Items]
Available-for-sale debt securities, allowance for credit losses	$ 0	$ 0	$ 0	$ 0
Purchase an available-for-sale debt securities with credit deterioration			0
Carrying value of investment	1,000,000		1,000,000		$ 1,000,000
Asset impairments	0	$ 0	0	0	400,000
Cumulative asset impairment charges	2,400,000		2,400,000
Unsecured loan converted to equity investment					500,000
Secured Loans Receivable [Member]
Schedule of Investments [Line Items]
Asset impairments			0	$ 0	500,000
Long-term Investments [Member]
Schedule of Investments [Line Items]
Secured note receivable, noncurrent	$ 400,000		$ 400,000		$ 400,000
Investment [Member] | Issuer Concentration [Member] | Market Value of Total Investment Portfolio [Member]
Schedule of Investments [Line Items]
Investment concentration risk percentage			5%

Investments - Realized and Unre

Investments - Realized and Unrealized Gains and Losses related to Marketable Equity Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Realized (loss) gain on equity securities sold	$ (293)	$ (79)	$ (318)	$ (55)
Unrealized (loss) gain on equity securities held	(4,268)	2,011	(7,630)	2,912
Total (loss) gain recognized, net	$ (4,561)	$ 1,932	$ (7,948)	$ 2,857

Investments - Cash Equivalents

Investments - Cash Equivalents and Investments held at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	$ 29,272	$ 30,066
Marketable equity securities	1,000	1,000
Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	53,121	70,259
Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	35,633	52,364
Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	17,488	17,895
Money Market Funds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	409	652
Money Market Funds [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	409	652
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	10,569	10,747
Corporate Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	10,569	10,747
Corporate Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	10,569	10,747
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,514	1,551
Municipal Fixed-Rate Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,514	1,551
Municipal Fixed-Rate Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,514	1,551
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,003	322
Asset-Backed Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,003	322
Asset-Backed Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	1,003	322
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	4,014	4,736
Mortgage/Agency-Backed Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	4,014	4,736
Mortgage/Agency-Backed Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	4,014	4,736
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	11,784	12,171
U.S. Government Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	11,784	12,171
U.S. Government Bonds [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	11,784	12,171
Foreign Government Securities / Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	388	539
Foreign Government Securities / Bonds [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	388	539
Foreign Government Securities / Bonds [Member] | Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale debt securities	388	539
Marketable Equity Securities - Various Industries [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	873	12,606
Marketable Equity Securities - Various Industries [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	873	12,606
Deferred Compensation Plan Assets [Member] | Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	22,567	26,935
Deferred Compensation Plan Assets [Member] | Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Marketable equity securities	$ 22,567	$ 26,935

Inventory - Components of Inven

Inventory - Components of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Raw materials	$ 116,307	$ 74,709
Work in process	2,258	2,143
Finished goods	78,351	63,039
Total Inventory, net	$ 196,916	$ 139,891

Inventory - Additional Informat

Inventory - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Inventory valuation reserves	$ 48.9	$ 44.6

Property, Plant and Equipment -

Property, Plant and Equipment - Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Engineering and other equipment	$ 134,748	$ 134,771
Computer hardware and software	74,141	72,274
Building	68,151	68,157
Building and land improvements	35,719	35,578
Furniture and fixtures	19,967	19,917
Land	4,575	4,575
Total property, plant and equipment	337,301	335,272
Less: accumulated depreciation	(283,869)	(279,506)
Total property, plant and equipment, net	$ 53,432	$ 55,766

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Asset impairments	$ 0	$ 0	$ 0	$ 0	$ 400,000
Depreciation	$ 2,700,000	$ 3,000,000	$ 5,500,000	$ 6,100,000

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Goodwill [Line Items]
Goodwill			$ 7,000,000		$ 7,000,000
Impairment of goodwill	$ 0	$ 0	0	$ 0
Network Solutions [Member]
Goodwill [Line Items]
Goodwill			6,600,000		400,000
Services & Support [Member]
Goodwill [Line Items]
Goodwill			$ 6,600,000		$ 400,000

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 35,821	$ 36,166
Accumulated Amortization	(18,348)	(16,873)
Net Book Value	17,473	19,293
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	20,451	20,796
Accumulated Amortization	(10,415)	(9,906)
Net Book Value	10,036	10,890
Developed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,200	8,200
Accumulated Amortization	(4,251)	(3,683)
Net Book Value	3,949	4,517
Licensed Technology [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,900	5,900
Accumulated Amortization	(2,813)	(2,486)
Net Book Value	3,087	3,414
Licensing Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	560	560
Accumulated Amortization	(262)	(225)
Net Book Value	298	335
Patent [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	500	500
Accumulated Amortization	(397)	(363)
Net Book Value	103	137
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	210	210
Accumulated Amortization	(210)	(210)
Net Book Value

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Impairment losses of intangible assets	$ 0	$ 0	$ 0	$ 0
Amortization expense	$ 900,000	$ 1,000,000	1,800,000	2,100,000
Impairment losses of long-lived assets			$ 0	$ 0

Intangible Assets - Estimated F

Intangible Assets - Estimated Future Amortization Expense Related to Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2022	$ 1,696
2023	3,305
2024	3,213
2025	3,019
2026	1,985
Thereafter	4,255
Net Book Value	$ 17,473	$ 19,293

Leases - Net Investment in Sale

Leases - Net Investment in Sales-Type Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Sales-Type Lease, Net Investment in Lease, before Allowance for Credit Loss [Abstract]
Current minimum lease payments receivable	$ 33	$ 92
Non-current minimum lease payments receivable		4
Total minimum lease payments receivable	33	96
Less: Current unearned revenue	23	70
Less: Non-current unearned revenue		1
Net investment in sales-type leases	$ 10	$ 25

Revolving Credit Agreements - A

Revolving Credit Agreements - Additional Information (Detail) - USD ($)			6 Months Ended
	May 19, 2022	Apr. 01, 2022	Jun. 30, 2022
Line Of Credit Facility [Line Items]
Repayment of debt under revolving credit agreement			$ 28,000,000
Cadence Bank, N.A [Member] | Secured Revolving Credit Facility [Member] | Revolving Credit and Security Agreement (The "Cadence Revolving Credit Agreement") [Member]
Line Of Credit Facility [Line Items]
Secured revolving credit facility amount	$ 25,000,000
Credit agreement maturity period	Nov. 03, 2022
Maximum loan to value ratio percentage	85%
Maximum interest rate in no event time	1.50%
Repayment of debt under revolving credit agreement			18,000,000
Cadence Bank, N.A [Member] | Secured Revolving Credit Facility [Member] | Revolving Credit and Security Agreement (The "Cadence Revolving Credit Agreement") [Member] | Screen Rate [Member]
Line Of Credit Facility [Line Items]
Debt instrument interest over screen rate	1.50%
Wells Fargo Bank [Member] | Secured Revolving Credit Facility [Member] | Credit Agreement and Revolving Line of Credit Note (The "Wells Revolving Credit Agreement") [Member]
Line Of Credit Facility [Line Items]
Secured revolving credit facility amount		$ 25,000,000
Credit agreement maturity period		Apr. 01, 2023
Repayment of debt under revolving credit agreement			$ 10,000,000
Credit facility, floor rate		0%
Senior Funded Debt to EBITDA Ratio One [Member] | Wells Fargo Bank [Member] | Secured Revolving Credit Facility [Member] | Credit Agreement and Revolving Line of Credit Note (The "Wells Revolving Credit Agreement") [Member] | Daily Simple SOFR [Member]
Line Of Credit Facility [Line Items]
Debt instrument interest over screen rate		1%
Senior Funded Debt to EBITDA Ratio Two [Member] | Wells Fargo Bank [Member] | Secured Revolving Credit Facility [Member] | Credit Agreement and Revolving Line of Credit Note (The "Wells Revolving Credit Agreement") [Member] | Daily Simple SOFR [Member]
Line Of Credit Facility [Line Items]
Debt instrument interest over screen rate		1.25%
Senior Funded Debt to EBITDA Ratio Three [Member] | Wells Fargo Bank [Member] | Secured Revolving Credit Facility [Member] | Credit Agreement and Revolving Line of Credit Note (The "Wells Revolving Credit Agreement") [Member] | Daily Simple SOFR [Member]
Line Of Credit Facility [Line Items]
Debt instrument interest over screen rate		1.50%
Senior Funded Debt to EBITDA Ratio Four [Member] | Wells Fargo Bank [Member] | Secured Revolving Credit Facility [Member] | Credit Agreement and Revolving Line of Credit Note (The "Wells Revolving Credit Agreement") [Member] | Daily Simple SOFR [Member]
Line Of Credit Facility [Line Items]
Debt instrument interest over screen rate		2%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - shares	6 Months Ended
	Jun. 30, 2022	Jul. 09, 2022
Class of Stock [Line Items]
Stock repurchased, shares	0
Additional shares authorized for purchase	2,500,000
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement	5,000,000
Subsequent Event [Member]
Class of Stock [Line Items]
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement		0

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss, Net of Tax, by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 352,316	$ 370,375	$ 357,102	$ 372,944
Other comprehensive (loss) income before reclassifications	(3,442)	66	(5,322)	(1,854)
Amounts reclassified from accumulated other comprehensive loss	302	389	540	353
Net current period other comprehensive income (loss)	(3,140)	455	(4,782)	(1,501)
Ending Balance	348,537	375,515	348,537	375,515
ASU 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	385	385	385	385
Ending Balance	385	385	385	385
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,556)	(13,595)	(11,914)	(11,639)
Ending Balance	(16,696)	(13,140)	(16,696)	(13,140)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(1,276)	(160)	(552)	32
Other comprehensive (loss) income before reclassifications	(589)	(272)	(1,564)	(329)
Amounts reclassified from accumulated other comprehensive loss	389	177	640	42
Net current period other comprehensive income (loss)	(200)	(95)	(924)	(287)
Ending Balance	(1,476)	(255)	(1,476)	(255)
Defined Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,626)	(9,522)	(5,613)	(9,621)
Amounts reclassified from accumulated other comprehensive loss	(87)	212	(100)	311
Net current period other comprehensive income (loss)	(87)	212	(100)	311
Ending Balance	(5,713)	(9,310)	(5,713)	(9,310)
Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(7,039)	(4,298)	(6,134)	(2,435)
Other comprehensive (loss) income before reclassifications	(2,853)	338	(3,758)	(1,525)
Net current period other comprehensive income (loss)	(2,853)	338	(3,758)	(1,525)
Ending Balance	$ (9,892)	$ (3,960)	$ (9,892)	$ (3,960)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Income Before Income Taxes	$ 4,291		$ 6,213		$ 756	$ 8,157
Tax benefit (expense)	(2,148)		(1,127)		260	(2,175)
Net Income	2,143	$ (1,127)	5,086	$ 896	1,016	5,982
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Income Before Income Taxes	(386)		(540)		(697)	(506)
Tax benefit (expense)	84		151		157	153
Net Income	(302)		(389)		(540)	(353)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Net investment gain (loss)	(512)		(233)		(842)	(55)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] | Other Income (Expense), Net [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit plan adjustments - actuarial gain	$ 126		$ (307)		$ 145	$ (451)

Stockholders' Equity - Tax Effe

Stockholders' Equity - Tax Effects Related to the Change in Each Component of Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Equity [Abstract]
Unrealized gain (loss) on available-for-sale securities, Before-Tax Amount	$ (775)		$ (358)		$ (2,058)	$ (433)
Unrealized gain (loss) on available-for-sale securities, Tax (Expense) Benefit	186		86		494	104
Unrealized gain (loss) on available-for-sale securities, Net-of-Tax Amount	(589)		(272)		(1,564)	(329)
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Before-Tax Amount	512		233		842	55
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Tax (Expense) Benefit	(123)		(56)		(202)	(13)
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Net-of-Tax Amount	389		177		640	42
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Before-Tax Amount	(126)		307		(145)	451
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Tax (Expense) Benefit	39		(95)		45	(140)
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Net-of-Tax Amount	(87)		212		(100)	311
Foreign currency translation adjustment, Before-Tax Amount	(2,853)		338		(3,758)	(1,525)
Foreign currency translation adjustment, Net-of-Tax Amount	(2,853)		338		(3,758)	(1,525)
Total Other Comprehensive Income (Loss), Before-Tax Amount	(3,242)		520		(5,119)	(1,452)
Total Other Comprehensive Income (Loss), Tax (Expense) Benefit	102		(65)		337	(49)
Other Comprehensive (Loss) Income, net of tax	$ (3,140)	$ (1,642)	$ 455	$ (1,956)	$ (4,782)	$ (1,501)

Earnings Per Share - Summary of

Earnings Per Share - Summary of Calculation of Basic and Diluted Earnings (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator
Net Income (Loss)	$ 2,143	$ (1,127)	$ 5,086	$ 896	$ 1,016	$ 5,982
Denominator
Weighted average number of shares – basic	49,123		48,449		49,110	48,393
Effect of dilutive securities
Stock options	84		816		111	722
PSUs, RSUs and restricted stock	602		161		592	110
Weighted average number of shares – diluted	49,809		49,426		49,813	49,225
Earnings per share - basic	$ 0.04		$ 0.10		$ 0.02	$ 0.12
Earnings per share - diluted	$ 0.04		$ 0.10		$ 0.02	$ 0.12

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded calculation of diluted earnings per share	200	400	100	600
Unvested Stock Options, PSUs, RSUs and Restricted Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive effect excluded calculation of diluted earnings per share	33	1	8	3

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2022 Category Segment
Segment Reporting [Abstract]
Number of reportable segments | Segment	2
Number of categories | Category	3

Segment Information - Revenue a

Segment Information - Revenue and Gross Profit of Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Revenue	$ 172,038	$ 143,232	$ 326,556	$ 270,765
Gross Profit	62,506	62,668	116,822	116,269
Network Solutions [Member]
Segment Reporting Information [Line Items]
Revenue	155,992	125,449	294,366	239,258
Gross Profit	56,071	55,435	103,791	104,243
Services & Support [Member]
Segment Reporting Information [Line Items]
Revenue	16,046	17,783	32,190	31,507
Gross Profit	$ 6,435	$ 7,233	$ 13,031	$ 12,026

Segment Information - Revenue I

Segment Information - Revenue Information by Category (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Revenue	$ 172,038	$ 143,232	$ 326,556	$ 270,765
Access & Aggregation [Member]
Disaggregation Of Revenue [Line Items]
Revenue	89,761	90,964	185,221	160,038
Subscriber Solutions & Experience [Member]
Disaggregation Of Revenue [Line Items]
Revenue	78,144	47,810	132,750	102,379
Traditional & Other Products [Member]
Disaggregation Of Revenue [Line Items]
Revenue	$ 4,133	$ 4,458	$ 8,585	$ 8,348

Segment Information - Revenue_2

Segment Information - Revenue Information by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue from External Customer [Line Items]
Revenue	$ 172,038	$ 143,232	$ 326,556	$ 270,765
United States [Member]
Revenue from External Customer [Line Items]
Revenue	105,752	94,656	204,801	181,141
United Kingdom [Member]
Revenue from External Customer [Line Items]
Revenue	28,838	13,566	59,243	21,501
Germany [Member]
Revenue from External Customer [Line Items]
Revenue	14,859	18,750	25,376	32,955
Other International [Member]
Revenue from External Customer [Line Items]
Revenue	$ 22,589	$ 16,260	$ 37,136	$ 35,168

Liability for Warranty Return_2

Liability for Warranty Returns - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Product Warranties Disclosures [Abstract]
Period of assurance-based warranty for product defects	90 days to five years
Liability for warranty obligations	$ 4,842	$ 5,143	$ 5,403	$ 5,997	$ 6,472	$ 7,146

Liability for Warranty Return_3

Liability for Warranty Returns - Summary of Warranty Expense and Write-off Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 5,143	$ 6,472	$ 5,403	$ 7,146
Plus: Amounts charged to cost and expenses	814	11	1,111	(220)
Less: Deductions	(1,115)	(486)	(1,672)	(929)
Balance at end of period	$ 4,842	$ 5,997	$ 4,842	$ 5,997

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions		6 Months Ended
	Mar. 31, 2020 Officer	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)
Contingencies And Commitments [Line Items]
Commitments related to performance bonds		$ 21.8	$ 22.9
Commitments related to performance bonds expiration month and year		2025-04
Commitments towards private equity funds		$ 4.9
Investment Commitments [Member]
Contingencies And Commitments [Line Items]
Aggregate investment committed in private equity funds		$ 5
Minimum [Member]
Contingencies And Commitments [Line Items]
Collateral value required to be maintained				$ 15
Current Executive Officers [Member]
Contingencies And Commitments [Line Items]
Number of officers | Officer	2
Former Executive Officers [Member]
Contingencies And Commitments [Line Items]
Number of officers | Officer	1

Restructuring - Additional Info

Restructuring - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Restructuring and Related Activities [Abstract]
Cumulative amount of restructuring expenses incurred for restructuring plan	$ 12.7

Restructuring - Schedule of Rec

Restructuring - Schedule of Reconciliation of Restructuring Liability (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Restructuring and Related Activities [Abstract]
Balance at beginning of period	$ 260		$ 1,514	$ 4,186	$ 4,186
Plus: Amounts charged to cost and expense	0	$ 8	2	$ 309	411
Less: Amounts paid	(13)		(1,269)		(3,083)
Balance at end of period	$ 247		$ 247		$ 1,514

Restructuring - Schedule of Com

Restructuring - Schedule of Components of Restructuring Expenses Including in Condensed Consolidated Statements of (Loss) Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	$ 0	$ 8	$ 2	$ 309	$ 411
Cost of Revenue [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	0	0	0	15
Selling, General and Administrative Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	0	3	2	145
Research and Development Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	0	5	0	149
Network Solutions [Member] | Cost of Revenue [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	0	0	0	12
Services & Support [Member] | Cost of Revenue [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	$ 0	$ 0	$ 0	$ 3

Restructuring - Schedule of C_2

Restructuring - Schedule of Components of Restructuring Expense by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	$ 0	$ 8	$ 2	$ 309	$ 411
United States [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	0	3	2	212
International [Member]
Restructuring Cost And Reserve [Line Items]
Total restructuring expenses	$ 0	$ 5		$ 97

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)

1 Months Ended

3 Months Ended

6 Months Ended

Aug. 05, 2022 USD ($)

Aug. 03, 2022 $ / shares

Jul. 15, 2022 USD ($) $ / shares shares

Aug. 30, 2021 $ / shares shares

Dec. 31, 2024

Sep. 30, 2024

Jun. 30, 2022 USD ($) $ / shares shares

Jun. 30, 2021 USD ($)

Jun. 30, 2022 USD ($) $ / shares shares

Jun. 30, 2021 USD ($)

Sep. 01, 2022 USD ($)

Jul. 22, 2022 shares

Jul. 18, 2022 USD ($)

Dec. 31, 2021 $ / shares shares

Subsequent Event [Line Items]

Common stock, par value | $ / shares

$ 0.01

$ 0.01

$ 0.01

$ 0.01

Common stock, shares outstanding | shares

49,126,000

49,126,000

49,063,000

Options available for issuance under stockholders-approved equity plan | shares

3,500,000

3,500,000

Scenario Forecast [Member]

Subsequent Event [Line Items]

Quarterly dividend payable, aggregate amount | $

$ 7,000,000

Subsequent Event [Member]

Subsequent Event [Line Items]

Dividend declaration date

Aug. 03, 2022

Common stock dividends per share declared | $ / shares

$ 0.09

Dividend record date

Aug. 18, 2022

Dividend payment date

Sep. 01, 2022

Exchange offer settled date

Jul. 15, 2022

Issuance of shares of common stock | shares

27,994,595

Debt instrument default interest rate percentage

2%

Subsequent Event [Member] | SOFR [Member]

Subsequent Event [Line Items]

Credit facility, floor rate

0%

Subsequent Event [Member] | EURIBOR [Member]

Subsequent Event [Line Items]

Credit facility, floor rate

0%

Minimum [Member] | Subsequent Event [Member] | Base Rate [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

0.50%

Minimum [Member] | Subsequent Event [Member] | SOFR [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

1.40%

Minimum [Member] | Subsequent Event [Member] | EURIBOR [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

1.50%

Maximum [Member]

Subsequent Event [Line Items]

Options available for issuance under stockholders-approved equity plan | shares

2,100,000

2,100,000

Maximum [Member] | Subsequent Event [Member] | Base Rate [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

1.25%

Maximum [Member] | Subsequent Event [Member] | SOFR [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

2.15%

Maximum [Member] | Subsequent Event [Member] | EURIBOR [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

2.25%

ADVA Optical Networking SE, [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Options available for issuance under stockholders-approved equity plan | shares

2,000,000

Acorn HoldCo, Inc., [Member]

Subsequent Event [Line Items]

Business Acquisition, Date of Acquisition Agreement

Aug. 30, 2021

Common stock, par value | $ / shares

$ 0.01

Acorn HoldCo, Inc., [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Common stock, shares outstanding | shares

33,957,538

Percentage of outstanding bearer shares

65.43%

Closing share price | $ / shares

$ 20.20

Acorn HoldCo, Inc., [Member] | Selling General and Administrative Expense and Research and Development Expense [Member]

Subsequent Event [Line Items]

Transaction costs incurred | $

$ 900,000

$ 2,400,000

$ 1,800,000

$ 3,400,000

Acorn HoldCo, Inc., [Member] | ADVA Optical Networking SE, [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Common stock provided in exchange for common stock | $

$ 565,500,000

Acorn HoldCo, Inc., [Member] | ADVA Optical Networking SE, [Member] | Common Stock [Member]

Subsequent Event [Line Items]

Number of shares issuable for each share of acquired entity | shares

0.8244

Wells Fargo Credit Agreement [Member] | Scenario Forecast [Member]

Subsequent Event [Line Items]

Credit agreement maturity period

Jul. 14, 2027

Net leverage ratio

2.75

3.25

Wells Fargo Credit Agreement [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Commitment fee percentage

0.25%

Consolidated interest coverage ratio

300

Wells Fargo Credit Agreement [Member] | Subsequent Event [Member] | Federal Reserve Bank Advances [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

1%

Wells Fargo Credit Agreement [Member] | Subsequent Event [Member] | SOFR [Member]

Subsequent Event [Line Items]

Debt instrument interest over screen rate

1%

Wells Fargo Credit Agreement [Member] | Acorn HoldCo, Inc., [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

New secured revolving credit facility amount | $

$ 100,000,000

Wells Fargo Credit Agreement [Member] | Acorn HoldCo, Inc., [Member] | Maximum [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Credit agreement current borrowing capacity | $

$ 400,000,000

Revolving Credit Facility [Member] | Acorn HoldCo, Inc., [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Credit agreement current borrowing capacity | $

$ 50,000,000

Letter of Credit [Member] | Acorn HoldCo, Inc., [Member] | Subsequent Event [Member]

Subsequent Event [Line Items]

Credit facility, average outstanding amount | $

$ 17,500,000