Casa Systems (CASSQ) 10-Q 30 Jul 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 23, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	CASA
Entity Registrant Name	Casa Systems, Inc.
Entity Central Index Key	0001333835
Current Fiscal Year End Date	--12-31
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-38324
Entity Tax Identification Number	75-3108867
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	100 Old River Road
Entity Address, City or Town	Andover
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01810
City Area Code	978
Local Phone Number	688-6706
Entity Common Stock, Shares Outstanding		85,528,136
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 168,654	$ 157,455
Accounts receivable, net of provision for doubtful accounts of $147 and $58 as of June 30, 2021 and December 31, 2020, respectively	65,570	94,124
Inventory	95,782	101,204
Prepaid expenses and other current assets	7,531	3,864
Prepaid income taxes	14,526	14,087
Total current assets	352,063	370,734
Property and equipment, net	25,471	28,880
Accounts receivable, net of current portion	65	143
Deferred tax assets	1,060	1,150
Goodwill	50,177	50,177
Intangible assets, net	34,171	35,844
Other assets	6,196	6,038
Total assets	469,203	492,966
Current liabilities:
Accounts payable	26,299	41,203
Accrued expenses and other current liabilities	29,417	39,793
Accrued income taxes	3,821	7,463
Deferred revenue	20,224	15,531
Current portion of long-term debt, net of unamortized debt issuance costs	8,418	15,171
Total current liabilities	88,179	119,161
Accrued income taxes, net of current portion	9,921	9,520
Deferred tax liabilities	7,359	7,282
Deferred revenue, net of current portion	5,328	3,520
Long-term debt, net of current portion and unamortized debt issuance costs	275,153	276,085
Other liabilities, net of current portion	1,306	1,024
Total liabilities	387,246	416,592
Commitments and contingencies (Note 17)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized as of June 30, 2021 and December 31, 2020; no shares issued and outstanding as of June 30, 2021 and December 31, 2020
Common stock, $0.001 par value; 500,000 shares authorized; 87,116 and 85,329 shares issued as of June 30, 2021 and December 31, 2020, respectively; 85,394 and 83,607 shares outstanding as of June 30, 2021 and December 31, 2020, respectively	87	85
Treasury stock, at cost; 1,722 shares	(4,826)	(4,826)
Additional paid-in capital	185,809	183,041
Accumulated other comprehensive income	594	337
Accumulated deficit	(99,707)	(102,263)
Total stockholders’ equity	81,957	76,374
Total liabilities and stockholders’ equity	$ 469,203	$ 492,966

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Provision for doubtful accounts	$ 147	$ 58
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares, outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	87,116,000	85,329,000
Common stock, shares outstanding	85,394,000	83,607,000
Treasury stock, shares	1,722,000	1,722,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Total revenue	$ 92,730	$ 83,350	$ 197,007	$ 166,973
Cost of revenue:
Total cost of revenue	47,215	40,220	95,452	81,190
Gross profit	45,515	43,130	101,555	85,783
Operating expenses:
Research and development	20,295	20,688	41,901	41,899
Selling, general and administrative	21,583	21,110	43,463	46,101
Total operating expenses	41,878	41,798	85,364	88,000
Income (loss) from operations	3,637	1,332	16,191	(2,217)
Other income (expense):
Interest income	103	271	217	677
Interest expense	(3,999)	(4,307)	(7,917)	(8,935)
(Loss) gain on foreign currency, net	(231)	528	(978)	680
Other income, net	479	35	551	97
Total other income (expense), net	(3,648)	(3,473)	(8,127)	(7,481)
(Loss) income before provision for (benefit from) income taxes	(11)	(2,141)	8,064	(9,698)
Provision for (benefit from) income taxes	3,182	887	5,508	(7,832)
Net (loss) income	(3,193)	(3,028)	2,556	(1,866)
Other comprehensive (loss) income—foreign currency translation adjustment, net of tax	593	99	257	(418)
Other comprehensive (loss) income—gain on foreign currency hedge, net of tax		171		527
Comprehensive (loss) income	(2,600)	(2,758)	2,813	(1,757)
Net (loss) income attributable to common stockholders:
Basic and diluted	$ (3,193)	$ (3,028)	$ 2,556	$ (1,866)
Net (loss) income per share attributable to common stockholders:
Basic	$ (0.04)	$ (0.04)	$ 0.03	$ (0.02)
Diluted	$ (0.04)	$ (0.04)	$ 0.03	$ (0.02)
Weighted-average shares used to compute net (loss) income per share attributable to common stockholders:
Basic	85,036	83,068	84,641	83,505
Diluted	85,036	83,068	89,013	83,505
Product
Revenue:
Total revenue	$ 80,469	$ 72,128	$ 174,267	$ 145,886
Cost of revenue:
Total cost of revenue	46,117	39,011	93,143	78,655
Service
Revenue:
Total revenue	12,261	11,222	22,740	21,087
Cost of revenue:
Total cost of revenue	$ 1,098	$ 1,209	$ 2,309	$ 2,535

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balances at Dec. 31, 2019	$ 38,564	$ 84		$ 169,561	$ (2,222)	$ (127,064)
Balances, shares at Dec. 31, 2019		84,333
Balance Treasury, shares at Dec. 31, 2019			495
Balance Treasury at Dec. 31, 2019			$ (1,795)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes	(72)	$ 1		(73)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes, shares		523
Cash flow hedges	527				527
Foreign currency translation adjustment, net of tax	(418)				(418)
Repurchases of treasury shares	(3,031)		$ (3,031)
Repurchases of treasury shares, shares			1,227
Stock-based compensation	6,008			6,008
Net income (loss)	(1,866)					(1,866)
Balances at Jun. 30, 2020	39,712	$ 85		175,496	(2,113)	(128,930)
Balances, shares at Jun. 30, 2020		84,856
Balance Treasury, shares at Jun. 30, 2020			1,722
Balance Treasury at Jun. 30, 2020			$ (4,826)
Balances at Mar. 31, 2020	38,921	$ 85		171,914	(2,383)	(125,902)
Balances, shares at Mar. 31, 2020		84,726
Balance Treasury, shares at Mar. 31, 2020			1,711
Balance Treasury at Mar. 31, 2020			$ (4,793)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes	75			75
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes, shares		130
Cash flow hedges	171				171
Foreign currency translation adjustment, net of tax	99				99
Repurchases of treasury shares	(33)		$ (33)
Repurchases of treasury shares, shares			11
Stock-based compensation	3,507			3,507
Net income (loss)	(3,028)					(3,028)
Balances at Jun. 30, 2020	39,712	$ 85		175,496	(2,113)	(128,930)
Balances, shares at Jun. 30, 2020		84,856
Balance Treasury, shares at Jun. 30, 2020			1,722
Balance Treasury at Jun. 30, 2020			$ (4,826)
Balances at Dec. 31, 2020	$ 76,374	$ 85		183,041	337	(102,263)
Balances, shares at Dec. 31, 2020		85,329
Balance Treasury, shares at Dec. 31, 2020	1,722		1,722
Balance Treasury at Dec. 31, 2020	$ 4,826		$ (4,826)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes	(4,488)	$ 2		(4,490)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes, shares		1,787
Foreign currency translation adjustment, net of tax	257				257
Stock-based compensation	7,258			7,258
Net income (loss)	2,556					2,556
Balances at Jun. 30, 2021	$ 81,957	$ 87		185,809	594	(99,707)
Balances, shares at Jun. 30, 2021		87,116
Balance Treasury, shares at Jun. 30, 2021	1,722		1,722
Balance Treasury at Jun. 30, 2021	$ 4,826		$ (4,826)
Balances at Mar. 31, 2021	80,835	$ 86		182,088	1	(96,514)
Balances, shares at Mar. 31, 2021		86,502
Balance Treasury, shares at Mar. 31, 2021			1,722
Balance Treasury at Mar. 31, 2021			$ (4,826)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes	(431)	$ 1		(432)
Exercise of stock options and common stock issued upon vesting of equity awards, net of shares withheld for employee taxes, shares		614
Foreign currency translation adjustment, net of tax	593				593
Stock-based compensation	4,153			4,153
Net income (loss)	(3,193)					(3,193)
Balances at Jun. 30, 2021	$ 81,957	$ 87		$ 185,809	$ 594	$ (99,707)
Balances, shares at Jun. 30, 2021		87,116
Balance Treasury, shares at Jun. 30, 2021	1,722		1,722
Balance Treasury at Jun. 30, 2021	$ 4,826		$ (4,826)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020
Cash flows provided by operating activities:
Net income (loss)		$ 2,556	$ (1,866)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		8,197	9,255
Stock-based compensation		7,547	6,016
Deferred income taxes		173	(420)
Increase in provision for doubtful accounts		89	23
Change in provision for excess and obsolete inventory		(6)	1,118
Gain on disposal of assets		4	10
Changes in operating assets and liabilities:
Accounts receivable		28,433	40,377
Inventory		5,372	6,217
Prepaid expenses and other assets		(3,792)	1,419
Prepaid income taxes		(441)	(7,624)
Accounts payable		(14,456)	1,331
Accrued expenses and other current liabilities		(10,210)	(2,480)
Accrued income taxes		(3,240)	(1,016)
Deferred revenue		6,489	(8,424)
Net cash provided by operating activities		26,715	43,936
Cash flows used in investing activities:
Purchases of property and equipment		(1,514)	(2,717)
Purchases of software licenses		(1,400)
Net cash used in investing activities		(2,914)	(2,717)
Cash flows used in financing activities:
Principal repayments of debt		(8,275)	(1,660)
Proceeds from exercise of stock options		1,187	414
Employee taxes paid related to net share settlement of equity awards		(5,675)	(487)
Payments of dividends and equitable adjustments		(59)	(622)
Repurchases of treasury stock			(3,031)
Net cash used in financing activities		(12,822)	(5,386)
Effect of exchange rate changes on cash and cash equivalents		214	(340)
Net increase in cash, cash equivalents and restricted cash		11,193	35,493
Cash, cash equivalents and restricted cash at beginning of period		158,461	114,657
Cash, cash equivalents and restricted cash at end of period	[1]	169,654	150,150
Supplemental disclosures of cash flow information:
Cash paid for interest		7,358	5,502
Cash paid for income taxes		7,564	1,889
Supplemental disclosures of non-cash operating, investing and financing activities:
Purchases of property and equipment included in accounts payable		265	564
Unpaid equitable adjustments included in accrued expenses and other current liabilities		$ 4	124
Fair value of cash flow hedges			$ 527
[1]	See Note 2 of the accompanying notes for a reconciliation of the ending balance of cash, cash equivalents and restricted cash shown in these unaudited condensed consolidated statements of cash flows.

Nature of Business and Basis of

Nature of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Casa Systems, Inc. (the “Company”) was incorporated under the laws of the State of Delaware on February 28, 2003. The Company is a global communications technology company headquartered in Andover, Massachusetts and has wholly owned subsidiaries in China, France, Canada, Ireland, Spain, Colombia, the Netherlands, Hong Kong, Australia, Germany, the United Kingdom and New Zealand. The Company offers physical, virtual and cloud-native 5G broadband and customer premise networking equipment for public and private high-speed data and multi-service communications networks. The Company’s core and edge broadband technology enables communications service providers and enterprises to cost-effectively and dynamically increase data network speed, add bandwidth capacity and new services, reduce network complexity, and reduce operating and capital expenditures. The Company is subject to a number of risks similar to other companies of comparable size and other companies selling and providing services to the communications service provider (“CSP”) industry. These risks include, but are not limited to, the level of capital spending by the CSPs, a lengthy sales cycle, dependence on the development of new products and services, unfavorable economic and market conditions, competition from larger and more established companies, limited management resources, dependence on a limited number of contract manufacturers and suppliers, the rapidly changing nature of the technology used by the CSPs and reliance on resellers and sales agents. Failure by the Company to anticipate or to respond adequately to technological developments in its industry, changes in customer or supplier requirements, changes in regulatory requirements or industry standards, or any significant delays in the development or introduction of products could have a material adverse effect on the Company’s operating results, financial condition and cash flows. The Company is an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and may remain an emerging growth company until the last day of the fiscal year following the fifth anniversary of the Company’s initial public offering, subject to specified conditions. The JOBS Act provides that an emerging growth company can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. The Company has elected not to “opt out” of such extended transition period, which means that when a standard is issued or revised, and it has different application dates for public or private companies, the Company is required to adopt the new or revised standard at or prior to the time private companies are required to adopt the new or revised standard, provided that the Company continues to be an emerging growth company. The JOBS Act provides that the decision to take advantage of the extended transition period for complying with new or revised accounting standards is irrevocable. The accompanying condensed consolidated balance sheet as of June 30, 2021, the condensed consolidated statements of operations and comprehensive (loss) income for the three and six months ended June 30, 2021 and 2020, the condensed consolidated statements of cash flows for the six months ended June 30, 2021 and 2020 and the condensed consolidated statements of stockholders’ equity for the three and six months ended June 30, 2021 and 2020 are unaudited. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2021 and 2020 are also unaudited. The accompanying condensed consolidated balance sheet as of December 31, 2020 was derived from the Company’s audited consolidated financial statements for the year ended December 31, 2020 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on February 25, 2021 (the “Annual Report on Form 10-K”). The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) regarding interim financial reporting. Certain information and note disclosures normally included in the consolidated financial statements prepared in accordance with GAAP have been condensed or omitted. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Annual Report on Form 10-K. There have been no changes to the Company’s accounting policies from those disclosed in the Annual Report on Form 10-K that would have a material impact on the Company’s condensed consolidated financial statements. The unaudited interim condensed consolidated financial statements have been prepared on a basis consistent with that used to prepare the audited annual consolidated financial statements and, in the opinion of management, include all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods, but are not necessarily indicative of the results of operations and cash flows to be anticipated for the full year ending December 31, 2021 or any future period. The accompanying condensed consolidated financial statements include the accounts and results of operations of the Company and its wholly - owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and judgments relied upon by management in preparing these condensed consolidated financial statements include revenue recognition, provision for doubtful accounts, reserves for excess and obsolete inventory, valuation of inventory and deferred inventory costs, the expensing and capitalization of software-related research and development costs, amortization and depreciation periods, the recoverability of net deferred tax assets, valuations of uncertain tax positions, warranty allowances, the valuation of equity instruments and stock-based compensation expense. Although the Company regularly reassesses the assumptions underlying these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period in which they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances existing at the time such estimates are made. The COVID-19 pandemic presents various risks to the Company, not all of which the Company is able to fully evaluate or even to foresee at the current time and could have a material effect upon the estimates and judgments relied upon by management in preparing these condensed consolidated financial statements. While the COVID-19 pandemic did not significantly adversely affect the Company’s financial results and business operations in the three and six months ended June 30, 2021, economic and health conditions in the United States and across most of the globe changed rapidly during the period and are continuing to change after the end of the quarter. Globally, all aspects of the Company’s business remain fully operational. The pandemic has led to increased demand for certain of the Company’s products, resulting in increased order volumes that have created additional pressure on the Company’s supply chain. In addition, certain of the Company’s products utilize components, for which there has been increased global demand. As a result, we have begun to see shortages of supply that have increased the likelihood of an adverse impact on the Company’s future revenue and gross margins and ability to fill orders for customers in a timely manner. The Company continues to work with its supply chain and contract manufacturers, as well as its customers, to minimize the possible extent of such impacts. However, at this time the Company is neither able to estimate the extent of these impacts nor predict whether its efforts to minimize or contain them will be successful. The Company intends to continue to monitor its business very closely for any effects of COVID-19 for as long as necessary. Subsequent Event Considerations The Company evaluates events or transactions that occur after the balance sheet date, but prior to the issuance of the financial statements, in order to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include all highly liquid investments maturing within three months from the date of purchase. As of June 30, 2021 and December 31, 2020, the Company’s cash and cash equivalents consisted of investments in certificates of deposit and money market mutual funds. Restricted cash as of June 30, 2021 and December 31, 2020 consisted of a certificate of deposit of $1,000 and $1,006, respectively, pledged as collateral for a stand-by letter of credit required to support a contractual obligation. The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows: June 30, 2021 June 30, 2020 Cash and cash equivalents $ 168,654 $ 149,148 Restricted cash included in other assets 1,000 1,002 $ 169,654 $ 150,150 Accounts Receivable Accounts receivable are presented net of a provision for doubtful accounts, which is an estimate of amounts that may not be collectible. Accounts receivable for customer contracts with customary payment terms, which are one year or less, are recorded at invoiced amounts and do not bear interest. The Company may, in limited circumstances, grant payment terms longer than one year. Payments due beyond 12 months from the balance sheet date are recorded as non-current assets. The Company generally does not require collateral, but the Company may, in certain instances based on its credit assessment, require full or partial prepayment prior to shipment. Accounts receivable as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Current portion of accounts receivable, net: Accounts receivable, net $ 65,497 $ 93,480 Accounts receivable, extended payment terms 73 644 65,570 94,124 Accounts receivable, net of current portion: Accounts receivable, extended payment terms 65 143 $ 65,635 $ 94,267 The Company performs ongoing credit evaluations of its customers and, if necessary, provides a provision for doubtful accounts and expected losses. When assessing and recording its provision for doubtful accounts, the Company evaluates the age of its accounts receivable, current economic trends, creditworthiness of the customer, customer payment history, and other specific customer and transaction information. The Company writes off accounts receivable against the provision when it determines a balance is uncollectible and no longer actively pursues collection of the receivable. Adjustments to the provision for doubtful accounts are recorded as selling, general and administrative expenses in the condensed consolidated statements of operations and comprehensive (loss) income. As of June 30, 2021 and December 31, 2020, the Company concluded that all amounts due under extended payment terms were collectible and no reserve for credit losses was recorded. During the six months ended June 30, 2021 and 2020, the Company did not provide a reserve for credit losses and did not write off any uncollectible receivables due under extended payment terms. Concentration of Risks Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. Cash and cash equivalents consist of demand deposits, savings accounts, money market mutual funds, and certificates of deposit with financial institutions, which may exceed Federal Deposit Insurance Corporation limits. The Company has not experienced any losses related to its cash and cash equivalents and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those that represent 10% or more of revenue or accounts receivable and are set forth in the following tables: Revenue Revenue Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Customer A 13 % * 16 % * Customer B * 22 % * 21 % Customer C 15 % * 17 % * Customer D * 13 % * * Customer E 11 % * * * Accounts Receivable, Net June 30, 2021 December 31, 2020 Customer A 24 % * Customer C 10 % * Customer F * 17 % * Less than 10% of total Certain of the components and subassemblies included in the Company’s products are obtained from a single source or a limited group of suppliers. Although the Company seeks to reduce dependence on those limited sources of suppliers and manufacturers, the partial or complete loss of certain of these sources could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships. Stock-Based Compensation The Company measures stock options and other stock-based awards granted to employees and directors based on the fair value on the date of the grant and recognizes compensation expense of those awards, net of estimated forfeitures, over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues stock options with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company classifies stock-based compensation expense in its consolidated statements of operations and comprehensive (loss) income in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. The Company recognizes compensation expense for only the portion of awards that are expected to vest. In developing a forfeiture rate estimate, the Company has considered its historical experience to estimate pre-vesting forfeitures for service-based awards. The impact of a forfeiture rate adjustment will be recognized in full in the period of adjustment, and if the actual forfeiture rate is materially different from the Company’s estimate, the Company may be required to record adjustments to stock-based compensation expense in future periods. The Company estimates the fair value of each stock option grant on the date of grant using the Black-Scholes option pricing model. The Company was a private company until December 14, 2017 and lacks sufficient company-specific historical and implied volatility information for its stock. Therefore, for all options granted in 2020 or before, the Company estimated its expected stock volatility based on the historical volatility of publicly traded peer companies. Beginning with options granted in 2021, the Company estimates its expected stock volatility using a weighted-average calculation based on the historical volatility of the Company and publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company does not have a history of declaring or paying cash dividends, except for the special cash dividends declared in November 2014, June 2016, December 2016, May 2017 and November 2017 and in those circumstances the board of directors approved cash dividends to be paid to holders of the Company’s stock options, stock appreciation rights (“SARs”) and restricted stock units (“RSUs”) upon vesting as an equitable adjustment to the holders of such instruments. The Company has also granted SARs to certain employees, which require the Company to pay in cash upon exercise an amount equal to the product of the excess of the per share fair market value of the Company’s common stock on the date of exercise over the exercise price, multiplied by the number of shares of common stock with respect to which the SAR is exercised. Because these awards may require the Company to settle the awards in cash, the Company accounts for them as a liability in the Company’s consolidated balance sheets. The Company recognizes the liability related to these awards, as well as related compensation expense over the period during which services are rendered until completed. As all SARs are now fully vested, the Company continue s to remeasure the fair market value of the liability until the award is either exercised or canceled, with changes in the fair value of the liability recorded in the consolidated statements of operations and comprehensive (loss) income . Impact of Recently Adopted Accounting Standards In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity Impact of Recently Issued Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases Amendments to FASB Accounting Standards Codification In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Other Other than the disclosures above, there have been no changes to the significant accounting policies disclosed in Note 2 “Summary of Significant Accounting Policies” to the Company’s consolidated financial statements included in the Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	3. Goodwill and Intangible Assets Intangible assets, net consisted of the following at June 30, 2021 and December 31, 2020: Cost Accumulated Amortization Net Balance Developed Technology $ 25,000 $ (7,144 ) $ 17,856 Customer Relationships 18,000 (3,600 ) 14,400 Trade Name 1,000 (664 ) 336 Purchased software 1,796 (217 ) 1,579 Totals as of June 30, 2021 $ 45,796 $ (11,625 ) $ 34,171 Cost Accumulated Amortization Net Balance Developed Technology $ 25,000 $ (5,358 ) $ 19,642 Customer Relationships 18,000 (2,700 ) 15,300 Trade Name 1,000 (498 ) 502 Purchased software 432 (32 ) 400 Totals as of December 31, 2020 $ 44,432 $ (8,588 ) $ 35,844 As of June 30, 2021, amortization expense on existing intangible assets for the next five years and beyond is as follows: Year Ending December 31, 2021 $ 3,060 2022 5,951 2023 5,753 2024 5,651 2025 5,651 Thereafter 8,105 $ 34,171 A summary of amortization expense recorded during the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Product cost of revenue $ 893 $ 893 $ 1,786 $ 1,786 Research and development 103 — 185 — Selling, general and administrative 533 533 1,066 1,067 Totals $ 1,529 $ 1,426 $ 3,037 $ 2,853 The Company’s goodwill is the result of its acquisition of NetComm on July 1, 2019 and represents the excess of purchase price over the estimated fair value of net assets acquired. There has been no change to the $50,177 carrying amount of goodwill since December 31, 2020.

Inventory

Inventory	6 Months Ended
	Jun. 30, 2021
Inventory Disclosure [Abstract]
Inventory	4. Inventory Inventory as of June 30, 2021 and December 31, 2020 June 30, 2021 December 31, 2020 Raw materials $ 43,597 $ 50,904 Work in process 1 19 Finished goods: Manufactured finished goods 51,243 49,764 Deferred inventory costs 941 517 $ 95,782 $ 101,204

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2021
Property Plant And Equipment [Abstract]
Property and Equipment	5 . Property and Equipment Property and equipment as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Computers and purchased software $ 24,878 $ 24,865 Leasehold improvements 4,182 4,148 Furniture and fixtures 2,660 2,644 Machinery and equipment 37,161 36,701 Land 3,091 3,091 Building 4,765 4,765 Building improvements 7,255 7,244 Trial systems at customers’ sites 4,383 5,300 88,375 88,758 Less: Accumulated depreciation and amortization (62,904 ) (59,878 ) $ 25,471 $ 28,880 During the six months ended June 30, 2021 and 2020, the Company transferred trial systems into inventory from property and equipment with values of $918 and $574, respectively, net of transfers of trial systems to cost of revenue. In addition, the Company transferred $17 and $328 of equipment into inventory from property and equipment during the six months ended June 30, 2021 and 2020, respectively. D epreciation and amortization expense on property and equipment totaled $2,459 and $3,055 for the three months ended June 30, 2021 and 2020, respectively and $5,160 and $6,402 for the six months ended June 30, 2021 and 2020, respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Accrued compensation and related taxes $ 15,505 $ 22,785 Accrued warranty 2,597 2,354 Other accrued expenses 11,315 14,654 $ 29,417 $ 39,793 Accrued Warranty Substantially all of the Company’s products are covered by warranties for software and hardware for periods ranging from 90 days to one year. In addition, in conjunction with customers’ renewals of maintenance and support contracts, the Company offers an extended warranty for periods typically of one to three years for agreed-upon fees. In the event of a failure of a hardware product or software covered by these warranties, the Company must repair or replace the software or hardware or, if those remedies are insufficient, and at the discretion of the Company, provide a refund. The Company’s warranty reserve, which is included in accrued expenses and other current liabilities in the condensed consolidated balance sheets, reflects estimated material, labor and other costs related to potential or actual software and hardware warranty claims for which the Company expects to incur an obligation. The Company’s estimates of anticipated rates of warranty claims and the costs associated therewith are primarily based on historical information and future forecasts. The Company periodically assesses the adequacy of the warranty reserve and adjusts the amount as necessary. If the historical data used to calculate the adequacy of the warranty reserve are not indicative of future requirements, additional or reduced warranty reserves may be required. A summary of changes in the amount reserved for warranty costs for the six months ended June 30, 2021 and 2020 is as follows: Six Months Ended June 30, 2021 2020 Warranty reserve at beginning of period $ 2,354 $ 2,448 Provisions 1,566 993 Charges (1,323 ) (1,329 ) Warranty reserve at end of period $ 2,597 $ 2,112

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. Fair Value Measurements The following tables present information about the fair value of the Company’s financial assets and liabilities as of June 30, 2021 and December 31, 2020 and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of June 30, 2021 Using: Level 1 Level 2 Level 3 Total Assets: Certificates of deposit—restricted cash $ — $ 1,000 $ — $ 1,000 Money market mutual funds 135,021 — — 135,021 Foreign currency forward contracts — 8 — 8 $ 135,021 $ 1,008 $ — $ 136,029 Liabilities: SARs $ — $ — $ 646 $ 646 $ — $ — $ 646 $ 646 Fair Value Measurements as of December 31, 2020 Using: Level 1 Level 2 Level 3 Total Assets: Certificates of deposit—restricted cash $ — $ 1,006 $ — $ 1,006 Money market mutual funds 114,404 — — 114,404 $ 114,404 $ 1,006 $ — $ 115,410 Liabilities: SARs $ — $ — $ 493 $ 493 $ — $ — $ 493 $ 493 During the six months ended June 30, 2021 and 2020, there were no There were no changes to the valuation techniques used to measure asset and liability fair values on a recurring basis during the six months ended June 30, 2021 from those included in the Company’s consolidated financial statements for the year ended December 31, 2020. The following table provides a summary of changes in the fair values of the Company’s stock appreciation rights (“SARs”) liability, for which fair value is determined by Level 3 inputs: Six Months Ended June 30, 2021 2020 Fair value at beginning of period $ 493 $ 264 Change in fair value 288 7 Exercises (135 ) — Fair value at end of period $ 646 $ 271

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2021
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments	8 . Derivative Instruments The Company has certain international customers that are billed in foreign currencies. To mitigate the volatility related to fluctuations in the foreign exchange rates for accounts receivable denominated in foreign currencies, the Company enters into foreign currency forward contracts. As of June 30, 2021, the Company had a foreign currency forward contract outstanding with a notional amount totaling 1,129 Euros maturing in the third quarter of 2021. As of December 31, 2020, The Company’s foreign currency forward contracts described above economically hedged certain risks but were not designated as hedges for financial reporting purposes, and accordingly, all changes in the fair value of the derivative instruments were recorded as unrealized foreign currency transaction gains or losses and were included in the condensed consolidated statements of operations and comprehensive (loss) income as a component of other income (expense). The Company records derivative instruments in the condensed consolidated balance sheet at their fair values. As of June 30, 2021, the Company recorded an asset of $8 The Company also faces exposure to foreign currency exchange rate fluctuations, as a certain portion of its expenses are denominated in currencies other than U.S. dollars. In certain instances, the Company utilizes forward contracts to hedge against foreign currency fluctuations. These contracts are used to minimize foreign gains or losses, as the gains or losses on the derivative are intended to offset the losses or gains on the underlying exposure. The Company does not engage in foreign currency speculation. The Company designed its foreign currency risk management strategy principally to mitigate the potential financial impact of changes in the value of transactions and balances denominated in foreign currencies resulting from changes in foreign currency exchange rates. The Company may enter into cash flow hedges that utilize foreign currency forward contracts to hedge specific forecasted transactions of its foreign subsidiaries with the goal of protecting its budgeted expenses against foreign currency exchange rate changes compared to its budgeted rates. During the six months ended June 30, 2020 At June 30, 2020, the Company had one outstanding cash flow hedge with a notional amount of 5,000 AUD to hedge certain Australian dollar cash flows incurred during the third quarter of 2020. As the cash flows which were hedged had not yet occurred, the Company recognized the change in fair value of $396 for the three months ended June 30, 2020 and the full fair value of $527 for the six months ended June 30, 2020 as accumulated other comprehensive income in the accompanying condensed consolidated statement of stockholders’ equity. The Company did not have any cash flow hedges outstanding as of June 30, 2021 and December 31, 2020.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes The Company’s provision for (benefit from) income taxes was $3,182 and $887 for the three months ended June 30, 2021 and 2020, respectively. The change in the provision for (benefit from) income taxes was primarily due to changes in the jurisdictional mix of earnings period over period. The Company’s effective income tax rate was 68.3% and 80.8% for the six months ended June 30, 2021 and 2020, respectively. The provision for (benefit from) income taxes was $5,508 and $(7,832) for the six months ended June 30, 2021 and 2020, respectively. The change in the provision for (benefit from) income taxes was primarily due to a discrete tax benefit of $9,310 recorded during the six months ended June 30, 2021 associated with the enactment of the CARES Act. The change in the provision for (benefit from) income taxes was also impacted by changes in the jurisdictional mix of earnings period over period. The provision for (benefit from) income taxes for the three and six months ended June 30, 2021 and 2020 differed from the federal statutory rate primarily due to the geographical mix of earnings and related foreign tax rate differential, permanent differences, research and development tax credits, foreign tax credits, the valuation allowance maintained against certain deferred tax assets and withholding taxes.

Debt

Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Debt	10. Debt The aggregate principal amount of debt outstanding as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, December 31, 2021 2020 Term loan $ 279,725 $ 288,000 Revolving credit facility 6,500 6,500 Total principal amount of debt outstanding $ 286,225 $ 294,500 Current and non-current debt obligations reflected in the condensed consolidated balance sheets as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, December 31, 2021 2020 Current liabilities: Term loan $ 3,000 $ 9,775 Revolving credit facility 6,500 6,500 Current portion of principal payment obligations 9,500 16,275 Unamortized debt issuance costs, current portion (1,082 ) (1,104 ) Current portion of long-term debt, net of unamortized debt issuance costs $ 8,418 $ 15,171 Non-current liabilities: Term loan $ 276,725 $ 278,225 Unamortized debt issuance costs, non-current portion (1,572 ) (2,140 ) Long-term debt, net of current portion and unamortized debt issuance costs $ 275,153 $ 276,085 As of June 30, 2021, aggregate minimum future principal payments of the Company’s debt are summarized as follows: Year Ending December 31, 2021 $ 8,000 2022 3,000 2023 275,225 Thereafter — $ 286,225 Term Loan and Revolving Credit Facilities On December 20, 2016, the Company entered into a credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, various lenders and JPMorgan Chase Bank, N.A. and Barclays Bank PLC providing for (i) a term loan facility of $300,000 and (ii) a revolving credit facility of up to $25,000 in revolving credit loans and letters of credit. As of June 30, 2021 and December 31, 2020, $279,725 and $288,000 in principal amount, respectively, were outstanding under the term loan facility (the “Term Loans”). As of June 30, 2021 and December 31, 2020, the Company had outstanding borrowings under the revolving credit facility of $6,500 Borrowings under the facilities bear interest at a floating rate, which can be either a Eurodollar rate plus an applicable margin or, at the Company’s option, a base rate (defined as the highest of (x) the JPMorgan Chase, N.A. prime rate, (y) the federal funds effective rate, plus one-half percent (0.50%) per annum and (z) a one-month Eurodollar rate plus 1.00% per annum) plus an applicable margin. The applicable margin for borrowings under the term loan facility is 4.00% per annum for Eurodollar rate loans (subject to a 1.00% per annum interest rate floor) and 3.00% per annum for base rate loans. The applicable margin for borrowings under the revolving credit facility is 1.75% per annum for Eurodollar rate loans and 0.75% per annum for base rate loans, subject to reduction based on the Company’s maintaining specified net leverage ratios. The interest rates payable under the facilities are subject to an increase of 2.00% per annum during the continuance of any payment default. For Eurodollar rate loans, the Company may select interest periods of one, three or six months or, with the consent of all relevant affected lenders, twelve months. Interest will be payable at the end of the selected interest period, but no less frequently than every three months within the selected interest period. Interest on any base rate loan is not set for any specified period and is payable quarterly. The Company has the right to convert Eurodollar rate loans into base rate loans and the right to convert base rate loans into Eurodollar rate loans at its option, subject, in the case of Eurodollar rate loans, to breakage costs if the conversion is effected prior to the end of the applicable interest period. As of June 30, 2021 and December 31, 2020, the interest rate on the Term Loans was 5.00% per annum, which was based on a three-month and six-month Eurodollar rate, respectively, at the applicable floor of 1.00% per annum plus the applicable margin of 4.00% per annum for Eurodollar rate loans. As of June 30, 2021, the interest rate on the revolving credit facility was 2.01% per annum, which was based on a six-month Eurodollar rate of 0.26% per annum plus the applicable margin of 1.75% per annum for Eurodollar rate loans. As of December 31, 2020, the interest rate on the revolving credit facility was 2.12% per annum, which was based on the six-month Eurodollar rate of 0.37% per annum plus the applicable margin of 1.75% per annum for Eurodollar rate loans. Upon entering into the term loan facility, the Company incurred debt issuance costs of $7,811, which were initially recorded as a reduction of the debt liability and are amortized to interest expense using the effective interest method from the issuance date of the Term Loan until the maturity date. Principal payments of $7,525 and $750 were made during the three months ended June 30, 2021 and 2020, respectively, and principal payments of $8,275 and $1,500 were made during the six months ended June 30, 2021 and 2020, respectively, under the term loan facility. No principal payments were made under the revolving credit facility during the three and six months ended June 30, 2021. Interest expense for the Term Loan and revolving credit facility, including the amortization of debt issuance costs, totaled $3,933 and $4,026 for the three months ended June 30, 2021 and 2020, respectively and totaled $7,802 and $8,474 for the six months ended June 30, 2021 and 2020, respectively. The revolving credit facility also requires payment of quarterly commitment fees at a rate of 0.25% per annum on the difference between committed amounts and amounts actually borrowed under the facility and customary letter of credit fees. For the three months ended June 30, 2021 and 2020, interest expense related to the fee for the unused amount of the revolving credit facility totaled $11 and $15, respectively and for the six months ended June 30, 2021 and 2020, interest expense related to the fee for the unused amount of the revolving credit facility totaled $22 and $30, respectively. The Term Loans mature on December 20, 2023, and the revolving credit facility matures on December 20, 2021. The Term Loans are subject to amortization in equal quarterly installments, which commenced on March 31, 2017, of principal in an annual aggregate amount equal to 1.0% of the original principal amount of the Term Loans of $300,000, with the remaining outstanding balance payable at the date of maturity. Voluntary prepayments of principal amounts outstanding under the term loan facility are permitted at any time; however, if a prepayment of principal is made with respect to a Eurodollar loan on a date other than the last day of the applicable interest period, the Company is required to compensate the lenders for any funding losses and expenses incurred as a result of the prepayment. Prior to the revolving credit facility maturity date, funds borrowed under the revolving credit facility may be borrowed, repaid and reborrowed, without premium or penalty. In addition, the Company is required to make mandatory prepayments under the facilities with respect to (i) 100% of the net cash proceeds from certain asset dispositions (including casualty and condemnation events) by the Company or certain of its subsidiaries, subject to certain exceptions and reinvestment provisions, (ii) 100% of the net cash proceeds from the issuance or incurrence of any additional debt by the Company or certain of its subsidiaries, subject to certain exceptions, and (iii) 50% of the Company’s excess cash flow, as defined in the credit agreement, subject to reduction upon its achievement of specified performance targets. In accordance with these provisions, a mandatory early prepayment of $6,775 was paid by the Company on April 2, 2021. This amount was included in the current portion of long-term debt, net of unamortized debt issuance costs on the condensed consolidated balance sheet as of December 31, 2020. The facilities are secured by, among other things, a first priority security interest, subject to permitted liens, in substantially all of the Company’s assets and all of the assets of certain of its subsidiaries and a pledge of certain of the stock of certain of its subsidiaries, in each case subject to specified exceptions. The facilities contain customary affirmative and negative covenants, including certain restrictions on the Company’s ability to pay dividends, and, with respect to the revolving credit facility, a financial covenant requiring the Company to maintain a specified total net leverage ratio in the event that on the last day of any fiscal quarter the Company has utilized more than 30% of its borrowing capacity under the facility. The Company was in compliance with all covenants as of June 30, 2021 and December 31, 2020. Commercial Mortgage Loan On July 1, 2015, the Company entered into a commercial mortgage loan agreement in the amount of $7,950 (the “Mortgage Loan”). Borrowings under the Mortgage Loan bore interest at a rate of 3.5% per annum and were repayable in 60 monthly installments of $46, consisting of principal and interest based on a 20-year amortization schedule. The remaining amount of unpaid principal under the Mortgage Loan was paid on the maturity date of July 1, 2020 utilizing the Company’s revolving credit facility. Upon entering into the Mortgage Loan, the Company incurred debt issuance cost of $45, which was initially recorded as a direct deduction from the debt liability and was amortized to interest expense using the effective interest method from the issuance date of the loan until the maturity date. The Mortgage Loan was paid on the maturity date of July 1, 2020, utilizing the Company’s revolving credit facility. The Company made principal payments under the Mortgage Loan of

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Stockholders' Equity	11. Stockholders’ Equity In connection with special dividends previously declared, the board of directors also approved cash payments to be made to holders of the Company’s stock options, SARs and restricted stock units (“RSUs”) as equitable adjustments to the holders of such instruments in accordance with the provisions of the Company’s equity incentive plans. These equitable adjustment payments are equal to an amount per share multiplied by the net number of shares subject to outstanding equity awards after applying the treasury stock method. The below table provides details of these equitable adjustment payments: Equitable Adjustment Payments Six Months Ended Equitable Adjustment Liability(1) Dividend Declaration Dates Equitable Adjustment per share Year of Final Vesting June 30, 2021 June 30, 2020 As of June 30, 2021 As of December 31, 2020 November 30, 2017 $ 0.5802 2021 $ 40 $ 121 $ 4 $ 30 May 10, 2017 1.1774 2021 53 171 — 31 December 27, 2016 2.3306 2020 2 276 — 2 June 17, 2016 0.5891 2020 — 54 — — Total $ 95 $ 622 $ 4 $ 63 (1) Net of estimated forfeitures. Actual payouts may vary based on actual forfeitures. Amounts are included in accrued expenses and other current liabilities in the accompanying condensed consolidated balance sheets. Stock Repurchase Program On February 21, 2019, the Company announced a stock repurchase program authorizing it to repurchase up to $75,000 of the Company’s common stock. There were no repurchases made during the three and six months ended June 30, 2021. During the three and six months ended June 30, 2020, the Company repurchased 11 and

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	12. Stock-based Compensation 2017 Stock Incentive Plan The Company’s 2017 Stock Incentive Plan (the “2017 Plan”) provides for the Company to sell or issue common stock or restricted common stock, or to grant qualified incentive stock options, nonqualified stock options, SARs, performance-based stock units (“PSUs”), RSUs or other stock-based awards to the Company’s employees, officers, directors, advisors and outside consultants. The total number of shares authorized for issuance under the 2017 Plan was 21,179 shares as of , of which 10,456 shares remained available for future grant. Stock Options The following table summarizes the outstanding stock option activity and a summary of information related to stock options as of and for the six months ended June 30, 2021 Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value (in years) Outstanding at January 1, 2021 7,120 $ 8.01 4.88 $ 9,367 Granted 77 8.96 Exercised (414 ) 2.86 Forfeited (144 ) 10.00 Outstanding at June 30, 2021 6,639 $ 8.30 4.41 $ 16,800 Options exercisable at June 30, 2021 6,197 $ 8.12 4.14 $ 16,086 Vested or expected to vest at June 30, 2021 6,616 $ 8.30 4.39 $ 16,754 The fair value of each option is estimated on the date of grant using the Black-Scholes option-pricing model using the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Risk-free interest rate 1.0% 0.4% 1.0% 0.4%-0.7% Expected term (in years) 6.1 6.1 6.1 6.1 Expected volatility 38.2% 31.4% 38.2% 29.3%-31.4% Expected dividend yield 0.0% 0.0% 0.0% 0.0% The weighted-average grant-date fair value of options granted during the six months ended June 30, 2021 and 2020 was $3.42 and $1.15 per share, respectively. Cash proceeds received upon the exercise of options were $1,187 and $414 during the six months ended June 30, 2021 and 2020, respectively. The intrinsic value of stock options exercised during the six months ended June 30, 2021 and 2020 was $2,496 and $373, respectively. The aggregate intrinsic value is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. Restricted Stock Units A summary of RSU activity under the Company’s 2011 Stock Incentive Plan (the “2011 Plan”) and the 2017 Plan for the six months ended June 30, 2021 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Unvested balance at January 1, 2021 4,231 $ 5.43 Granted 756 9.15 Vested (1,133 ) 5.93 $ 9,392 Forfeited (212 ) 4.81 Unvested balance at June 30, 2021 3,642 $ 6.08 The Company withheld 744 and 117 Performance-Based Stock Units During the six months ended June 30, 2021 and 2020, the Company granted PSUs to certain employees that vest over a three-year three-year Compensation expense is based on the estimated value of the awards on the grant date, and is recognized over the period from the grant date through the expected vest dates of each vesting condition, both of which were estimated based on a Monte Carlo simulation model applying the following key assumptions: Six Months Ended June 30, 2021 2020 Risk-free interest rate 0.2% 1.2% Volatility 78.6% 70.0% Dividend yield 0.0% 0.0% Cost of equity 12.0% 11.0% A summary of PSU activity for the six months ended June 30, 2021 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Unvested balance at January 1, 2021 737 $ 3.22 Granted 442 7.89 Vested (737 ) 3.22 $ 6,449 Forfeited — — Unvested balance at June 30, 2021 442 $ 7.89 Stock Appreciation Rights Over time, the Company has granted SARs that allow the holder the right, upon exercise, to receive in cash the amount of the difference between the fair value of the Company’s common stock at the date of exercise and the price of the underlying common stock at the date of grant of each SAR. The SARs vested over a four-year Stock-Based Compensation Expense Stock-based compensation expense related to stock options, RSUs, SARs and PSUs for the three and six months ended June 30, 2021 and 2020 was classified in the condensed consolidated statements of operations and comprehensive (loss) income as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Cost of revenue $ 33 $ 39 $ 66 $ 70 Research and development expenses 543 650 1,414 1,087 Selling, general and administrative expenses 3,518 2,890 6,067 4,859 Total stock-based compensation $ 4,094 $ 3,579 $ 7,547 $ 6,016 The Company recognized stock-based compensation expense for the three and six months ended June 30, 2021 and 2020 in the condensed consolidated balance sheet as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Change in fair value of SAR Liability $ (59 ) $ 72 $ 289 $ 8 Recognized as additional paid-in capital 4,153 3,507 7,258 6,008 Total stock-based compensation $ 4,094 $ 3,579 $ 7,547 $ 6,016 As of June 30, 2021, there was $23,345 of unrecognized compensation cost related to outstanding stock options, RSUs, SARs and PSUs, which is expected to be recognized over a weighted-average period of 2.62 years.

Net (Loss) Income per Share

Net (Loss) Income per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net (Loss) Income per Share	13. Net (Loss) Income per Share Basic and diluted net (loss) income per share attributable to common stockholders was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net (loss) income attributable to common stockholders, basic and diluted $ (3,193 ) $ (3,028 ) $ 2,556 $ (1,866 ) Denominator: Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, basic 85,036 83,068 84,641 83,505 Dilutive effect of stock options — — 2,003 — Dilutive effect of restricted stock units — — 2,369 — Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, diluted 85,036 83,068 89,013 83,505 Net (loss) income per share attributable to common stockholders: Basic $ (0.04 ) $ (0.04 ) $ 0.03 $ (0.02 ) Diluted $ (0.04 ) $ (0.04 ) $ 0.03 $ (0.02 ) The following potential common shares, presented based on amounts outstanding at each period end, were excluded from the computation of diluted net (loss) income per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Options to purchase common stock 6,639 7,562 2,358 7,562 Unvested restricted stock units 3,642 4,112 831 4,112 Unvested performance-based stock units 442 983 — 983

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	14. Revenue from Contracts with Customers Disaggregation of revenue The Company disaggregates its revenue by product and service in the condensed consolidated statements of operations and comprehensive (loss) income. Performance obligations related to product revenue are recognized at a point in time, while performance obligations related to service revenue are recognized over time. The Company also disaggregates its revenue based on geographic locations of its customers, as determined by the customer’s shipping address, summarized as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 North America: United States $ 23,951 $ 29,349 $ 60,863 $ 58,789 Canada 24,550 4,229 50,788 8,742 Total North America 48,501 33,578 111,651 67,531 Europe, Middle East and Africa: 6,577 7,350 12,931 21,446 Asia-Pacific: Australia 20,800 26,255 44,198 47,959 Other 8,893 10,385 15,694 21,870 Total Asia-Pacific 29,693 36,640 59,892 69,829 Latin America 7,959 5,782 12,533 8,167 Total revenue ( 1) $ 92,730 $ 83,350 $ 197,007 $ 166,973 (1) Other than the United States, Canada and Australia, no individual countries represented 10% or more of the Company’s total revenue for any of the periods presented. The Company also disaggregates its revenue based on product line summarized as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Product revenue: Wireless $ 33,323 $ 15,510 $ 73,011 $ 36,167 Fixed telco 16,137 23,819 31,022 41,751 Cable 31,009 32,799 70,234 67,968 Total product revenue 80,469 72,128 174,267 145,886 Service revenue: Wireless 1,684 1,074 2,275 2,848 Fixed telco 1,043 301 2,649 551 Cable 9,534 9,847 17,816 17,688 Total service revenue 12,261 11,222 22,740 21,087 Total revenue $ 92,730 $ 83,350 $ 197,007 $ 166,973 Costs to Obtain or Fulfill a Contract As of June 30, 2021 and December 31, 2020, the Company had short-term capitalized contract costs of $92 and $95, respectively, which are included in prepaid expenses and other current assets and had long-term capitalized contract costs of $63 and $70, respectively, which are included in other assets in the accompanying condensed consolidated balance sheets. During the three months ended June 30, 2021 and 2020, amortization expense associated with capitalized contract costs was $29 and $196, respectively, Contract Balances Contract liabilities consist of deferred revenue and include payments received in advance of performance under the contract. Such amounts are recognized as revenue when the Company satisfies its performance obligations, consistent with the above methodology. For the three and six months ended June 30, 2021, the Company recognized $4,969 The Company receives payments from customers based upon contractual billing terms. Accounts receivable are recorded when the right to consideration becomes unconditional. Contract assets include amounts related to the Company’s contractual right to consideration for both completed and partially completed performance obligations that may not have been invoiced. As of June 30, 2021 and December 31, 2020, the Company included contract assets of $288 and $771, respectively, which is netted with deferred revenue in the accompanying condensed consolidated balance sheets. Transaction price allocated to the remaining performance obligations As of June 30, 2021, the aggregate remaining amount of revenue expected to be recognized related to unsatisfied or partially unsatisfied performance obligations is $25,552, which consists of deferred revenue. The Company expects approximately 79% of this amount to be recognized in the next twelve months with the remaining amounts to be recognized over the next two to five years. Other Revenue Recognition Policies The Company’s customary payment terms are generally 90 days or less. If the Company provides extended payment terms that represent a significant financing component, the Company adjusts the amount of promised consideration for the time value of money using an appropriate discount rate and recognizes interest income separate from the revenue recognized on contracts with customers. During the three months ended June 30, 2021 and 2020, the Company recorded interest income of $4 and $13,

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Segment Information	15. Segment Information The Company operates as one operating segment. Operating segments are defined as components of an enterprise for which separate financial information is regularly evaluated by the Company’s chief operating decision maker, or decision-making group, in deciding how to allocate resources and assess performance. The Company has determined that its chief operating decision maker is its President and Chief Executive Officer. The Company’s chief operating decision maker reviews the Company’s financial information on a consolidated basis for purposes of allocating resources and assessing financial performance. Since the Company operates as one operating segment, all required financial segment information can be found in these condensed consolidated financial statements. The Company’s property and equipment, net by location was as follows: June 30, 2021 December 31, 2020 United States $ 18,657 $ 20,988 China 2,722 2,986 Australia 2,434 2,849 Other 1,658 2,057 Total property and equipment, net $ 25,471 $ 28,880

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related Parties	16. Related Parties Employment of Rongke Xie Rongke Xie, who serves as Deputy General Manager of Guangzhou Casa Communication Technology LTD (“Casa China”), a subsidiary of the Company, is the sister of Lucy Xie, the Company’s Senior Vice President of Operations and a member of the Company’s board of directors. Casa China paid Rongke Xie $150 and $122 in total compensation during the six months ended June 30, 2021 and 2020, respectively, for her services as an employee. In March 2020, February 2019 and June 2018, the Company granted to Rongke Xie 90, 8 and 5 RSUs, respectively, which vest over four annual periods. The grant-date fair value of the awards totaled $400, which will be recorded as stock-based compensation expense over the vesting period of the awards. During the three months ended June 30, 2021 and 2020, the Company recognized selling, general and administrative expenses of $25

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies Indemnification The Company has, in the ordinary course of business, agreed to defend and indemnify certain customers against third-party claims asserting (i) infringement of certain intellectual property rights, which may include patents, copyrights, trademarks or trade secrets, and (ii) certain other harms caused by the acts or omissions on the Company. As permitted under Delaware law, the Company indemnifies its officers, directors and employees for certain events or occurrences that happen by reason of their relationship with or position held at the Company. As of June 30, 2021 and December 31, 2020, the Company had not experienced any losses related to these indemnification obligations and no material claims were outstanding where a contingent loss was considered to be probable or reasonably estimable. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related liabilities were recorded in its condensed consolidated financial statements. Litigation The complete response to this section regarding legal proceedings is incorporated by reference herein to Part II Item I in this 10-Q.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and judgments relied upon by management in preparing these condensed consolidated financial statements include revenue recognition, provision for doubtful accounts, reserves for excess and obsolete inventory, valuation of inventory and deferred inventory costs, the expensing and capitalization of software-related research and development costs, amortization and depreciation periods, the recoverability of net deferred tax assets, valuations of uncertain tax positions, warranty allowances, the valuation of equity instruments and stock-based compensation expense. Although the Company regularly reassesses the assumptions underlying these estimates, actual results could differ materially from these estimates. Changes in estimates are recorded in the period in which they become known. The Company bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances existing at the time such estimates are made. The COVID-19 pandemic presents various risks to the Company, not all of which the Company is able to fully evaluate or even to foresee at the current time and could have a material effect upon the estimates and judgments relied upon by management in preparing these condensed consolidated financial statements. While the COVID-19 pandemic did not significantly adversely affect the Company’s financial results and business operations in the three and six months ended June 30, 2021, economic and health conditions in the United States and across most of the globe changed rapidly during the period and are continuing to change after the end of the quarter. Globally, all aspects of the Company’s business remain fully operational. The pandemic has led to increased demand for certain of the Company’s products, resulting in increased order volumes that have created additional pressure on the Company’s supply chain. In addition, certain of the Company’s products utilize components, for which there has been increased global demand. As a result, we have begun to see shortages of supply that have increased the likelihood of an adverse impact on the Company’s future revenue and gross margins and ability to fill orders for customers in a timely manner. The Company continues to work with its supply chain and contract manufacturers, as well as its customers, to minimize the possible extent of such impacts. However, at this time the Company is neither able to estimate the extent of these impacts nor predict whether its efforts to minimize or contain them will be successful. The Company intends to continue to monitor its business very closely for any effects of COVID-19 for as long as necessary.
Subsequent Event Considerations	Subsequent Event Considerations The Company evaluates events or transactions that occur after the balance sheet date, but prior to the issuance of the financial statements, in order to provide additional evidence for certain estimates or to identify matters that require additional disclosure. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include all highly liquid investments maturing within three months from the date of purchase. As of June 30, 2021 and December 31, 2020, the Company’s cash and cash equivalents consisted of investments in certificates of deposit and money market mutual funds. Restricted cash as of June 30, 2021 and December 31, 2020 consisted of a certificate of deposit of $1,000 and $1,006, respectively, pledged as collateral for a stand-by letter of credit required to support a contractual obligation. The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows: June 30, 2021 June 30, 2020 Cash and cash equivalents $ 168,654 $ 149,148 Restricted cash included in other assets 1,000 1,002 $ 169,654 $ 150,150
Accounts Receivable	Accounts Receivable Accounts receivable are presented net of a provision for doubtful accounts, which is an estimate of amounts that may not be collectible. Accounts receivable for customer contracts with customary payment terms, which are one year or less, are recorded at invoiced amounts and do not bear interest. The Company may, in limited circumstances, grant payment terms longer than one year. Payments due beyond 12 months from the balance sheet date are recorded as non-current assets. The Company generally does not require collateral, but the Company may, in certain instances based on its credit assessment, require full or partial prepayment prior to shipment. Accounts receivable as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Current portion of accounts receivable, net: Accounts receivable, net $ 65,497 $ 93,480 Accounts receivable, extended payment terms 73 644 65,570 94,124 Accounts receivable, net of current portion: Accounts receivable, extended payment terms 65 143 $ 65,635 $ 94,267 The Company performs ongoing credit evaluations of its customers and, if necessary, provides a provision for doubtful accounts and expected losses. When assessing and recording its provision for doubtful accounts, the Company evaluates the age of its accounts receivable, current economic trends, creditworthiness of the customer, customer payment history, and other specific customer and transaction information. The Company writes off accounts receivable against the provision when it determines a balance is uncollectible and no longer actively pursues collection of the receivable. Adjustments to the provision for doubtful accounts are recorded as selling, general and administrative expenses in the condensed consolidated statements of operations and comprehensive (loss) income. As of June 30, 2021 and December 31, 2020, the Company concluded that all amounts due under extended payment terms were collectible and no reserve for credit losses was recorded. During the six months ended June 30, 2021 and 2020, the Company did not provide a reserve for credit losses and did not write off any uncollectible receivables due under extended payment terms.
Concentration of Risks	Concentration of Risks Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. Cash and cash equivalents consist of demand deposits, savings accounts, money market mutual funds, and certificates of deposit with financial institutions, which may exceed Federal Deposit Insurance Corporation limits. The Company has not experienced any losses related to its cash and cash equivalents and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Significant customers are those that represent 10% or more of revenue or accounts receivable and are set forth in the following tables: Revenue Revenue Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Customer A 13 % * 16 % * Customer B * 22 % * 21 % Customer C 15 % * 17 % * Customer D * 13 % * * Customer E 11 % * * * Accounts Receivable, Net June 30, 2021 December 31, 2020 Customer A 24 % * Customer C 10 % * Customer F * 17 % * Less than 10% of total Certain of the components and subassemblies included in the Company’s products are obtained from a single source or a limited group of suppliers. Although the Company seeks to reduce dependence on those limited sources of suppliers and manufacturers, the partial or complete loss of certain of these sources could have a material adverse effect on the Company’s operating results, financial condition and cash flows and damage its customer relationships.
Stock-Based Compensation	Stock-Based Compensation The Company measures stock options and other stock-based awards granted to employees and directors based on the fair value on the date of the grant and recognizes compensation expense of those awards, net of estimated forfeitures, over the requisite service period, which is generally the vesting period of the respective award. Generally, the Company issues stock options with only service-based vesting conditions and records the expense for these awards using the straight-line method. The Company classifies stock-based compensation expense in its consolidated statements of operations and comprehensive (loss) income in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified. The Company recognizes compensation expense for only the portion of awards that are expected to vest. In developing a forfeiture rate estimate, the Company has considered its historical experience to estimate pre-vesting forfeitures for service-based awards. The impact of a forfeiture rate adjustment will be recognized in full in the period of adjustment, and if the actual forfeiture rate is materially different from the Company’s estimate, the Company may be required to record adjustments to stock-based compensation expense in future periods. The Company estimates the fair value of each stock option grant on the date of grant using the Black-Scholes option pricing model. The Company was a private company until December 14, 2017 and lacks sufficient company-specific historical and implied volatility information for its stock. Therefore, for all options granted in 2020 or before, the Company estimated its expected stock volatility based on the historical volatility of publicly traded peer companies. Beginning with options granted in 2021, the Company estimates its expected stock volatility using a weighted-average calculation based on the historical volatility of the Company and publicly traded peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. The expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company does not have a history of declaring or paying cash dividends, except for the special cash dividends declared in November 2014, June 2016, December 2016, May 2017 and November 2017 and in those circumstances the board of directors approved cash dividends to be paid to holders of the Company’s stock options, stock appreciation rights (“SARs”) and restricted stock units (“RSUs”) upon vesting as an equitable adjustment to the holders of such instruments. The Company has also granted SARs to certain employees, which require the Company to pay in cash upon exercise an amount equal to the product of the excess of the per share fair market value of the Company’s common stock on the date of exercise over the exercise price, multiplied by the number of shares of common stock with respect to which the SAR is exercised. Because these awards may require the Company to settle the awards in cash, the Company accounts for them as a liability in the Company’s consolidated balance sheets. The Company recognizes the liability related to these awards, as well as related compensation expense over the period during which services are rendered until completed. As all SARs are now fully vested, the Company continue s to remeasure the fair market value of the liability until the award is either exercised or canceled, with changes in the fair value of the liability recorded in the consolidated statements of operations and comprehensive (loss) income .
Impact of Recently Adopted and Issued Accounting Standards	Impact of Recently Adopted Accounting Standards In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity Impact of Recently Issued Accounting Standards In February 2016, the FASB issued ASU 2016-02, Leases Amendments to FASB Accounting Standards Codification In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842)
Other	Other Other than the disclosures above, there have been no changes to the significant accounting policies disclosed in Note 2 “Summary of Significant Accounting Policies” to the Company’s consolidated financial statements included in the Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash in Accompanying Condensed Consolidated Balance Sheets	The following table is a reconciliation of cash, cash equivalents and restricted cash included in the accompanying condensed consolidated balance sheets that sum to the total cash, cash equivalents and restricted cash included in the accompanying condensed consolidated statements of cash flows: June 30, 2021 June 30, 2020 Cash and cash equivalents $ 168,654 $ 149,148 Restricted cash included in other assets 1,000 1,002 $ 169,654 $ 150,150
Schedule of Accounts Receivable	Accounts receivable as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Current portion of accounts receivable, net: Accounts receivable, net $ 65,497 $ 93,480 Accounts receivable, extended payment terms 73 644 65,570 94,124 Accounts receivable, net of current portion: Accounts receivable, extended payment terms 65 143 $ 65,635 $ 94,267
Schedule of Significant Customers Represent 10% or More of Revenue or Accounts Receivable	Significant customers are those that represent 10% or more of revenue or accounts receivable and are set forth in the following tables: Revenue Revenue Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Customer A 13 % * 16 % * Customer B * 22 % * 21 % Customer C 15 % * 17 % * Customer D * 13 % * * Customer E 11 % * * * Accounts Receivable, Net June 30, 2021 December 31, 2020 Customer A 24 % * Customer C 10 % * Customer F * 17 % * Less than 10% of total

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets Net	Intangible assets, net consisted of the following at June 30, 2021 and December 31, 2020: Cost Accumulated Amortization Net Balance Developed Technology $ 25,000 $ (7,144 ) $ 17,856 Customer Relationships 18,000 (3,600 ) 14,400 Trade Name 1,000 (664 ) 336 Purchased software 1,796 (217 ) 1,579 Totals as of June 30, 2021 $ 45,796 $ (11,625 ) $ 34,171 Cost Accumulated Amortization Net Balance Developed Technology $ 25,000 $ (5,358 ) $ 19,642 Customer Relationships 18,000 (2,700 ) 15,300 Trade Name 1,000 (498 ) 502 Purchased software 432 (32 ) 400 Totals as of December 31, 2020 $ 44,432 $ (8,588 ) $ 35,844
Schedule of Amortization Expense on Existing Intangible Assets	As of June 30, 2021, amortization expense on existing intangible assets for the next five years and beyond is as follows: Year Ending December 31, 2021 $ 3,060 2022 5,951 2023 5,753 2024 5,651 2025 5,651 Thereafter 8,105 $ 34,171
Summary of Amortization Expense	A summary of amortization expense recorded during the three and six months ended June 30, 2021 and 2020 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Product cost of revenue $ 893 $ 893 $ 1,786 $ 1,786 Research and development 103 — 185 — Selling, general and administrative 533 533 1,066 1,067 Totals $ 1,529 $ 1,426 $ 3,037 $ 2,853

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2021
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory as of June 30, 2021 and December 31, 2020 June 30, 2021 December 31, 2020 Raw materials $ 43,597 $ 50,904 Work in process 1 19 Finished goods: Manufactured finished goods 51,243 49,764 Deferred inventory costs 941 517 $ 95,782 $ 101,204

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2021
Property Plant And Equipment [Abstract]
Summary of Components of Property and Equipment	Property and equipment as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Computers and purchased software $ 24,878 $ 24,865 Leasehold improvements 4,182 4,148 Furniture and fixtures 2,660 2,644 Machinery and equipment 37,161 36,701 Land 3,091 3,091 Building 4,765 4,765 Building improvements 7,255 7,244 Trial systems at customers’ sites 4,383 5,300 88,375 88,758 Less: Accumulated depreciation and amortization (62,904 ) (59,878 ) $ 25,471 $ 28,880

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, 2021 December 31, 2020 Accrued compensation and related taxes $ 15,505 $ 22,785 Accrued warranty 2,597 2,354 Other accrued expenses 11,315 14,654 $ 29,417 $ 39,793
Summary of Changes in Amount Reserved for Warranty Costs	A summary of changes in the amount reserved for warranty costs for the six months ended June 30, 2021 and 2020 is as follows: Six Months Ended June 30, 2021 2020 Warranty reserve at beginning of period $ 2,354 $ 2,448 Provisions 1,566 993 Charges (1,323 ) (1,329 ) Warranty reserve at end of period $ 2,597 $ 2,112

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	The following tables present information about the fair value of the Company’s financial assets and liabilities as of June 30, 2021 and December 31, 2020 and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of June 30, 2021 Using: Level 1 Level 2 Level 3 Total Assets: Certificates of deposit—restricted cash $ — $ 1,000 $ — $ 1,000 Money market mutual funds 135,021 — — 135,021 Foreign currency forward contracts — 8 — 8 $ 135,021 $ 1,008 $ — $ 136,029 Liabilities: SARs $ — $ — $ 646 $ 646 $ — $ — $ 646 $ 646 Fair Value Measurements as of December 31, 2020 Using: Level 1 Level 2 Level 3 Total Assets: Certificates of deposit—restricted cash $ — $ 1,006 $ — $ 1,006 Money market mutual funds 114,404 — — 114,404 $ 114,404 $ 1,006 $ — $ 115,410 Liabilities: SARs $ — $ — $ 493 $ 493 $ — $ — $ 493 $ 493
Summary of Changes in Fair Values of Stock Appreciation Rights (SARs) Liability	The following table provides a summary of changes in the fair values of the Company’s stock appreciation rights (“SARs”) liability, for which fair value is determined by Level 3 inputs: Six Months Ended June 30, 2021 2020 Fair value at beginning of period $ 493 $ 264 Change in fair value 288 7 Exercises (135 ) — Fair value at end of period $ 646 $ 271

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Schedule of Aggregate Principal Amount of Debt Outstanding	The aggregate principal amount of debt outstanding as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, December 31, 2021 2020 Term loan $ 279,725 $ 288,000 Revolving credit facility 6,500 6,500 Total principal amount of debt outstanding $ 286,225 $ 294,500
Schedule of Current and Non-Current Debt Obligations	Current and non-current debt obligations reflected in the condensed consolidated balance sheets as of June 30, 2021 and December 31, 2020 consisted of the following: June 30, December 31, 2021 2020 Current liabilities: Term loan $ 3,000 $ 9,775 Revolving credit facility 6,500 6,500 Current portion of principal payment obligations 9,500 16,275 Unamortized debt issuance costs, current portion (1,082 ) (1,104 ) Current portion of long-term debt, net of unamortized debt issuance costs $ 8,418 $ 15,171 Non-current liabilities: Term loan $ 276,725 $ 278,225 Unamortized debt issuance costs, non-current portion (1,572 ) (2,140 ) Long-term debt, net of current portion and unamortized debt issuance costs $ 275,153 $ 276,085
Schedule of Aggregate Minimum Future Principal Payments of Debt	As of June 30, 2021, aggregate minimum future principal payments of the Company’s debt are summarized as follows: Year Ending December 31, 2021 $ 8,000 2022 3,000 2023 275,225 Thereafter — $ 286,225

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Schedule of Equitable Adjustment Payments	The below table provides details of these equitable adjustment payments: Equitable Adjustment Payments Six Months Ended Equitable Adjustment Liability(1) Dividend Declaration Dates Equitable Adjustment per share Year of Final Vesting June 30, 2021 June 30, 2020 As of June 30, 2021 As of December 31, 2020 November 30, 2017 $ 0.5802 2021 $ 40 $ 121 $ 4 $ 30 May 10, 2017 1.1774 2021 53 171 — 31 December 27, 2016 2.3306 2020 2 276 — 2 June 17, 2016 0.5891 2020 — 54 — — Total $ 95 $ 622 $ 4 $ 63 (1) Net of estimated forfeitures. Actual payouts may vary based on actual forfeitures. Amounts are included in accrued expenses and other current liabilities in the accompanying condensed consolidated balance sheets.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Outstanding Stock Option and Information Related to Stock Options Activity	The following table summarizes the outstanding stock option activity and a summary of information related to stock options as of and for the six months ended June 30, 2021 Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value (in years) Outstanding at January 1, 2021 7,120 $ 8.01 4.88 $ 9,367 Granted 77 8.96 Exercised (414 ) 2.86 Forfeited (144 ) 10.00 Outstanding at June 30, 2021 6,639 $ 8.30 4.41 $ 16,800 Options exercisable at June 30, 2021 6,197 $ 8.12 4.14 $ 16,086 Vested or expected to vest at June 30, 2021 6,616 $ 8.30 4.39 $ 16,754
Assumptions of Estimated Fair Value of Option on the Date of Grant Using Black-Scholes Option Pricing Model	The fair value of each option is estimated on the date of grant using the Black-Scholes option-pricing model using the following assumptions: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Risk-free interest rate 1.0% 0.4% 1.0% 0.4%-0.7% Expected term (in years) 6.1 6.1 6.1 6.1 Expected volatility 38.2% 31.4% 38.2% 29.3%-31.4% Expected dividend yield 0.0% 0.0% 0.0% 0.0%
Summary of RSU Activity	A summary of RSU activity under the Company’s 2011 Stock Incentive Plan (the “2011 Plan”) and the 2017 Plan for the six months ended June 30, 2021 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Unvested balance at January 1, 2021 4,231 $ 5.43 Granted 756 9.15 Vested (1,133 ) 5.93 $ 9,392 Forfeited (212 ) 4.81 Unvested balance at June 30, 2021 3,642 $ 6.08
Assumptions of Estimated Based on Monte Carlo Simulation Model	Compensation expense is based on the estimated value of the awards on the grant date, and is recognized over the period from the grant date through the expected vest dates of each vesting condition, both of which were estimated based on a Monte Carlo simulation model applying the following key assumptions: Six Months Ended June 30, 2021 2020 Risk-free interest rate 0.2% 1.2% Volatility 78.6% 70.0% Dividend yield 0.0% 0.0% Cost of equity 12.0% 11.0%
Summary of PSU Activity	A summary of PSU activity for the six months ended June 30, 2021 is as follows: Number of Shares Weighted- Average Grant Date Fair Value Aggregate Fair Value Unvested balance at January 1, 2021 737 $ 3.22 Granted 442 7.89 Vested (737 ) 3.22 $ 6,449 Forfeited — — Unvested balance at June 30, 2021 442 $ 7.89
Schedule of Stock-based Compensation Expense	Stock-based compensation expense related to stock options, RSUs, SARs and PSUs for the three and six months ended June 30, 2021 and 2020 was classified in the condensed consolidated statements of operations and comprehensive (loss) income as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Cost of revenue $ 33 $ 39 $ 66 $ 70 Research and development expenses 543 650 1,414 1,087 Selling, general and administrative expenses 3,518 2,890 6,067 4,859 Total stock-based compensation $ 4,094 $ 3,579 $ 7,547 $ 6,016 The Company recognized stock-based compensation expense for the three and six months ended June 30, 2021 and 2020 in the condensed consolidated balance sheet as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Change in fair value of SAR Liability $ (59 ) $ 72 $ 289 $ 8 Recognized as additional paid-in capital 4,153 3,507 7,258 6,008 Total stock-based compensation $ 4,094 $ 3,579 $ 7,547 $ 6,016

Net (Loss) Income per Share (Ta

Net (Loss) Income per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net (Loss) Income Per Share Attributable to Common Stockholders	Basic and diluted net (loss) income per share attributable to common stockholders was calculated as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net (loss) income attributable to common stockholders, basic and diluted $ (3,193 ) $ (3,028 ) $ 2,556 $ (1,866 ) Denominator: Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, basic 85,036 83,068 84,641 83,505 Dilutive effect of stock options — — 2,003 — Dilutive effect of restricted stock units — — 2,369 — Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, diluted 85,036 83,068 89,013 83,505 Net (loss) income per share attributable to common stockholders: Basic $ (0.04 ) $ (0.04 ) $ 0.03 $ (0.02 ) Diluted $ (0.04 ) $ (0.04 ) $ 0.03 $ (0.02 )
Schedule of Potential Common Shares Excluded from the Computation of Diluted Net (Loss) Income Per Share Attributable to Common Stockholders	The following potential common shares, presented based on amounts outstanding at each period end, were excluded from the computation of diluted net (loss) income per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Options to purchase common stock 6,639 7,562 2,358 7,562 Unvested restricted stock units 3,642 4,112 831 4,112 Unvested performance-based stock units 442 983 — 983

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
Summary of Disaggregation of Revenue Based on Geographic Locations Determined by Customer's Shipping Address	The Company also disaggregates its revenue based on geographic locations of its customers, as determined by the customer’s shipping address, summarized as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 North America: United States $ 23,951 $ 29,349 $ 60,863 $ 58,789 Canada 24,550 4,229 50,788 8,742 Total North America 48,501 33,578 111,651 67,531 Europe, Middle East and Africa: 6,577 7,350 12,931 21,446 Asia-Pacific: Australia 20,800 26,255 44,198 47,959 Other 8,893 10,385 15,694 21,870 Total Asia-Pacific 29,693 36,640 59,892 69,829 Latin America 7,959 5,782 12,533 8,167 Total revenue ( 1) $ 92,730 $ 83,350 $ 197,007 $ 166,973 (1) Other than the United States, Canada and Australia, no individual countries represented 10% or more of the Company’s total revenue for any of the periods presented.
Summary of Disaggregates of Revenue Based on Product Line	The Company also disaggregates its revenue based on product line summarized as follows: Three Months Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Product revenue: Wireless $ 33,323 $ 15,510 $ 73,011 $ 36,167 Fixed telco 16,137 23,819 31,022 41,751 Cable 31,009 32,799 70,234 67,968 Total product revenue 80,469 72,128 174,267 145,886 Service revenue: Wireless 1,684 1,074 2,275 2,848 Fixed telco 1,043 301 2,649 551 Cable 9,534 9,847 17,816 17,688 Total service revenue 12,261 11,222 22,740 21,087 Total revenue $ 92,730 $ 83,350 $ 197,007 $ 166,973

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Schedule of Property and Equipment, Net by Location	The Company’s property and equipment, net by location was as follows: June 30, 2021 December 31, 2020 United States $ 18,657 $ 20,988 China 2,722 2,986 Australia 2,434 2,849 Other 1,658 2,057 Total property and equipment, net $ 25,471 $ 28,880

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended
	Aug. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Significant Accounting Policies [Line Items]
Change in accounting principle accounting standards update adopted	true
Change in accounting principle, accounting standards update, early adoption [true false]	true
Change in accounting principle accounting standards update immaterial effect	true
Accounting Standards Update [Extensible List]	casa:AccountingStandardsUpdate202006Member
Accounts Receivable, Extended Payment Terms
Significant Accounting Policies [Line Items]
Reserve for credit losses		$ 0	$ 0
Write off of uncollectible receivables		0	$ 0
Certificates of Deposit
Significant Accounting Policies [Line Items]
Restricted cash		$ 1,000,000		$ 1,006,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash in Accompanying Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2021		Dec. 31, 2020	Jun. 30, 2020		Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 168,654		$ 157,455	$ 149,148
Restricted cash included in other assets	$ 1,000			$ 1,002
Restricted Cash and Cash Equivalents, Noncurrent, Asset, Statement of Financial Position [Extensible List]	Other assets			Other assets
Cash and cash equivalents, restricted cash	$ 169,654	[1]	$ 158,461	$ 150,150	[1]	$ 114,657
[1]	See Note 2 of the accompanying notes for a reconciliation of the ending balance of cash, cash equivalents and restricted cash shown in these unaudited condensed consolidated statements of cash flows.

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current portion of accounts receivable, net:
Current portion of accounts receivable, net	$ 65,570	$ 94,124
Accounts receivable, net of current portion:
Accounts receivable, net of current portion	65	143
Accounts receivable	65,635	94,267
Accounts Receivable, Net
Current portion of accounts receivable, net:
Current portion of accounts receivable, net	65,497	93,480
Accounts Receivable, Extended Payment Terms
Current portion of accounts receivable, net:
Current portion of accounts receivable, net	$ 73	$ 644

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Significant Customers Represent 10% or More of Revenue or Accounts Receivable (Details) - Customer Concentration Risk	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Customer A | Revenue
Concentration Risk [Line Items]
Concentration risk percentage	13.00%		16.00%
Customer A | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage			24.00%
Customer B | Revenue
Concentration Risk [Line Items]
Concentration risk percentage		22.00%		21.00%
Customer C | Revenue
Concentration Risk [Line Items]
Concentration risk percentage	15.00%		17.00%
Customer C | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage			10.00%
Customer D | Revenue
Concentration Risk [Line Items]
Concentration risk percentage		13.00%
Customer E | Revenue
Concentration Risk [Line Items]
Concentration risk percentage	11.00%
Customer F | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage					17.00%

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Finite Lived Intangible Assets [Line Items]
Cost	$ 45,796	$ 44,432
Accumulated Amortization	(11,625)	(8,588)
Net Balance	34,171	35,844
Developed Technology
Finite Lived Intangible Assets [Line Items]
Cost	25,000	25,000
Accumulated Amortization	(7,144)	(5,358)
Net Balance	17,856	19,642
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Cost	18,000	18,000
Accumulated Amortization	(3,600)	(2,700)
Net Balance	14,400	15,300
Trade Name
Finite Lived Intangible Assets [Line Items]
Cost	1,000	1,000
Accumulated Amortization	(664)	(498)
Net Balance	336	502
Purchased Software
Finite Lived Intangible Assets [Line Items]
Cost	1,796	432
Accumulated Amortization	(217)	(32)
Net Balance	$ 1,579	$ 400

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Amortization Expense on Existing Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
2021	$ 3,060
2022	5,951
2023	5,753
2024	5,651
2025	5,651
Thereafter	8,105
Net Balance	$ 34,171	$ 35,844

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Summary of Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1,529	$ 1,426	$ 3,037	$ 2,853
Product Cost of Revenue
Finite Lived Intangible Assets [Line Items]
Amortization expense	893	893	1,786	1,786
Research and Development
Finite Lived Intangible Assets [Line Items]
Amortization expense	103		185
Selling, General and Administrative Expenses
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 533	$ 533	$ 1,066	$ 1,067

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 50,177	$ 50,177

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 43,597	$ 50,904
Work in process	1	19
Finished goods:
Manufactured finished goods	51,243	49,764
Deferred inventory costs	941	517
Total inventory	$ 95,782	$ 101,204

Property and Equipment - Summar

Property and Equipment - Summary of Components of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 88,375	$ 88,758
Less: Accumulated depreciation and amortization	(62,904)	(59,878)
Property and equipment, net	25,471	28,880
Computers and Purchased Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	24,878	24,865
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	4,182	4,148
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,660	2,644
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	37,161	36,701
Land
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,091	3,091
Building
Property Plant And Equipment [Line Items]
Property and equipment, gross	4,765	4,765
Building Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	7,255	7,244
Trial Systems at Customers' Sites
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,383	$ 5,300

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Property Plant And Equipment [Line Items]
Depreciation and amortization expense on property and equipment	$ 2,459	$ 3,055	$ 5,160	$ 6,402
Trial Systems
Property Plant And Equipment [Line Items]
Transfers to inventory from property and equipment			918	574
Equipment
Property Plant And Equipment [Line Items]
Transfers to inventory from property and equipment			$ 17	$ 328

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued compensation and related taxes	$ 15,505	$ 22,785
Accrued warranty	2,597	2,354
Other accrued expenses	11,315	14,654
Total accrued expenses and other current liabilities	$ 29,417	$ 39,793

Accrued Expenses and Other Cu_4

Accrued Expenses and Other Current Liabilities - Additional Information (Details)	6 Months Ended
	Jun. 30, 2021
Accrued Expenses And Other Current Liabilities [Line Items]
Standard product warranty description	the Company’s products are covered by warranties for software and hardware for periods ranging from 90 days to one year.
Extended product warranty description	the Company offers an extended warranty for periods typically of one to three years for agreed-upon fees.
Minimum
Accrued Expenses And Other Current Liabilities [Line Items]
Product warranties period for software and hardware	90 days
Extended product warranty period for renewals of maintenance and support contracts	1 year
Maximum
Accrued Expenses And Other Current Liabilities [Line Items]
Product warranties period for software and hardware	1 year
Extended product warranty period for renewals of maintenance and support contracts	3 years

Accrued Expenses and Other Cu_5

Accrued Expenses and Other Current Liabilities - Summary of Changes in Amount Reserved for Warranty Costs (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Product Warranties Disclosures [Abstract]
Warranty reserve at beginning of period	$ 2,354	$ 2,448
Provisions	1,566	993
Charges	(1,323)	(1,329)
Warranty reserve at end of period	$ 2,597	$ 2,112

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets:
Assets fair value	$ 136,029	$ 115,410
Liabilities:
Liabilities fair value	646	493
Certificates of Deposit - Restricted Cash
Assets:
Assets fair value	1,000	1,006
Money Market Mutual Funds
Assets:
Assets fair value	135,021	114,404
Foreign Currency Forward Contracts
Assets:
Assets fair value	8
Level 1
Assets:
Assets fair value	135,021	114,404
Level 1 | Money Market Mutual Funds
Assets:
Assets fair value	135,021	114,404
Level 2
Assets:
Assets fair value	1,008	1,006
Level 2 | Certificates of Deposit - Restricted Cash
Assets:
Assets fair value	1,000	1,006
Level 2 | Foreign Currency Forward Contracts
Assets:
Assets fair value	8
Level 3
Liabilities:
Liabilities fair value	646	493
SARs | Share Based Compensation Liability
Liabilities:
Liabilities fair value	646	493
SARs | Level 3 | Share Based Compensation Liability
Liabilities:
Liabilities fair value	$ 646	$ 493

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair value, assets, transfers from Level 1 to Level 2	$ 0	$ 0
Fair value, assets, transfers from Level 2 to Level 1	0	0
Fair value, liabilities, transfers from Level 1 to Level 2	0	0
Fair value, liabilities, transfers from Level 2 to Level 1	0	0
Fair value, assets, transfers into Level 3	0	0
Fair value, assets, transfers out of Level 3	0	0
Fair value, liabilities, transfers into Level 3	0	0
Fair value, liabilities, transfers out of Level 3	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in Fair Values of Stock Appreciation Rights (SARs) Liability (Details) - Level 3 - SARs - Share Based Compensation Liability - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at beginning of period	$ 493	$ 264
Change in fair value	288	7
Exercises	(135)
Fair value at end of period	$ 646	$ 271

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Details) $ in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020AUD ($)	Jun. 30, 2020AUD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2021EUR (€)	Dec. 31, 2020USD ($)	Dec. 31, 2020EUR (€)
Australian Subsidiary
Derivatives Fair Value [Line Items]
Fair value of derivative amount recognized	$ 888
Australian Subsidiary | Product Cost of Revenue
Derivatives Fair Value [Line Items]
Fair value of derivative amount recognized	67
Australian Subsidiary | Research and Development
Derivatives Fair Value [Line Items]
Fair value of derivative amount recognized	537
Australian Subsidiary | Selling, General and Administrative Expense
Derivatives Fair Value [Line Items]
Fair value of derivative amount recognized	284
Australian Subsidiary | Cash Flow Hedges
Derivatives Fair Value [Line Items]
Amount of gain reclassified from other comprehensive (loss) income	225
Derivative notional amount outstanding	5,000	$ 5,000
Fair value of cash flow hedges	396	396
Australian Subsidiary | Prepaid Expenses and Other Current Assets | Cash Flow Hedges
Derivatives Fair Value [Line Items]
Derivative asset	$ 527	527
Foreign Currency Forward Contracts | Prepaid Expenses and Other Current Assets
Derivatives Fair Value [Line Items]
Derivatives asset fair value			$ 8		$ 0
Foreign Currency Forward Contracts | Accrued Expenses And Other Current Liabilities
Derivatives Fair Value [Line Items]
Liability derivatives			$ 0		$ 0
Foreign Currency Forward Contracts | Australian Subsidiary
Derivatives Fair Value [Line Items]
Outstanding notional amounts | €				€ 1,129,000		€ 0
Foreign Currency Forward Contracts One | Australian Subsidiary | Cash Flow Hedges
Derivatives Fair Value [Line Items]
Derivative notional amounts settled		$ 8,500

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate			68.30%	80.80%
Provision for (benefit from) income taxes	$ 3,182	$ 887	$ 5,508	$ (7,832)
Discrete tax benefit			$ 9,310

Debt - Schedule of Aggregate Pr

Debt - Schedule of Aggregate Principal Amount of Debt Outstanding (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total principal amount of debt outstanding	$ 286,225	$ 294,500
Revolving Credit Facility
Debt Instrument [Line Items]
Total principal amount of debt outstanding	6,500	6,500
Term Loan
Debt Instrument [Line Items]
Total principal amount of debt outstanding	$ 279,725	$ 288,000

Debt - Schedule of Current and

Debt - Schedule of Current and Non-Current Debt Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current liabilities:
Current portion of principal payment obligations	$ 9,500	$ 16,275
Revolving credit facility	6,500	6,500
Unamortized debt issuance costs, current portion	(1,082)	(1,104)
Current portion of long-term debt, net of unamortized debt issuance costs	8,418	15,171
Non-current liabilities:
Unamortized debt issuance costs, non-current portion	(1,572)	(2,140)
Long-term debt, net of current portion and unamortized debt issuance costs	275,153	276,085
Term Loan
Current liabilities:
Current portion of principal payment obligations	3,000	9,775
Non-current liabilities:
Non-current portion of principal payment obligations	$ 276,725	$ 278,225

Debt - Schedule of Aggregate Mi

Debt - Schedule of Aggregate Minimum Future Principal Payments of Debt (Details) $ in Thousands	Jun. 30, 2021USD ($)
Debt Disclosure [Abstract]
2021	$ 8,000
2022	3,000
2023	275,225
Aggregate minimum future principal payments of debt	$ 286,225

Debt - Additional Information (

Debt - Additional Information (Details)	Dec. 20, 2016USD ($)	Jul. 01, 2015USD ($)Installment	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Outstanding borrowings			$ 286,225,000		$ 286,225,000
JPMorgan Chase Bank, N.A. and Barclays Bank PLC and Various Lenders | Maximum
Debt Instrument [Line Items]
Maximum amount of increase in facilities					$ 70,000,000
JPMorgan Chase Bank, N. A.
Debt Instrument [Line Items]
Debt instrument, interest rate description					Borrowings under the facilities bear interest at a floating rate, which can be either a Eurodollar rate plus an applicable margin or, at the Company’s option, a base rate (defined as the highest of (x) the JPMorgan Chase, N.A. prime rate, (y) the federal funds effective rate, plus one-half percent (0.50%) per annum and (z) a one-month Eurodollar rate plus 1.00% per annum) plus an applicable margin. The applicable margin for borrowings under the term loan facility is 4.00% per annum for Eurodollar rate loans (subject to a 1.00% per annum interest rate floor) and 3.00% per annum for base rate loans. The applicable margin for borrowings under the revolving credit facility is 1.75% per annum for Eurodollar rate loans and 0.75% per annum for base rate loans, subject to reduction based on the Company’s maintaining specified net leverage ratios. The interest rates payable under the facilities are subject to an increase of 2.00% per annum during the continuance of any payment default.
Debt instrument prepayment description					In addition, the Company is required to make mandatory prepayments under the facilities with respect to (i) 100% of the net cash proceeds from certain asset dispositions (including casualty and condemnation events) by the Company or certain of its subsidiaries, subject to certain exceptions and reinvestment provisions, (ii) 100% of the net cash proceeds from the issuance or incurrence of any additional debt by the Company or certain of its subsidiaries, subject to certain exceptions, and (iii) 50% of the Company’s excess cash flow, as defined in the credit agreement, subject to reduction upon its achievement of specified performance targets.
Percentage of net proceeds from asset dispositions to be used for mandatory prepayment	100.00%
Percentage of net cash proceeds from issuances or incurrence of additional Debt to be used for mandatory prepayment	100.00%
Percentage on excess cash flow for mandatory prepayments of debt	50.00%
Debt instrument, mandatory prepayment of debt payable							$ 6,775
JPMorgan Chase Bank, N. A. | Minimum
Debt Instrument [Line Items]
Line of credit facility borrowing capacity utilized percentage			30.00%		30.00%		30.00%
Term Loan Facility | JPMorgan Chase Bank, N.A. and Barclays Bank PLC and Various Lenders
Debt Instrument [Line Items]
Maximum borrowing amount under facility	$ 300,000,000
Outstanding borrowings			$ 279,725,000		$ 279,725,000		$ 288,000,000
Term Loan Facility | JPMorgan Chase Bank, N. A.
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage	4.00%
Debt instrument, interest rate description					As of June 30, 2021 and December 31, 2020, the interest rate on the Term Loans was 5.00% per annum, which was based on a three-month and six-month Eurodollar rate, respectively, at the applicable floor of 1.00% per annum plus the applicable margin of 4.00% per annum for Eurodollar rate loans.
Debt instrument, effective interest rate percentage			5.00%		5.00%		5.00%
Debt issuance costs	$ 7,811,000
Debt instrument, principal payment			$ 7,525,000	$ 750,000	$ 8,275,000	$ 1,500,000
Interest expense, including amortization of debt issuance costs			$ 3,933,000	4,026,000	$ 7,802,000	8,474,000
Debt instrument, maturity date	Dec. 20, 2023
Original principal amount of term loan amortization percentage	1.00%
Principal amount of loan	$ 300,000,000
Term Loan Facility | JPMorgan Chase Bank, N. A. | Eurodollar Rate
Debt Instrument [Line Items]
Debt instrument, variable interest rate percentage					4.00%		4.00%
Debt instrument, effective interest rate percentage			1.00%		1.00%		1.00%
Term Loan Facility | JPMorgan Chase Bank, N. A. | Floor Rate
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage	1.00%
Term Loan Facility | JPMorgan Chase Bank, N. A. | Base Rate
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage	3.00%
Commercial Mortgage Loan
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage		3.50%
Debt instrument, principal payment				80,000		160,000
Interest expense, including amortization of debt issuance costs				60,000		120,000
Debt instrument, maturity date		Jul. 1, 2020
Principal amount of loan		$ 7,950,000
Debt instrument, number of periodic payment installments | Installment		60
Debt instrument, principal and interest payment		$ 46,000
Debt instrument payment, amortization period		20 years
Debt issuance cost		$ 45,000
Revolving Credit Facility | JPMorgan Chase Bank, N.A. and Barclays Bank PLC and Various Lenders
Debt Instrument [Line Items]
Maximum borrowing amount under facility	$ 25,000,000
Outstanding borrowings			$ 6,500,000		$ 6,500,000		$ 6,500,000
Revolving Credit Facility | JPMorgan Chase Bank, N. A.
Debt Instrument [Line Items]
Debt instrument, interest rate increase	2.00%
Line of credit facility, interest rate			2.01%		2.01%		2.12%
Line of credit facility, interest rate description					As of June 30, 2021, the interest rate on the revolving credit facility was 2.01% per annum, which was based on a six-month Eurodollar rate of 0.26% per annum plus the applicable margin of 1.75% per annum for Eurodollar rate loans. As of December 31, 2020, the interest rate on the revolving credit facility was 2.12% per annum, which was based on the six-month Eurodollar rate of 0.37% per annum plus the applicable margin of 1.75% per annum for Eurodollar rate loans
Payment of quarterly commitment fees percentage			0.25%
Interest expense related to the fee for the unused amount			$ 11,000	$ 15,000	$ 22,000	$ 30,000
Debt instrument, maturity date	Dec. 20, 2021
Revolving Credit Facility | JPMorgan Chase Bank, N. A. | Federal Funds Effective Rate
Debt Instrument [Line Items]
Debt instrument, variable interest rate percentage	0.50%
Revolving Credit Facility | JPMorgan Chase Bank, N. A. | Eurodollar Rate
Debt Instrument [Line Items]
Debt instrument, variable interest rate percentage	1.00%				1.75%		1.75%
Debt instrument, interest rate stated percentage	1.75%
Line of credit facility, interest rate			0.26%		0.26%		0.37%
Revolving Credit Facility | JPMorgan Chase Bank, N. A. | Base Rate
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage	0.75%
Stand-by Letter of Credit | JPMorgan Chase Bank, N.A. and Barclays Bank PLC and Various Lenders
Debt Instrument [Line Items]
Line of credit facility, used as collateral amount			$ 1,503,000		$ 1,503,000		$ 1,454,000

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Equitable Adjustment Payments (Details) - Vested Equity Awards - USD ($) $ / shares in Units, $ in Thousands	Nov. 30, 2017	May 10, 2017	Dec. 27, 2016	Jun. 17, 2016	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Class Of Stock [Line Items]
Equitable Adjustment Payments					$ 95	$ 622
Accrued Expenses And Other Current Liabilities
Class Of Stock [Line Items]
Equitable Adjustment Liability					4		$ 63
November 30, 2017 Special Dividend
Class Of Stock [Line Items]
Dividend Declaration Dates	Nov. 30, 2017
Equitable Adjustment per share	$ 0.5802
Year of Final Vesting	2021
Equitable Adjustment Payments					40	121
November 30, 2017 Special Dividend | Accrued Expenses And Other Current Liabilities
Class Of Stock [Line Items]
Equitable Adjustment Liability					4		30
May 10, 2017 Special Dividend
Class Of Stock [Line Items]
Dividend Declaration Dates		May 10, 2017
Equitable Adjustment per share		$ 1.1774
Year of Final Vesting		2021
Equitable Adjustment Payments					53	171
May 10, 2017 Special Dividend | Accrued Expenses And Other Current Liabilities
Class Of Stock [Line Items]
Equitable Adjustment Liability							31
December 27, 2016 Special Dividend
Class Of Stock [Line Items]
Dividend Declaration Dates			Dec. 27, 2016
Equitable Adjustment per share			$ 2.3306
Year of Final Vesting			2020
Equitable Adjustment Payments					$ 2	276
December 27, 2016 Special Dividend | Accrued Expenses And Other Current Liabilities
Class Of Stock [Line Items]
Equitable Adjustment Liability							$ 2
June 17, 2016 Special Dividend
Class Of Stock [Line Items]
Dividend Declaration Dates				Jun. 17, 2016
Equitable Adjustment per share				$ 0.5891
Year of Final Vesting				2020
Equitable Adjustment Payments						$ 54

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - Common Stock - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Feb. 21, 2019
Class Of Stock [Line Items]
Stock repurchase program, common stock remaining authorized to be repurchased	$ 70,208,000		$ 70,208,000
Stock repurchase program, stock repurchased, shares	0	11,000	0	1,227,000
Stock repurchase program, stock repurchased, value		$ 33,000		$ 3,031,000
Maximum
Class Of Stock [Line Items]
Stock repurchase program, common stock authorized to be repurchased					$ 75,000,000

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cash proceeds received upon the exercise of options		$ 1,187	$ 414
Fair value of liability		646		$ 493
Unrecognized compensation cost		$ 23,345
Weighted-average period of unrecognized compensation cost expected to be recognized		2 years 7 months 13 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value per share of options		$ 3.42	$ 1.15
Cash proceeds received upon the exercise of options		$ 1,187	$ 414
Intrinsic value of stock options exercised		$ 2,496	$ 373
Performance-Based Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	3 years	3 years
Number of award outstanding		442,000		737,000
Stock Appreciation Rights
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period		4 years
Award expiration period		10 years
Number of award outstanding		200,000
Exercised fair value of SAR		$ 6.75
Number of SAR exercised		20,000
Fair value of SAR		$ 3.23
Stock Appreciation Rights | Accrued Expenses And Other Current Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of liability		$ 646		$ 493
2017 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for grant		21,179,000
Number of remaining shares available for grant		10,456,000
2011 and 2017 Stock Incentive Plan | Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of award outstanding		3,642,000		4,231,000
2011 and 2017 Stock Incentive Plan | Restricted Stock Units | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock in settlement of employee tax withholding obligations		744,000	117,000

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Outstanding Stock Option and Information Related to Stock Options Activity (Details) - 2017 Stock Incentive Plan - Stock Options $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance | shares	7,120
Number of Shares, Granted | shares	77
Number of Shares, Exercised | shares	(414)
Number of Shares, Forfeited | shares	(144)
Number of Shares, Outstanding, Ending Balance | shares	6,639	7,120
Number of Shares, Options exercisable at June 30, 2021 | shares	6,197
Number of Shares, Vested or expected to vest at June 30, 2021 | shares	6,616
Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 8.01
Weighted-Average Exercise Price, Granted | $ / shares	8.96
Weighted-Average Exercise Price, Exercised | $ / shares	2.86
Weighted-Average Exercise Price, Forfeited | $ / shares	10
Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares	8.30	$ 8.01
Weighted-Average Exercise Price, Options exercisable at June 30, 2021 | $ / shares	8.12
Weighted-Average Exercise Price, Vested or expected to vest at June 30, 2021 | $ / shares	$ 8.30
Weighted-Average Remaining Contractual Term, Outstanding	4 years 4 months 28 days	4 years 10 months 17 days
Weighted-Average Remaining Contractual Term, Options exercisable at June 30, 2021	4 years 1 month 20 days
Weighted-Average Remaining Contractual Term, Vested or expected to vest at June 30, 2021	4 years 4 months 20 days
Aggregate Intrinsic Value, Outstanding | $	$ 16,800	$ 9,367
Aggregate Intrinsic Value, Options exercisable at June 30, 2021 | $	16,086
Aggregate Intrinsic Value, Vested or expected to vest at June 30, 2021 | $	$ 16,754

Stock-based Compensation - Assu

Stock-based Compensation - Assumptions of Estimated Fair Value of Option on the Date of Grant Using Black-Scholes Option Pricing Model (Details) - Stock Options	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.00%	0.40%	1.00%
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days	6 years 1 month 6 days
Expected volatility	38.20%	31.40%	38.20%
Expected volatility, Minimum				29.30%
Expected volatility, Maximum				31.40%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate				0.40%
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate				0.70%

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of RSU Activity (Details) - 2011 and 2017 Stock Incentive Plan - Restricted Stock Units $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested, Beginning Balance | shares	4,231
Number of Shares, Granted | shares	756
Number of Shares, Vested | shares	(1,133)
Number of Shares, Forfeited | shares	(212)
Number of Shares, Unvested, Ending Balance | shares	3,642
Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares	$ 5.43
Weighted-Average Grant Date Fair Value, Granted | $ / shares	9.15
Weighted-Average Grant Date Fair Value, Vested | $ / shares	5.93
Weighted-Average Grant Date Fair Value, Forfeited | $ / shares	4.81
Weighted-Average Grant Date Fair Value, Unvested, Ending Balance | $ / shares	$ 6.08
Aggregate Fair Value, Vested | $	$ 9,392

Stock-based Compensation - As_2

Stock-based Compensation - Assumptions of Estimated Based on Monte Carlo Simulation Model (Details) - Performance-Based Stock Units	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.20%	1.20%
Expected volatility	78.60%	70.00%
Expected dividend yield	0.00%	0.00%
Cost of equity	12.00%	11.00%

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of PSU Activity (Details) - Performance-Based Stock Units $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested, Beginning Balance | shares	737
Number of Shares, Granted | shares	442
Number of Shares, Vested | shares	(737)
Number of Shares, Unvested, Ending Balance | shares	442
Weighted-Average Grant Date Fair Value, Unvested, Beginning Balance | $ / shares	$ 3.22
Weighted-Average Grant Date Fair Value, Granted | $ / shares	7.89
Weighted-Average Grant Date Fair Value, Vested | $ / shares	3.22
Weighted-Average Grant Date Fair Value, Unvested, Ending Balance | $ / shares	$ 7.89
Aggregate Fair Value, Vested | $	$ 6,449

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 4,094	$ 3,579	$ 7,547	$ 6,016
Product Cost of Revenue
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	33	39	66	70
Research and Development Expenses
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	543	650	1,414	1,087
Selling, General and Administrative Expenses
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 3,518	$ 2,890	$ 6,067	$ 4,859

Stock-based Compensation - Su_4

Stock-based Compensation - Summary of Stock-based Compensation Expense Recognized in the Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Change in fair value of SAR Liability	$ (59)	$ 72	$ 289	$ 8
Recognized as additional paid-in capital	4,153	3,507	7,258	6,008
Total stock-based compensation	$ 4,094	$ 3,579	$ 7,547	$ 6,016

Net (Loss) Income per Share - S

Net (Loss) Income per Share - Schedule of Basic and Diluted Net (Loss) Income Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net (loss) income attributable to common stockholders, basic and diluted	$ (3,193)	$ (3,028)	$ 2,556	$ (1,866)
Denominator:
Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, basic	85,036	83,068	84,641	83,505
Dilutive effect of stock options			2,003
Dilutive effect of restricted stock units			2,369
Weighted-average shares used to compute net (loss) income per share attributable to common stockholders, diluted	85,036	83,068	89,013	83,505
Net (loss) income per share attributable to common stockholders:
Basic	$ (0.04)	$ (0.04)	$ 0.03	$ (0.02)
Diluted	$ (0.04)	$ (0.04)	$ 0.03	$ (0.02)

Net (Loss) Income per Share -_2

Net (Loss) Income per Share - Schedule of Potential Common Shares Excluded from the Computation of Diluted Net (Loss) Income Per Share Attributable to Common Stockholders (Details) (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from computation of diluted net income per share	6,639	7,562	2,358	7,562
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from computation of diluted net income per share	3,642	4,112	831	4,112
Unvested Performance-Based Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from computation of diluted net income per share	442	983		983

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Summary of Disaggregation of Revenue Based on Geographic Locations Determined by Customer's Shipping Address (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 92,730	$ 83,350	$ 197,007	$ 166,973
North America - United States
Disaggregation Of Revenue [Line Items]
Total revenue	23,951	29,349	60,863	58,789
North America - Canada
Disaggregation Of Revenue [Line Items]
Total revenue	24,550	4,229	50,788	8,742
North America
Disaggregation Of Revenue [Line Items]
Total revenue	48,501	33,578	111,651	67,531
Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Total revenue	6,577	7,350	12,931	21,446
Asia-Pacific - Australia
Disaggregation Of Revenue [Line Items]
Total revenue	20,800	26,255	44,198	47,959
Asia-Pacific - Other
Disaggregation Of Revenue [Line Items]
Total revenue	8,893	10,385	15,694	21,870
Asia-Pacific
Disaggregation Of Revenue [Line Items]
Total revenue	29,693	36,640	59,892	69,829
Latin America
Disaggregation Of Revenue [Line Items]
Total revenue	$ 7,959	$ 5,782	$ 12,533	$ 8,167

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Summary of Disaggregation of Revenue Based on Geographic Locations Determined by Customer's Shipping Address (Parenthetical) (Details)	6 Months Ended
	Jun. 30, 2021Country
Other than United States and Australia
Disaggregation Of Revenue [Line Items]
Number of countries represents 10% or more of total revenue	0
Revenue | Geographic Concentration Risk
Disaggregation Of Revenue [Line Items]
Concentration risk percentage	10.00%

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Summary of Disaggregates of Revenue Based on Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Total revenue	$ 92,730	$ 83,350	$ 197,007	$ 166,973
Product - Wireless
Disaggregation Of Revenue [Line Items]
Total revenue	33,323	15,510	73,011	36,167
Product - Fixed Telco
Disaggregation Of Revenue [Line Items]
Total revenue	16,137	23,819	31,022	41,751
Product - Cable
Disaggregation Of Revenue [Line Items]
Total revenue	31,009	32,799	70,234	67,968
Product
Disaggregation Of Revenue [Line Items]
Total revenue	80,469	72,128	174,267	145,886
Service - Wireless
Disaggregation Of Revenue [Line Items]
Total revenue	1,684	1,074	2,275	2,848
Service - Fixed Telco
Disaggregation Of Revenue [Line Items]
Total revenue	1,043	301	2,649	551
Service - Cable
Disaggregation Of Revenue [Line Items]
Total revenue	9,534	9,847	17,816	17,688
Service
Disaggregation Of Revenue [Line Items]
Total revenue	$ 12,261	$ 11,222	$ 22,740	$ 21,087

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Revenue remaining performance obligation amount	$ 25,552		$ 25,552
Prepaid Expenses and Other Current Assets
Disaggregation Of Revenue [Line Items]
Short-term capitalized contract costs	92		92		$ 95
Contract assets	288		288		771
Other Assets
Disaggregation Of Revenue [Line Items]
Long-term capitalized contract costs	63		63		$ 70
Deferred Revenue
Disaggregation Of Revenue [Line Items]
Revenue	4,969	$ 13,600	11,979	$ 28,539
Selling, General and Administrative Expense
Disaggregation Of Revenue [Line Items]
Amortization of capitalized contract costs	29	196	52	449
Interest Income
Disaggregation Of Revenue [Line Items]
Other revenue	$ 4	$ 13	$ 8	$ 47

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Additional Information (Details1)	Jun. 30, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-07-01
Disaggregation Of Revenue [Line Items]
Revenue remaining performance obligation, percentage	79.00%
Revenue, remaining performance obligation, expected timing of satisfaction period	12 months
Minimum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-07-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction period	2 years
Maximum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-07-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction period	5 years

Segment Information - Additiona

Segment Information - Additional Information (Details)	6 Months Ended
	Jun. 30, 2021Segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Information - Schedule

Segment Information - Schedule of Property and Equipment, Net by Location (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Property and equipment, net	$ 25,471	$ 28,880
United States
Segment Reporting Information [Line Items]
Property and equipment, net	18,657	20,988
China
Segment Reporting Information [Line Items]
Property and equipment, net	2,722	2,986
Australia
Segment Reporting Information [Line Items]
Property and equipment, net	2,434	2,849
Other
Segment Reporting Information [Line Items]
Property and equipment, net	$ 1,658	$ 2,057

Related Parties - Additional In

Related Parties - Additional Information (Details) - Rongke Xie - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	Mar. 31, 2020	Feb. 28, 2019	Jun. 30, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Related Party Transaction [Line Items]
Compensation paid						$ 150	$ 122
Restricted Stock Units
Related Party Transaction [Line Items]
Number of shares granted	90	8	5
Vesting period						4 years
Aggregate fair value vested						$ 400
Selling, general and administrative expenses recognized				$ 25	$ 24	$ 50	$ 37

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Indemnification obligations material claims, outstanding	$ 0	$ 0