Five9 (FIVN) 10-K 28 Feb 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 22, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-36383
Entity Registrant Name	Five9, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3394123
Entity Address, Address Line One	3001 Bishop Drive
Entity Address, Address Line Two	Suite 350
Entity Address, City or Town	San Ramon
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94583
City Area Code	925
Local Phone Number	201-2000
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	FIVN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 10,269.5
Entity Common Stock, Shares Outstanding		69,149,622
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the 2022 Annual Stockholders’ Meeting, which the registrant expects to file with the Securities and Exchange Commission within 120 days of December 31, 2021, are incorporated by reference into Part III (Items 10, 11,12, 13 and 14) of this Annual Report on Form 10-K.
Entity Central Index Key	0001288847
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Name	KPMG LLP
Auditor Location	Santa Clara, California
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 90,878	$ 220,372
Marketable investments	378,980	383,171
Accounts receivable, net	83,731	48,731
Prepaid expenses and other current assets	30,342	16,149
Deferred contract acquisition costs, net	33,295	20,695
Total current assets	617,226	689,118
Property and equipment, net	77,785	51,213
Operating lease right-of-use assets	48,703	9,010
Intangible assets, net	39,897	51,684
Goodwill	165,420	165,420
Marketable investments	147,377	42,127
Other assets	11,871	3,236
Deferred contract acquisition costs, net — less current portion	84,663	51,934
Total assets	1,192,942	1,063,742
Current liabilities:
Accounts payable	20,510	17,145
Accrued and other current liabilities	78,577	44,450
Operating lease liabilities	9,826	3,912
Accrued federal fees	2,282	3,745
Sales tax liabilities	2,660	1,714
Finance lease liabilities	0	612
Deferred revenue	43,720	31,983
Total current liabilities	157,575	103,561
Convertible senior notes	768,599	643,316
Sales tax liabilities — less current portion	877	857
Operating lease liabilities — less current portion	47,088	5,379
Other long-term liabilities	7,671	31,465
Total liabilities	981,810	784,578
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized, no shares issued and outstanding as of December 31, 2021 and 2020	0	0
Common stock, $0.001 par value; 450,000 shares authorized, 68,488 shares and 66,496 shares issued and outstanding as of December 31, 2021 and 2020, respectively	68	67
Additional paid-in capital	439,787	476,941
Accumulated other comprehensive (loss) income	(287)	335
Accumulated deficit	(228,436)	(198,179)
Total stockholders’ equity	211,132	279,164
Total liabilities and stockholders’ equity	$ 1,192,942	$ 1,063,742

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	450,000,000	450,000,000
Common stock, shares issued (in shares)	68,488,337	66,496,060
Common stock, shares outstanding (in shares)	68,488,337	66,496,060

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 609,591	$ 434,908	$ 328,006
Cost of revenue	271,099	180,284	134,511
Gross profit	338,492	254,624	193,495
Operating expenses:
Research and development	106,897	68,747	45,190
Sales and marketing	193,929	132,413	95,592
General and administrative	93,916	65,769	49,446
Total operating expenses	394,742	266,929	190,228
(Loss) income from operations	(56,250)	(12,305)	3,267
Other (expense) income, net:
Interest expense	(8,027)	(28,348)	(13,794)
Loss on early extinguishment of debt	0	(6,964)	0
Other (expense) and interest income	(8)	3,034	6,079
Total other (expense) income, net	(8,035)	(32,278)	(7,715)
Loss before income taxes	(64,285)	(44,583)	(4,448)
(Benefit from) provision for income taxes	(11,285)	(2,453)	104
Net loss	$ (53,000)	$ (42,130)	$ (4,552)
Net loss per share:
Basic (in USD per share)	$ (0.79)	$ (0.66)	$ (0.08)
Diluted (in USD per share)	$ (0.79)	$ (0.66)	$ (0.08)
Shares used in computing net loss per share:
Basic (in shares)	67,512	64,154	60,371
Diluted (in shares)	67,512	64,154	60,371
Comprehensive Loss:
Net loss	$ (53,000)	$ (42,130)	$ (4,552)
Other comprehensive (loss) income	(622)	(241)	669
Comprehensive loss	$ (53,622)	$ (42,371)	$ (3,883)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	[1]	Common Stock	Additional Paid-In Capital	Additional Paid-In CapitalCumulative Effect, Period of Adoption, Adjustment	[1]	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated DeficitCumulative Effect, Period of Adoption, Adjustment	[1]
Beginning balance (in share) at Dec. 31, 2018				59,210
Beginning balance at Dec. 31, 2018	$ 142,748			$ 59	$ 294,279			$ (93)	$ (151,497)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				932
Issuance of common stock upon exercise of stock options	7,705			$ 1	7,704
Issuance of common stock upon vesting of restricted stock units (in shares)				1,204
Issuance of common stock upon vesting of restricted stock units	0			$ 1	(1)
Issuance of common stock under ESPP (in shares)				198
Issuance of common stock under ESPP	7,823				7,823
Stock-based compensation	42,065				42,065
Other comprehensive (loss) income	669							669
Net loss	(4,552)								(4,552)
Ending balance (in shares) at Dec. 31, 2019				61,544
Ending balance at Dec. 31, 2019	196,458			$ 61	351,870			576	(156,049)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)				558
Issuance of common stock upon exercise of stock options	11,656			$ 1	11,655
Issuance of common stock upon vesting of restricted stock units (in shares)				1,210
Issuance of common stock upon vesting of restricted stock units	0			$ 1	(1)
Issuance of common stock under ESPP (in shares)				169
Issuance of common stock under ESPP	11,470			$ 1	11,469
Equity component of issuance of the 2025 convertible senior notes, net of issuance costs	154,363				154,363
Purchase of capped calls related to the 2025 convertible senior notes	(90,448)				(90,448)
Equity component from conversion of the 2023 convertible senior notes	(336,592)				(336,592)
Fair value of Inference assumed unvested stock options for services completed prior to the acquisition	192				192
Issuance of common stock upon partial conversion of the 2023 convertible senior notes (in shares)				3,015
Issuance of common stock upon partial conversion of the 2023 convertible senior notes	309,689			$ 3	309,686
Stock-based compensation	64,747				64,747
Other comprehensive (loss) income	(241)							(241)
Net loss	(42,130)								(42,130)
Ending balance (in shares) at Dec. 31, 2020				66,496
Ending balance at Dec. 31, 2020	$ 279,164	$ (145,669)		$ 67	476,941	$ (168,412)		335	(198,179)	$ 22,743
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2020-06
Issuance of common stock upon vesting of restricted stock units (in shares)				1,097
Issuance of common stock upon vesting of restricted stock units	$ (1)			$ 1	(2)
Issuance of common stock upon partial conversion of the 2023 convertible senior notes (in shares)				454
Issuance of common stock upon partial conversion of the 2023 convertible senior notes	(353)				(353)
Partial unwind of capped calls and retirement of common stock related to the 2023 convertible senior notes (in shares)				(69)
Partial unwind of capped calls and retirement of common stock related to the 2023 convertible senior notes	9				9
Issuance of common stock upon exercise of stock options and warrants (in shares)				389
Issuance of common stock upon exercise of stock options and warrants	7,402				7,402
Issuance of common stock under ESPP (in shares)				121
Issuance of common stock under ESPP	15,397				15,397
Stock-based compensation	108,805				108,805
Other comprehensive (loss) income	(622)							(622)
Net loss	(53,000)								(53,000)
Ending balance (in shares) at Dec. 31, 2021				68,488
Ending balance at Dec. 31, 2021	$ 211,132			$ 68	$ 439,787			$ (287)	$ (228,436)
[1]	Effective January 1, 2021, the Company adopted ASU 2020-06. Accordingly, the Company recorded a net reduction to opening accumulated deficit of $22.7 million and a net reduction to opening additional paid-in capital of $168.4 million as of January 1, 2021 due to the cumulative impact of adopting this new standard. See Note 1 for more information.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (53,000)	$ (42,130)	$ (4,552)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	38,732	25,087	14,374
Amortization of operating lease right-of-use assets	8,698	5,687	4,735
Amortization of deferred contract acquisition costs	26,050	16,495	11,320
Amortization of premium on marketable investments	6,385	3,090	(1,108)
Provision for doubtful accounts	808	754	90
Stock-based compensation	108,805	64,747	42,065
Amortization of debt discount and issuance costs	3,957	25,738	12,788
Gain on sale of convertible note held for investment	0	0	(217)
Loss on early extinguishment of debt	0	6,964	0
Deferred taxes	(6,907)	(178)	0
Change in fair value of contingent consideration	5,640	0	0
Tax benefit of valuation allowance associated with an acquisition	0	(2,910)	0
Other	396	(147)	448
Changes in operating assets and liabilities:
Accounts receivable	(35,986)	(9,958)	(12,935)
Prepaid expenses and other current assets	(14,193)	(5,313)	(2,671)
Deferred contract acquisition costs	(71,380)	(45,454)	(24,103)
Other assets	(1,729)	(1,911)	(348)
Accounts payable	4,305	6,181	2,549
Accrued and other current liabilities	20,562	9,374	(544)
Accrued federal fees and sales tax liability	(497)	1,302	1,010
Deferred revenue	10,462	7,971	8,695
Other liabilities	(22,623)	1,913	(375)
Net cash provided by operating activities	28,485	67,302	51,221
Cash flows from investing activities:
Purchases of marketable investments	(680,490)	(620,948)	(359,470)
Proceeds from sales of marketable investments	44,288	1,899	19,433
Proceeds from maturities of marketable investments	527,940	432,579	309,307
Purchases of property and equipment	(42,216)	(30,422)	(19,228)
Cash paid to acquire Inference and Virtual Observer	0	(165,338)	0
Cash paid to acquire substantially all of the assets of Whendu	0	(100)	(13,890)
Proceeds from sale of convertible note held for investment	0	0	217
Net cash used in investing activities	(150,478)	(382,330)	(63,631)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes	0	728,812	0
Payments for capped call transactions	0	(90,448)	0
Repurchase of a portion of 2023 convertible senior notes, net of costs	(24,688)	(200,350)	0
Proceeds from exercise of common stock options	7,402	11,656	7,705
Proceeds from sale of common stock under ESPP	15,397	11,469	7,823
Payment of holdbacks related to acquisitions	(5,000)	0	0
Payments of finance leases	(612)	(3,715)	(7,054)
Net cash (used in) provided by financing activities	(7,501)	457,424	8,474
Net (decrease) increase in cash and cash equivalents	(129,494)	142,396	(3,936)
Cash and cash equivalents:
Beginning of year	220,372	77,976	81,912
End of year	90,878	220,372	77,976
Supplemental disclosures of cash flow data:
Cash paid for interest	4,073	2,324	1,029
Cash paid for income taxes	31	293	281
Non-cash investing and financing activities:
Equipment purchased and unpaid at period-end	13,871	8,114	2,890
Capitalization of leasehold improvement through non-cash lease incentive	5,121	0	79
Acquisition and related transaction costs accrued at period-end	$ 0	$ 586	$ 1,895

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Five9, Inc. and its wholly-owned subsidiaries (the “Company”) is a provider of cloud software for contact centers. The Company was incorporated in Delaware in 2001 and is headquartered in San Ramon, California. The Company has offices in Europe, Asia and Australia, which primarily provide research, development, sales, marketing, and client support services. Termination of Proposed Merger with Zoom On July 16, 2021, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) by and among the Company, Zoom Video Communications, Inc., a Delaware corporation (“Zoom”), and Summer Merger Sub, Inc., a Delaware corporation and a direct, wholly owned subsidiary of Zoom (“Merger Sub”). The Merger Agreement provided for the merger of Merger Sub with and into the Company (the “Merger”), with the Company surviving the Merger and continuing as a wholly owned subsidiary of Zoom. On September 30, 2021, at a special meeting of the Company’s stockholders, a vote to approve the Merger was unsuccessful. As a result, immediately following the special meeting, on September 30, 2021, the Company and Zoom mutually agreed to terminate the Merger Agreement, effective immediately. Except as otherwise set forth in the Merger Agreement, none of the Company, Zoom or Merger Sub shall have any further liability thereunder. The Company incurred approximately $7.6 million in transaction costs related to the Merger recorded in general and administrative expense in its consolidated statements of operations and comprehensive loss. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding annual financial reporting. All intercompany transactions and balances have been eliminated in consolidation. Certain prior period amounts within operating and investing activities in the consolidated statements of cash flows have been reclassified to conform to the current period presentation. The consolidated balance sheet and the consolidated statement of stockholders' equity included in this Annual Report as of December 31, 2021 differ from the Form 10-K for the year ended December 31, 2020 as it reflects an immaterial error correction due to the reclassification of $2.3 million from treasury stock to additional paid-in-capital. This reclassification was from the shares received for the partial unwind of capped calls related to the 2023 convertible senior notes. Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The significant estimates made by management affect revenue and related reserves, as well as the fair value of liabilities assumed through business combinations. Management periodically evaluates such estimates and they are adjusted prospectively based upon such periodic evaluation. Actual results could differ from those estimates. Foreign Currency The functional currency of the Company’s foreign subsidiaries is the U.S. dollar. For these subsidiaries, the monetary assets and liabilities are re-measured into U.S. dollars at the current exchange rate as of the balance sheet date, and all non-monetary assets and liabilities are re-measured into U.S. dollars at historical exchange rates. Revenues are primarily denominated in U.S. dollars. Expenses are converted using average rates in effect on a monthly basis. Exchange gains and losses resulting from foreign currency transactions were not significant in any period and are reported in “Other (expense) income, net” in the consolidated statements of operations and comprehensive loss. Cash and Cash Equivalents The Company’s cash and cash equivalents consist of highly liquid investments with maturities of three months or less at the time of purchase. The Company’s cash equivalents consist of investments in money market funds, U.S. treasury securities, U.S. agency securities and commercial paper. Marketable Investments The Company’s marketable investments consist of U.S. agency securities and government sponsored securities, U.S. treasury securities, certificates of deposit, municipal bonds, corporate bonds and commercial paper. The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Marketable investments are carried at fair value. Concentration Risks Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and cash equivalents, marketable investments and accounts receivable. A significant portion of the Company’s cash and cash equivalents is held at three large reputable financial institutions. Total cash and cash equivalents in excess of insured limits were $89.2 million and $218.3 million as of December 31, 2021 and 2020, respectively. The Company has not experienced any losses in such accounts. As of December 31, 2021 and 2020, no single client represented more than 10% of accounts receivable. For the years ended December 31, 2021, 2020 and 2019, no single client represented more than 10% of revenue. Allowance for Doubtful Accounts The Company uses an expected credit loss model, which requires it to consider historical loss rates and expectations of forward-looking losses to estimate its allowance for doubtful accounts on its trade accounts receivables, unbilled accounts receivables and contract assets. The following table presents the changes in the allowance for doubtful accounts (in thousands): Year Ended December 31, 2021 2020 Balance, beginning of period $ 127 $ 11 Add: bad debt expense 808 754 Less: write-offs, net of recoveries (715) (638) Balance, end of period $ 220 $ 127 Property and Equipment, Net Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Category Estimated Useful Lives Computer and network equipment 3 to 5 years Computer software 3 years Development costs 1 to 5 years Furniture and fixtures 7 years Leasehold improvements Shorter of useful life or lease term Maintenance and repairs are charged to expense as incurred, and improvements and betterments are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation and amortization are removed from the consolidated balance sheet and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss in the period realized. The Company evaluates the recoverability of property and equipment for possible impairment whenever events or circumstances indicate that the carrying amount of such assets or asset groups may not be recoverable. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets or asset groups are expected to generate. If such evaluation indicates that the carrying amount of the assets or asset groups is not recoverable, the carrying amount of such assets or asset groups is reduced to fair value. No impairment losses have been recognized in any of the periods presented. Business Combinations The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired and liabilities assumed as of the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value to these tangible and intangible assets and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially established in connection with a business combination as of the acquisition date. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to its consolidated statements of operations and comprehensive loss. Goodwill and Intangible Assets The Company records goodwill when the consideration paid in a business combination exceeds the fair value of the net tangible assets and the identified intangible assets acquired. Goodwill is not amortized, but instead is required to be tested for impairment annually and whenever events or changes in circumstances indicate that the carrying value of goodwill may exceed its fair value. The Company performs testing for impairment of goodwill in its fourth quarter, or as events occur or circumstances change that would more likely than not reduce the fair value of the Company’s single reporting unit below its carrying amount. A qualitative assessment is first made to determine whether it is necessary to perform the quantitative goodwill impairment test. This initial qualitative assessment includes, among other things, consideration of: (i) market capitalization of the Company; (ii) past, current and projected future earnings and equity; (iii) recent trends and market conditions; and (iv) valuation metrics involving similar companies that are publicly-traded and acquisitions of similar companies, if available. If this initial qualitative assessment indicates that it is more likely than not that impairment exists, a second quantitative assessment will be performed, involving a comparison between the estimated fair values of the Company’s single reporting unit with its respective carrying amount including goodwill. If the carrying value exceeds estimated fair value, an impairment charge is recorded for the excess. Intangible assets, consisting of acquired developed technology, domain names and customer relationships, are carried at cost less accumulated amortization. All intangible assets have been determined to have definite lives and are amortized on a straight-line basis over their estimated remaining economic lives, ranging from three Revenue Recognition Revenue is recognized when control of the promised services is transferred to customers in an amount that reflects the consideration that the Company expects to receive in exchange for those services. The Company generates all of its revenue from contracts with customers. In contracts with multiple performance obligations, it identifies each performance obligation and evaluates whether the performance obligations are distinct within the context of the contract at contract inception. Performance obligations that are not distinct at contract inception are combined. The Company allocates the transaction price to each distinct performance obligation proportionately based on the estimated standalone selling price for each performance obligation. The Company then looks to how services are transferred to the customer in order to determine the timing of revenue recognition. Most services provided under the Company’s agreements result in the transfer of control over time. The Company’s revenue consists of subscription services and related usage as well as professional services. The Company charges clients subscription fees, usually billed on a monthly basis, for access to the Company’s VCC solution. The subscription fees are primarily based on the number of agent seats, as well as the specific VCC functionalities and applications deployed by the client. Agent seats are defined as the maximum number of named agents allowed to concurrently access the VCC cloud platform. Clients typically have more named agents than agent seats. Multiple named agents may use an agent seat, though not simultaneously. Substantially all of the Company’s clients purchase both subscriptions and related telephony usage. A small percentage of the Company’s clients subscribe to its platform but purchase telephony usage directly from a wholesale telecommunications service provider. The Company does not sell telephony usage on a stand-alone basis to any client. The related usage fees are generally based on the volume of minutes used for inbound and outbound client interactions. Revenue generated from telephony usage is presented in revenue and cost of sales on a gross basis, as the Company is the party that controls the service and is responsible for fulfilling the promise to provide the call service by diverting the calls to selected carriers. The Company also offers bundled plans, generally for smaller deployments, whereby the client is charged a single monthly fixed fee per agent seat that includes both subscription and unlimited usage in the contiguous 48 states and, in some cases, Canada. Professional services revenue is derived primarily from VCC implementations, including application configuration, system integration, optimization, education and training services. Clients are not permitted to take possession of the Company’s software. The Company offers monthly, annual and multiple-year contracts to its clients, generally with 30 days’ notice required for reductions in the number of agent seats. Increases in the number of agent seats can be provisioned almost immediately. The Company’s clients, therefore, are able to adjust the number of agent seats used to meet their changing contact center needs. The Company’s larger clients typically choose annual contracts, which generally include an implementation and ramp period of several months. Fixed subscription fees, including bundled plans, are generally billed monthly in advance, while related usage fees are billed in arrears. Support activities include technical assistance for the Company’s solution and upgrades and enhancements to the VCC cloud platform on a when-and-if-available basis, which are not billed separately. The Company generally requires advance deposits from its clients based on estimated usage when such usage is not billed as part of a bundled plan. Any unused portion of the deposit is refundable to the client upon termination of the arrangement, provided all amounts due have been paid. All fees, except usage deposits, are non-refundable. Professional services are primarily billed on a fixed-fee basis. Revenue for professional services is recognized over time, as services are performed. The estimation of variable consideration for each performance obligation requires the Company to make subjective judgments resulting in estimated variable consideration that is included in the transaction fee. This is done to the extent that it is probable, in the Company’s judgment, that a significant reversal in the amount of cumulative revenue recognized under the contract will not occur. The Company estimates the variable consideration in order to allocate the overall transaction fee on a relative stand-alone selling price basis to its multiple performance obligations. When services are included in the contract with the customer and are not sold at their stand-alone selling price, the Company is required to estimate the number of seats the customer will use, especially during the initial ramp period of the contract, during which the Company bills under an ‘actual usage’ model for subscription-related services. The Company recognizes revenue on fixed fee professional services performance obligations based on the proportion of labor hours expended compared to the total hours expected to complete the related performance obligation. The determination of the total labor hours expected to complete the performance obligations involves judgment, which influences the initial stand-alone selling price estimate as well as the timing of professional services revenue recognition, although this is typically resolved in a short time frame. When a contract with a customer is signed, the Company assesses whether collection of the fees under the arrangement is probable. The Company assesses collection based on a number of factors, including past transaction history and the creditworthiness of the client. The Company maintains a revenue reserve for potential credits to be issued in accordance with service level agreements or for other revenue adjustments. Deferred Revenue Deferred revenue consists of billings or payments received from clients for subscription service, usage and professional services in advance of revenue recognition and is recognized in accordance with the Company’s revenue recognition policy discussed above. The Company generally invoices its clients monthly in advance for subscription services. Accordingly, the deferred revenue balance does not represent the total contract value of sales arrangements. Cost of Revenue Cost of revenue consists primarily of personnel costs, including stock-based compensation, fees that the Company pays to telecommunications providers for usage, USF contributions and other regulatory costs, depreciation and related expenses of the servers and equipment, costs to build out and maintain co-location data centers, costs of public cloud-based data centers, allocated office and facility costs and amortization of acquired technology. Personnel costs include those associated with support of the Company’s solution, clients and data center operations, as well as with providing professional services. Data center costs include costs to build out and setup, as well as co-location fees for the right to place the Company’s servers in data centers owned by third parties. Research and Development Research and development expenses consist primarily of salary and related expenses, including stock-based compensation, for personnel related to the development of improvements and expanded features for the Company’s services, as well as quality assurance, testing, product management and allocated overhead. Research and development costs are expensed as incurred except for internal use software development costs that qualify for capitalization. The Company reviews development costs incurred for internal-use software in the application development stage and assesses costs for capitalization. Advertising Costs The Company primarily advertises its services through the internet and in conjunction with partners. Advertising costs are expensed as incurred and were $20.8 million, $15.6 million and $13.4 million for the years ended December 31, 2021, 2020 and 2019, respectively. Commissions Commissions consist of variable compensation earned by sales personnel and referral fees the Company pays to third parties. The Company defers all incremental commission costs to obtain the contract, and amortizes these costs over a period of benefit determined to be five years. Commission expense was $31.1 million, $21.9 million and $15.0 million for the years ended December 31, 2021, 2020 and 2019, respectively. Stock-Based Compensation All stock-based compensation granted to employees and non-employee directors is measured at the grant date fair value of the award. The Company estimates the fair value of stock options and purchase rights under the Company’s Equity Incentive Plans and the 2014 Employee Stock Purchase Plan (“2014 ESPP Plan” or “ESPP”), respectively, using the Black-Scholes option-pricing model. The fair value of restricted stock awards is equal to the fair value of the Company’s common stock on the date of grant. Compensation expense is recognized net of actual forfeitures using the straight-line method over the service period, which is generally the vesting period. Income Taxes The Company accounts for income taxes using the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in operations in the period that includes the enactment date. The Company records a valuation allowance to reduce its deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. As of December 31, 2021, and 2020, the Company recorded a full valuation allowance against the U.S. net deferred tax assets because of its history of operating losses in the United States. As of December 31, 2021 and 2020, the Company recognized a net deferred tax asset balance of $6.9 million and deferred tax liabilities of $4.4 million, respectively, related to its operations in the UK and Australia. The Company classifies interest and penalties on unrecognized tax benefits as income tax expense. Comprehensive loss Comprehensive loss consists of net loss, unrealized gains or losses on available-for-sale marketable investments, and the effects of foreign currency translation adjustments. The Company presents comprehensive loss as part of the consolidated statements of operations. The changes in the accumulated balances of the components of other comprehensive loss were not material for the periods presented. Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock outstanding during the period, and excludes any dilutive effects of employee stock-based awards and potential shares issuable upon conversion of the convertible senior notes. Diluted net loss per share is computed giving effect to all potentially dilutive shares of common stock, including common stock issuable upon exercise of stock options, vesting of restricted stock units and shares of common stock issuable upon conversion of convertible senior notes. In periods of net loss, all potentially issuable shares of common stock are excluded from the diluted net loss per share computation because they are anti-dilutive. Therefore, basic and diluted net loss per share are the same for all years presented in the Company’s consolidated statements of operations and comprehensive loss. Indemnification The Company, in the ordinary course of business, enters into agreements of varying scope and terms pursuant to which it agrees to indemnify clients, vendors, lessors, business partners and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, including breach of security, services to be provided by the Company or from intellectual property infringement claims made by third parties. To date, the Company has not incurred any material costs as a result of such indemnification provisions and the Company has not accrued any liabilities related to such obligations in the consolidated financial statements as of December 31, 2021 and 2020. Segment Information The Company has determined that its Chief Executive Officer is its chief operating decision maker. The Company’s Chief Executive Officer reviews financial information presented on a consolidated basis for purposes of assessing performance and making decisions on how to allocate resources. Accordingly, the Company has determined that it operates in a single reportable segment. Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU No. 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 ("ASU 2020-06"), which simplifies the accounting for convertible instruments by removing the separation models for (1) convertible debt with a cash conversion feature and (2) convertible instruments with a beneficial conversion feature. The Company elected to early adopt ASU 2020-06 as of January 1, 2021 using a modified retrospective transition method. Applying the transition guidance, the Company was required to apply the guidance to all impacted financial instruments that were outstanding as of January 1, 2021 with the cumulative effect recognized as an adjustment to the opening balance of accumulated deficit. As a result of early adopting ASU 2020-06, the Company made certain adjustments to its accounting for the outstanding 0.125% convertible senior notes due 2023 (the "2023 convertible senior notes") and the outstanding 0.500% convertible senior notes due 2025 (the "2025 convertible senior notes", and, together with the 2023 convertible senior notes, the "convertible senior notes"). The adoption of ASU 2020-06 resulted in the re-combination of the liability and equity components of the convertible senior notes into a single liability instrument, which required the Company to record a $168.4 million decrease in additional paid in capital from the derecognition of the separated equity components of these convertible senior notes, a $145.7 million increase in debt from the derecognition of the discount associated with the separated equity components of the convertible senior notes, and a $22.7 million cumulative effect decrease to the opening balance of its accumulated deficit as of January 1, 2021 upon transition. Interest expense recognized in future periods will be reduced as a result of accounting for the convertible senior notes as a single liability instrument. Since the Company had a net loss for the year ended December 31, 2021, the convertible senior notes were determined to be anti-dilutive and therefore had no impact to basic or diluted net loss per share for fiscal 2021 as a result of adopting ASU 2020-06. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which amends its guidance to simplify the accounting for income taxes by, among other things, removing exceptions to certain general principles in Topic 740, Income Taxes. The standard was effective for the Company beginning in the first quarter of 2021. The Company adopted ASU 2019-12 and concluded that the impact on its consolidated financial statements was immaterial. Recent Accounting Pronouncements Not Yet Effective The Company has reviewed, or is in the process of evaluating, all issued, but not yet effective, accounting pronouncements and does not believe the future adoption of any such accounting pronouncements will cause a material impact on its consolidated financial position, operating results or statements of cash flows.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Contract Balances The following table provides information about accounts receivable, net, deferred contract acquisition costs, net, contract assets and contract liabilities from contracts with customers (in thousands): December 31, 2021 December 31, 2020 Accounts receivable, net $ 83,731 $ 48,731 Deferred contract acquisition costs, net: Current $ 33,295 $ 20,695 Non-current 84,663 51,934 Total deferred contract acquisition costs, net $ 117,958 $ 72,629 Contract assets and contract liabilities: Contract assets (included in prepaid expenses and other current assets) $ 2,593 $ 1,297 Contract liabilities (deferred revenue) 43,720 31,983 Noncurrent contract liabilities (deferred revenue) (included in other long term liabilities) 2,097 3,373 Net contract liabilities $ (43,224) $ (34,059) The Company receives payments from customers based upon billing cycles. Invoice payment terms are usually 30 days or less. Accounts receivable are recorded when the right to consideration becomes unconditional. Deferred contract acquisition costs are recorded when incurred and are amortized over an estimated customer benefit period of five years. The Company’s contract assets consist of unbilled amounts typically resulting from professional services revenue recognition when it exceeds the total amounts billed to the customer. The Company’s contract liabilities consist of advance payments and billings in excess of revenue recognized. In the year ended December 31, 2021, the Company recognized revenue of $29.4 million related to its contract liabilities at December 31, 2020. Remaining Performance Obligations As of December 31, 2021, the aggregate amount of the total transaction price allocated in contracts with original duration of greater than one year to the remaining performance obligations was $544.3 million. The Company expects to recognize revenue on approximately three-fourths of the remaining performance obligations over the next 24 months, with the balance recognized thereafter. The Company has elected the optional exemption, which allows for the exclusion of the amounts for remaining performance obligations that are part of contracts with an original expected duration of one year or less. Such remaining performance obligations represent unsatisfied or partially unsatisfied performance obligations pursuant to ASC 606.

Investments and Fair Value Meas

Investments and Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Investments and Fair Value Measurements	Investments and Fair Value Measurements Marketable Investments The Company’s marketable investments have been classified and accounted for as available-for-sale. The Company’s marketable investments as of December 31, 2021 and 2020 were as follows (in thousands): December 31, 2021 Short-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 1,615 $ — $ — $ 1,615 U.S. treasury 83,237 — (24) 83,213 U.S. agency securities 159,070 — (65) 159,005 Commercial paper 47,555 — — 47,555 Municipal bonds 75,337 — (96) 75,241 Corporate bonds 12,355 2 (6) 12,351 Total $ 379,169 $ 2 $ (191) $ 378,980 December 31, 2021 Long-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 746 $ — $ (2) $ 744 U.S. treasury 63,566 — (251) 63,315 U.S. agency securities 63,960 — (254) 63,706 Municipal bonds 18,655 — (64) 18,591 Corporate bonds 1,026 — (5) 1,021 Total $ 147,953 $ — $ (576) $ 147,377 December 31, 2020 Short-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 3,479 $ 1 $ — $ 3,480 U.S. treasury 287,315 41 (4) 287,352 U.S. agency securities 67,227 12 (6) 67,233 Commercial paper 5,093 — — 5,093 Municipal bonds 2,684 1 (1) 2,684 Corporate bonds 17,323 6 — 17,329 Total $ 383,121 $ 61 $ (11) $ 383,171 December 31, 2020 Long-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury $ 10,189 $ — $ — $ 10,189 U.S. agency securities 31,469 9 (1) 31,477 Municipal bonds 461 — — 461 Total $ 42,119 $ 9 $ (1) $ 42,127 The following table presents the gross unrealized losses and the fair value for those marketable investments that were in an unrealized loss position for less than 12 months as of December 31, 2021 and 2020 (in thousands): December 31, 2021 December 31, 2020 Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Certificates of deposit (2) 2,010 — — U.S. treasury (275) 140,527 (4) 78,549 U.S. agency securities (320) 222,710 (7) 39,443 Municipal bonds (160) 87,184 (1) 1,201 Corporate bonds (10) 9,428 (1) 1,347 Total $ (767) $ 461,859 $ (13) $ 120,540 Although the Company had certain available-for-sale debt securities in an unrealized loss position as of December 31, 2021, no impairment loss was recorded since it did not intend to sell them, did not anticipate a need to sell them, and the decline in fair value was not due to any credit-related factors. The amortized cost and fair values of the Company’s marketable investments by contractual maturity as of December 31, 2021 and 2020 were as follows (in thousands): December 31, 2021 December 31, 2020 Cost Fair Value Cost Fair Value Due within one year $ 379,169 $ 378,980 $ 383,121 $ 383,171 Due after one year 147,953 147,377 42,119 42,127 Total $ 527,122 $ 526,357 $ 425,240 $ 425,298 Fair Value Measurements The Company carries cash equivalents and marketable investments at fair value. Fair value is based on the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: Level 1 — Observable inputs, which include unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 inputs, such as quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are based on management’s assumptions, including fair value measurements determined by using pricing models, discounted cash flow methodologies or similar techniques. The Company determined the fair value of its Level 1 financial instruments, which are traded in active markets, using quoted market prices for identical instruments. Marketable investments classified within Level 2 of the fair value hierarchy are valued based on other observable inputs, including broker or dealer quotations or alternative pricing sources. When quoted prices in active markets for identical assets or liabilities are not available, the Company relies on non-binding quotes from its investment managers, which are based on proprietary valuation models of independent pricing services. These models generally use inputs such as observable market data, quoted market prices for similar instruments, historical pricing trends of a security as relative to its peers. To validate the fair value determination provided by its investment managers, the Company reviews the pricing movement in the context of overall market trends and trading information from its investment managers. The Company performs routine procedures such as comparing prices obtained from independent source to ensure that appropriate fair values are recorded. The following tables set forth the Company’s assets measured at fair value by level within the fair value hierarchy (in thousands): December 31, 2021 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 31,380 $ — $ — $ 31,380 Certificates of deposit — 747 — 747 Total cash equivalents $ 31,380 $ 747 $ — $ 32,127 Marketable investments (short and long-term) Certificates of deposit $ — $ 2,359 $ — $ 2,359 U.S. Treasury 146,528 — — 146,528 U.S. agency and government sponsored securities — 222,711 — 222,711 Commercial paper — 47,555 — 47,555 Municipal bonds — 93,832 — 93,832 Corporate bonds — 13,372 — 13,372 Total marketable investments $ 146,528 $ 379,829 $ — $ 526,357 Liabilities Contingent consideration $ — $ — $ 23,740 $ 23,740 December 31, 2020 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 89,888 $ — $ — $ 89,888 U.S. Treasury 39,997 — — 39,997 Total cash equivalents $ 129,885 $ — $ — $ 129,885 Marketable investments (short and long-term) Certificates of deposit $ — $ 3,480 $ — $ 3,480 U.S. Treasury 297,540 — — 297,540 U.S. agency securities — 98,711 — 98,711 Commercial paper — 5,093 — 5,093 Municipal bonds — 3,145 — 3,145 Corporate bonds — 17,329 — 17,329 Total marketable investments $ 297,540 $ 127,758 $ — $ 425,298 Liabilities Contingent consideration $ — $ — $ 18,100 $ 18,100 As of December 31, 2021 and 2020, the estimated fair value of the Company’s outstanding 2023 convertible senior notes was $114.9 million and $253.1 million, respectively. As of December 31, 2021 and 2020, the estimated fair value of the Company's outstanding 2025 convertible senior notes was $917.3 million and $1,098.5 million, respectively. The fair values were determined based on the quoted price of the convertible senior notes in an inactive market on the last trading day of the reporting period and have been classified as Level 2 in the fair value hierarchy. See Note 6 for further information on the Company’s convertible senior notes. As part of the agreement to acquire Inference Solutions Inc. (“Inference”) in November 2020, the Company may be obligated to pay contingent earn out consideration of up to $24.0 million based upon achievement of certain milestones and relative thresholds during the earn out measurement period which ended on December 31, 2021. The fair value of the contingent consideration arrangement, estimated to be $23.7 million as of December 31, 2021, is classified within Level 3 and is determined using a probability-based scenario analysis approach. The resulting probability-weighted contingent consideration amounts were discounted based on the Company’s estimated cost of debt. During the year ended December 31, 2021, the Company recognized $5.6 million of contingent consideration expense due to an increase in fair value of the contingent consideration as a result of the estimated achievement of the forecast the shorter time to payment. As of December 31, 2021, the Company does not expect any material change to the fair value of the contingent consideration other than due to the time value of money. A reconciliation of the beginning and ending balance for contingent consideration consisted of the following (in thousands): Year Ended December 31, 2021 Balance, December 31. 2020 $ 18,100 Change in fair value of contingent consideration 5,640 Balance, December 31, 2021 $ 23,740 There were no assets or liabilities measured at fair value on a non-recurring basis as of December 31, 2021 and 2020. The fair value of the Company’s other financial instruments, including accounts receivable, accounts payable and other current liabilities, approximate their carrying value due to the relatively short maturity of those instruments. The carrying amounts of the Company’s operating and finance leases approximate their fair value, which is the present value of expected future cash payments based on assumptions about current interest rates and the creditworthiness of the Company.

Financial Statement Components

Financial Statement Components	12 Months Ended
	Dec. 31, 2021
Financial Statement Components [Abstract]
Financial Statement Components	Financial Statement Components Cash and cash equivalents consisted of the following (in thousands): December 31, 2021 2020 Cash $ 58,751 $ 90,487 Certificates of deposit 747 — Money market funds 31,380 89,888 U.S. Treasury — 39,997 Total cash and cash equivalents $ 90,878 $ 220,372 Accounts receivable, net consisted of the following (in thousands): December 31, 2021 2020 Trade accounts receivable $ 75,970 $ 42,366 Unbilled trade accounts receivable, net of advance client deposits 7,981 6,492 Allowance for doubtful accounts (220) (127) Accounts receivable, net $ 83,731 $ 48,731 Prepaid expenses and other current assets consisted of the following (in thousands): December 31, 2021 2020 Prepaid expenses $ 21,306 $ 9,816 Other current assets 6,443 5,036 Contract assets 2,593 1,297 Prepaid expenses and other current assets $ 30,342 $ 16,149 Property and equipment, net consisted of the following (in thousands): December 31, 2021 2020 Computer and network equipment $ 116,701 $ 89,763 Computer software 44,268 25,888 Internal-use software development costs 500 500 Furniture and fixtures 3,953 3,372 Leasehold improvements 5,914 2,335 Property and equipment 171,336 121,858 Accumulated depreciation and amortization (93,551) (70,645) Property and equipment, net $ 77,785 $ 51,213 Depreciation and amortization expense associated with property and equipment was $26.9 million, $18.2 million and $13.5 million for the years ended December 31, 2021, 2020 and 2019, respectively. Property and equipment capitalized under finance lease obligations consists primarily of computer and network equipment and was as follows (in thousands): December 31, 2021 2020 Gross $ 42,541 $ 45,021 Less: accumulated depreciation and amortization (41,689) (41,908) Total $ 852 $ 3,113 Other assets consisted of the following (in thousands): December 31, 2021 2020 Other assets $ 4,964 $ 3,236 Deferred tax assets 6,907 — Total $ 11,871 $ 3,236 Accrued and other current liabilities consisted of the following (in thousands): December 31, 2021 2020 Accrued expenses $ 20,108 $ 15,217 Accrued compensation and benefits 34,729 29,233 Contingent consideration 23,740 — Accrued and other current liabilities $ 78,577 $ 44,450 Other long-term liabilities consisted of the following (in thousands): December 31, 2021 2020 Deferred revenue $ 2,097 $ 3,373 Deferred tax liabilities — 4,438 Other long-term liabilities 5,574 5,554 Contingent consideration — 18,100 Other long-term liabilities $ 7,671 $ 31,465

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill Goodwill was recorded as a result of the Company’s acquisitions of Face It, Corp., which the Company also refers to as SoCoCare, in October 2013, Virtual Observer in April 2020, and Inference in November 2020. See Note 14 for further details of the Virtual Observer and Inference acquisitions. The following table summarizes the activity in the Company's goodwill balances during the years ended December 31, 2021 and 2020 (in thousands): Goodwill Beginning of the period, January 1, 2020 $ 11,798 Addition (Inference) 130,976 Addition (Virtual Observer) 22,646 End of the period, December 31, 2020 165,420 Addition — End of the period, December 31, 2021 $ 165,420 During the fourth quarter of 2021, the Company completed its annual goodwill impairment test. Based on its assessment of the qualitative factors, the Company’s management concluded that the fair value of the Company’s goodwill was more likely than not greater than its carrying amount as of December 31, 2021. As such, it was not necessary to perform the quantitative goodwill impairment test. Subsequent to the 2021 annual impairment test, the Company believes there have been no significant events or circumstances negatively affecting the valuation of goodwill. As of December 31, 2021 and 2020, there was no impairment to the carrying value of the Company’s goodwill. Intangible Assets Intangible assets were acquired in connection with the Company’s acquisitions of SoCoCare in October 2013, Whendu in November 2019, Virtual Observer in April 2020, and Inference in November 2020. See Note 14 for further details of the Virtual Observer and Inference acquisitions. The following table summarizes the activity in the Company's intangible asset balances during the years ended December 31, 2021 and 2020 (in thousands): Intangible Assets Beginning of the period, January 1, 2020 $ 15,533 Addition (Inference) 30,100 Addition (Virtual Observer) 12,800 Addition (Whendu) 100 Amortization (6,849) End of the period, December 31, 2020 51,684 Amortization (11,787) End of the period, December 31, 2021 $ 39,897 The components of intangible assets were as follows (in thousands): December 31, 2021 December 31, 2020 Gross Carrying Amount Accumulated Net Weighted Average Remaining Amortization Period (Years) Gross Accumulated Net Weighted Average Remaining Amortization Period (Years) Developed technology $ 56,214 $ (17,821) $ 38,393 4.0 $ 56,214 $ (6,761) $ 49,453 4.9 Acquired workforce 470 (334) 136 0.9 470 (177) 293 1.9 Customer relationships 1,600 (421) 1,179 3.7 1,600 (101) 1,499 4.7 Trademarks 500 (311) 189 0.9 500 (61) 439 1.8 Total $ 58,784 $ (18,887) $ 39,897 4.0 $ 58,784 $ (7,100) $ 51,684 4.9 Amortization expense related to intangible assets was $11.8 million, $6.8 million and $0.9 million for the years ended December 31, 2021, 2020 and 2019, respectively. The increase in amortization expense from 2019 to 2020 and 2020 to 2021 was due to the acquisition of intangible assets from Whendu in November 2019, Virtual Observer in April 2020, and Inference in November 2020. As of December 31, 2021, the expected future amortization expense for intangible assets was as follows (in thousands): Period Expected Future 2022 $ 11,705 2023 10,870 2024 7,527 2025 5,595 2026 4,200 Thereafter — Total $ 39,897 Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate an asset’s carrying value may not be recoverable. The Company concluded that there was no impairment to the carrying value of its intangible assets as of December 31, 2021 and 2020.

Debt

Debt	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt	Debt 2025 Convertible Senior Notes and Related Capped Call Transactions In May and June 2020, the Company issued $747.5 million aggregate principal amount of 2025 convertible senior notes in a private offering, which aggregate principal amount included the exercise in full of the initial purchasers’ option to purchase up to an additional $97.5 million principal amount of the 2025 convertible senior notes. The 2025 convertible senior notes mature on June 1, 2025 and bear interest at a fixed rate of 0.500% per annum, payable semiannually in arrears on June 1 and December 1 of each year, beginning on December 1, 2020. In addition, under the terms of the 2025 convertible senior notes, the Company was obligated to pay additional interest on the 2025 convertible senior notes at a rate equal to 0.500% per annum for the period from June 13, 2021 through July 8, 2021, after which such additional interest is no longer payable. The total net proceeds from the issuance of the 2025 convertible senior notes, after deducting initial purchasers' discounts and commissions and estimated debt issuance costs, were approximately $728.8 million. Each $1,000 principal amount of the 2025 convertible senior notes is initially convertible into 7.4437 shares of the Company’s common stock (the “2025 Conversion Option”), which is equivalent to an initial conversion price of approximately $134.34 per share of common stock, subject to adjustment upon the occurrence of specified events. The initial conversion price represents a premium of approximately 30% to the $103.34 per share closing price of the Company’s common stock on The Nasdaq Global Market on May 21, 2020. The 2025 convertible senior notes are convertible, in multiples of $1,000 principal amount, at the option of the holders prior to the close of business on the business day immediately preceding March 1, 2025, only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on September 30, 2020 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the “2025 Measurement Period”) in which the trading price (as defined in the 2025 Indenture governing the 2025 convertible senior notes) per $1,000 principal amount of the 2025 convertible senior notes for each trading day of the 2025 Measurement Period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate in effect on each such trading day; (3) if the Company calls any or all of the 2025 convertible senior notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. On or after March 1, 2025 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their 2025 convertible senior notes, in multiples of $1,000 principal amount, at the option of the holder regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. If the Company undergoes a fundamental change (as defined in the indenture governing the 2025 convertible senior notes), subject to certain conditions, holders may require the Company to repurchase for cash all or any portion of their 2025 convertible senior notes, in principal amounts of $1,000 or a multiple thereof, at a fundamental change repurchase price equal to 100% of the principal amount of the 2025 convertible senior notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. In addition, following certain corporate events or if the Company issues a notice of redemption, it will, under certain circumstances, increase the conversion rate for holders who elect to convert their notes in connection with such corporate event or during the relevant redemption period. There have been no changes to the initial conversion price of the 2025 convertible senior notes since issuance. The closing market price of the Company's common stock of $137.32 per share as of December 31, 2021, the last trading day during the three months ended December 31, 2021, was below $174.64 per share, which represents 130% of the initial conversion price of $134.34 per share. Additionally, the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day, December 31, 2021, was not greater than or equal to 130% of the initial conversion price. As such, during the three months ended December 31, 2021, the conditions allowing holders of the 2025 convertible senior notes to convert were not met. The 2025 convertible senior notes are therefore not convertible for the three months ending March 31, 2022. The Company may not redeem the 2025 convertible senior notes prior to June 6, 2023. The Company may redeem for cash all or any portion of the 2025 convertible senior notes, at its option, on or after June 6, 2023 and prior to March 1, 2025 if the last reported sale price of its common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending not more than two trading days immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2025 convertible senior notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2025 convertible senior notes. The 2025 convertible senior notes are the Company’s senior unsecured obligations and rank senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the 2025 convertible senior notes; equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated (including the 2023 convertible senior notes); effectively junior in right of payment to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries. Prior to the adoption of ASU 2020-06 on January 1, 2021 and in accounting for the issuance of the 2025 convertible senior notes, the 2025 convertible senior notes were separated into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated conversion feature. The carrying amount of the equity component representing the 2025 Conversion Option was $158.3 million and was determined by deducting the fair value of the liability component from the par value of the 2025 convertible senior notes. The equity component was recorded in additional paid-in-capital and was not re-measured as long as it continued to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount (the “Debt Discount”) was amortized to interest expense over the contractual term of the 2025 convertible senior notes at an effective interest rate of 5.76%. Prior to the adoption of ASU 2020-06 on January 1, 2021 and in accounting for the debt issuance costs of $18.7 million related to the 2025 convertible senior notes, the Company allocated the total amount incurred to the liability and equity components of the 2025 convertible senior notes based on their relative values. Issuance costs attributable to the liability component were $14.7 million and were amortized to interest expense using the effective interest method over the contractual term of the 2025 convertible senior notes. Issuance costs attributable to the equity component were netted with the equity component in additional paid-in-capital. On January 1, 2021, the Company elected to early adopt ASU 2020-06 based on a modified retrospective transition method. Under such transition, prior-period information has not been retrospectively adjusted. In accounting for the 2025 convertible senior notes after adoption of ASU 2020-06, the 2025 convertible senior notes are accounted for as a single liability, and the carrying amount of the 2025 convertible senior notes is $734.7 million as of December 31, 2021, with principal of $747.5 million, net of issuance cost of $12.8 million. The 2025 senior convertible notes were classified as long term liabilities as of December 31, 2021. The issuance cost related to the 2025 convertible senior notes is being amortized to interest expense over the contractual term of the 2025 convertible senior notes at an effective interest rate of 1.0%. The net carrying amount of the 2025 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Principal $ 747,500 $ 747,500 Unamortized debt discount — (141,792) Unamortized issuance costs (12,835) (13,192) Net carrying amount $ 734,665 $ 592,516 The net carrying amount of the equity component of the 2025 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Equity component $ — $ 158,321 Issuance costs — (3,958) Net carrying amount $ — $ 154,363 Interest expense related to the 2025 convertible senior notes was as follows (in thousands): Year Ended December 31, 2021 December 31, 2020 Contractual interest expense $ 4,007 $ 2,230 Amortization of debt discount — 16,528 Amortization of issuance costs 3,674 1,538 Total interest expense $ 7,681 $ 20,296 In connection with the issuance of the 2025 convertible senior notes, the Company entered into privately negotiated capped call transactions (the “2025 Capped Call Transactions”) with certain financial institutions. The 2025 Capped Call Transactions are expected generally to reduce the potential dilution to the Company’s common stock in connection with any conversion of the 2025 convertible senior notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted 2025 convertible senior notes, as the case may be, with such reduction and/or offset subject to a cap based on the cap price. The initial cap price of the 2025 Capped Call Transactions was $206.68 per share and is subject to certain adjustments under the terms of the 2025 Capped Call Transactions. The 2025 Capped Call Transactions cover, subject to anti-dilution adjustments, approximately 5.6 million shares of the Company’s common stock. For accounting purposes, the 2025 Capped Call Transactions are separate transactions, and not integrated with the issuance of the 2025 convertible senior notes. As these transactions meet certain accounting criteria, the 2025 Capped Call Transactions are recorded in stockholders’ equity and are not accounted for as derivatives. The cost to the Company of the 2025 Capped Call Transactions was $90.5 million during the year ended December 31, 2020, which was recorded as a reduction to additional paid-in capital. Maturity of the Company’s 2025 convertible senior notes as of December 31, 2021 was as follows (in thousands): Period Amount to Mature 2025 (Maturity date of June 1, 2025) $ 747,500 Total $ 747,500 2023 Convertible Senior Notes and Related Capped Call Transactions In May 2018, the Company issued $258.8 million aggregate principal amount of the 2023 convertible senior notes in a private offering. The 2023 convertible senior notes mature on May 1, 2023 and bear interest at a fixed rate of 0.125% per annum, payable semiannually in arrears on May 1 and November 1 of each year. The total net proceeds from the offering, after deducting initial purchasers' discounts and commissions and estimated debt issuance costs, was approximately $250.8 million. In May 2020, the Company used part of the net proceeds from the issuance of the 2025 convertible senior notes to repurchase, exchange or otherwise retire approximately $181.0 million aggregate principal amount of the 2023 convertible senior notes in privately-negotiated transactions for aggregate consideration of $449.6 million, consisting of $181.0 million in cash and 2,723,581 shares of the Company’s common stock (the "2023 Note Repurchase Transactions"). As of December 31, 2021, after giving effect to the 2023 Note Repurchase Transactions and other settlements upon conversion requests, approximately $33.9 million aggregate principal amount of 2023 convertible senior notes remained outstanding. The 2023 Note Repurchase Transactions were accounted for as a debt extinguishment. Pursuant to ASC Subtopic 470-20 under existing accounting rules prior to ASU 2020-06 adoption, total consideration for the 2023 Note Repurchase Transactions was separated into liability and equity components by estimating the fair value of a similar liability without a conversion option and assigning the residual value to the equity component. The gain or loss on extinguishment of the debt was subsequently determined by comparing the repurchase consideration allocated to the liability component to the sum of the carrying value of the liability component, net of the proportionate amounts of unamortized debt discount and the remaining unamortized debt issuance costs. Of the $449.6 million in aggregate consideration paid by the Company in connection with the 2023 Note Repurchase Transactions, $155.8 million and $293.8 million were allocated to the debt and equity components, respectively, using an effective interest rate of 5.32% to determine the fair value of the liability component. This interest rate was based on the income and market-based approaches used to determine the effective interest rate of the 2023 convertible senior notes, adjusted for the remaining term of the 2023 convertible senior notes. As of the settlement of the 2023 Note Repurchase Transactions, the carrying value of the 2023 convertible senior notes subject to the 2023 Note Repurchase Transactions, net of unamortized debt discount and issuance costs, was $150.4 million. The Company also incurred approximately $0.5 million in third party transaction costs related to the 2023 Note Repurchase Transactions. These costs were allocated to the liability and equity components in proportion to the allocation of consideration transferred at settlement and accounted for as debt extinguishment costs and equity reacquisition costs, respectively. The 2023 Note Repurchase Transactions resulted in a $5.8 million loss on early debt extinguishment in the second quarter of fiscal 2020, of which $2.7 million consisted of unamortized debt issuance costs. Each $1,000 principal amount of the 2023 convertible senior notes was initially convertible into 24.4978 shares of the Company’s common stock (the “2023 Conversion Option”), which is equivalent to an initial conversion price of approximately $40.82 per share of common stock, subject to adjustment upon the occurrence of specified events. The 2023 convertible senior notes are convertible, in multiples of $1,000 principal amount, at the option of the holders at any time prior to the close of business on the business day immediately preceding November 1, 2022, only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ended on September 30, 2018 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the “2023 Measurement Period”) in which the trading price (as defined in the indenture governing the 2023 convertible senior notes) per $1,000 principal amount of the 2023 convertible senior notes for each trading day of the 2023 Measurement Period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate in effect on each such trading day; (3) if the Company calls any or all of the 2023 convertible senior notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. On or after November 1, 2022 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their 2023 convertible senior notes, in multiples of $1,000 principal amount, at the option of the holder regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. If the Company undergoes a fundamental change (as defined in the indenture governing the 2023 convertible senior notes), subject to certain conditions, holders may require the Company to repurchase for cash all or any portion of their 2023 convertible senior notes, in principal amounts of $1,000 or a multiple thereof, at a fundamental change repurchase price equal to 100% of the principal amount of the 2023 convertible senior notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date. In addition, following certain corporate events that occur prior to the maturity date or if the Company issues a notice of redemption, it will, under certain circumstances, increase the conversion rate for holders who elect to convert their 2023 convertible senior notes in connection with such corporate event or during the relevant redemption period. There have been no changes to the initial conversion price of the 2023 convertible senior notes since issuance. During each of the quarters from the third quarter of 2019 through the fourth quarter of 2021, one of the triggers for convertibility of the 2023 convertible senior notes was triggered as the last reported sale price of the Company’s common stock was greater than $53.07 per share, which represents 130% of the initial conversion price of $40.82 per share, for at least 20 trading days in the period of 30 consecutive trading days ended on, and including, the last trading day of the quarter for each quarter of 2020 and 2021. As a result, the 2023 convertible senior notes were convertible, in multiples of $1,000 principal amount, at the option of the 2023 convertible senior note holders between October 1, 2019 to December 31, 2021, and are also currently convertible between January 1, 2022 and March 31, 2022. Whether the 2023 convertible senior notes will be convertible after March 31, 2022 will depend on the continued satisfaction of this condition or other conversion conditions in the future. During 2020, the Company paid $18.9 million in cash and issued 307,037 shares of its common stock to settle aggregate principal amount of $18.9 million of its 2023 convertible senior notes. During 2021, the Company paid $24.7 million in cash and issued 453,943 shares of its common stock to settle aggregate principal amount of $24.6 million of its 2023 convertible senior notes. As of December 31, 2021, approximately $34.2 million aggregate principal amount of the 2023 convertible senior notes remained outstanding. The conversions that occurred prior to January 1, 2021 resulted in a $1.2 million loss on early debt extinguishment. The conversions that occurred during 2021 were subject to ASU 2020-06 and such conversions were accounted for as contractual conversions, which did not result in any gain or loss upon their settlement. During 2020, the Company received 15,714 shares from the partial unwind of capped calls resulting from the settlement of its 2023 convertible senior notes. During 2021, the Company received an additional 68,905 shares from the partial unwind of capped calls resulting from the settlement of its 2023 convertible senior notes. The receipt of the 15,714 and 68,905 shares reduced the number of shares of common stock outstanding. In addition, on or prior to December 31, 2021, the Company received elections to convert aggregate principal amount of $34.0 million of its 2023 convertible senior notes that remain unsettled as of the end of the fourth quarter of 2021. The Company expects to settle these conversions in cash or a combination of cash and shares during the first quarter of 2022. The Company has the option to settle any future election conversion notices in cash, shares, or a combination of cash and shares. The 2023 convertible senior notes became redeemable at the Company's option on May 5, 2021. The Company may redeem for cash all or any portion of the 2023 convertible senior notes, at its option, if the last reported sale price of its common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending not more than two trading days immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2023 convertible senior notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2023 convertible senior notes. The 2023 convertible senior notes are the Company’s senior unsecured obligations and rank senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the 2023 convertible senior notes; equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated (including the 2025 convertible senior notes); effectively junior in right of payment to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries. Prior to the adoption of ASU 2020-06 on January 1, 2021 and in accounting for the issuance of the 2023 convertible senior notes, the 2023 convertible senior notes were separated into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated conversion feature. The equity component was recorded in additional paid-in-capital and was not re-measured as long as it continued to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount (the "Debt Discount") was amortized to interest expense over the contractual term of the 2023 convertible senior notes at an effective interest rate of 6.39%. Prior to the adoption of ASU 2020-06 on January 1, 2021 and in accounting for the debt issuance costs of $8.0 million related to the 2023 convertible senior notes, the Company allocated the total amount incurred to the liability and equity components of the 2023 convertible senior notes based on their relative values. Issuance costs attributable to the liability component were $6.0 million and were amortized to interest expense using the effective interest method over the contractual term of the 2023 convertible senior notes. Issuance costs attributable to the equity component were netted with the equity component in additional paid-in-capital. After the adoption of ASU 2020-06, the 2023 convertible senior notes are accounted for as a single liability, and the carrying amount of the 2023 convertible senior notes was $33.9 million as of December 31, 2021, with principal of $34.2 million , net of issuance cost of $0.3 million. The 2023 senior convertible notes were classified as long term liabilities during 2021. The issuance cost related to the 2023 convertible senior notes is being amortized to interest expense over the contractual term of the 2023 convertible senior notes at an effective interest rate of 0.76%. The net carrying amount of the 2023 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Principal $ 34,225 $ 58,867 Unamortized debt discount — (7,367) Unamortized issuance costs (291) (700) Net carrying amount $ 33,934 $ 50,800 The net carrying amount of the equity component of the 2023 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Equity component $ — $ 14,505 Issuance costs — (455) Net carrying amount $ — $ 14,050 Interest expense related to the 2023 convertible senior notes was as follows (in thousands): Year Ended December 31, 2021 December 31, 2020 December 31, 2018 Contractual interest expense $ 42 $ 184 $ 324 Amortization of debt discount — 7,006 11,683 Amortization of issuance costs 283 666 1,105 Total interest expense $ 325 $ 7,856 $ 13,112 In connection with the issuance of the 2023 convertible senior notes, the Company entered into privately negotiated capped call transactions (the “2023 Capped Call Transactions”) with certain financial institutions. The 2023 Capped Call Transactions are expected generally to reduce the potential dilution to the Company’s common stock upon any conversion of the 2023 convertible senior notes and/or offset any cash payments the Company is required to make in excess of the principal amount of converted 2023 convertible senior notes, as the case may be, with such reduction and/or offset subject to a cap based on the cap price. The initial cap price of the 2023 Capped Call Transactions was $62.80 per share, and is subject to certain adjustments under the terms of the 2023 Capped Call Transactions. The 2023 Capped Call Transactions cover, subject to anti-dilution adjustments, approximately 6.3 million shares of the Company’s common stock. For accounting purposes, the 2023 Capped Call Transactions are separate transactions, and not integrated with the issuance of the 2023 convertible senior notes. As these transactions meet certain accounting criteria, the 2023 Capped Call Transactions are recorded in stockholders’ equity and are not accounted for as derivatives. The cost of $31.4 million incurred in connection with the 2023 Capped Call Transactions was recorded as a reduction to additional paid-in capital. In connection with the 2023 Note Repurchase Transactions, the Company amended the 2023 Capped Call Transactions such that the portion associated with the 2023 convertible senior notes subject to the 2023 Note Repurchase Transactions would remain outstanding notwithstanding the retirement of $181.0 million aggregate principal amount of 2023 convertible senior notes. Following such amendment, the 2023 Capped Call Transactions continue to meet the accounting criteria to be recorded in stockholders’ equity and are not accounted for as derivatives. Maturity of the Company’s 2023 convertible senior notes as of December 31, 2021 was as follows (in thousands): Period Amount to Mature 2023 (Maturity date of May 1, 2023) $ 34,225 Total $ 34,225

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Capital Structure Common Stock The Company is authorized to issue 450,000,000 shares of common stock with a par value of $0.001 per share. As of December 31, 2021 and 2020, the Company had 68,488,337 and 66,496,060 shares of common stock issued and outstanding, respectively. During 2021 and 2020, the Company issued 453,943 and 3,030,618 shares, respectively, of common stock in connection with 2023 convertible senior note settlements. During 2021 and 2020, the Company also received 68,905 and 15,714 shares, respectively, from the partial unwind of capped calls resulting from the settlement of its 2023 convertible senior notes. The receipt of the 68,905 and 15,714 shares reduced the number of shares of common stock outstanding. See Note 6 for further details. Holders of the Company’s common stock are entitled to dividends, if and when declared by the board of directors. In the event of liquidation, dissolution or winding up, subject to the rights of the holders of any then outstanding shares of preferred stock, holders of common stock will be entitled to receive the assets and funds of the Company that are legally available for distribution. Preferred Stock The Company is authorized to designate and issue up to 5,000,000 shares of preferred stock with a par value of $0.001 per share in one or more series without stockholder approval and to fix the rights, preferences, privileges and restrictions thereof. As of December 31, 2021 and 2020, there were no shares of preferred stock issued and outstanding. Common Stock Reserved for Future Issuance Shares of common stock reserved for future issuance related to outstanding equity awards and employee equity incentive plans as of December 31, 2021, were as follows (in thousands): Common Stock Reserved Stock options outstanding 1,982 Restricted stock units outstanding 2,560 Shares available for future grant under 2014 Plan 13,379 Shares available for future issuance under ESPP 3,076 Total shares of common stock reserved 20,997 Equity Incentive Plans Prior to the Company’s initial public offering (“IPO”) in April 2014, the Company granted stock options under its Amended and Restated 2004 Equity Incentive Plan, as amended (“ 2004 Plan”). Under the terms of the 2004 Plan, the Company had the ability to grant incentive and nonstatutory stock options. Incentive stock options could only be granted to Company employees. Nonstatutory stock options could be granted to Company employees, directors and consultants. Such options are exercisable at prices, as determined by the board of directors, generally equal to the fair value of the Company’s common stock at the date of grant. Options granted to employees generally vest over a four-year period, with an initial vesting period of 12 months for 25% of the shares, and the remaining 75% of the shares vesting monthly on a ratable basis over the remaining 36 months. Options generally expire 10 years after the grant date and are generally exercisable upon vesting. Vested options generally expire 90 days after termination of the optionee’s employment or relationship as a consultant or director, unless otherwise extended by the terms of the stock option agreement. In March 2014, the Company’s board of directors and stockholders approved the 2014 Equity Incentive Plan (“2014 Plan”) and 5,300,000 shares of common stock were authorized for issuance under the 2014 Plan. In addition, on the first day of each year beginning in 2015 and ending in 2024, the 2014 Plan provides for an annual automatic increase to the shares reserved for issuance in an amount equal to 5% of the total number of shares outstanding on December 31st of the preceding calendar year or a lesser number as determined by the Company’s board of directors. Pursuant to the automatic annual increase, 3,424,416 additional shares were reserved under the 2014 Plan on January 1, 2022. No further grants were made under the 2004 Plan once the 2014 Plan became effective on April 3, 2014. Upon the effectiveness of the 2014 Plan, all shares reserved for future issuance under the 2004 Plan became available for issuance under the 2014 Plan. Additionally, any forfeited or expired shares that would have otherwise returned to the 2004 Plan instead return to the 2014 Plan. The 2014 Plan allows the Company to grant stock options, restricted stock units (“RSUs”), restricted stock awards, performance stock awards, stock appreciation rights, performance cash awards, and other stock awards. To date, the Company has granted stock options and RSUs under the 2014 Plan. Stock options granted under the 2014 Plan are in general at a price equal to the fair market value of the common stock on the date of grant and vest over four years. The Company’s stock options expire 10 years from the date of grant. Each RSU granted under the 2014 Plan represents a right to receive one share of the Company’s common stock when the RSU vests. RSUs generally vest over one In connection with the Company’s acquisition of Inference, the Company assumed unvested stock options that had been granted under the Inference Technologies Group Inc. 2018 Equity Incentive Plan. Each of the assumed stock options are subject to substantially the same terms and conditions as applied to the assumed stock options immediately prior to the acquisition date, except that the number of shares of the Company’s common stock subject to each assumed stock option and the exercise price has been adjusted in accordance with the terms of the acquisition agreement. If these assumed stock options are cancelled, forfeited or expire unexercised, the underlying shares do not become available for future grant. As of the acquisition date, the estimated fair value of the assumed unvested options was $7.6 million, of which $0.2 million was recognized as goodwill and the balance of $7.4 million is being recognized as stock-based compensation expense over the remaining service period of the assumed unvested stock options. Stock Options A summary of the Company’s stock option activity during the year ended December 31, 2021 is as follows (in thousands, except years and per share data): Number of Shares Weighted Weighted Aggregate Intrinsic Value (1) Outstanding as of December 31, 2020 2,255 $ 26.33 Options granted 156 180.75 Options exercised (389) 19.03 Options forfeited or expired (40) 80.47 Outstanding as of December 31, 2021 1,982 38.65 4.9 $ 202,425 Vested and expected to vest as of December 31, 2021 1,982 38.65 4.9 202,425 Exercisable as of December 31, 2021 1,544 22.02 4.0 179,180 (1) The aggregate intrinsic value amounts are computed based on the difference between the exercise price of the stock options and the fair market value of the Company’s common stock of $137.32 per share as of December 31, 2021 for all in-the-money stock options outstanding. Following is additional information pertaining to the Company’s stock option activity (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Weighted average grant date fair value per share of options granted, excluding assumed stock options $ 78.72 $ 38.80 $ 24.06 Weighted average grant date fair value per share of assumed stock options — 125.96 — Intrinsic value of options exercised (1) 59,762 47,529 42,204 Total fair value of options vested during the period 12,760 7,846 5,342 Cash received from options exercised 7,402 11,656 7,705 (1) Intrinsic value of options exercised is the difference between the fair market value of the Company’s common stock at the time of exercise and the exercise price paid. Restricted Stock Units A summary of RSU activity during the year ended December 31, 2021 is as follows (in thousands, except years and per share data): Number of Shares Weighted Average Grant Date Fair Value Per Share Outstanding as of December 31, 2020 2,267 $ 65.42 RSUs granted 2,234 177.00 RSUs vested and released (1,097) 69.06 RSUs forfeited or cancelled (844) 170.59 Outstanding as of December 31, 2021 2,560 125.65 During the third quarter of 2021, the Company granted 0.7 million RSU awards conditional upon the close of the Merger. The Company cancelled these grants on September 30, 2021, the termination date of the Merger. In October 2021, the Company subsequently granted 0.7 million RSU awards to its employees. Following is additional information pertaining to the Company’s RSU activity (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Weighted average grant date fair value per share of RSUs granted $ 177.00 $ 86.15 $ 53.33 Total fair value of RSUs vested during the period 174,500 136,805 68,072 Employee Stock Purchase Plan In March 2014, the Company’s board of directors and stockholders adopted the 2014 ESPP and the shares authorized for issuance thereunder. The 2014 ESPP became effective on April 3, 2014. The 2014 ESPP permits eligible employees to purchase shares of the Company’s common stock through payroll deductions with up to 15% of their pre-tax earnings subject to certain Internal Revenue Code limitations. The purchase price of the shares is 85% of the lower of the fair market value of the Company’s common stock on the first day of a six month offering period, except for the initial offering period, or the relevant purchase date. In addition, no participant may purchase more than 1,500 shares of common stock in each purchase period. The number of shares of common stock originally reserved for issuance under the 2014 ESPP was 880,000 shares, which increases automatically each year, beginning on January 1, 2015 and continuing through January 1, 2024, by the lesser of (i) 1% of the total number of shares of the Company’s common stock outstanding on December 31 of the preceding calendar year; (ii) 1,000,000 shares of common stock (subject to adjustment to reflect any split or combination of its common stock); or (iii) such lesser number as determined by its board of directors. Pursuant to the automatic annual increase, 684,883 additional shares were reserved under the 2014 ESPP on January 1, 2022. During 2021 and 2020, 120,992 and 168,737 shares were purchased by employees under the 2014 ESPP at a weighted average price of $127.36 and $67.97 per share, respectively. Stock-Based Compensation Stock-based compensation expenses for the years ended December 31, 2021, 2020 and 2019 were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Cost of revenue $ 17,734 $ 9,422 $ 6,334 Research and development 29,179 14,043 7,658 Sales and marketing 35,269 20,164 11,368 General and administrative 26,623 21,118 16,705 Total stock-based compensation $ 108,805 $ 64,747 $ 42,065 As of December 31, 2021, unrecognized stock-based compensation expense by award type and their expected weighted-average recognition periods are summarized in the following table (in thousands, except years). Stock Option RSU ESPP Unrecognized stock-based compensation expense $ 21,723 $ 297,934 $ 2,604 Weighted-average amortization period 2.5 years 2.5 years 0.4 years The Company recognizes stock-based compensation expense that is calculated based upon awards that have vested, reduced for actual forfeitures. All stock-based compensation for equity awards granted to employees and non-employee directors is measured based on the grant date fair value of the award. The Company values RSUs at the closing market price of its common stock on the date of grant. The Company estimates the fair value of each stock option and purchase right under the 2014 ESPP granted to employees on the date of grant using the Black-Scholes option-pricing model and using the assumptions disclosed in the table below. Expected volatility is based upon the weighting of the Company’s historical volatility. Prior to 2020, expected volatility was based upon the weighting of the Company’s historical volatility and the historical volatility of a peer group of publicly traded companies. The expected term of options granted is estimated using the simplified method by taking the average of the vesting term and the contractual term of the option. The expected volatility assumption for purchase rights under the 2014 ESPP is based on the historical volatility of the Company’s common stock. The risk-free rate for the expected term of the awards is based on U.S. Treasury zero-coupon issues at the time of grant. The Company has not paid, and does not anticipate paying, cash dividends on its shares of common stock. Accordingly, the expected dividend yield is zero. The weighted average assumptions used to value stock options and purchase rights under the 2014 ESPP granted during the years ended December 31, 2021, 2020 and 2019 were as follows: Stock Options Year Ended December 31, 2021 2020 (1) 2019 Expected term (years) 6.0 5.7 6.1 Volatility 47% 47% 46% Risk-free interest rate 1.0% 0.9% 2.3% Dividend yield — — — (1) The weighted average assumptions for the year ended December 31, 2020 includes assumed stock options. The weighted average assumptions, excluding the assumed stock options, were an expected term of 6.0 years, volatility of 47%, risk-free interest rate of 1.0% and dividend yield of 0%. The weighted average assumptions of the assumed stock options were an expected term of 4.3 years, volatility of 47%, risk-free interest rate of 0.3% and dividend yield of 0%. ESPP Granted In November 2021 May 2021 November 2020 May 2020 November 2019 May 2019 Expected term (years) 0.5 0.5 0.5 0.5 0.5 0.5 Volatility 46% 49% 50% 50% 46% 51% Risk-free interest rate 0.2% 0.1% 0.1% 0.2% 2.4% 2.5% Dividend yield — — — — — —

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per ShareBasic net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock outstanding during the period, and excludes any dilutive effects of employee stock-based awards and potential shares upon conversion of the convertible senior notes. Diluted net loss per share is computed giving effect to all potentially dilutive shares of common stock, including common stock issuable upon exercise of stock options, vesting of RSUs and shares of common stock issuable upon conversion of convertible senior notes. As the Company had net losses for the years ended December 31, 2021, 2020 and 2019, all potentially issuable shares of common stock were determined to be anti-dilutive. The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Net loss $ (53,000) $ (42,130) $ (4,552) Weighted-average shares used in computing basic and diluted net loss per share 67,512 64,154 60,371 Basic and diluted net loss per share $ (0.79) $ (0.66) $ (0.08) The following securities were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive (in thousands): December 31, 2021 2020 2019 Stock options 1,982 2,255 2,530 Restricted stock units 2,560 2,267 2,372 Convertible senior notes (1) 6,663 910 1,619 Total 11,205 5,432 6,521 (1) The convertible senior notes were calculated under the if-converted method for 2021 due to the adoption of ASU 2020-06 and under the treasury stock method for 2020 and 2019. Prior to the adoption of ASU 2020-06, the Company used the treasury stock method for calculating any potential dilutive effect of the conversion spread of its convertible senior notes. The conversion spread had a dilutive impact for the 2023 convertible senior notes during the years ended December 31, 2020 and 2019 since the average market price of the Company’s common stock during the period exceeded the initial conversion price of $40.82 per share. However, the potential shares of common stock issuable upon the conversion of the 2023 convertible senior notes were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following table presents components of loss before income taxes for the periods presented (in thousands): Year Ended December 31, 2021 2020 2019 United States $ (59,856) $ (44,303) $ (5,340) International (4,429) (280) 892 Loss before income taxes $ (64,285) $ (44,583) $ (4,448) Provision for (benefit from) income taxes for the periods presented consisted of (in thousands): Year Ended December 31, 2021 2020 2019 Current: U.S. federal $ — $ — $ — U.S. state 262 401 61 Foreign (202) 233 43 Total provision for income taxes - Current 60 634 104 Deferred: U.S. federal — (2,495) — U.S. state — (414) — Foreign (11,345) (178) — Total (benefit from) income taxes - Deferred (11,345) (3,087) — Total (benefit from) provision for income taxes $ (11,285) $ (2,453) $ 104 The Company recorded a deferred income tax benefit during 2021 principally due to a restructuring of its Australian subsidiary organization which allowed for the step-up in tax basis of certain intangible assets, and net operating loss carryover increases for current year losses, against which no valuation allowance was recorded. Income tax (benefit) expense differed from the amount computed by applying the U.S. federal statutory income tax rate of 21% to pre-tax (loss) income for the periods presented as a result of the following (in thousands): Year Ended December 31, 2021 2020 2019 U.S. federal tax at statutory rate $ (13,500) $ (9,362) $ (934) U.S. state income taxes 262 (345) (65) Section 162(m) 7,543 6,472 5,623 Non-deductible expenses 1,361 1,944 276 Research and development credit (1,181) (837) (860) Stock-based compensation (25,241) (23,800) (16,619) Tax benefit from acquisition/reorganizations (5,877) (2,495) — Foreign taxes (4,760) 118 (10) Other 20 533 (119) Change in valuation allowance 30,088 25,319 12,812 Total (benefit from) provision for income taxes $ (11,285) $ (2,453) $ 104 The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities as of December 31, 2021 and 2020 related to the following (in thousands): December 31, 2021 2020 Deferred tax assets: Net operating loss and credit carryforwards $ 133,433 $ 95,180 Accrued liabilities 12,719 6,244 Allowance for doubtful accounts 712 766 Amortized intangibles 872 — Deferred revenue 1,351 782 Accrued compensation 3,963 3,596 Long-term lease liabilities 13,618 1,418 Gross deferred tax assets 166,668 107,986 Valuation allowance (121,835) (51,127) Net deferred tax assets 44,833 56,859 Deferred tax liabilities: Property and equipment (2,633) (876) Amortized intangibles — (11,041) Other (509) (92) Right of use assets (11,573) (1,276) Deferred compensation - Current (23,211) (12,180) Convertible senior notes — (35,832) Gross deferred tax liabilities (37,926) (61,297) Net deferred taxes $ 6,907 $ (4,438) The Company has not provided for U.S. income taxes on undistributed earnings of its foreign subsidiaries because it intends to permanently re-invest those earnings outside the United States. The undistributed earnings of the Company’s foreign subsidiaries were immaterial as of December 31, 2021 and 2020. A valuation allowance is provided for deferred tax assets where the recoverability of the assets is uncertain. The determination to provide a valuation allowance is dependent upon the assessment of whether it is more likely than not that sufficient future taxable income will be generated to utilize the deferred tax assets. Based on the weight of the available evidence, which includes the Company’s historical operating losses, lack of taxable income and the accumulated deficit for the year ended December 31, 2021, the Company has provided a valuation allowance against its U.S. net deferred tax assets. However, the Company has recorded net foreign deferred tax assets associated with its U.K. and Australia operations totaling $6.9 million. The net change in the valuation allowance for the years ended December 31, 2021 and 2020 was an increase of $70.7 million and a decrease of $8.8 million, respectively. The increase in the valuation allowance in the current year was primarily attributed to the Company's adoption of ASU 2020-06 resulting in the reversal of previously recognized deferred taxes related to the convertible debt option. In addition, the net operating loss for the current year contributed to the increase in the valuation allowance. As of December 31, 2021, the Company had net operating loss carryforwards for federal, state and foreign income tax purposes of $495.3 million, $306.8 million and $18.8 million, respectively, available to reduce future income subject to income taxes. If not utilized, the federal and state net operating loss carryforwards will begin to expire in 2024 and 2028, respectively, while the foreign net operating loss carryforwards do not expire. As of December 31, 2021, the Company also had gross research credit carryforwards for federal and California state tax purposes of $8.4 million and $5.8 million, available to reduce future income subject to income taxes. The federal research credit carryforwards will begin to expire in 2022 and the California state research credits can be carried forward indefinitely. The Internal Revenue Code (“IRC”) of 1986, as amended, imposes restrictions on the utilization of net operating losses and credits in the event of an “ownership change” of a corporation. Accordingly, a company’s ability to use net operating losses and credits may be subject to substantial limitation as prescribed under the IRC Sections 382 and 383 and similar state provisions. Events that may cause limitations in the amount of the net operating losses and credits that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. In the event the Company has changes in ownership, net operating losses and research and development credit carryforwards, which are fully reserved by the deferred tax asset valuation allowance, could be limited and may expire unutilized. Beginning in 2022, the Tax Cuts and Jobs Act of 2017 (“TCJA”) eliminates the option to deduct research and development expenditures currently and requires taxpayers to capitalize and amortize them over five years pursuant to IRC Section 174. Although Congress is considering legislation that would defer the amortization requirement to later years, it is not certain that the provision will be repealed or otherwise modified. If the requirement is not modified, it will reduce the Company’s net operating losses beginning in 2022. Given the Company’s carryover attributes, this is not expected to have a material impact on the consolidated financial statements. Subsequent to year end, the Company completed a reorganization of its Australian entities, the ultimate result of which was to repatriate the ownership of certain intellectual property to the United States. As a result, the Company will increase its deferred tax assets and its valuation allowance during the first quarter of 2022 by approximately $2.1 million with no net impact on its earnings. Unrecognized Tax Benefits The table below shows the changes in the gross amount of unrecognized tax benefits for the periods presented (in thousands): Year Ended December 31, 2021 2020 2019 Unrecognized benefit — beginning of period $ 6,076 $ 4,471 $ 10,723 Gross increases — current year tax positions 1,851 1,605 963 Gross decreases — prior year tax positions — — (7,215) Settlements with tax authorities (284) — — Unrecognized benefit — end of period $ 7,643 $ 6,076 $ 4,471 As of December 31, 2021 and 2020, the Company had $0.0 million and $0.3 million, respectively, of total unrecognized tax benefits, if recognized, would have an impact on its effective tax rate. The Company recognizes interest and penalties related to uncertain tax positions as income tax expense. The Company does not anticipate its total unrecognized tax benefits as of December 31, 2021 will significantly change due to settlement of examination or the expiration of statutes of limitation during the next 12 months. The Company is currently unaware of any uncertain tax positions that could result in significant additional payments, accruals or other material deviation in this estimate over the next 12 months. The Company is subject to taxation in the United States, various states and several foreign jurisdictions. Due to the Company’s net carryover of unused operating losses, all years from 2001 forward remain subject to future examination by the U.S. federal and state tax authorities. The Company’s foreign tax returns are open to audit under the statutes of limitation of the respective foreign countries in which its subsidiaries are located. The Company considers all undistributed earnings of its foreign subsidiaries indefinitely reinvested.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments As of December 31, 2021, $781.7 million of aggregate principal of the convertible senior notes were outstanding. The 2023 convertible senior notes and the 2025 convertible senior notes are due on May 1, 2023 and June 1, 2025, respectively. See Note 6 for more information concerning the convertible senior notes. The Company had outstanding operating lease obligations of $64.0 million as of December 31, 2021. See Note 13 for further details. As of December 31, 2021, the Company also had outstanding cloud service agreement commitments totaling $61.1 million, of which $21.8 million is expected to be paid in 2022 and the remaining $39.3 million in 2023. Hosting and Telecommunication Usage Services The Company has agreements with third parties to provide co-location hosting and telecommunication usage services. The agreements require payments per month for a fixed period of time in exchange for certain guarantees of network and telecommunication availability. As of December 31, 2021, future minimum payments under these arrangements were as follows in thousands): Year Ending December 31, Hosting Services Telecommunication Usage Services 2022 $ 1,342 $ 7,151 2023 588 5,481 2024 226 3,532 2025 — 176 Thereafter $ — $ 75 Total future minimum payment $ 2,156 $ 16,415 Universal Services Fund Liability The Company is classified as a telecommunications service provider for regulatory purposes and is required to make contributions to the USF based on the revenue the Company receives from the resale of interstate and international telecommunications services. In order to comply with the obligation to make direct contributions, the Company is registered with the USAC, which is charged by the FCC with administering the USF, and has been remitting the required contributions to USAC since its registration with the USAC in April 2013. In June 2015, in connection with the Company’s late registration with the USAC and past failure to make USF contributions prior to 2013, the Company entered into a consent decree with the FCC Enforcement Bureau. In the consent decree, the Company agreed to pay a civil penalty of $2.0 million to the U.S. Treasury, which was paid in installments ending on December 31, 2018. The Company also agreed to make USF contributions of $3.9 million based on its revenues for the period from 2008 to 2012. The Company is still in dispute with the FCC regarding whether the Company is liable for USF contributions related to the period from 2003 through 2007. As of December 31, 2021, the Company had accrued $0.1 million in interest related to the disputed assessments for the period of 2003 through 2007. State and Local Taxes and Surcharges The Company, based on analysis of its activities, has determined that it is obligated to collect and remit U.S. state or local sales, use, gross receipts, excise and utility user taxes, as well as fees or surcharges as a communications service provider in certain U.S. states, municipalities or local tax jurisdictions. The Company is registered for, collecting and remitting applicable taxes where such a determination has been made. Prior to the Company’s making such determination, the Company neither collected nor remitted these taxes, fees or surcharges to applicable local, municipal or state jurisdictions. The Company continues to analyze its activities to determine if it is subject to these taxes in additional jurisdictions and based on the Company’s ongoing assessment of its U.S. state and local tax collection and remittance obligations, the Company registers for tax and regulatory purposes in such jurisdictions and commences collecting and remitting applicable state and local taxes and surcharges to these jurisdictions. As of December 31, 2021 and 2020, the Company had total accrued liabilities of $1.0 million and $1.1 million, respectively, for such contingent sales taxes and surcharges that were not being collected from its clients but may be imposed by various taxing authorities, of which $0.2 million and $0.2 million, respectively, were included in current “Sales tax liabilities” on the consolidated balance sheets, and the remaining were included in non-current “Sales tax liabilities” on the consolidated balance sheets. The Company’s estimate of the probable loss incurred under this contingency is based on its analysis of the source location of its usage-based fees and the regulations and rules in each tax jurisdiction. Legal Matters The Company is involved in various legal and regulatory matters arising in the normal course of business. In management’s opinion, resolution of these matters is not expected to have a material impact on the Company’s consolidated results of operations, cash flows, or its financial position. However, due to the uncertain nature of legal matters, an unfavorable resolution of a matter could materially affect the Company’s future consolidated results of operations, cash flows or financial position in a particular period. The Company expenses legal fees as incurred. Indemnification Agreements

Geographical Information

Geographical Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Geographical Information	Geographical Information The following table summarizes revenues by geographic region based on client billing address (in thousands): Year Ended December 31, 2021 2020 2019 United States $ 556,385 $ 400,509 $ 301,536 International 53,206 34,399 26,470 Total revenue $ 609,591 $ 434,908 $ 328,006 The following table summarizes total property and equipment, net in the respective locations (in thousands): December 31, 2021 2020 United States $ 68,674 $ 43,339 International 9,111 7,874 Property and equipment, net $ 77,785 $ 51,213

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans The Company has a 401(k) plan to provide tax deferred salary deductions for all eligible employees. Participants may make voluntary contributions to the 401(k) plan, limited by certain Internal Revenue Service restrictions. The Company is responsible for the administrative costs of the 401(k) plan. The Company began matching employee contributions in cash in the fourth quarter of 2019. The contribution expense for the year ended December 31, 2021 and 2020 was $1.8 million and $1.4 million, respectively. The Company complies with the requirement of maintaining a retirement plan for employees in the Philippines. This plan is a non-contributory and defined benefit type that provides retirement to employees equal to approximately one month salary for every year of credited service for employees who attain the normal retirement of age of 60 with at least five years of service. The benefits are paid in a lump sum amount upon retirement from the Company. Total defined benefit liability was $0.6 million as of each of December 31, 2021 and 2020. Total retirement expense for this plan was $0.2 million, $0.1 million, and $0.1 million for the years ended December 31, 2021, 2020, and 2019, respectively.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Leases The Company has leases for offices, data centers and computer and networking equipment that expire at various dates through 2031. The Company’s leases have remaining terms of one three The Company's Bishop Ranch Lease commenced on February 1, 2021, has a lease term of 10 years, and has a total commitment over its term of $46.4 million, which was the primary component of the increase in operating lease costs, operating lease right-of-use assets and operating lease liabilities for the year ended December 31, 2021. The components of lease expenses were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Operating lease cost $ 10,238 $ 6,142 $ 5,153 Finance lease cost: Amortization of right-of-use assets $ 438 $ 748 $ 6,345 Interest on finance lease liabilities — 212 704 Total finance lease cost $ 438 $ 960 $ 7,049 Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash used in operating leases $ (7,178) $ (6,531) $ (5,237) Financing cash used in finance leases (612) (3,715) (7,054) Right of use assets obtained in exchange for lease obligations: Operating leases 50,101 5,980 5,737 Finance leases — — — Supplemental balance sheet information related to leases was as follows (in thousands): December 31, 2021 2020 Operating leases Operating lease right-of-use assets $ 48,703 $ 9,010 Operating lease liabilities: $ 9,826 $ 3,912 Operating lease liabilities — less current portion 47,088 5,379 Total operating lease liabilities $ 56,914 $ 9,291 Finance leases Property and equipment, gross $ 42,541 $ 45,021 Less: accumulated depreciation and amortization (41,689) (41,908) Property and equipment, net $ 852 $ 3,113 Finance lease liabilities: Finance leases $ — $ 612 Finance lease liabilities — less current portion — — Total finance lease liabilities $ — $ 612 Weighted average remaining terms were as follows (in years): December 31, 2021 2020 Weighted average remaining lease term Operating leases 7.3 years 2.6 years Finance leases 0.0 years 0.5 years Weighted average discount rates were as follows: December 31, 2021 2020 Weighted average discount rate Operating leases 3.2 % 4.5 % Finance leases — % 7.9 % Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases 2022 $ 11,383 $ — 2023 10,633 — 2024 7,744 — 2025 5,583 — 2026 5,752 — Thereafter 22,858 Total future minimum lease payments 63,953 — Less: imputed interest (7,039) — Total $ 56,914 $ — As of December 31, 2021, the Company entered into an additional data center operating lease that had not yet commenced, representing a total commitment of $0.2 million with a one year term. This data center lease is expected to commence on March 1, 2022. The Company also entered into an additional facility operating lease that commenced in January 2022
Leases	Leases The Company has leases for offices, data centers and computer and networking equipment that expire at various dates through 2031. The Company’s leases have remaining terms of one three The Company's Bishop Ranch Lease commenced on February 1, 2021, has a lease term of 10 years, and has a total commitment over its term of $46.4 million, which was the primary component of the increase in operating lease costs, operating lease right-of-use assets and operating lease liabilities for the year ended December 31, 2021. The components of lease expenses were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Operating lease cost $ 10,238 $ 6,142 $ 5,153 Finance lease cost: Amortization of right-of-use assets $ 438 $ 748 $ 6,345 Interest on finance lease liabilities — 212 704 Total finance lease cost $ 438 $ 960 $ 7,049 Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash used in operating leases $ (7,178) $ (6,531) $ (5,237) Financing cash used in finance leases (612) (3,715) (7,054) Right of use assets obtained in exchange for lease obligations: Operating leases 50,101 5,980 5,737 Finance leases — — — Supplemental balance sheet information related to leases was as follows (in thousands): December 31, 2021 2020 Operating leases Operating lease right-of-use assets $ 48,703 $ 9,010 Operating lease liabilities: $ 9,826 $ 3,912 Operating lease liabilities — less current portion 47,088 5,379 Total operating lease liabilities $ 56,914 $ 9,291 Finance leases Property and equipment, gross $ 42,541 $ 45,021 Less: accumulated depreciation and amortization (41,689) (41,908) Property and equipment, net $ 852 $ 3,113 Finance lease liabilities: Finance leases $ — $ 612 Finance lease liabilities — less current portion — — Total finance lease liabilities $ — $ 612 Weighted average remaining terms were as follows (in years): December 31, 2021 2020 Weighted average remaining lease term Operating leases 7.3 years 2.6 years Finance leases 0.0 years 0.5 years Weighted average discount rates were as follows: December 31, 2021 2020 Weighted average discount rate Operating leases 3.2 % 4.5 % Finance leases — % 7.9 % Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases 2022 $ 11,383 $ — 2023 10,633 — 2024 7,744 — 2025 5,583 — 2026 5,752 — Thereafter 22,858 Total future minimum lease payments 63,953 — Less: imputed interest (7,039) — Total $ 56,914 $ — As of December 31, 2021, the Company entered into an additional data center operating lease that had not yet commenced, representing a total commitment of $0.2 million with a one year term. This data center lease is expected to commence on March 1, 2022. The Company also entered into an additional facility operating lease that commenced in January 2022

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions	Acquisitions Inference Solutions On November 18, 2020, the Company acquired all of the issued and outstanding shares of Inference for total consideration of approximately $156.7 million. The total consideration comprised of $137.0 million in cash, net of cash acquired, and $18.1 million in estimated fair value of contingent earn out consideration. The contingent earn out consideration is up to $24.0 million and is based upon achievement of certain milestones and relative thresholds during the earn out measurement period which ended on December 31, 2021. The range of amounts that the Company could pay under the contingent consideration arrangement is between $0.0 million and $24.0 million. The fair value of the contingent earn out consideration is estimated to be $23.7 million as of December 31, 2021. See Note 3 for additional information regarding the contingent consideration arrangement. This acquisition, which was accounted for as a business combination, is intended to accelerate the Company’s AI position through the addition of Inference’s widely deployed IVA platform. The excess of the purchase price over identifiable intangible assets and net tangible assets in the amount of $131.0 million was allocated to goodwill, which is not deductible for tax purposes. The fair values assigned to assets acquired and liabilities assumed are based on management’s best estimates and assumptions as of the reporting date and are considered final. The following table presents the final allocation of the purchase price at the acquisition date (in thousands): Cash $ 1,394 Property and equipment acquired 124 Other assets acquired 2,238 Acquired technology 28,600 Customer relationships 1,100 Trade name and trademarks 400 Goodwill 130,976 Total assets acquired 164,832 Liabilities assumed (3,525) Deferred tax liability (4,616) Total consideration $ 156,691 Total consideration (net of cash acquired) $ 155,297 The acquired technology, customer relationships, and trade name will be amortized on a straight-line basis over their assigned useful lives of six years, five years, and two years, respectively. The Company used the income approach to estimate the fair value of intangible assets acquired. In connection with this acquisition, the Company incurred approximately $0.3 million and $2.9 million of acquisition costs in 2021 and 2020, respectively, which have been expensed as incurred and included in general and administrative expense in the consolidated statements of operations and comprehensive loss. The results of operations of this acquisition are included in the accompanying consolidated statements of operations and comprehensive loss from the date of acquisition. Virtual Observer On April 1, 2020, the Company acquired all of the issued and outstanding shares of common stock of Virtual Observer, formerly Coordinated Systems, Inc., for cash consideration of approximately $32.2 million, subject to adjustment, pursuant to a stock purchase agreement by and among the Company and Robert H. Hutcheon, David R. Brower and Daniel J. McGrail, dated January 15, 2020. This acquisition, which was accounted for as a business combination, is intended to expand the Company's portfolio to include a cloud-based Workforce Optimization (“WFO”) offering as a complement to its ongoing strategic partnerships with leading WFO providers. The excess of the purchase price over identifiable intangible assets and net tangible assets in the amount of $22.6 million was allocated to goodwill, which is not deductible for tax purposes. The fair values assigned to assets acquired and liabilities assumed are based on management’s best estimates and assumptions as of the reporting date and are considered final. The following table presents the final allocation of the purchase price at the acquisition date (in thousands): Cash $ 168 Tangible assets acquired 200 Acquired technology 12,200 Customer relationships 500 Trade name and trademarks 100 Goodwill 22,646 Total assets acquired 35,814 Deferred tax liability (2,910) Liabilities assumed (682) Total $ 32,222 The acquired technology, customer relationships, and trade name and trademarks will be amortized on a straight-line basis over their estimated useful lives of five years, five years, and two years, respectively. The Company used the income approach to estimate the fair value of intangible assets acquired. In connection with this acquisition, the Company incurred total acquisition-related transaction costs of $0.9 million and $0.3 million in 2020 and 2019, respectively, that have been expensed as incurred and included in general and administrative expenses in the consolidated statements of operations and comprehensive loss.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) Selected quarterly financial information for 2021 and 2020 is as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands, except per share data) Revenue $ 173,599 $ 154,328 $ 143,782 $ 137,882 $ 127,885 $ 112,143 $ 99,792 $ 95,088 Cost of revenue (1)(2) 79,764 67,137 64,395 59,803 51,233 46,561 42,453 40,037 Gross profit 93,835 87,191 79,387 78,079 76,652 65,582 57,339 55,051 Operating expenses: Research and development (1)(2) 30,448 29,680 24,648 22,121 18,676 17,674 17,208 15,189 Sales and marketing (1)(2) 53,394 49,712 46,024 44,799 37,053 32,969 32,231 30,160 General and administrative (1)(2) 21,972 26,790 22,909 22,245 18,258 16,724 16,129 14,658 Total operating expenses 105,814 106,182 93,581 89,165 73,987 67,367 65,568 60,007 (Loss) income from operations (11,979) (18,991) (14,194) (11,086) 2,665 (1,785) (8,229) (4,956) Other (expense) income, net: Interest expense (2,024) (1,947) (2,118) (1,938) (9,481) (9,649) (5,734) (3,484) Loss on early extinguishment of debt — — — — (887) (282) (5,794) — Other (expense) and interest income (43) 213 (353) 175 501 631 829 1,072 Total other (expense) income, net (2,067) (1,734) (2,471) (1,763) (9,867) (9,300) (10,699) (2,412) Loss before income taxes (14,046) (20,725) (16,665) (12,849) (7,202) (11,085) (18,928) (7,368) (Benefit from) provision for income taxes (10,445) (188) (135) (517) 8 346 (2,876) 69 Net loss $ (3,601) $ (20,537) $ (16,530) $ (12,332) $ (7,210) $ (11,431) $ (16,052) $ (7,437) Net loss per share: Basic $ (0.05) $ (0.30) $ (0.25) $ (0.18) $ (0.11) $ (0.17) $ (0.25) $ (0.12) Diluted $ (0.05) $ (0.30) $ (0.25) $ (0.18) $ (0.11) $ (0.17) $ (0.25) $ (0.12) Shares used in computing net loss per share: Basic 68,207 67,800 67,292 66,721 66,133 65,460 63,282 61,705 Diluted 68,207 67,800 67,292 66,721 66,133 65,460 63,282 61,705 (1) Included stock-based compensation as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands) Cost of revenue $ 6,854 $ 3,994 $ 3,781 $ 3,105 $ 2,331 $ 2,603 $ 2,499 $ 1,989 Research and development 9,163 9,101 6,152 4,763 3,674 3,876 3,684 2,806 Sales and marketing 11,987 8,304 8,208 6,771 5,366 5,427 5,265 4,106 General and administrative 7,597 5,996 6,760 6,269 5,505 5,380 5,343 4,893 Total stock-based compensation $ 35,601 $ 27,395 $ 24,901 $ 20,908 $ 16,876 $ 17,286 $ 16,791 $ 13,794 (2) Included depreciation and amortization expenses as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands) Cost of revenue $ 8,301 $ 7,658 $ 7,825 $ 7,087 $ 5,948 $ 5,171 $ 5,120 $ 3,940 Research and development 948 1,004 729 596 488 512 497 465 Sales and marketing 1 1 1 1 2 1 2 2 General and administrative 1,288 1,117 1,096 1,079 899 853 624 563 Total depreciation and amortization $ 10,538 $ 9,780 $ 9,651 $ 8,763 $ 7,337 $ 6,537 $ 6,243 $ 4,970

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding annual financial reporting. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The significant estimates made by management affect revenue and related reserves, as well as the fair value of liabilities assumed through business combinations. Management periodically evaluates such estimates and they are adjusted prospectively based upon such periodic evaluation. Actual results could differ from those estimates.
Foreign Currency	Foreign Currency The functional currency of the Company’s foreign subsidiaries is the U.S. dollar. For these subsidiaries, the monetary assets and liabilities are re-measured into U.S. dollars at the current exchange rate as of the balance sheet date, and all non-monetary assets and liabilities are re-measured into U.S. dollars at historical exchange rates. Revenues are primarily denominated in U.S. dollars. Expenses are converted using average rates in effect on a monthly basis. Exchange gains and losses resulting from foreign currency transactions were not significant in any period and are reported in “Other (expense) income, net” in the consolidated statements of operations and comprehensive loss.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company’s cash and cash equivalents consist of highly liquid investments with maturities of three months or less at the time of purchase. The Company’s cash equivalents consist of investments in money market funds, U.S. treasury securities, U.S. agency securities and commercial paper.
Marketable Investments	Marketable Investments The Company’s marketable investments consist of U.S. agency securities and government sponsored securities, U.S. treasury securities, certificates of deposit, municipal bonds, corporate bonds and commercial paper. The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Marketable investments are carried at fair value.
Concentration Risks	Concentration RisksFinancial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and cash equivalents, marketable investments and accounts receivable. A significant portion of the Company’s cash and cash equivalents is held at three large reputable financial institutions.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company uses an expected credit loss model, which requires it to consider historical loss rates and expectations of forward-looking losses to estimate its allowance for doubtful accounts on its trade accounts receivables, unbilled accounts receivables and contract assets.
Property and Equipment, Net	Property and Equipment, Net Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Category Estimated Useful Lives Computer and network equipment 3 to 5 years Computer software 3 years Development costs 1 to 5 years Furniture and fixtures 7 years Leasehold improvements Shorter of useful life or lease term Maintenance and repairs are charged to expense as incurred, and improvements and betterments are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation and amortization are removed from the consolidated balance sheet and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss in the period realized. The Company evaluates the recoverability of property and equipment for possible impairment whenever events or circumstances indicate that the carrying amount of such assets or asset groups may not be recoverable.
Business Combinations	Business Combinations The Company uses its best estimates and assumptions to assign fair value to the tangible and intangible assets acquired and liabilities assumed as of the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value to these tangible and intangible assets and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially established in connection with a business combination as of the acquisition date. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to its consolidated statements of operations and comprehensive loss.
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Company records goodwill when the consideration paid in a business combination exceeds the fair value of the net tangible assets and the identified intangible assets acquired. Goodwill is not amortized, but instead is required to be tested for impairment annually and whenever events or changes in circumstances indicate that the carrying value of goodwill may exceed its fair value. The Company performs testing for impairment of goodwill in its fourth quarter, or as events occur or circumstances change that would more likely than not reduce the fair value of the Company’s single reporting unit below its carrying amount. A qualitative assessment is first made to determine whether it is necessary to perform the quantitative goodwill impairment test. This initial qualitative assessment includes, among other things, consideration of: (i) market capitalization of the Company; (ii) past, current and projected future earnings and equity; (iii) recent trends and market conditions; and (iv) valuation metrics involving similar companies that are publicly-traded and acquisitions of similar companies, if available. If this initial qualitative assessment indicates that it is more likely than not that impairment exists, a second quantitative assessment will be performed, involving a comparison between the estimated fair values of the Company’s single reporting unit with its respective carrying amount including goodwill. If the carrying value exceeds estimated fair value, an impairment charge is recorded for the excess. three
Revenue Recognition	Revenue Recognition Revenue is recognized when control of the promised services is transferred to customers in an amount that reflects the consideration that the Company expects to receive in exchange for those services. The Company generates all of its revenue from contracts with customers. In contracts with multiple performance obligations, it identifies each performance obligation and evaluates whether the performance obligations are distinct within the context of the contract at contract inception. Performance obligations that are not distinct at contract inception are combined. The Company allocates the transaction price to each distinct performance obligation proportionately based on the estimated standalone selling price for each performance obligation. The Company then looks to how services are transferred to the customer in order to determine the timing of revenue recognition. Most services provided under the Company’s agreements result in the transfer of control over time. The Company’s revenue consists of subscription services and related usage as well as professional services. The Company charges clients subscription fees, usually billed on a monthly basis, for access to the Company’s VCC solution. The subscription fees are primarily based on the number of agent seats, as well as the specific VCC functionalities and applications deployed by the client. Agent seats are defined as the maximum number of named agents allowed to concurrently access the VCC cloud platform. Clients typically have more named agents than agent seats. Multiple named agents may use an agent seat, though not simultaneously. Substantially all of the Company’s clients purchase both subscriptions and related telephony usage. A small percentage of the Company’s clients subscribe to its platform but purchase telephony usage directly from a wholesale telecommunications service provider. The Company does not sell telephony usage on a stand-alone basis to any client. The related usage fees are generally based on the volume of minutes used for inbound and outbound client interactions. Revenue generated from telephony usage is presented in revenue and cost of sales on a gross basis, as the Company is the party that controls the service and is responsible for fulfilling the promise to provide the call service by diverting the calls to selected carriers. The Company also offers bundled plans, generally for smaller deployments, whereby the client is charged a single monthly fixed fee per agent seat that includes both subscription and unlimited usage in the contiguous 48 states and, in some cases, Canada. Professional services revenue is derived primarily from VCC implementations, including application configuration, system integration, optimization, education and training services. Clients are not permitted to take possession of the Company’s software. The Company offers monthly, annual and multiple-year contracts to its clients, generally with 30 days’ notice required for reductions in the number of agent seats. Increases in the number of agent seats can be provisioned almost immediately. The Company’s clients, therefore, are able to adjust the number of agent seats used to meet their changing contact center needs. The Company’s larger clients typically choose annual contracts, which generally include an implementation and ramp period of several months. Fixed subscription fees, including bundled plans, are generally billed monthly in advance, while related usage fees are billed in arrears. Support activities include technical assistance for the Company’s solution and upgrades and enhancements to the VCC cloud platform on a when-and-if-available basis, which are not billed separately. The Company generally requires advance deposits from its clients based on estimated usage when such usage is not billed as part of a bundled plan. Any unused portion of the deposit is refundable to the client upon termination of the arrangement, provided all amounts due have been paid. All fees, except usage deposits, are non-refundable. Professional services are primarily billed on a fixed-fee basis. Revenue for professional services is recognized over time, as services are performed. The estimation of variable consideration for each performance obligation requires the Company to make subjective judgments resulting in estimated variable consideration that is included in the transaction fee. This is done to the extent that it is probable, in the Company’s judgment, that a significant reversal in the amount of cumulative revenue recognized under the contract will not occur. The Company estimates the variable consideration in order to allocate the overall transaction fee on a relative stand-alone selling price basis to its multiple performance obligations. When services are included in the contract with the customer and are not sold at their stand-alone selling price, the Company is required to estimate the number of seats the customer will use, especially during the initial ramp period of the contract, during which the Company bills under an ‘actual usage’ model for subscription-related services. The Company recognizes revenue on fixed fee professional services performance obligations based on the proportion of labor hours expended compared to the total hours expected to complete the related performance obligation. The determination of the total labor hours expected to complete the performance obligations involves judgment, which influences the initial stand-alone selling price estimate as well as the timing of professional services revenue recognition, although this is typically resolved in a short time frame. When a contract with a customer is signed, the Company assesses whether collection of the fees under the arrangement is probable. The Company assesses collection based on a number of factors, including past transaction history and the creditworthiness of the client. The Company maintains a revenue reserve for potential credits to be issued in accordance with service level agreements or for other revenue adjustments. Deferred Revenue Deferred revenue consists of billings or payments received from clients for subscription service, usage and professional services in advance of revenue recognition and is recognized in accordance with the Company’s revenue recognition policy discussed above. The Company generally invoices its clients monthly in advance for subscription services. Accordingly, the deferred revenue balance does not represent the total contract value of sales arrangements.
Research and Development	Research and DevelopmentResearch and development expenses consist primarily of salary and related expenses, including stock-based compensation, for personnel related to the development of improvements and expanded features for the Company’s services, as well as quality assurance, testing, product management and allocated overhead. Research and development costs are expensed as incurred except for internal use software development costs that qualify for capitalization. The Company reviews development costs incurred for internal-use software in the application development stage and assesses costs for capitalization.
Advertising Costs	Advertising CostsThe Company primarily advertises its services through the internet and in conjunction with partners. Advertising costs are expensed as incurred
Commissions	CommissionsCommissions consist of variable compensation earned by sales personnel and referral fees the Company pays to third parties. The Company defers all incremental commission costs to obtain the contract, and amortizes these costs over a period of benefit determined to be five years.
Stock-Based Compensation	Stock-Based Compensation All stock-based compensation granted to employees and non-employee directors is measured at the grant date fair value of the award. The Company estimates the fair value of stock options and purchase rights under the Company’s Equity Incentive Plans and the 2014 Employee Stock Purchase Plan (“2014 ESPP Plan” or “ESPP”), respectively, using the Black-Scholes option-pricing model. The fair value of restricted stock awards is equal to the fair value of the Company’s common stock on the date of grant. Compensation expense is recognized net of actual forfeitures using the straight-line method over the service period, which is generally the vesting period.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in operations in the period that includes the enactment date. The Company records a valuation allowance to reduce its deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. As of December 31, 2021, and 2020, the Company recorded a full valuation allowance against the U.S. net deferred tax assets because of its history of operating losses in the United States. As of December 31, 2021 and 2020, the Company recognized a net deferred tax asset balance of $6.9 million and deferred tax liabilities of $4.4 million, respectively, related to its operations in the UK and Australia. The Company classifies interest and penalties on unrecognized tax benefits as income tax expense.
Comprehensive loss	Comprehensive loss Comprehensive loss consists of net loss, unrealized gains or losses on available-for-sale marketable investments, and the effects of foreign currency translation adjustments. The Company presents comprehensive loss
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock outstanding during the period, and excludes any dilutive effects of employee stock-based awards and potential shares issuable upon conversion of the convertible senior notes. Diluted net loss per share is computed giving effect to all potentially dilutive shares of common stock, including common stock issuable upon exercise of stock options, vesting of restricted stock units and shares of common stock issuable upon conversion of convertible senior notes. In periods of net loss, all potentially issuable shares of common stock are excluded from the diluted net loss per share computation because they are anti-dilutive. Therefore, basic and diluted net loss per share are the same for all years presented in the Company’s consolidated statements of operations and comprehensive loss.
Indemnification	IndemnificationThe Company, in the ordinary course of business, enters into agreements of varying scope and terms pursuant to which it agrees to indemnify clients, vendors, lessors, business partners and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, including breach of security, services to be provided by the Company or from intellectual property infringement claims made by third parties.
Segment Information	Segment Information The Company has determined that its Chief Executive Officer is its chief operating decision maker. The Company’s Chief Executive Officer reviews financial information presented on a consolidated basis for purposes of assessing performance and making decisions on how to allocate resources. Accordingly, the Company has determined that it operates in a single reportable segment.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Effective	Recently Adopted Accounting Pronouncements In August 2020, the FASB issued ASU No. 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 ("ASU 2020-06"), which simplifies the accounting for convertible instruments by removing the separation models for (1) convertible debt with a cash conversion feature and (2) convertible instruments with a beneficial conversion feature. The Company elected to early adopt ASU 2020-06 as of January 1, 2021 using a modified retrospective transition method. Applying the transition guidance, the Company was required to apply the guidance to all impacted financial instruments that were outstanding as of January 1, 2021 with the cumulative effect recognized as an adjustment to the opening balance of accumulated deficit. As a result of early adopting ASU 2020-06, the Company made certain adjustments to its accounting for the outstanding 0.125% convertible senior notes due 2023 (the "2023 convertible senior notes") and the outstanding 0.500% convertible senior notes due 2025 (the "2025 convertible senior notes", and, together with the 2023 convertible senior notes, the "convertible senior notes"). The adoption of ASU 2020-06 resulted in the re-combination of the liability and equity components of the convertible senior notes into a single liability instrument, which required the Company to record a $168.4 million decrease in additional paid in capital from the derecognition of the separated equity components of these convertible senior notes, a $145.7 million increase in debt from the derecognition of the discount associated with the separated equity components of the convertible senior notes, and a $22.7 million cumulative effect decrease to the opening balance of its accumulated deficit as of January 1, 2021 upon transition. Interest expense recognized in future periods will be reduced as a result of accounting for the convertible senior notes as a single liability instrument. Since the Company had a net loss for the year ended December 31, 2021, the convertible senior notes were determined to be anti-dilutive and therefore had no impact to basic or diluted net loss per share for fiscal 2021 as a result of adopting ASU 2020-06. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which amends its guidance to simplify the accounting for income taxes by, among other things, removing exceptions to certain general principles in Topic 740, Income Taxes. The standard was effective for the Company beginning in the first quarter of 2021. The Company adopted ASU 2019-12 and concluded that the impact on its consolidated financial statements was immaterial. Recent Accounting Pronouncements Not Yet Effective The Company has reviewed, or is in the process of evaluating, all issued, but not yet effective, accounting pronouncements and does not believe the future adoption of any such accounting pronouncements will cause a material impact on its consolidated financial position, operating results or statements of cash flows.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of allowance for doubtful accounts	The following table presents the changes in the allowance for doubtful accounts (in thousands): Year Ended December 31, 2021 2020 Balance, beginning of period $ 127 $ 11 Add: bad debt expense 808 754 Less: write-offs, net of recoveries (715) (638) Balance, end of period $ 220 $ 127
Schedule of estimated useful lives	Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows: Asset Category Estimated Useful Lives Computer and network equipment 3 to 5 years Computer software 3 years Development costs 1 to 5 years Furniture and fixtures 7 years Leasehold improvements Shorter of useful life or lease term

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Contract with customer, asset and liability	The following table provides information about accounts receivable, net, deferred contract acquisition costs, net, contract assets and contract liabilities from contracts with customers (in thousands): December 31, 2021 December 31, 2020 Accounts receivable, net $ 83,731 $ 48,731 Deferred contract acquisition costs, net: Current $ 33,295 $ 20,695 Non-current 84,663 51,934 Total deferred contract acquisition costs, net $ 117,958 $ 72,629 Contract assets and contract liabilities: Contract assets (included in prepaid expenses and other current assets) $ 2,593 $ 1,297 Contract liabilities (deferred revenue) 43,720 31,983 Noncurrent contract liabilities (deferred revenue) (included in other long term liabilities) 2,097 3,373 Net contract liabilities $ (43,224) $ (34,059)

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of marketable investments	The Company’s marketable investments have been classified and accounted for as available-for-sale. The Company’s marketable investments as of December 31, 2021 and 2020 were as follows (in thousands): December 31, 2021 Short-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 1,615 $ — $ — $ 1,615 U.S. treasury 83,237 — (24) 83,213 U.S. agency securities 159,070 — (65) 159,005 Commercial paper 47,555 — — 47,555 Municipal bonds 75,337 — (96) 75,241 Corporate bonds 12,355 2 (6) 12,351 Total $ 379,169 $ 2 $ (191) $ 378,980 December 31, 2021 Long-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 746 $ — $ (2) $ 744 U.S. treasury 63,566 — (251) 63,315 U.S. agency securities 63,960 — (254) 63,706 Municipal bonds 18,655 — (64) 18,591 Corporate bonds 1,026 — (5) 1,021 Total $ 147,953 $ — $ (576) $ 147,377 December 31, 2020 Short-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Certificates of deposit $ 3,479 $ 1 $ — $ 3,480 U.S. treasury 287,315 41 (4) 287,352 U.S. agency securities 67,227 12 (6) 67,233 Commercial paper 5,093 — — 5,093 Municipal bonds 2,684 1 (1) 2,684 Corporate bonds 17,323 6 — 17,329 Total $ 383,121 $ 61 $ (11) $ 383,171 December 31, 2020 Long-Term Marketable Investments Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury $ 10,189 $ — $ — $ 10,189 U.S. agency securities 31,469 9 (1) 31,477 Municipal bonds 461 — — 461 Total $ 42,119 $ 9 $ (1) $ 42,127
Schedule of gross unrealized losses and fair value of marketable investments	The following table presents the gross unrealized losses and the fair value for those marketable investments that were in an unrealized loss position for less than 12 months as of December 31, 2021 and 2020 (in thousands): December 31, 2021 December 31, 2020 Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Certificates of deposit (2) 2,010 — — U.S. treasury (275) 140,527 (4) 78,549 U.S. agency securities (320) 222,710 (7) 39,443 Municipal bonds (160) 87,184 (1) 1,201 Corporate bonds (10) 9,428 (1) 1,347 Total $ (767) $ 461,859 $ (13) $ 120,540
Schedule of marketable investments by contractual maturity	The amortized cost and fair values of the Company’s marketable investments by contractual maturity as of December 31, 2021 and 2020 were as follows (in thousands): December 31, 2021 December 31, 2020 Cost Fair Value Cost Fair Value Due within one year $ 379,169 $ 378,980 $ 383,121 $ 383,171 Due after one year 147,953 147,377 42,119 42,127 Total $ 527,122 $ 526,357 $ 425,240 $ 425,298
Schedule of assets carried at fair value	The following tables set forth the Company’s assets measured at fair value by level within the fair value hierarchy (in thousands): December 31, 2021 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 31,380 $ — $ — $ 31,380 Certificates of deposit — 747 — 747 Total cash equivalents $ 31,380 $ 747 $ — $ 32,127 Marketable investments (short and long-term) Certificates of deposit $ — $ 2,359 $ — $ 2,359 U.S. Treasury 146,528 — — 146,528 U.S. agency and government sponsored securities — 222,711 — 222,711 Commercial paper — 47,555 — 47,555 Municipal bonds — 93,832 — 93,832 Corporate bonds — 13,372 — 13,372 Total marketable investments $ 146,528 $ 379,829 $ — $ 526,357 Liabilities Contingent consideration $ — $ — $ 23,740 $ 23,740 December 31, 2020 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 89,888 $ — $ — $ 89,888 U.S. Treasury 39,997 — — 39,997 Total cash equivalents $ 129,885 $ — $ — $ 129,885 Marketable investments (short and long-term) Certificates of deposit $ — $ 3,480 $ — $ 3,480 U.S. Treasury 297,540 — — 297,540 U.S. agency securities — 98,711 — 98,711 Commercial paper — 5,093 — 5,093 Municipal bonds — 3,145 — 3,145 Corporate bonds — 17,329 — 17,329 Total marketable investments $ 297,540 $ 127,758 $ — $ 425,298 Liabilities Contingent consideration $ — $ — $ 18,100 $ 18,100
Summary of the Changes for Contingent Consideration Liabilities	A reconciliation of the beginning and ending balance for contingent consideration consisted of the following (in thousands): Year Ended December 31, 2021 Balance, December 31. 2020 $ 18,100 Change in fair value of contingent consideration 5,640 Balance, December 31, 2021 $ 23,740

Financial Statement Components

Financial Statement Components (Tables)	12 Months Ended
	Dec. 31, 2021
Financial Statement Components [Abstract]
Schedule of cash and cash equivalents	Cash and cash equivalents consisted of the following (in thousands): December 31, 2021 2020 Cash $ 58,751 $ 90,487 Certificates of deposit 747 — Money market funds 31,380 89,888 U.S. Treasury — 39,997 Total cash and cash equivalents $ 90,878 $ 220,372
Schedule of accounts receivable	Accounts receivable, net consisted of the following (in thousands): December 31, 2021 2020 Trade accounts receivable $ 75,970 $ 42,366 Unbilled trade accounts receivable, net of advance client deposits 7,981 6,492 Allowance for doubtful accounts (220) (127) Accounts receivable, net $ 83,731 $ 48,731
Schedule of prepaid expenses and other current assets	Prepaid expenses and other current assets consisted of the following (in thousands): December 31, 2021 2020 Prepaid expenses $ 21,306 $ 9,816 Other current assets 6,443 5,036 Contract assets 2,593 1,297 Prepaid expenses and other current assets $ 30,342 $ 16,149
Schedule of useful lives of property and equipment	Property and equipment, net consisted of the following (in thousands): December 31, 2021 2020 Computer and network equipment $ 116,701 $ 89,763 Computer software 44,268 25,888 Internal-use software development costs 500 500 Furniture and fixtures 3,953 3,372 Leasehold improvements 5,914 2,335 Property and equipment 171,336 121,858 Accumulated depreciation and amortization (93,551) (70,645) Property and equipment, net $ 77,785 $ 51,213
Schedule of property and equipment capitalized under finance lease obligations	Property and equipment capitalized under finance lease obligations consists primarily of computer and network equipment and was as follows (in thousands): December 31, 2021 2020 Gross $ 42,541 $ 45,021 Less: accumulated depreciation and amortization (41,689) (41,908) Total $ 852 $ 3,113
Schedule of other assets	Other assets consisted of the following (in thousands): December 31, 2021 2020 Other assets $ 4,964 $ 3,236 Deferred tax assets 6,907 — Total $ 11,871 $ 3,236
Schedule of accrued and other current liabilities	Accrued and other current liabilities consisted of the following (in thousands): December 31, 2021 2020 Accrued expenses $ 20,108 $ 15,217 Accrued compensation and benefits 34,729 29,233 Contingent consideration 23,740 — Accrued and other current liabilities $ 78,577 $ 44,450
Schedule of long-term liabilities	Other long-term liabilities consisted of the following (in thousands): December 31, 2021 2020 Deferred revenue $ 2,097 $ 3,373 Deferred tax liabilities — 4,438 Other long-term liabilities 5,574 5,554 Contingent consideration — 18,100 Other long-term liabilities $ 7,671 $ 31,465

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill activity	The following table summarizes the activity in the Company's goodwill balances during the years ended December 31, 2021 and 2020 (in thousands): Goodwill Beginning of the period, January 1, 2020 $ 11,798 Addition (Inference) 130,976 Addition (Virtual Observer) 22,646 End of the period, December 31, 2020 165,420 Addition — End of the period, December 31, 2021 $ 165,420
Intangible assets activity	The following table summarizes the activity in the Company's intangible asset balances during the years ended December 31, 2021 and 2020 (in thousands): Intangible Assets Beginning of the period, January 1, 2020 $ 15,533 Addition (Inference) 30,100 Addition (Virtual Observer) 12,800 Addition (Whendu) 100 Amortization (6,849) End of the period, December 31, 2020 51,684 Amortization (11,787) End of the period, December 31, 2021 $ 39,897
Schedule of intangible assets	The components of intangible assets were as follows (in thousands): December 31, 2021 December 31, 2020 Gross Carrying Amount Accumulated Net Weighted Average Remaining Amortization Period (Years) Gross Accumulated Net Weighted Average Remaining Amortization Period (Years) Developed technology $ 56,214 $ (17,821) $ 38,393 4.0 $ 56,214 $ (6,761) $ 49,453 4.9 Acquired workforce 470 (334) 136 0.9 470 (177) 293 1.9 Customer relationships 1,600 (421) 1,179 3.7 1,600 (101) 1,499 4.7 Trademarks 500 (311) 189 0.9 500 (61) 439 1.8 Total $ 58,784 $ (18,887) $ 39,897 4.0 $ 58,784 $ (7,100) $ 51,684 4.9
Schedule of expected future amortization expense of intangible assets	As of December 31, 2021, the expected future amortization expense for intangible assets was as follows (in thousands): Period Expected Future 2022 $ 11,705 2023 10,870 2024 7,527 2025 5,595 2026 4,200 Thereafter — Total $ 39,897

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2021
Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Schedule of Net Carrying Amount of Notes and Impact to Additional Paid-in Capital	The net carrying amount of the 2025 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Principal $ 747,500 $ 747,500 Unamortized debt discount — (141,792) Unamortized issuance costs (12,835) (13,192) Net carrying amount $ 734,665 $ 592,516 The net carrying amount of the equity component of the 2025 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Equity component $ — $ 158,321 Issuance costs — (3,958) Net carrying amount $ — $ 154,363
Schedule of Interest Expense Related to the Notes	Interest expense related to the 2025 convertible senior notes was as follows (in thousands): Year Ended December 31, 2021 December 31, 2020 Contractual interest expense $ 4,007 $ 2,230 Amortization of debt discount — 16,528 Amortization of issuance costs 3,674 1,538 Total interest expense $ 7,681 $ 20,296
Schedule of Maturities of Debt	Maturity of the Company’s 2025 convertible senior notes as of December 31, 2021 was as follows (in thousands): Period Amount to Mature 2025 (Maturity date of June 1, 2025) $ 747,500 Total $ 747,500
Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Schedule of Net Carrying Amount of Notes and Impact to Additional Paid-in Capital	The net carrying amount of the 2023 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Principal $ 34,225 $ 58,867 Unamortized debt discount — (7,367) Unamortized issuance costs (291) (700) Net carrying amount $ 33,934 $ 50,800 The net carrying amount of the equity component of the 2023 convertible senior notes as of December 31, 2021 (post-ASU 2020-06 adoption) and as of December 31, 2020 (pre-ASU 2020-06 adoption) was as follows (in thousands): December 31, 2021 December 31, 2020 Equity component $ — $ 14,505 Issuance costs — (455) Net carrying amount $ — $ 14,050
Schedule of Interest Expense Related to the Notes	Interest expense related to the 2023 convertible senior notes was as follows (in thousands): Year Ended December 31, 2021 December 31, 2020 December 31, 2018 Contractual interest expense $ 42 $ 184 $ 324 Amortization of debt discount — 7,006 11,683 Amortization of issuance costs 283 666 1,105 Total interest expense $ 325 $ 7,856 $ 13,112
Schedule of Maturities of Debt	Maturity of the Company’s 2023 convertible senior notes as of December 31, 2021 was as follows (in thousands): Period Amount to Mature 2023 (Maturity date of May 1, 2023) $ 34,225 Total $ 34,225

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of common stock reserved for future issuance	Shares of common stock reserved for future issuance related to outstanding equity awards and employee equity incentive plans as of December 31, 2021, were as follows (in thousands): Common Stock Reserved Stock options outstanding 1,982 Restricted stock units outstanding 2,560 Shares available for future grant under 2014 Plan 13,379 Shares available for future issuance under ESPP 3,076 Total shares of common stock reserved 20,997
Schedule of stock option activities	A summary of the Company’s stock option activity during the year ended December 31, 2021 is as follows (in thousands, except years and per share data): Number of Shares Weighted Weighted Aggregate Intrinsic Value (1) Outstanding as of December 31, 2020 2,255 $ 26.33 Options granted 156 180.75 Options exercised (389) 19.03 Options forfeited or expired (40) 80.47 Outstanding as of December 31, 2021 1,982 38.65 4.9 $ 202,425 Vested and expected to vest as of December 31, 2021 1,982 38.65 4.9 202,425 Exercisable as of December 31, 2021 1,544 22.02 4.0 179,180 (1) The aggregate intrinsic value amounts are computed based on the difference between the exercise price of the stock options and the fair market value of the Company’s common stock of $137.32 per share as of December 31, 2021 for all in-the-money stock options outstanding. Following is additional information pertaining to the Company’s stock option activity (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Weighted average grant date fair value per share of options granted, excluding assumed stock options $ 78.72 $ 38.80 $ 24.06 Weighted average grant date fair value per share of assumed stock options — 125.96 — Intrinsic value of options exercised (1) 59,762 47,529 42,204 Total fair value of options vested during the period 12,760 7,846 5,342 Cash received from options exercised 7,402 11,656 7,705 (1) Intrinsic value of options exercised is the difference between the fair market value of the Company’s common stock at the time of exercise and the exercise price paid.
Schedule of RSU activities	A summary of RSU activity during the year ended December 31, 2021 is as follows (in thousands, except years and per share data): Number of Shares Weighted Average Grant Date Fair Value Per Share Outstanding as of December 31, 2020 2,267 $ 65.42 RSUs granted 2,234 177.00 RSUs vested and released (1,097) 69.06 RSUs forfeited or cancelled (844) 170.59 Outstanding as of December 31, 2021 2,560 125.65 During the third quarter of 2021, the Company granted 0.7 million RSU awards conditional upon the close of the Merger. The Company cancelled these grants on September 30, 2021, the termination date of the Merger. In October 2021, the Company subsequently granted 0.7 million RSU awards to its employees. Following is additional information pertaining to the Company’s RSU activity (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Weighted average grant date fair value per share of RSUs granted $ 177.00 $ 86.15 $ 53.33 Total fair value of RSUs vested during the period 174,500 136,805 68,072
Schedule of stock-based compensation expense	Stock-based compensation expenses for the years ended December 31, 2021, 2020 and 2019 were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Cost of revenue $ 17,734 $ 9,422 $ 6,334 Research and development 29,179 14,043 7,658 Sales and marketing 35,269 20,164 11,368 General and administrative 26,623 21,118 16,705 Total stock-based compensation $ 108,805 $ 64,747 $ 42,065
Schedule of unrecognized compensation expense	As of December 31, 2021, unrecognized stock-based compensation expense by award type and their expected weighted-average recognition periods are summarized in the following table (in thousands, except years). Stock Option RSU ESPP Unrecognized stock-based compensation expense $ 21,723 $ 297,934 $ 2,604 Weighted-average amortization period 2.5 years 2.5 years 0.4 years
Schedule of valuation assumptions, stock option	The weighted average assumptions used to value stock options and purchase rights under the 2014 ESPP granted during the years ended December 31, 2021, 2020 and 2019 were as follows: Stock Options Year Ended December 31, 2021 2020 (1) 2019 Expected term (years) 6.0 5.7 6.1 Volatility 47% 47% 46% Risk-free interest rate 1.0% 0.9% 2.3% Dividend yield — — —
Schedule of valuation assumptions for stock option purchase plan	ESPP Granted In November 2021 May 2021 November 2020 May 2020 November 2019 May 2019 Expected term (years) 0.5 0.5 0.5 0.5 0.5 0.5 Volatility 46% 49% 50% 50% 46% 51% Risk-free interest rate 0.2% 0.1% 0.1% 0.2% 2.4% 2.5% Dividend yield — — — — — —

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of basic and diluted net loss per share	The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Net loss $ (53,000) $ (42,130) $ (4,552) Weighted-average shares used in computing basic and diluted net loss per share 67,512 64,154 60,371 Basic and diluted net loss per share $ (0.79) $ (0.66) $ (0.08)
Schedule of securities excluded from calculation of diluted net loss per share	The following securities were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive (in thousands): December 31, 2021 2020 2019 Stock options 1,982 2,255 2,530 Restricted stock units 2,560 2,267 2,372 Convertible senior notes (1) 6,663 910 1,619 Total 11,205 5,432 6,521

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of components of loss before income taxes	The following table presents components of loss before income taxes for the periods presented (in thousands): Year Ended December 31, 2021 2020 2019 United States $ (59,856) $ (44,303) $ (5,340) International (4,429) (280) 892 Loss before income taxes $ (64,285) $ (44,583) $ (4,448)
Schedule of components of provision for income taxes	Provision for (benefit from) income taxes for the periods presented consisted of (in thousands): Year Ended December 31, 2021 2020 2019 Current: U.S. federal $ — $ — $ — U.S. state 262 401 61 Foreign (202) 233 43 Total provision for income taxes - Current 60 634 104 Deferred: U.S. federal — (2,495) — U.S. state — (414) — Foreign (11,345) (178) — Total (benefit from) income taxes - Deferred (11,345) (3,087) — Total (benefit from) provision for income taxes $ (11,285) $ (2,453) $ 104
Schedule of effective income tax reconciliation	Income tax (benefit) expense differed from the amount computed by applying the U.S. federal statutory income tax rate of 21% to pre-tax (loss) income for the periods presented as a result of the following (in thousands): Year Ended December 31, 2021 2020 2019 U.S. federal tax at statutory rate $ (13,500) $ (9,362) $ (934) U.S. state income taxes 262 (345) (65) Section 162(m) 7,543 6,472 5,623 Non-deductible expenses 1,361 1,944 276 Research and development credit (1,181) (837) (860) Stock-based compensation (25,241) (23,800) (16,619) Tax benefit from acquisition/reorganizations (5,877) (2,495) — Foreign taxes (4,760) 118 (10) Other 20 533 (119) Change in valuation allowance 30,088 25,319 12,812 Total (benefit from) provision for income taxes $ (11,285) $ (2,453) $ 104
Schedule of deferred tax assets and liabilities	The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities as of December 31, 2021 and 2020 related to the following (in thousands): December 31, 2021 2020 Deferred tax assets: Net operating loss and credit carryforwards $ 133,433 $ 95,180 Accrued liabilities 12,719 6,244 Allowance for doubtful accounts 712 766 Amortized intangibles 872 — Deferred revenue 1,351 782 Accrued compensation 3,963 3,596 Long-term lease liabilities 13,618 1,418 Gross deferred tax assets 166,668 107,986 Valuation allowance (121,835) (51,127) Net deferred tax assets 44,833 56,859 Deferred tax liabilities: Property and equipment (2,633) (876) Amortized intangibles — (11,041) Other (509) (92) Right of use assets (11,573) (1,276) Deferred compensation - Current (23,211) (12,180) Convertible senior notes — (35,832) Gross deferred tax liabilities (37,926) (61,297) Net deferred taxes $ 6,907 $ (4,438)
Schedule of unrecognized tax benefits rollforward	The table below shows the changes in the gross amount of unrecognized tax benefits for the periods presented (in thousands): Year Ended December 31, 2021 2020 2019 Unrecognized benefit — beginning of period $ 6,076 $ 4,471 $ 10,723 Gross increases — current year tax positions 1,851 1,605 963 Gross decreases — prior year tax positions — — (7,215) Settlements with tax authorities (284) — — Unrecognized benefit — end of period $ 7,643 $ 6,076 $ 4,471

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments for hosting, telecommunication usage, and maintenance services	As of December 31, 2021, future minimum payments under these arrangements were as follows in thousands): Year Ending December 31, Hosting Services Telecommunication Usage Services 2022 $ 1,342 $ 7,151 2023 588 5,481 2024 226 3,532 2025 — 176 Thereafter $ — $ 75 Total future minimum payment $ 2,156 $ 16,415

Geographical Information (Table

Geographical Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of revenues and property and equipment by geographic region	The following table summarizes revenues by geographic region based on client billing address (in thousands): Year Ended December 31, 2021 2020 2019 United States $ 556,385 $ 400,509 $ 301,536 International 53,206 34,399 26,470 Total revenue $ 609,591 $ 434,908 $ 328,006 The following table summarizes total property and equipment, net in the respective locations (in thousands): December 31, 2021 2020 United States $ 68,674 $ 43,339 International 9,111 7,874 Property and equipment, net $ 77,785 $ 51,213

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Schedule of lease obligations	The components of lease expenses were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Operating lease cost $ 10,238 $ 6,142 $ 5,153 Finance lease cost: Amortization of right-of-use assets $ 438 $ 748 $ 6,345 Interest on finance lease liabilities — 212 704 Total finance lease cost $ 438 $ 960 $ 7,049 Supplemental cash flow information related to leases was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash used in operating leases $ (7,178) $ (6,531) $ (5,237) Financing cash used in finance leases (612) (3,715) (7,054) Right of use assets obtained in exchange for lease obligations: Operating leases 50,101 5,980 5,737 Finance leases — — — Weighted average remaining terms were as follows (in years): December 31, 2021 2020 Weighted average remaining lease term Operating leases 7.3 years 2.6 years Finance leases 0.0 years 0.5 years Weighted average discount rates were as follows: December 31, 2021 2020 Weighted average discount rate Operating leases 3.2 % 4.5 % Finance leases — % 7.9 %
Schedule of balance sheet information related to leases	Supplemental balance sheet information related to leases was as follows (in thousands): December 31, 2021 2020 Operating leases Operating lease right-of-use assets $ 48,703 $ 9,010 Operating lease liabilities: $ 9,826 $ 3,912 Operating lease liabilities — less current portion 47,088 5,379 Total operating lease liabilities $ 56,914 $ 9,291 Finance leases Property and equipment, gross $ 42,541 $ 45,021 Less: accumulated depreciation and amortization (41,689) (41,908) Property and equipment, net $ 852 $ 3,113 Finance lease liabilities: Finance leases $ — $ 612 Finance lease liabilities — less current portion — — Total finance lease liabilities $ — $ 612
Schedule of operating lease maturities	Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases 2022 $ 11,383 $ — 2023 10,633 — 2024 7,744 — 2025 5,583 — 2026 5,752 — Thereafter 22,858 Total future minimum lease payments 63,953 — Less: imputed interest (7,039) — Total $ 56,914 $ —
Schedule of finance lease maturities	Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases 2022 $ 11,383 $ — 2023 10,633 — 2024 7,744 — 2025 5,583 — 2026 5,752 — Thereafter 22,858 Total future minimum lease payments 63,953 — Less: imputed interest (7,039) — Total $ 56,914 $ —

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Schedule of recognized identified assets acquired and liabilities assumed	The following table presents the final allocation of the purchase price at the acquisition date (in thousands): Cash $ 1,394 Property and equipment acquired 124 Other assets acquired 2,238 Acquired technology 28,600 Customer relationships 1,100 Trade name and trademarks 400 Goodwill 130,976 Total assets acquired 164,832 Liabilities assumed (3,525) Deferred tax liability (4,616) Total consideration $ 156,691 Total consideration (net of cash acquired) $ 155,297 Cash $ 168 Tangible assets acquired 200 Acquired technology 12,200 Customer relationships 500 Trade name and trademarks 100 Goodwill 22,646 Total assets acquired 35,814 Deferred tax liability (2,910) Liabilities assumed (682) Total $ 32,222

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	Selected quarterly financial information for 2021 and 2020 is as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands, except per share data) Revenue $ 173,599 $ 154,328 $ 143,782 $ 137,882 $ 127,885 $ 112,143 $ 99,792 $ 95,088 Cost of revenue (1)(2) 79,764 67,137 64,395 59,803 51,233 46,561 42,453 40,037 Gross profit 93,835 87,191 79,387 78,079 76,652 65,582 57,339 55,051 Operating expenses: Research and development (1)(2) 30,448 29,680 24,648 22,121 18,676 17,674 17,208 15,189 Sales and marketing (1)(2) 53,394 49,712 46,024 44,799 37,053 32,969 32,231 30,160 General and administrative (1)(2) 21,972 26,790 22,909 22,245 18,258 16,724 16,129 14,658 Total operating expenses 105,814 106,182 93,581 89,165 73,987 67,367 65,568 60,007 (Loss) income from operations (11,979) (18,991) (14,194) (11,086) 2,665 (1,785) (8,229) (4,956) Other (expense) income, net: Interest expense (2,024) (1,947) (2,118) (1,938) (9,481) (9,649) (5,734) (3,484) Loss on early extinguishment of debt — — — — (887) (282) (5,794) — Other (expense) and interest income (43) 213 (353) 175 501 631 829 1,072 Total other (expense) income, net (2,067) (1,734) (2,471) (1,763) (9,867) (9,300) (10,699) (2,412) Loss before income taxes (14,046) (20,725) (16,665) (12,849) (7,202) (11,085) (18,928) (7,368) (Benefit from) provision for income taxes (10,445) (188) (135) (517) 8 346 (2,876) 69 Net loss $ (3,601) $ (20,537) $ (16,530) $ (12,332) $ (7,210) $ (11,431) $ (16,052) $ (7,437) Net loss per share: Basic $ (0.05) $ (0.30) $ (0.25) $ (0.18) $ (0.11) $ (0.17) $ (0.25) $ (0.12) Diluted $ (0.05) $ (0.30) $ (0.25) $ (0.18) $ (0.11) $ (0.17) $ (0.25) $ (0.12) Shares used in computing net loss per share: Basic 68,207 67,800 67,292 66,721 66,133 65,460 63,282 61,705 Diluted 68,207 67,800 67,292 66,721 66,133 65,460 63,282 61,705 (1) Included stock-based compensation as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands) Cost of revenue $ 6,854 $ 3,994 $ 3,781 $ 3,105 $ 2,331 $ 2,603 $ 2,499 $ 1,989 Research and development 9,163 9,101 6,152 4,763 3,674 3,876 3,684 2,806 Sales and marketing 11,987 8,304 8,208 6,771 5,366 5,427 5,265 4,106 General and administrative 7,597 5,996 6,760 6,269 5,505 5,380 5,343 4,893 Total stock-based compensation $ 35,601 $ 27,395 $ 24,901 $ 20,908 $ 16,876 $ 17,286 $ 16,791 $ 13,794 (2) Included depreciation and amortization expenses as follows: Quarter Ended Dec. 31, 2021 Sept. 30, 2021 Jun. 30, 2021 Mar. 31, 2021 Dec. 31, 2020 Sept. 30, 2020 Jun. 30, 2020 Mar. 31, 2020 (unaudited, in thousands) Cost of revenue $ 8,301 $ 7,658 $ 7,825 $ 7,087 $ 5,948 $ 5,171 $ 5,120 $ 3,940 Research and development 948 1,004 729 596 488 512 497 465 Sales and marketing 1 1 1 1 2 1 2 2 General and administrative 1,288 1,117 1,096 1,079 899 853 624 563 Total depreciation and amortization $ 10,538 $ 9,780 $ 9,651 $ 8,763 $ 7,337 $ 6,537 $ 6,243 $ 4,970

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Termination of Zoom Proposed Merger and Basis of Presentation (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity		$ 211,132	$ 279,164	$ 196,458	$ 142,748
Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity		$ 439,787	476,941	$ 351,870	$ 294,279
Revision of Prior Period, Error Correction, Adjustment | Unwind Of Partially Capped Calls On Convertible Debt | Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity			2,300
Revision of Prior Period, Error Correction, Adjustment | Unwind Of Partially Capped Calls On Convertible Debt | Treasury Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity			$ (2,300)
Five9, Inc. | Five9, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Business combination, acquisition related costs	$ 7,600

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Concentration Risks (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash, uninsured amount	$ 89.2	$ 218.3

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of period	$ 127	$ 11
Add: bad debt expense	808	754	$ 90
Less: write-offs, net of recoveries	(715)	(638)
Balance, end of period	$ 220	$ 127	$ 11

Description of Business and S_7

Description of Business and Summary of Significant Accounting Policies - Property and Equipment, Net (Details)	12 Months Ended
	Dec. 31, 2021
Computer and network equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life, in years	3 years
Computer and network equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life, in years	5 years
Computer software
Property, Plant and Equipment [Line Items]
Useful life, in years	3 years
Development costs | Minimum
Property, Plant and Equipment [Line Items]
Useful life, in years	1 year
Development costs | Maximum
Property, Plant and Equipment [Line Items]
Useful life, in years	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life, in years	7 years

Description of Business and S_8

Description of Business and Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining amortization period	4 years	4 years 10 months 24 days
Minimum
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining amortization period	3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Weighted average remaining amortization period	6 years

Description of Business and S_9

Description of Business and Summary of Significant Accounting Policies - Advertising Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Advertising expense	$ 20.8	$ 15.6	$ 13.4

Description of Business and _10

Description of Business and Summary of Significant Accounting Policies - Commissions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Commission expense	$ 31.1	$ 21.9	$ 15

Description of Business and _11

Description of Business and Summary of Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Deferred tax assets	$ 6,907
Deferred tax liabilities		$ 4,438
U.K. and Australia
Tax Credit Carryforward [Line Items]
Deferred tax assets	$ 6,900	6,900
Deferred tax liabilities		$ 4,400

Description of Business and _12

Description of Business and Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity		$ 211,132	$ 279,164			$ 196,458	$ 142,748
Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity		439,787	476,941			351,870	294,279
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity		$ (228,436)	(198,179)			$ (156,049)	$ (151,497)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity	[1]		(145,669)
Cumulative Effect, Period of Adoption, Adjustment | Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity	[1]		(168,412)
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity	[1]		22,743
Convertible Senior Notes, Due 2023 | Convertible debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stated interest rate on debt (percent)								0.125%
Convertible Senior Notes, Due 2025 | Convertible debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stated interest rate on debt (percent)				0.50%	0.50%
Accounting Standards Update 2020-06 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity			145,700
Accounting Standards Update 2020-06 | Cumulative Effect, Period of Adoption, Adjustment | Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity			(168,400)
Accounting Standards Update 2020-06 | Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to stockholders' equity			$ (22,700)
[1]	Effective January 1, 2021, the Company adopted ASU 2020-06. Accordingly, the Company recorded a net reduction to opening accumulated deficit of $22.7 million and a net reduction to opening additional paid-in capital of $168.4 million as of January 1, 2021 due to the cumulative impact of adopting this new standard. See Note 1 for more information.

Revenue - Contract Balances (De

Revenue - Contract Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 83,731	$ 48,731
Deferred contract acquisition costs, net:
Current	33,295	20,695
Non-current	84,663	51,934
Total deferred contract acquisition costs, net	117,958	72,629
Contract assets and contract liabilities:
Contract assets (included in prepaid expenses and other current assets)	2,593	1,297
Contract liabilities (deferred revenue)	43,720	31,983
Noncurrent contract liabilities (deferred revenue) (included in other long term liabilities)	2,097	3,373
Net contract liabilities	$ (43,224)	$ (34,059)

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract revenue recognized	$ 29.4
Remaining performance obligation	$ 544.3
Performance obligation, description of timing	The Company expects to recognize revenue on approximately three-fourths of the remaining performance obligations over the next 24 months, with the balance recognized thereafter. The Company has elected the optional exemption, which allows for the exclusion of the amounts for remaining performance obligations that are part of contracts with an original expected duration of one year or less. Such remaining performance obligations represent unsatisfied or partially unsatisfied performance obligations pursuant to ASC 606.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Performance obligation satisfaction period (in months)	24 months
Remaining performance obligation, percentage	75.00%
Contract acquisition costs
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Amortization period of capitalized contract cost (in years)	5 years

Investments and Fair Value Me_3

Investments and Fair Value Measurements - Schedule of Marketable Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Cost	$ 527,122	$ 425,240
Fair Value	526,357	425,298
Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	379,169	383,121
Gross Unrealized Gains	2	61
Gross Unrealized Losses	(191)	(11)
Fair Value	378,980	383,171
Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	147,953	42,119
Gross Unrealized Gains	0	9
Gross Unrealized Losses	(576)	(1)
Fair Value	147,377	42,127
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Fair Value	2,359	3,480
Certificates of deposit | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	1,615	3,479
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	1,615	3,480
Certificates of deposit | Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	746
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Fair Value	744
U.S. treasury
Debt Securities, Available-for-sale [Line Items]
Fair Value	146,528	297,540
U.S. treasury | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	83,237	287,315
Gross Unrealized Gains	0	41
Gross Unrealized Losses	(24)	(4)
Fair Value	83,213	287,352
U.S. treasury | Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	63,566	10,189
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(251)	0
Fair Value	63,315	10,189
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Fair Value		98,711
U.S. agency securities | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	159,070	67,227
Gross Unrealized Gains	0	12
Gross Unrealized Losses	(65)	(6)
Fair Value	159,005	67,233
U.S. agency securities | Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	63,960	31,469
Gross Unrealized Gains	0	9
Gross Unrealized Losses	(254)	(1)
Fair Value	63,706	31,477
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Fair Value	47,555	5,093
Commercial paper | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	47,555	5,093
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	47,555	5,093
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value	93,832	3,145
Municipal bonds | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	75,337	2,684
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(96)	(1)
Fair Value	75,241	2,684
Municipal bonds | Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	18,655	461
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(64)	0
Fair Value	18,591	461
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value	13,372	17,329
Corporate bonds | Short-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	12,355	17,323
Gross Unrealized Gains	2	6
Gross Unrealized Losses	(6)	0
Fair Value	12,351	$ 17,329
Corporate bonds | Long-Term Marketable Investments
Debt Securities, Available-for-sale [Line Items]
Cost	1,026
Gross Unrealized Gains	0
Gross Unrealized Losses	(5)
Fair Value	$ 1,021

Investments and Fair Value Me_4

Investments and Fair Value Measurements - Schedule of Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	$ (767)	$ (13)
Fair Value	461,859	120,540
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(2)	0
Fair Value	2,010	0
U.S. treasury
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(275)	(4)
Fair Value	140,527	78,549
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(320)	(7)
Fair Value	222,710	39,443
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(160)	(1)
Fair Value	87,184	1,201
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Losses	(10)	(1)
Fair Value	$ 9,428	$ 1,347

Investments and Fair Value Me_5

Investments and Fair Value Measurements - Maturity Dates (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cost
Due within one year	$ 379,169	$ 383,121
Due after one year	147,953	42,119
Cost	527,122	425,240
Fair Value
Due within one year	378,980	383,171
Due after one year	147,377	42,127
Fair Value	$ 526,357	$ 425,298

Investments and Fair Value Me_6

Investments and Fair Value Measurements - Schedule of Assets Carried at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash equivalents	$ 32,127	$ 129,885
Marketable investments	526,357	425,298
Liabilities
Contingent consideration	23,740	18,100
Level 1
Assets
Cash equivalents	31,380	129,885
Marketable investments	146,528	297,540
Liabilities
Contingent consideration	0	0
Level 2
Assets
Cash equivalents	747	0
Marketable investments	379,829	127,758
Liabilities
Contingent consideration	0	0
Level 3
Assets
Cash equivalents	0	0
Marketable investments	0	0
Liabilities
Contingent consideration	23,740	18,100
Certificates of deposit
Assets
Marketable investments	2,359	3,480
Certificates of deposit | Level 1
Assets
Marketable investments	0	0
Certificates of deposit | Level 2
Assets
Marketable investments	2,359	3,480
Certificates of deposit | Level 3
Assets
Marketable investments	0	0
U.S. treasury
Assets
Marketable investments	146,528	297,540
U.S. treasury | Level 1
Assets
Marketable investments	146,528	297,540
U.S. treasury | Level 2
Assets
Marketable investments	0	0
U.S. treasury | Level 3
Assets
Marketable investments	0	0
U.S. agency and government sponsored securities
Assets
Marketable investments	222,711
U.S. agency and government sponsored securities | Level 1
Assets
Marketable investments	0
U.S. agency and government sponsored securities | Level 2
Assets
Marketable investments	222,711
U.S. agency and government sponsored securities | Level 3
Assets
Marketable investments	0
U.S. agency securities
Assets
Marketable investments		98,711
U.S. agency securities | Level 1
Assets
Marketable investments		0
U.S. agency securities | Level 2
Assets
Marketable investments		98,711
U.S. agency securities | Level 3
Assets
Marketable investments		0
Commercial paper
Assets
Marketable investments	47,555	5,093
Commercial paper | Level 1
Assets
Marketable investments	0	0
Commercial paper | Level 2
Assets
Marketable investments	47,555	5,093
Commercial paper | Level 3
Assets
Marketable investments	0	0
Municipal bonds
Assets
Marketable investments	93,832	3,145
Municipal bonds | Level 1
Assets
Marketable investments	0	0
Municipal bonds | Level 2
Assets
Marketable investments	93,832	3,145
Municipal bonds | Level 3
Assets
Marketable investments	0	0
Corporate bonds
Assets
Marketable investments	13,372	17,329
Corporate bonds | Level 1
Assets
Marketable investments	0	0
Corporate bonds | Level 2
Assets
Marketable investments	13,372	17,329
Corporate bonds | Level 3
Assets
Marketable investments	0	0
Money market funds
Assets
Cash equivalents	31,380	89,888
Money market funds | Level 1
Assets
Cash equivalents	31,380	89,888
Money market funds | Level 2
Assets
Cash equivalents	0	0
Money market funds | Level 3
Assets
Cash equivalents	0	0
Certificates of deposit
Assets
Cash equivalents	747
Certificates of deposit | Level 1
Assets
Cash equivalents	0
Certificates of deposit | Level 2
Assets
Cash equivalents	747
Certificates of deposit | Level 3
Assets
Cash equivalents	$ 0
U.S. Treasury
Assets
Cash equivalents		39,997
U.S. Treasury | Level 1
Assets
Cash equivalents		39,997
U.S. Treasury | Level 2
Assets
Cash equivalents		0
U.S. Treasury | Level 3
Assets
Cash equivalents		$ 0

Investments and Fair Value Me_7

Investments and Fair Value Measurements - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2020	Nov. 18, 2020
Debt Instrument [Line Items]
Impairment loss on available-for-sale debt securities		$ 0
Contingent consideration	$ 23,740,000	18,100,000
Change in fair value of contingent consideration	5,640,000	0	$ 0
Inference Solutions
Debt Instrument [Line Items]
Contingent consideration	23,700,000			$ 24,000,000	$ 18,100,000
Level 2
Debt Instrument [Line Items]
Contingent consideration	0	0
Level 3
Debt Instrument [Line Items]
Contingent consideration	23,740,000	18,100,000
Level 3 | Inference Solutions
Debt Instrument [Line Items]
Change in fair value of contingent consideration	5,600,000
Nonrecurring
Debt Instrument [Line Items]
Assets and liabilities measured at fair value on nonrecurring basis	0	0
Convertible Senior Notes, Due 2023 | Level 2 | Convertible debt
Debt Instrument [Line Items]
Fair value of long-term debt	114,900,000	253,100,000
Convertible Senior Notes, Due 2025 | Level 2 | Convertible debt
Debt Instrument [Line Items]
Fair value of long-term debt	$ 917,300,000	$ 1,098,500,000

Investments and Fair Value Me_8

Investments and Fair Value Measurements - Reconciliation of Contingent Consideration (Details) - Liability - Fair Value, Recurring $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Summary of changes in contingent consideration liabilities
Balance, December 31. 2020	$ 18,100
Change in fair value of contingent consideration	5,640
Balance, December 31, 2021	$ 23,740

Financial Statement Component_2

Financial Statement Components - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents
Cash and cash equivalents	$ 90,878	$ 220,372
Cash
Cash and Cash Equivalents
Cash and cash equivalents	58,751	90,487
Certificates of deposit
Cash and Cash Equivalents
Cash and cash equivalents	747	0
Money market funds
Cash and Cash Equivalents
Cash and cash equivalents	31,380	89,888
U.S. treasury
Cash and Cash Equivalents
Cash and cash equivalents	$ 0	$ 39,997

Financial Statement Component_3

Financial Statement Components - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable
Allowance for doubtful accounts	$ (220)	$ (127)	$ (11)
Accounts receivable, net	83,731	48,731
Trade accounts receivable
Accounts Receivable
Trade accounts receivable	75,970	42,366
Unbilled trade accounts receivable, net of advance client deposits
Accounts Receivable
Trade accounts receivable	$ 7,981	$ 6,492

Financial Statement Component_4

Financial Statement Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Statement Components [Abstract]
Prepaid expenses	$ 21,306	$ 9,816
Other current assets	6,443	5,036
Contract assets (included in prepaid expenses and other current assets)	2,593	1,297
Prepaid expenses and other current assets	$ 30,342	$ 16,149

Financial Statement Component_5

Financial Statement Components - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment	$ 171,336	$ 121,858
Accumulated depreciation and amortization	(93,551)	(70,645)
Property and equipment, net	77,785	51,213
Depreciation and amortization of property and equipment	26,900	18,200	$ 13,500
Computer and network equipment
Property, Plant and Equipment [Line Items]
Property and equipment	116,701	89,763
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	44,268	25,888
Internal-use software development costs
Property, Plant and Equipment [Line Items]
Property and equipment, gross	500	500
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,953	3,372
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5,914	$ 2,335

Financial Statement Component_6

Financial Statement Components - Property and Equipment Capitalized Under Finance Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Statement Components [Abstract]
Gross	$ 42,541	$ 45,021
Less: accumulated depreciation and amortization	(41,689)	(41,908)
Property and equipment, net	$ 852	$ 3,113

Financial Statement Component_7

Financial Statement Components - Schedule of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other assets	$ 4,964	$ 3,236
Deferred tax assets	6,907	0
Other assets	$ 11,871	$ 3,236

Financial Statement Component_8

Financial Statement Components - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Statement Components [Abstract]
Accrued expenses	$ 20,108	$ 15,217
Accrued compensation and benefits	34,729	29,233
Contingent consideration	23,740	0
Accrued and other current liabilities	$ 78,577	$ 44,450

Financial Statement Component_9

Financial Statement Components - Schedule of Other Long-term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Statement Components [Abstract]
Deferred revenue	$ 2,097	$ 3,373
Deferred tax liabilities	0	4,438
Other long-term liabilities	5,574	5,554
Contingent consideration	0	18,100
Other long-term liabilities	$ 7,671	$ 31,465

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill and Intangible Asset Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 165,420	$ 11,798
Goodwill, Ending Balance	165,420	165,420	$ 11,798
Intangible Assets [Roll Forward]
Intangible assets, beginning balance	51,684	15,533
Amortization	(11,787)	(6,849)	(900)
Intangible assets, ending balance	39,897	51,684	$ 15,533
Inference Solutions
Goodwill [Roll Forward]
Addition		130,976
Intangible Assets [Roll Forward]
Addition		30,100
Virtual Observer
Goodwill [Roll Forward]
Addition	$ 0	22,646
Intangible Assets [Roll Forward]
Addition		12,800
Whendu
Intangible Assets [Roll Forward]
Addition		$ 100

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment, accumulated	$ 0	$ 0
Amortization of intangible assets	11,787,000	6,849,000	$ 900,000
Impairment of intangible assets	$ 0	$ 0

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 58,784	$ 58,784
Accumulated Amortization	(18,887)	(7,100)
Total	$ 39,897	$ 51,684	$ 15,533
Weighted Average Remaining Amortization Period (Years)	4 years	4 years 10 months 24 days
Developed technology
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 56,214	$ 56,214
Accumulated Amortization	(17,821)	(6,761)
Total	$ 38,393	$ 49,453
Weighted Average Remaining Amortization Period (Years)	4 years	4 years 10 months 24 days
Acquired workforce
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 470	$ 470
Accumulated Amortization	(334)	(177)
Total	$ 136	$ 293
Weighted Average Remaining Amortization Period (Years)	10 months 24 days	1 year 10 months 24 days
Customer relationships
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 1,600	$ 1,600
Accumulated Amortization	(421)	(101)
Total	$ 1,179	$ 1,499
Weighted Average Remaining Amortization Period (Years)	3 years 8 months 12 days	4 years 8 months 12 days
Trademarks
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 500	$ 500
Accumulated Amortization	(311)	(61)
Total	$ 189	$ 439
Weighted Average Remaining Amortization Period (Years)	10 months 24 days	1 year 9 months 18 days

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Expected Future Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 11,705
2023	10,870
2024	7,527
2025	5,595
2026	4,200
Thereafter	0
Total	$ 39,897	$ 51,684	$ 15,533

Debt - Convertible Senior Notes

Debt - Convertible Senior Notes and Capped Call (Details)	1 Months Ended		2 Months Ended	3 Months Ended								12 Months Ended			30 Months Ended
	May 31, 2020USD ($)shares	May 31, 2018USD ($)$ / shares	Jun. 30, 2020USD ($)$ / shares	Dec. 31, 2021USD ($)$ / sharesshares	Sep. 30, 2021USD ($)	Jun. 30, 2021USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)$ / shares	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2021USD ($)day$ / sharesRateshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)	Dec. 31, 2021USD ($)daytrigger$ / sharesshares	May 21, 2020$ / shares
Debt Instrument [Line Items]
Debt balance				$ 781,700,000								$ 781,700,000			$ 781,700,000
Purchase of capped calls related to the 2025 convertible senior notes													$ 90,448,000
Loss on early extinguishment of debt				$ 0	$ 0	$ 0	$ 0	$ 887,000	$ 282,000	$ 5,794,000	$ 0	$ 0	$ 6,964,000	$ 0
Common Stock
Debt Instrument [Line Items]
Issuance of common stock upon partial conversion of the 2023 convertible senior notes (in shares) | shares												454,000	3,015,000
Treasury Stock
Debt Instrument [Line Items]
Partial unwind of capped calls related to the 2023 convertible senior notes (in shares) | shares												68,905	15,714
Convertible Senior Notes, Due 2023 | Treasury Stock
Debt Instrument [Line Items]
Partial unwind of capped calls related to the 2023 convertible senior notes (in shares) | shares												68,905	15,714
Convertible debt | Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Stated interest rate on debt (percent)		0.125%
Proceeds from issuance of debt		$ 250,800,000
Multiple of principle amount												$ 1,000			$ 1,000
Conversion ratio on convertible debt | Rate												2449.78%
Conversion price on convertible debt (in USD per share) | $ / shares				$ 40.82								$ 40.82			$ 40.82
Sinking fund payment												$ 0
Equity component								14,505,000					$ 14,505,000
Effective interest rate on debt (percent)	5.32%			6.39%								6.39%			6.39%
Payment on debt issuance cost		8,000,000										$ 300,000
Debt issuance costs		$ 6,000,000		$ 291,000				700,000				291,000	700,000		$ 291,000
Convertible debt				33,900,000								33,900,000			33,900,000
Debt balance				$ 34,225,000				58,867,000				$ 34,225,000	58,867,000		$ 34,225,000
Amortization of debt issuance costs, Effective interest rate | Rate												0.76%
Cap price of the capped call transactions (in dollars per share) | $ / shares		$ 62.80
Number of shares covered in the capped call transactions (in shares) | shares				6,300,000								6,300,000			6,300,000
Cost of capped call transactions recorded in additional paid in capital				$ 31,400,000								$ 31,400,000			$ 31,400,000
Debt instrument, repurchase amount	$ 181,000,000
Aggregate consideration to repurchase note	449,600,000
Cash consideration to repurchase note	181,000,000
Debt instrument, convertible, carrying amount of debt component	155,800,000
Net carrying amount	293,800,000							$ 14,050,000					14,050,000
Carrying value of debt subject to repurchase, net	150,400,000
Third party transaction costs	$ 500,000
Loss on early extinguishment of debt										5,800,000		$ 1,200,000
Debt issuance costs, gross, within extinguishment of debt			$ 2,700,000							$ 2,700,000
Number of conversion features triggered | trigger															1
Conversion price per share requiring conversion (in USD per share) | $ / shares				$ 53.07								$ 53.07			$ 53.07
Cash payment to settle aggregate principal												$ 24,700,000	18,900,000
Debt instrument, conversion multiple of aggregate principal amount												24,600,000	$ 18,900,000
Conversion of aggregate principal amount, term one												$ 34,000,000
Convertible debt | Convertible Senior Notes, Due 2023 | Common Stock
Debt Instrument [Line Items]
Issuance of common stock upon partial conversion of the 2023 convertible senior notes (in shares) | shares	2,723,581
Debt instrument, conversion multiple of aggregate principal amount (in shares) | shares												453,943	307,037
Convertible debt | Convertible Senior Notes, Due 2023 | Fundamental change event
Debt Instrument [Line Items]
Debt redemption price as percentage of principal amount												100.00%
Convertible debt | Convertible Senior Notes, Due 2023 | On or after May 5, 2021
Debt Instrument [Line Items]
Number of trading days | day												20
Number of consecutive trading days | day												30
Threshold percentage of stock price trigger												130.00%
Debt redemption price as percentage of principal amount												100.00%
Number of trading days preceding notice of redemption | day												2
Convertible debt | Convertible Senior Notes, Due 2023 | Convertible, term one
Debt Instrument [Line Items]
Number of trading days | day												20			20
Number of consecutive trading days | day												30			30
Threshold percentage of stock price trigger												130.00%			130.00%
Convertible debt | Convertible Senior Notes, Due 2023 | Convertible, term two
Debt Instrument [Line Items]
Number of trading days | day												5
Number of consecutive trading days | day												5
Threshold percentage of stock price trigger												98.00%
Convertible debt | Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Stated interest rate on debt (percent)			0.50%						0.50%	0.50%
Stated additional interest rate on debt (percent)			0.00500							0.00500
Proceeds from issuance of debt			$ 728,800,000
Multiple of principle amount												$ 1,000
Conversion ratio on convertible debt | Rate												744.37%
Conversion price on convertible debt (in USD per share) | $ / shares				134.34								$ 134.34			$ 134.34
Premium on conversion price in relation to closing price (percentage)																30.00%
Closing price of common stock (in dollars per share) | $ / shares								$ 137.32					$ 137.32			$ 103.34
Share price of common stock with conversion premium (in dollars per share) | $ / shares				$ 174.64								$ 174.64			$ 174.64
Sinking fund payment												$ 0
Equity component								$ 158,321,000					$ 158,321,000
Effective interest rate on debt (percent)				5.76%								5.76%			5.76%
Payment on debt issuance cost			18,700,000									$ 12,800,000
Debt issuance costs			$ 14,700,000	$ 12,835,000				13,192,000		$ 14,700,000		12,835,000	13,192,000		$ 12,835,000
Convertible debt				734,700,000								734,700,000			734,700,000
Debt balance				$ 747,500,000				747,500,000				$ 747,500,000	747,500,000		$ 747,500,000
Amortization of debt issuance costs, Effective interest rate | Rate												1.00%
Cap price of the capped call transactions (in dollars per share) | $ / shares			$ 206.68
Number of shares covered in the capped call transactions (in shares) | shares				5,600,000								5,600,000			5,600,000
Purchase of capped calls related to the 2025 convertible senior notes													90,500,000
Net carrying amount								$ 154,363,000					$ 154,363,000
Convertible debt | Convertible Senior Notes, Due 2025 | Fundamental change event
Debt Instrument [Line Items]
Debt redemption price as percentage of principal amount												100.00%
Convertible debt | Convertible Senior Notes, Due 2025 | On or after June 6, 2023
Debt Instrument [Line Items]
Number of trading days | day												20
Number of consecutive trading days | day												30
Threshold percentage of stock price trigger												130.00%
Debt redemption price as percentage of principal amount												100.00%
Convertible debt | Convertible Senior Notes, Due 2025 | Convertible, term one
Debt Instrument [Line Items]
Number of trading days | day												20
Number of consecutive trading days | day												30
Threshold percentage of stock price trigger												130.00%
Convertible debt | Convertible Senior Notes, Due 2025 | Convertible, term two
Debt Instrument [Line Items]
Number of trading days | day												5
Number of consecutive trading days | day												5
Threshold percentage of stock price trigger												98.00%
Private placement | Convertible debt | Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Aggregate principal amount of debt		$ 258,800,000
Private placement | Convertible debt | Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Aggregate principal amount of debt			$ 747,500,000							747,500,000
Option to purchase additional debt through private offering			$ 97,500,000							$ 97,500,000

Debt - Schedule of Net Carrying

Debt - Schedule of Net Carrying Amount of the Liability Component of the Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	May 31, 2018
Debt Instrument [Line Items]
Principal	$ 781,700
Convertible debt | Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Principal	747,500	$ 747,500
Unamortized debt discount	0	(141,792)
Unamortized issuance costs	(12,835)	(13,192)	$ (14,700)
Net carrying amount	734,665	592,516
Convertible debt | Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Principal	34,225	58,867
Unamortized debt discount	0	(7,367)
Unamortized issuance costs	(291)	(700)		$ (6,000)
Net carrying amount	$ 33,934	$ 50,800

Debt - Schedule of Equity Compo

Debt - Schedule of Equity Component of Debt (Details) - Convertible debt - USD ($) $ in Thousands	Dec. 31, 2020	May 31, 2020
Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Equity component	$ 158,321
Issuance costs	(3,958)
Net carrying amount	154,363
Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Equity component	14,505
Issuance costs	(455)
Net carrying amount	$ 14,050	$ 293,800

Debt - Schedule of Interest Exp

Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total interest expense	$ 2,024	$ 1,947	$ 2,118	$ 1,938	$ 9,481	$ 9,649	$ 5,734	$ 3,484	$ 8,027	$ 28,348	$ 13,794
Convertible Senior Notes, Due 2025 | Convertible debt
Debt Instrument [Line Items]
Contractual interest expense									4,007	2,230
Amortization of debt discount									0	16,528
Amortization of issuance costs									3,674	1,538
Total interest expense									7,681	20,296
Convertible Senior Notes, Due 2023 | Convertible debt
Debt Instrument [Line Items]
Contractual interest expense									42	184	324
Amortization of debt discount									0	7,006	11,683
Amortization of issuance costs									283	666	1,105
Total interest expense									$ 325	$ 7,856	$ 13,112

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total	$ 781,700
Convertible Senior Notes, Due 2025 | Convertible debt
Debt Instrument [Line Items]
2025 (Maturity date of June 1, 2025)	747,500
Total	747,500	$ 747,500
Convertible Senior Notes, Due 2023 | Convertible debt
Debt Instrument [Line Items]
2023 (Maturity date of May 1, 2023)	34,225
Total	$ 34,225	$ 58,867

Stockholders' Equity - Capital

Stockholders' Equity - Capital Structure (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	450,000,000	450,000,000
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares issued (in shares)	68,488,337	66,496,060
Common stock, shares outstanding (in shares)	68,488,337	66,496,060
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common Stock
Class of Stock [Line Items]
Issuance of common stock upon partial conversion of the 2023 convertible senior notes, gross (in shares)	453,943	3,030,618
Treasury Stock
Class of Stock [Line Items]
Partial unwind of capped calls related to the 2023 convertible senior notes (in shares)	68,905	15,714
Treasury Stock | Convertible Senior Notes, Due 2023
Class of Stock [Line Items]
Partial unwind of capped calls related to the 2023 convertible senior notes (in shares)	68,905	15,714

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2021	Apr. 03, 2014
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	20,997,000
Shares available for future grant under 2014 Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	13,379,000
Stock options outstanding
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	1,982,000
Restricted stock units outstanding
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	2,560,000
Shares available for future issuance under ESPP
Class of Stock [Line Items]
Shares of common stock reserved for future issuance (in shares)	3,076,000	880,000

Stockholders' Equity - Equity I

Stockholders' Equity - Equity Incentive Plans (Details) - USD ($) $ in Thousands	Nov. 18, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Recognized goodwill in relation to options assumed		$ 165,420	$ 165,420	$ 11,798
Stock-based compensation expense		$ 108,805	$ 64,747	$ 42,065
Inference Solutions
Share-based Compensation Arrangement by Share-based Payment Award
Recognized goodwill in relation to options assumed	$ 130,976
Stock options | Inference Solutions
Share-based Compensation Arrangement by Share-based Payment Award
Options assumed, estimated fair value on date of acquisition	7,600
Recognized goodwill in relation to options assumed	200
Stock-based compensation expense	$ 7,400
2004 Equity Incentive Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		4 years
Award expiration period (in years)		10 years
Expiration period, after termination of employment or relationship of consultant or director		90 days
2004 Equity Incentive Plan | Stock options | Tranche One
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		12 months
Award vesting, percentage of award		25.00%
2004 Equity Incentive Plan | Stock options | Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		36 months
Award vesting, percentage of award		75.00%
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares authorized for issuance (in shares)					5,300,000
Automatic annual increase in common stock reserved for issuance, percentage		5.00%
Shares of common stock reserved for future issuance (in shares)		3,424,416
2014 Equity Incentive Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		4 years
Award expiration period (in years)		10 years
Expiration period, after termination of employment or relationship of consultant or director		3 months
2014 Equity Incentive Plan | Restricted stock units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		1 year
2014 Equity Incentive Plan | Restricted stock units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period (in years)		4 years

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Option Activities (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Additional information pertaining to stock options
Fair market value of common stock (in usd per share)	$ 137.32
Cash received from options exercised	$ 7,402	$ 11,656	$ 7,705
Stock options
Number of Shares
Outstanding, beginning balance (in shares)	2,255
Options granted (in shares)	156
Options exercised (in shares)	(389)
Options forfeited or expired (in shares)	(40)
Outstanding, ending balance (in shares)	1,982	2,255
Weighted Average Exercise Price
Outstanding, beginning balance, weighted-average exercise price (in USD per share)	$ 26.33
Options granted, weighted-average exercise price (in USD per share)	180.75
Options exercised, weighted-average exercise price (in USD per share)	19.03
Options forfeited or expired, weighted-average exercise price (in USD per share)	80.47
Outstanding, ending balance, weighted-average exercise price (in USD per share)	$ 38.65	$ 26.33
Weighted average remaining contractual life	4 years 10 months 24 days
Outstanding, Aggregate intrinsic value	$ 202,425
Vested and expected to vest as of December 31, 2021
Vested and expected to vest (in shares)	1,982
Outstanding, weighted-average exercise price (in USD per share)	$ 38.65
Outstanding, weighted average remaining contractual life	4 years 10 months 24 days
Vested and expected to vest, aggregate intrinsic value	$ 202,425
Additional information pertaining to stock options
Exercisable (in shares)	1,544
Exercisable, weighted-average exercise price (in USD per share)	$ 22.02
Exercisable, weighted average remaining contractual life	4 years
Exercisable, aggregate intrinsic value	$ 179,180
Weighted average grant date fair value per share of options granted, excluding assumed stock options (in USD per share)	$ 78.72	38.80	$ 24.06
Weighted average grant date fair value per share of assumed stock options (in USD per share)	$ 0	$ 125,960	$ 0
Intrinsic value of options exercised	$ 59,762	$ 47,529	$ 42,204
Total fair value of options vested during the period	12,760	7,846	5,342
Cash received from options exercised	$ 7,402	$ 11,656	$ 7,705

Stockholders' Equity - RSU Acti

Stockholders' Equity - RSU Activities (Details) - Restricted stock units - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Outstanding, beginning balance (in shares)			2,267
RSUs granted (in shares)	700	700	2,234
RSUs vested and released (in shares)			(1,097)
RSUs forfeited or cancelled (in shares)			(844)
Outstanding, ending balance (in shares)		2,560	2,560	2,267
Weighted Average Grant Date Fair Value Per Share
Outstanding, beginning balance, weighted-average grant date fair value per share (in USD per share)			$ 65.42
RSUs granted, weighted-average grant date value per share (USD per share)			177	$ 86.15	$ 53.33
RSUs vested and released, weighted-average grant date fair value per share (in USD per share)			69.06
RSUs forfeited or cancelled, weighted-average grant date fair value per share (in USD per share)			170.59
Outstanding, ending balance, weighted-average grant date fair value per share (in USD per share)		$ 125.65	125.65	65.42
Weighted average grant date fair value per share of RSUs granted (in USD per share)			$ 177	$ 86.15	$ 53.33
Total fair value of RSUs vested during the period			$ 174,500	$ 136,805	$ 68,072

Stockholders' Equity - ESPP (De

Stockholders' Equity - ESPP (Details) - $ / shares	1 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2021	Dec. 31, 2020	Apr. 03, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock reserved for future issuance (in shares)		20,997,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award
Maximum employee subscription rate, percentage of pre-tax earnings	15.00%
Purchase price of shares, percentage of the fair market value of the Company's common stock	85.00%
Offering period (in months)	6 months
Maximum number of shares per employee per purchase period (in shares)	1,500
Shares of common stock reserved for future issuance (in shares)		3,076,000		880,000
Automatic annual increase in common stock reserved for issuance, percentage		1.00%
Maximum annual increase of shares reserved (in shares)		1,000,000
Shares of common stock reserved for future issuance (in shares)		684,883
Issuance of common stock under ESPP (in shares)		120,992	168,737
Weighted-average price per share (in USD per share)		$ 127.36	$ 67.97

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock-based Compensation Expense
Stock-based compensation expense	$ 108,805	$ 64,747	$ 42,065
Stock options
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 21,723
Weighted-average amortization period	2 years 6 months
Restricted stock units
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 297,934
Weighted-average amortization period	2 years 6 months
ESPP
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 2,604
Weighted-average amortization period	4 months 24 days
Cost of revenue
Stock-based Compensation Expense
Stock-based compensation expense	$ 17,734	9,422	6,334
Research and development
Stock-based Compensation Expense
Stock-based compensation expense	29,179	14,043	7,658
Sales and marketing
Stock-based Compensation Expense
Stock-based compensation expense	35,269	20,164	11,368
General and administrative
Stock-based Compensation Expense
Stock-based compensation expense	$ 26,623	$ 21,118	$ 16,705

Stockholders' Equity - Option a

Stockholders' Equity - Option and ESPP Valuation Assumptions (Details)	1 Months Ended						12 Months Ended
	Nov. 30, 2021	May 31, 2021	Nov. 30, 2020	May 31, 2020	Nov. 30, 2019	May 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock options and purchase rights
Class of Stock [Line Items]
Expected term (years)							6 years	5 years 8 months 12 days	6 years 1 month 6 days
Volatility							47.00%	47.00%	46.00%
Risk-free interest rate							1.00%	0.90%	2.30%
Dividend yield							0.00%	0.00%	0.00%
Purchase rights
Class of Stock [Line Items]
Expected term (years)								6 years
Volatility								47.00%
Risk-free interest rate								1.00%
Dividend yield								0.00%
Stock options
Class of Stock [Line Items]
Expected term (years)								4 years 3 months 18 days
Volatility								47.00%
Risk-free interest rate								0.30%
Dividend yield								0.00%
ESPP
Class of Stock [Line Items]
Expected term (years)	6 months	6 months	6 months	6 months	6 months	6 months
Volatility	46.00%	49.00%	50.00%	50.00%	46.00%	51.00%
Risk-free interest rate	0.20%	0.10%	0.10%	0.20%	2.40%	2.50%
Dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Net Loss Per Share - Basic and

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net loss	$ (3,601)	$ (20,537)	$ (16,530)	$ (12,332)	$ (7,210)	$ (11,431)	$ (16,052)	$ (7,437)	$ (53,000)	$ (42,130)	$ (4,552)
Weighted-average shares used in computing basic net loss per share (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371
Weighted-average shares used in computing diluted net loss per share (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371
Basic net loss per share (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)
Diluted net loss per share (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	11,205	5,432	6,521
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	1,982	2,255	2,530
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	2,560	2,267	2,372
Convertible senior notes(1)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	6,663	910	1,619

Net Loss Per Share - Narrative

Net Loss Per Share - Narrative (Details)	Dec. 31, 2021$ / shares
Convertible Senior Notes, Due 2023 | Convertible debt
Debt Instrument [Line Items]
Conversion price on convertible debt (in USD per share)	$ 40.82

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Loss before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United States									$ (59,856)	$ (44,303)	$ (5,340)
International									(4,429)	(280)	892
Loss before income taxes	$ (14,046)	$ (20,725)	$ (16,665)	$ (12,849)	$ (7,202)	$ (11,085)	$ (18,928)	$ (7,368)	$ (64,285)	$ (44,583)	$ (4,448)

Income Taxes - Schedule of Co_2

Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current:
U.S. federal									$ 0	$ 0	$ 0
U.S. state									262	401	61
Foreign									(202)	233	43
Total (benefit from) provision for income taxes									60	634	104
Deferred:
U.S. federal									0	(2,495)	0
U.S. state									0	(414)	0
Foreign									(11,345)	(178)	0
Total (benefit from) income taxes - Deferred									(11,345)	(3,087)	0
Total (benefit from) provision for income taxes	$ (10,445)	$ (188)	$ (135)	$ (517)	$ 8	$ 346	$ (2,876)	$ 69	$ (11,285)	$ (2,453)	$ 104

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Amount Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
U.S. federal tax at statutory rate									$ (13,500)	$ (9,362)	$ (934)
U.S. state income taxes									262	(345)	(65)
Section 162(m)									7,543	6,472	5,623
Non-deductible expenses									1,361	1,944	276
Research and development credit									(1,181)	(837)	(860)
Stock-based compensation									(25,241)	(23,800)	(16,619)
Tax benefit from acquisition/reorganizations									(5,877)	(2,495)	0
Foreign taxes									(4,760)	118	(10)
Other									20	533	(119)
Change in valuation allowance									30,088	25,319	12,812
Total (benefit from) provision for income taxes	$ (10,445)	$ (188)	$ (135)	$ (517)	$ 8	$ 346	$ (2,876)	$ 69	$ (11,285)	$ (2,453)	$ 104

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss and credit carryforwards	$ 133,433	$ 95,180
Accrued liabilities	12,719	6,244
Allowance for doubtful accounts	712	766
Amortized intangibles	872	0
Deferred revenue	1,351	782
Accrued compensation	3,963	3,596
Long-term lease liabilities	13,618	1,418
Gross deferred tax assets	166,668	107,986
Valuation allowance	(121,835)	(51,127)
Net deferred tax assets	44,833	56,859
Deferred tax liabilities:
Property and equipment	(2,633)	(876)
Amortized intangibles	0	(11,041)
Other	(509)	(92)
Right of use assets	(11,573)	(1,276)
Deferred compensation - Current	(23,211)	(12,180)
Convertible senior notes	0	(35,832)
Gross deferred tax liabilities	(37,926)	(61,297)
Net deferred taxes	$ 6,907
Net deferred taxes		$ (4,438)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
U.S. federal income tax rate (percent)		21.00%
Deferred tax assets		$ 6,907
Limitation on use of net operating loss, cumulative ownership change, more than		50.00%
Limitation on use of net operating loss, cumulative ownership change, period of change (in years)		3 years
Unrecognized tax benefits that would impact effective tax rate		$ 0	$ 300
Forecast
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance for deferred tax assets	$ 2,100
U.K. and Australia
Operating Loss Carryforwards [Line Items]
Deferred tax assets		6,900	6,900
Federal
Operating Loss Carryforwards [Line Items]
Increase (decrease) in valuation allowance for deferred tax assets		70,700	$ (8,800)
Net operating loss carryforwards		495,300
Federal | Research and Development Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards		8,400
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		306,800
State | Research and Development Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards		5,800
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		$ 18,800

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits
Unrecognized benefit — beginning of period	$ 6,076	$ 4,471	$ 10,723
Gross increases — current year tax positions	1,851	1,605	963
Gross decreases — prior year tax positions	0	0	(7,215)
Settlements with tax authorities	(284)	0	0
Unrecognized benefit — end of period	$ 7,643	$ 6,076	$ 4,471

Commitments and Contingencies -

Commitments and Contingencies - Commitments (Details) $ in Thousands	Dec. 31, 2021USD ($)
Other Commitments [Line Items]
Debt balance	$ 781,700
Outstanding operating lease obligations	63,953
Purchase Commitment - Cloud Services Agreement
Other Commitments [Line Items]
Expiring commercial commitment balance	61,100
Commercial commitment to be paid year one	21,800
Commercial commitment to be paid year two	$ 39,300

Commitments and Contingencies_2

Commitments and Contingencies - Hosting and Telecommunications Usage Services (Details) $ in Thousands	Dec. 31, 2021USD ($)
Hosting Services
Unrecorded Unconditional Purchase Obligation [Line Items]
2022	$ 1,342
2023	588
2024	226
2025	0
Thereafter	0
Total future minimum payment	2,156
Telecommunication Usage Services
Unrecorded Unconditional Purchase Obligation [Line Items]
2022	7,151
2023	5,481
2024	3,532
2025	176
Thereafter	75
Total future minimum payment	$ 16,415

Commitments and Contingencies_3

Commitments and Contingencies - Universal Services Fund Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2015
Loss Contingencies [Line Items]
Accrued federal fees	$ 2,282	$ 3,745
Civil penalty
Loss Contingencies [Line Items]
Accrued federal fees			$ 2,000
Year 2008 through 2012 | USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees			$ 3,900
Disputed portion | Year 2003 To Year 2007 | USF Obligations
Loss Contingencies [Line Items]
Disputed liability related to reversal of interest and penalties	$ 100

Commitments and Contingencies_4

Commitments and Contingencies - State and Local Taxes and Surcharges (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Sales tax liability - current	$ 2,660	$ 1,714
Contingent sales tax liabilities
Loss Contingencies [Line Items]
Sales tax liability	1,000	1,100
Sales tax liability - current	$ 200	$ 200

Geographical Information - Sche

Geographical Information - Schedule of Revenue and Property and Equipment by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets
Revenue	$ 173,599	$ 154,328	$ 143,782	$ 137,882	$ 127,885	$ 112,143	$ 99,792	$ 95,088	$ 609,591	$ 434,908	$ 328,006
Property and equipment, net	77,785				51,213				77,785	51,213
United States
Revenues from External Customers and Long-Lived Assets
Revenue									556,385	400,509	301,536
Property and equipment, net	68,674				43,339				68,674	43,339
International
Revenues from External Customers and Long-Lived Assets
Revenue									53,206	34,399	$ 26,470
Property and equipment, net	$ 9,111				$ 7,874				$ 9,111	$ 7,874

Retirement Plans (Details)

Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Contribution expense	$ 1.8	$ 1.4
Requisite service period (in years)	5 years
Defined benefit liability	$ 0.6	0.6
Retirement expense	$ 0.2	$ 0.1	$ 0.1

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Feb. 01, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease, termination notice, period (in days)	30 days
Operating lease liability	$ 56,914		$ 9,291
Data Center
Lessee, Lease, Description [Line Items]
Amount of lease obligation, not yet commenced	200
Building
Lessee, Lease, Description [Line Items]
Amount of lease obligation, not yet commenced	$ 300
Operating lease not yet commenced, term of lease (in years)	3 years
Bishop Ranch Building Lease
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)		10 years
Operating lease liability		$ 46,400
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	1 year
Operating lease, extension term (in years)	3 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	10 years
Operating lease, extension term (in years)	5 years

Leases - Lease Cost and Supplem

Leases - Lease Cost and Supplemental Cash Flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 10,238	$ 6,142	$ 5,153
Finance lease cost:
Amortization of right-of-use assets	438	748	6,345
Interest on finance lease liabilities	0	212	704
Total finance lease cost	438	960	7,049
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash used in operating leases	(7,178)	(6,531)	(5,237)
Financing cash used in finance leases	(612)	(3,715)	(7,054)
Right of use assets obtained in exchange for lease obligations:
Operating leases	50,101	5,980	5,737
Finance leases	$ 0	$ 0	$ 0

Leases - Balance Sheet Disclosu

Leases - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating leases
Operating lease right-of-use assets	$ 48,703	$ 9,010
Operating lease liabilities:
Operating lease liabilities	9,826	3,912
Operating lease liabilities — less current portion	47,088	5,379
Total operating lease liabilities	56,914	9,291
Finance leases
Property and equipment, gross	42,541	45,021
Less: accumulated depreciation and amortization	(41,689)	(41,908)
Property and equipment, net	$ 852	$ 3,113
Finance lease, right-of-use asset, Balance Sheet location [Extensible Enumeration]	Property and equipment, net	Property and equipment, net
Finance lease liabilities:
Finance lease liabilities	$ 0	$ 612
Finance lease liabilities — less current portion	0	0
Total finance lease liabilities	$ 0	$ 612

Leases - Weighted Average Remai

Leases - Weighted Average Remaining Terms and Discount Rates (Details)	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Weighted average remaining lease term, Operating leases (in years)	7 years 3 months 18 days	2 years 7 months 6 days
Weighted average remaining lease term, Finance leases (in years)	0 years	6 months
Weighted average discount rate, Operating leases	3.20%	4.50%
Weighted average discount rate, Finance leases	0.00%	7.90%

Leases - Lease Maturities (Deta

Leases - Lease Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2022	$ 11,383
2023	10,633
2024	7,744
2025	5,583
2026	5,752
Thereafter	22,858
Total future minimum lease payments	63,953
Less: imputed interest	(7,039)
Total	56,914	$ 9,291
Finance Leases
2022	0
2023	0
2024	0
2025	0
2026	0
Thereafter
Total future minimum lease payments	0
Less: imputed interest	0
Total	$ 0	$ 612

Acquisitions - Inference Soluti

Acquisitions - Inference Solutions Narrative (Details) - USD ($) $ in Thousands	Nov. 18, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2020
Business Acquisition [Line Items]
Cash paid to acquire Virtual Observer		$ 0	$ 165,338	$ 0
Contingent consideration		23,740	18,100
Goodwill		165,420	165,420	$ 11,798
Inference Solutions
Business Acquisition [Line Items]
Cash consideration	$ 156,700
Cash paid to acquire Virtual Observer	137,000
Contingent consideration	18,100	23,700			$ 24,000
Contingent consideration, range of outcomes, low		0
Contingent consideration, range of outcomes, high		24,000
Goodwill	$ 130,976
Business combination, acquisition related costs		300	$ 2,900
Inference Solutions | Acquired technology
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	6 years
Inference Solutions | Customer relationships
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	5 years
Inference Solutions | Trade name and trademarks
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	2 years
Inference Solutions | Maximum
Business Acquisition [Line Items]
Contingent consideration		$ 24,000

Acquisitions - Inference Solu_2

Acquisitions - Inference Solutions Table (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Nov. 18, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 165,420	$ 165,420		$ 11,798
Inference Solutions
Business Acquisition [Line Items]
Cash			$ 1,394
Property and equipment acquired			124
Other assets acquired			2,238
Goodwill			130,976
Total assets acquired			164,832
Liabilities assumed			(3,525)
Deferred tax liability			(4,616)
Total			156,691
Total consideration (net of cash acquired)			155,297
Inference Solutions | Acquired technology
Business Acquisition [Line Items]
Finite-lived intangibles acquired			28,600
Inference Solutions | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles acquired			1,100
Inference Solutions | Trade name and trademarks
Business Acquisition [Line Items]
Finite-lived intangibles acquired			$ 400

Acquisitions - Virtual Observer

Acquisitions - Virtual Observer Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Cash paid to acquire Inference Solutions		$ 0	$ 165,338	$ 0
Goodwill		$ 165,420	165,420	11,798
Virtual Observer
Business Acquisition [Line Items]
Cash paid to acquire Inference Solutions	$ 32,200
Goodwill	$ 22,646
Business combination, acquisition related costs			$ 900	$ 300
Virtual Observer | Acquired technology
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	5 years
Virtual Observer | Customer relationships
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	5 years
Virtual Observer | Trade name and trademarks
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life (years)	2 years

Acquisitions - Virtual Observ_2

Acquisitions - Virtual Observer Table (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Apr. 01, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 165,420	$ 165,420		$ 11,798
Virtual Observer
Business Acquisition [Line Items]
Cash			$ 168
Tangible assets acquired			200
Goodwill			22,646
Total assets acquired			35,814
Deferred tax liability			(2,910)
Liabilities assumed			(682)
Total			32,222
Virtual Observer | Acquired technology
Business Acquisition [Line Items]
Finite-lived intangibles acquired			12,200
Virtual Observer | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangibles acquired			500
Virtual Observer | Trade name and trademarks
Business Acquisition [Line Items]
Finite-lived intangibles acquired			$ 100

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) - Schedule of Quarterly Financial Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 173,599	$ 154,328	$ 143,782	$ 137,882	$ 127,885	$ 112,143	$ 99,792	$ 95,088	$ 609,591	$ 434,908	$ 328,006
Cost of revenue	79,764	67,137	64,395	59,803	51,233	46,561	42,453	40,037	271,099	180,284	134,511
Gross profit	93,835	87,191	79,387	78,079	76,652	65,582	57,339	55,051	338,492	254,624	193,495
Operating expenses:
Research and development	30,448	29,680	24,648	22,121	18,676	17,674	17,208	15,189	106,897	68,747	45,190
Sales and marketing	53,394	49,712	46,024	44,799	37,053	32,969	32,231	30,160	193,929	132,413	95,592
General and administrative	21,972	26,790	22,909	22,245	18,258	16,724	16,129	14,658	93,916	65,769	49,446
Total operating expenses	105,814	106,182	93,581	89,165	73,987	67,367	65,568	60,007	394,742	266,929	190,228
(Loss) income from operations	(11,979)	(18,991)	(14,194)	(11,086)	2,665	(1,785)	(8,229)	(4,956)	(56,250)	(12,305)	3,267
Other (expense) income, net:
Interest expense	(2,024)	(1,947)	(2,118)	(1,938)	(9,481)	(9,649)	(5,734)	(3,484)	(8,027)	(28,348)	(13,794)
Loss on early extinguishment of debt	0	0	0	0	(887)	(282)	(5,794)	0	0	(6,964)	0
Other (expense) and interest income	(43)	213	(353)	175	501	631	829	1,072	(8)	3,034	6,079
Total other (expense) income, net	(2,067)	(1,734)	(2,471)	(1,763)	(9,867)	(9,300)	(10,699)	(2,412)	(8,035)	(32,278)	(7,715)
Loss before income taxes	(14,046)	(20,725)	(16,665)	(12,849)	(7,202)	(11,085)	(18,928)	(7,368)	(64,285)	(44,583)	(4,448)
(Benefit from) provision for income taxes	(10,445)	(188)	(135)	(517)	8	346	(2,876)	69	(11,285)	(2,453)	104
Net loss	$ (3,601)	$ (20,537)	$ (16,530)	$ (12,332)	$ (7,210)	$ (11,431)	$ (16,052)	$ (7,437)	$ (53,000)	$ (42,130)	$ (4,552)
Net loss per share:
Basic (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)
Diluted (in USD per share)	$ (0.05)	$ (0.30)	$ (0.25)	$ (0.18)	$ (0.11)	$ (0.17)	$ (0.25)	$ (0.12)	$ (0.79)	$ (0.66)	$ (0.08)
Shares used in computing net loss per share:
Basic (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371
Diluted (in shares)	68,207	67,800	67,292	66,721	66,133	65,460	63,282	61,705	67,512	64,154	60,371

Selected Quarterly Financial _4

Selected Quarterly Financial Data (Unaudited) - Allocation of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information [Line Items]
Total stock-based compensation	$ 35,601	$ 27,395	$ 24,901	$ 20,908	$ 16,876	$ 17,286	$ 16,791	$ 13,794	$ 108,805	$ 64,747	$ 42,065
Cost of revenue
Quarterly Financial Information [Line Items]
Total stock-based compensation	6,854	3,994	3,781	3,105	2,331	2,603	2,499	1,989
Research and development
Quarterly Financial Information [Line Items]
Total stock-based compensation	9,163	9,101	6,152	4,763	3,674	3,876	3,684	2,806
Sales and marketing
Quarterly Financial Information [Line Items]
Total stock-based compensation	11,987	8,304	8,208	6,771	5,366	5,427	5,265	4,106
General and administrative
Quarterly Financial Information [Line Items]
Total stock-based compensation	$ 7,597	$ 5,996	$ 6,760	$ 6,269	$ 5,505	$ 5,380	$ 5,343	$ 4,893

Selected Quarterly Financial _5

Selected Quarterly Financial Data (Unaudited) - Allocation of Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information [Line Items]
Total depreciation and amortization	$ 10,538	$ 9,780	$ 9,651	$ 8,763	$ 7,337	$ 6,537	$ 6,243	$ 4,970	$ 38,732	$ 25,087	$ 14,374
Cost of revenue
Quarterly Financial Information [Line Items]
Total depreciation and amortization	8,301	7,658	7,825	7,087	5,948	5,171	5,120	3,940
Research and development
Quarterly Financial Information [Line Items]
Total depreciation and amortization	948	1,004	729	596	488	512	497	465
Sales and marketing
Quarterly Financial Information [Line Items]
Total depreciation and amortization	1	1	1	1	2	1	2	2
General and administrative
Quarterly Financial Information [Line Items]
Total depreciation and amortization	$ 1,288	$ 1,117	$ 1,096	$ 1,079	$ 899	$ 853	$ 624	$ 563