Five9 (FIVN) 10-Q 3 Aug 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2020	Jul. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
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	Bishop Ranch 8
Entity Address, Address Line Two	4000 Executive Parkway
Entity Address, Address Line Three	Suite 400
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, par value $0.001 per share
Trading Symbol	FIVN
Security Exchange Name	NASDAQ
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		65,335,870
Entity Central Index Key	0001288847
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 233,235	$ 77,976
Debt Securities, Available-for-sale, Current	452,708	241,973
Accounts receivable, net	39,607	37,655
Prepaid expenses and other current assets	17,529	10,656
Deferred contract acquisition costs	16,151	13,014
Total current assets	759,230	381,274
Property and equipment, net	39,799	33,190
Operating lease right-of-use assets	10,006	8,746
Intangible assets, net	25,605	15,533
Goodwill	34,444	11,798
Marketable Securities	82,064	0
Other assets	2,789	1,184
Deferred contract acquisition costs — less current portion	39,366	30,655
Total assets	993,303	482,380
Current liabilities:
Accounts payable	12,045	10,156
Accrued and other current liabilities	34,817	18,385
Operating lease liabilities	5,247	5,064
Accrued federal fees	1,670	2,303
Sales tax liabilities	1,565	1,885
Finance lease liabilities	2,032	3,518
Deferred revenue	26,306	24,681
Total current liabilities	83,682	65,992
Convertible senior notes	642,203	209,604
Sales tax liabilities — less current portion	847	838
Operating lease liabilities — less current portion	5,249	4,329
Finance lease liabilities — less current portion	100	809
Other long-term liabilities	6,814	4,350
Total liabilities	738,895	285,922
Commitments and contingencies
Stockholders’ equity:
Common stock	65	61
Additional paid-in capital	432,877	351,870
Accumulated other comprehensive income	1,004	576
Accumulated deficit	(179,538)	(156,049)
Total stockholders’ equity	254,408	196,458
Total liabilities and stockholders’ equity	$ 993,303	$ 482,380

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenue	$ 99,792	$ 77,436	$ 194,880	$ 151,974
Cost of revenue	42,453	31,248	82,490	62,099
Gross profit	57,339	46,188	112,390	89,875
Operating expenses:
Research and development	17,208	10,811	32,397	21,357
Sales and marketing	32,231	23,250	62,391	44,951
General and administrative	16,129	12,042	30,787	23,804
Total operating expenses	65,568	46,103	125,575	90,112
Income (loss) from operations	(8,229)	85	(13,185)	(237)
Other income (expense), net:
Interest expense	(5,734)	(3,406)	(9,218)	(6,802)
Interest income and other	(4,965)	1,490	(3,893)	3,235
Total other income (expense), net	(10,699)	(1,916)	(13,111)	(3,567)
Loss before income taxes	(18,928)	(1,831)	(26,296)	(3,804)
Provision for (benefit from) income taxes	(2,876)	29	(2,807)	(20)
Net loss	$ (16,052)	$ (1,860)	$ (23,489)	$ (3,784)
Net loss per share:
Basic and diluted (in usd per share)	$ (0.25)	$ (0.03)	$ (0.38)	$ (0.06)
Shares used in computing net loss per share:
Basic and diluted (in shares)	63,282	60,058	62,494	59,714
Comprehensive Loss:
Net loss	$ (16,052)	$ (1,860)	$ (23,489)	$ (3,784)
Other comprehensive income (loss)	(626)	65	428	239
Comprehensive loss	$ (16,678)	$ (1,795)	$ (23,061)	$ (3,545)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2018	$ 142,748	$ 59	$ 294,279	$ (93)	$ (151,497)
Beginning balance (in shares) at Dec. 31, 2018		59,210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	4,249	$ 2	4,247
Issuance of common stock upon exercise of stock options (in shares)		660
Issuance of common stock upon vesting of restricted stock units (in shares)		640
Issuance of common stock under ESPP	3,996		3,996
Issuance of common stock under ESPP (in shares)		109
Stock-based compensation	19,122		19,122
Other comprehensive income	239			239
Net loss	(3,784)				(3,784)
Ending balance at Jun. 30, 2019	166,570	$ 61	321,644	146	(155,281)
Ending balance (in shares) at Jun. 30, 2019		60,619
Beginning balance at Mar. 31, 2019	150,666	$ 60	303,946	81	(153,421)
Beginning balance (in shares) at Mar. 31, 2019		59,637
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	3,267	$ 1	3,266
Issuance of common stock upon exercise of stock options (in shares)		444
Issuance of common stock upon vesting of restricted stock units (in shares)		429
Issuance of common stock under ESPP	3,996		3,996
Issuance of common stock under ESPP (in shares)		109
Stock-based compensation	10,436		10,436
Other comprehensive income	65			65
Net loss	(1,860)				(1,860)
Ending balance at Jun. 30, 2019	166,570	$ 61	321,644	146	(155,281)
Ending balance (in shares) at Jun. 30, 2019		60,619
Beginning balance at Dec. 31, 2019	196,458	$ 61	351,870	576	(156,049)
Beginning balance (in shares) at Dec. 31, 2019		61,544
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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	(293,809)		(293,809)
Issuance of common stock upon partial conversion of the 2023 convertible senior notes	268,573	$ 3	268,570
Equity component from partial repurchase of 2023 convertible senior notes (in shares)		2,724
Issuance of common stock upon exercise of stock options	6,080		6,080
Issuance of common stock upon exercise of stock options (in shares)		321
Issuance of common stock upon vesting of restricted stock units	1	$ 1
Issuance of common stock upon vesting of restricted stock units (in shares)		604
Issuance of common stock under ESPP	5,666		5,666
Issuance of common stock under ESPP (in shares)		103
Stock-based compensation	30,585		30,585
Other comprehensive income	428			428
Net loss	(23,489)				(23,489)
Ending balance at Jun. 30, 2020	254,408	$ 65	432,877	1,004	(179,538)
Ending balance (in shares) at Jun. 30, 2020		65,296
Beginning balance at Mar. 31, 2020	206,466	$ 62	368,260	1,630	(163,486)
Beginning balance (in shares) at Mar. 31, 2020		61,992
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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	293,809		293,809
Issuance of common stock upon partial conversion of the 2023 convertible senior notes	268,573	$ 3	268,570
Equity component from partial repurchase of 2023 convertible senior notes (in shares)		2,724
Issuance of common stock upon exercise of stock options	3,484		3,484
Issuance of common stock upon exercise of stock options (in shares)		161
Issuance of common stock upon vesting of restricted stock units (in shares)		316
Issuance of common stock under ESPP	5,666		5,666
Issuance of common stock under ESPP (in shares)		103
Stock-based compensation	16,791		16,791
Other comprehensive income	(626)			(626)
Net loss	(16,052)				(16,052)
Ending balance at Jun. 30, 2020	$ 254,408	$ 65	$ 432,877	$ 1,004	$ (179,538)
Ending balance (in shares) at Jun. 30, 2020		65,296

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (23,489)	$ (3,784)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	11,213	6,553
Amortization of operating lease right-of-use assets	2,786	2,147
Amortization of premium on marketable investments	630	(883)
Provision for doubtful accounts	353	30
Stock-based compensation	30,585	19,122
Gain on sale of convertible note held for investment	0	(217)
Amortization of debt discount and issuance costs	8,571	6,234
Loss on early extinguishment of debt	5,794	0
Tax benefit of valuation allowance associated with an acquisition	(2,910)	0
Others	82	(23)
Changes in operating assets and liabilities:
Accounts receivable	(2,119)	(3,378)
Prepaid expenses and other current assets	(7,065)	(4,053)
Deferred contract acquisition costs	(11,848)	(5,488)
Other assets	(1,604)	(12,571)
Accounts payable	2,553	159
Accrued and other current liabilities	9,561	6,516
Accrued federal fees and sales tax liability	(945)	(337)
Deferred revenue	3,292	2,539
Other liabilities	(281)	5,412
Net cash provided by operating activities	25,159	17,978
Cash flows from investing activities:
Purchases of marketable investments	(460,899)	(151,308)
Proceeds from maturities of marketable investments	167,850	165,354
Purchases of property and equipment	(14,891)	(8,226)
Cash paid to acquire Virtual Observer	(28,313)	0
Cash paid to acquire substantially all of the assets of Whendu LLC	(100)	0
Proceeds from sale of convertible note held for investment	0	217
Net cash (used in) provided by investing activities	(336,353)	6,037
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net of issuance costs	728,812	0
Payments for capped call transactions related to the 2025 convertible senior notes	(90,448)	0
Repurchase of a portion of 2023 convertible senior notes, net of costs	(181,462)	0
Proceeds from exercise of common stock options	6,080	4,248
Proceeds from sale of common stock under ESPP	5,666	3,996
Payments of finance leases	(2,195)	(3,702)
Net cash provided by financing activities	466,453	4,542
Net increase in cash and cash equivalents	155,259	28,557
Cash and cash equivalents:
Beginning of period	77,976	81,912
End of period	233,235	110,469
Supplemental disclosures of cash flow data:
Cash paid for interest	305	590
Cash paid for income taxes	141	153
Non-cash investing and financing activities:
Equipment purchased and unpaid at period-end	2,838	1,602
Capitalization of leasehold improvement through non-cash lease incentive	0	42
Acquisition and related transaction costs accrued at period-end	$ 3,700	$ 0

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2020
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 and Asia, which primarily provide research, development, sales, marketing, and client support services. Basis of Presentation The accompanying condensed 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 interim financial reporting. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. In the opinion of management, the condensed consolidated financial statements reflect all adjustments, which are normal and recurring in nature, necessary for fair financial statement presentation. All intercompany transactions and balances have been eliminated in consolidation. Certain prior period amounts included in the condensed consolidated financial statements have been reclassified to conform to the current period presentation. Use of Estimates The preparation of condensed 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 condensed 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. Management periodically evaluates such estimates and they are adjusted prospectively based upon such periodic evaluation. Actual results could differ from those estimates. Significant Accounting Policies The Company’s significant accounting policies are disclosed in its Annual Report on Form 10-K for the year ended December 31, 2019. Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires measurement and recognition of expected credit losses for financial assets held at amortized cost, including trade receivables. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in more timely recognition of credit losses. The Company adopted ASU 2016-13 using the modified retrospective method on January 1, 2020. The adoption of ASU 2016-13 did not have a material impact on the Company’s consolidated financial position, operating results or cash flows. See Notes 3 and 4 for further information on the impact of this adoption. Recent Accounting Pronouncements Not Yet Effective 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 provisions, removing exceptions to certain general principles in Topic 740, Income Taxes. The standard will be effective for the Company beginning in the first quarter of 2021, with early adoption permitted. The Company is currently evaluating the impact that the adoption of ASU 2019-12 will have on its consolidated financial statements. The Company has reviewed or is in the process of evaluating all other 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 cash flows.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Contract Balances The following table provides information about accounts receivable, net, deferred contract acquisition costs, contract assets and contract liabilities from contracts with customers (in thousands): June 30, 2020 December 31, 2019 Accounts receivable, net $ 39,607 $ 37,655 Deferred contract acquisition costs: Current $ 16,151 $ 13,014 Non-current 39,366 30,655 Total deferred contract acquisition costs $ 55,517 $ 43,669 Contract assets and contract liabilities: Contract assets (included in prepaid expenses and other current assets) $ 771 $ 825 Contract liabilities (deferred revenue) 26,306 24,681 Contract liabilities (deferred revenue) (included in other long-term liabilities) 3,701 1,550 Net contract liabilities $ (29,236) $ (25,406) 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 a 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 three and six months ended June 30, 2020, the Company recognized revenue of $4.0 million and $20.0 million, respectively, related to its contract liabilities at December 31, 2019. Remaining Performance Obligations As of June 30, 2020, 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 $242.0 million. The Company expects to recognize revenue on approximately four-fifths of the remaining performance obligation 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	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020 and December 31, 2019 were as follows (in thousands): June 30, 2020 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term Marketable Investments: Certificates of deposit $ 3,976 $ 1 $ — $ 3,977 U.S. treasury 283,830 217 (9) 284,038 U.S. agency securities 136,087 275 (3) 136,359 Commercial paper 5,387 — — 5,387 Municipal bonds 7,454 4 — 7,458 Corporate bonds 15,483 14 (8) 15,489 Total $ 452,217 $ 511 $ (20) $ 452,708 Long-term Marketable Investments: U.S. treasury $ 40,005 $ — $ (8) $ 39,997 U.S. agency securities 40,273 9 — 40,282 Corporate bonds 1,783 2 — 1,785 Total $ 82,061 $ 11 $ (8) $ 82,064 December 31, 2019 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term Marketable Investments: Certificates of deposit $ 161 $ 1 $ — $ 162 U.S. treasury 31,933 8 (1) 31,940 U.S. agency securities 177,629 110 (9) 177,730 Commercial paper 15,240 — — 15,240 Municipal bonds 3,014 1 — 3,015 Corporate bonds 13,876 10 — 13,886 Total $ 241,853 $ 130 $ (10) $ 241,973 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 June 30, 2020 and December 31, 2019 (in thousands): June 30, 2020 December 31, 2019 Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value U.S. treasury $ (17) $ 174,600 $ (1) $ 12,926 U.S. agency securities (4) 56,328 (9) 36,322 Municipal bonds (1) 512 Corporate bonds (8) 5,127 — 251 Total $ (30) $ 236,567 $ (10) $ 49,499 Although the Company had certain available-for-sale debt securities in an unrealized loss position as of June 30, 2020, 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, which it is now required to assess upon adoption of ASU 2016-13. The amortized cost and fair value of the Company’s marketable investments by contractual maturity as of June 30, 2020 were as follows: Cost Fair Value Due within one year $ 452,217 $ 452,708 Due after one year through two years 82,061 82,064 Total $ 534,278 $ 534,772 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): June 30, 2020 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 54,325 $ — $ — $ 54,325 U.S. treasury 110,979 — — 110,979 Municipal bonds — 1,457 — 1,457 Total cash equivalents $ 165,304 $ 1,457 $ — $ 166,761 Marketable investments (Short and Long-term) Certificates of deposit $ — $ 3,977 $ — $ 3,977 U.S. treasury 324,036 — — 324,036 U.S. agency securities — 176,640 — 176,640 Commercial paper — 5,387 — 5,387 Municipal bonds — 7,458 — 7,458 Corporate bonds — 17,274 — 17,274 Total marketable investments $ 324,036 $ 210,736 $ — $ 534,772 December 31, 2019 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 2,179 $ — $ — $ 2,179 Commercial paper — 2,697 — 2,697 Total cash equivalents $ 2,179 $ 2,697 $ — $ 4,876 Marketable investments Certificates of deposit $ — $ 162 $ — $ 162 U.S. treasury 31,940 — — 31,940 U.S. agency securities — 177,730 — 177,730 Commercial paper — 15,240 — 15,240 Municipal bonds — 3,015 — 3,015 Corporate bonds — 13,886 — 13,886 Total marketable investments $ 31,940 $ 210,033 $ — $ 241,973 As of June 30, 2020 and December 31, 2019, the estimated fair value of the Company’s outstanding 0.125% convertible senior notes due 2023 (the "2023 convertible senior notes") was $210.7 million and $437.0 million, respectively. As of June 30, 2020, the estimated fair value of the Company's 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") was $802.4 million. 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 has been classified as Level 2 in the fair value hierarchy. See Note 6 for further information on the Company’s convertible senior notes. There were no assets or liabilities measured at fair value on a non-recurring basis as of June 30, 2020 and December 31, 2019. The Company’s other financial instruments’ fair value, including accounts receivable, accounts payable and other current liabilities, approximate its carrying value due to the relatively short maturity of those instruments. The carrying amounts of the Company’s 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	6 Months Ended
	Jun. 30, 2020
Financial Statement Components [Abstract]
Financial Statement Components	Financial Statement Components Cash and cash equivalents consisted of the following (in thousands): June 30, 2020 December 31, 2019 Cash $ 66,474 $ 73,100 Money market funds 54,325 2,179 U.S. treasury 110,979 — Commercial paper — 2,697 Municipal bonds 1,457 — Total cash and cash equivalents $ 233,235 $ 77,976 Accounts receivable, net consisted of the following (in thousands): June 30, 2020 December 31, 2019 Trade accounts receivable $ 35,887 $ 34,591 Unbilled trade accounts receivable, net of advance client deposits 3,835 3,075 Allowance for doubtful accounts (115) (11) Accounts receivable, net $ 39,607 $ 37,655 The Company's adoption of ASU 2016-13 on January 1, 2020 required it to shift from an incurred loss impairment model to 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 adoption of this new standard resulted in an increase to the allowance for doubtful accounts reserve of $0.1 million and $0.3 million during the three and six months ended June 30, 2020, respectively. The following table presents the change in the allowance for doubtful accounts, including consideration of expected credit losses, for the three and six months ended June 30, 2020 (in thousands): Three Months Ended Six Months June 30, 2020 June 30, 2020 Balance, beginning of period $ (168) $ (11) Add: Bad debt expense (excluding expected credit loss portion) (23) (45) Add: Bad debt expense (expected credit loss portion) (74) (307) Less: Write-offs, net of recoveries (excluding expected credit loss portion) 18 29 Less: Write-offs, net of recoveries (expected credit loss portion) $ 132 $ 219 Balance, end of period $ (115) $ (115) Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2020 December 31, 2019 Prepaid expenses $ 10,071 $ 4,901 Other current assets 6,687 4,930 Contract assets 771 825 Prepaid expenses and other current assets $ 17,529 $ 10,656 Property and equipment, net consisted of the following (in thousands): June 30, 2020 December 31, 2019 Computer and network equipment $ 77,828 $ 67,378 Computer software 18,301 14,157 Internal-use software development costs 500 500 Furniture and fixtures 2,869 2,918 Leasehold improvements 2,090 2,264 Property and equipment 101,588 87,217 Accumulated depreciation and amortization (61,789) (54,027) Property and equipment, net $ 39,799 $ 33,190 Depreciation and amortization expense associated with property and equipment was $4.5 million and $8.4 million for the three and six months ended June 30, 2020, respectively, and $3.3 million and $6.4 million for the three and six months ended June 30, 2019, respectively. Property and equipment capitalized under finance lease obligations consists primarily of computer and network equipment and was as follows (in thousands): June 30, 2020 December 31, 2019 Gross $ 46,520 $ 46,671 Less: accumulated depreciation and amortization (41,539) (39,190) Total $ 4,981 $ 7,481 Accrued and other current liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Accrued compensation and benefits $ 24,974 $ 14,233 Accrued expenses 9,843 4,152 Accrued and other current liabilities $ 34,817 $ 18,385

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill of $22.6 million and intangible assets of $12.8 million were recorded as a result of the Company's acquisition of Virtual Observer, formerly Coordinated Systems, Inc., in April 2020. See Note 13 for further details. The following table summarizes the activity in the Company's goodwill and intangible asset balances during the six months ended June 30, 2020 (in thousands): Goodwill Intangible Assets Beginning of the period, December 31, 2019 $ 11,798 $ 15,533 Addition (Virtual Observer) 22,646 12,800 Addition (Whendu) — 100 Amortization — (2,828) End of the period, June 30, 2020 $ 34,444 $ 25,605 The components of intangible assets were as follows (in thousands): June 30, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Amortization period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Amortization period (Years) Developed technology $ 30,075 $ (5,404) $ 24,671 4.0 $ 17,777 $ (2,690) $ 15,087 3.9 Acquired workforce 470 (99) 371 2.4 467 (21) 446 2.9 Customer relationships 500 (25) 475 4.8 — — — Trademarks 100 (12) 88 1.8 — — — Total $ 31,145 $ (5,540) $ 25,605 4.0 $ 18,244 $ (2,711) $ 15,533 3.8 Amortization expense for intangible assets was $1.7 million and $2.8 million during the three and six months ended June 30, 2020, respectively, and $0.1 million and $0.2 million during the three and six months ended June 30, 2019. The increase in amortization expense during the three and six months ended June 30, 2020 was due to the acquisition of intangible assets from Whendu LLC ("Whendu") in November 2019 and from Virtual Observer in April 2020. As of June 30, 2020, the expected future amortization expense for intangible assets was as follows (in thousands): Period Expected Future Amortization Expense Remaining 2020 $ 3,404 2021 6,600 2022 6,542 2023 5,883 2024 2,540 Thereafter 636 Total $ 25,605

Debt

Debt	6 Months Ended
	Jun. 30, 2020
Debt Disclosure [Abstract]
Debt	Debt 0.500% Convertible Senior Notes and Related Capped Call Transactions In May and June 2020, the Company issued $747.5 million aggregate principal amount of the 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. 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. The closing market price of the Company's common stock of $110.67 per share as of June 30, 2020, the last trading day during the three months ended June 30, 2020, 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, June 30, 2020, was not greater than or equal to 130% of the initial conversion price. As such, during the three months ended June 30, 2020, the conditions allowing holders of the 2025 convertible senior notes to convert were not met. The 2025 convertible senior notes were therefore not convertible during the three months ended June 30, 2020. 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 will 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. 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 is not re-measured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount (the “Debt Discount”) is being amortized to interest expense over the contractual term of the notes at an effective interest rate of 5.76%. The debt component was classified as long term liabilities during the three months ended June 30, 2020. 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 are being 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. The net carrying amount of the liability component of the 2025 convertible senior notes was as follows (in thousands): June 30, 2020 Principal $ 747,500 Unamortized debt discount (155,792) Unamortized issuance costs (14,494) Net carrying amount $ 577,214 The net carrying amount of the equity component of the 2025 convertible senior notes was as follows (in thousands): June 30, 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): Three Months Ended June 30, 2020 Contractual interest expense $ 362 Amortization of debt discount 2,528 Amortization of issuance costs 235 Total interest expense $ 3,125 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, which was recorded as a reduction to additional paid-in capital. The net impact to the Company's stockholders' equity as of June 30, 2020, included in additional paid-in capital, relating to the issuance of the 2025 convertible senior notes was as follows (in thousands): June 30, 2020 Conversion option $ 158,321 Payments for capped call transactions (90,448) Issuance costs (3,958) Total $ 63,915 Maturity of the Company’s 2025 convertible senior notes as of June 30, 2020 was as follows (in thousands): Period Amount to Mature 2025 (Maturity date of June 1, 2025) $ 747,500 Total $ 747,500 0.125% Convertible Senior Notes and Related Capped Call Transactions In May 2018, the Company issued $258.8 million aggregate principal amount of 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 June 30, 2020, after giving effect to the 2023 Note Repurchase Transactions, approximately $77.7 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, 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. During each of the first and second quarters of 2020, 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 of the first and second quarters of 2020. 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 April 1, 2020 to June 30, 2020, and are currently convertible between July 1, 2020 to September 30, 2020. Whether the 2023 convertible senior notes will be convertible after September 30, 2020 will depend on the continued satisfaction of this condition or other conversion conditions in the future. Through June 30, 2020, we settled aggregate principal amount of $5,000. In addition, the Company received elections to convert aggregate principal amount of $5,002,000 that remain unsettled as of the end of the second quarter of 2020. From July 1, 2020 through the date of this filing, the Company received additional elections to convert aggregate principal amount of $13,652,000. The Company has and expects to settle these conversions in cash or a combination of cash and shares during the second half of 2020. The Company has the option to settle any future election conversion notices in cash, shares, or a combination of cash and shares. The Company may not redeem the 2023 convertible senior notes prior to May 5, 2021. The Company may redeem for cash all or any portion of the 2023 convertible senior notes, at its option, on or after May 5, 2021 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. 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 carrying amount of the equity component representing the conversion option was $63.8 million and was determined by deducting the fair value of the liability component from the par value of the 2023 convertible senior notes. The equity component was recorded in additional paid-in-capital and is not re-measured as long as it continues to meet the conditions for equity classification. The Debt Discount is being amortized to interest expense over the contractual term of the 2023 convertible senior notes at an effective interest rate of 6.39%. 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 are being 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. The net carrying amount of the liability component of the 2023 convertible senior notes was as follows (in thousands): June 30, 2020 December 31, 2019 Principal $ 77,745 $ 258,750 Unamortized debt discount (11,649) (44,881) Unamortized issuance costs (1,107) (4,265) Net carrying amount $ 64,989 $ 209,604 The net carrying amount of the equity component of the 2023 convertible senior notes continued to meet the conditions for equity classification as presented below (in thousands): June 30, 2020 December 31, 2019 Equity component $ 19,158 $ 63,756 Issuance costs (600) (1,998) Net carrying amount $ 18,558 $ 61,758 Interest expense related to the 2023 convertible senior notes was as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Contractual interest expense $ 60 $ 81 $ 141 $ 162 Amortization of debt discount 2,272 2,888 5,304 5,698 Amortization of issuance costs 216 267 504 536 Total interest expense $ 2,548 $ 3,236 $ 5,949 $ 6,396 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 June 30, 2020 was as follows (in thousands): Period Amount to Mature 2023 (Maturity date of May 1, 2023) $ 77,745 Total $ 77,745

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020 and December 31, 2019, the Company had 65,295,611 and 61,543,634 shares of common stock issued and outstanding, respectively. In May 2020, in connection with the 2023 Note Repurchase Transactions, the Company issued 2,723,581 shares of common stock. See Note 6 for further details. 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 June 30, 2020 and December 31, 2019, 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 were as follows (in thousands): June 30, 2020 Stock options outstanding 2,431 Restricted stock units outstanding 2,753 Shares available for future grant under 2014 Plan 11,684 Shares available for future issuance under ESPP 2,598 Total shares of common stock reserved 19,466 Stock Options A summary of the Company’s stock option activity during the six months ended June 30, 2020 is as follows (in thousands, except years and per share data): Number of Weighted Weighted Aggregate Outstanding as of December 31, 2019 2,530 $ 19.38 Options granted (weighted average grant date fair value of $33.39 per share) 227 73.25 Options exercised (322) 18.91 Options forfeited or expired (4) 36.70 Outstanding as of June 30, 2020 2,431 $ 24.45 5.9 $ 209,602 The aggregate intrinsic value disclosed in the above table is 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 $110.67 per share as of June 30, 2020 for all in-the-money stock options outstanding. Restricted Stock Units A summary of the Company’s restricted stock unit, or RSU, activity during the six months ended June 30, 2020 is as follows (in thousands, except per share data): Number of Shares Weighted Average Grant Date Fair Value Per Share Outstanding as of December 31, 2019 2,372 $ 41.32 RSUs granted 1,050 73.26 RSUs vested and released (604) 37.97 RSUs forfeited (65) 48.56 Outstanding as of June 30, 2020 2,753 $ 54.54 Stock-Based Compensation Stock-based compensation expenses were as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Cost of revenue $ 2,499 $ 1,658 $ 4,488 $ 2,887 Research and development 3,684 1,907 6,491 3,377 Sales and marketing 5,265 2,749 9,371 4,998 General and administrative 5,343 4,122 10,235 7,860 Total stock-based compensation $ 16,791 $ 10,436 $ 30,585 $ 19,122 As of June 30, 2020, 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 $ 17,414 $ 141,383 $ 2,506 Weighted-average amortization period 2.9 years 3.1 years 0.4 years The weighted-average assumptions used to value stock options granted during the periods presented were as follows: Stock Options Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Expected term (years) 6.0 6.1 6.0 6.1 Volatility 48 % 46 % 47 % 46 % Risk-free interest rate 0.4 % 2.4 % 1.1 % 2.5 % Dividend yield (1) — — — — (1) 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.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
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. 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. The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Net loss $ (16,052) $ (1,860) $ (23,489) $ (3,784) Weighted-average shares of common stock outstanding 63,282 60,058 62,494 59,714 Basic and diluted net loss per share $ (0.25) $ (0.03) $ (0.38) $ (0.06) The following securities were excluded from the calculation of diluted net loss per share because their effect would have been anti-dilutive (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Stock options 2,431 2,693 2,431 2,693 Restricted stock units 2,753 2,598 2,753 2,598 Convertible senior notes 1,106 1,241 984 1,245 Total 6,290 6,532 6,168 6,536

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The (benefit from) income taxes for the three and six months ended June 30, 2020 was approximately $(2.9) million and $(2.8) million, respectively. The provision for (benefit from) income taxes for the three and six months ended June 30, 2019 was approximately $29 thousand and $(20) thousand, respectively. The (benefit from) income taxes for the three and six months ended June 30, 2020 consisted primarily of foreign income taxes, state minimum taxes, as well as a benefit for a true-up to foreign income taxes. The provision for (benefit from) income taxes for the three and six months ended June 30, 2019 consisted primarily of foreign income taxes and state minimum taxes. For the three and six months ended June 30, 2020, the provision for income taxes differed from the statutory amount due to reduction in the valuation allowance resulting from the recording of deferred tax liabilities related to the Virtual Observer acquisition. For the three and six months ended June 30, 2019, the provision for (benefit from) income taxes differed from the statutory amount primarily due to the Company realizing no benefit for current year losses due to maintaining a full valuation allowance against its domestic net deferred tax assets. The realization of tax benefits of deferred tax assets is dependent upon future levels of taxable income, of an appropriate character, in the periods the items are expected to be deductible or taxable. Based on the available objective evidence, the Company does not believe it is more likely than not that the net deferred tax assets will be realizable. Accordingly, the Company has provided a full valuation allowance against the domestic net deferred tax assets as of June 30, 2020 and December 31, 2019. The Company intends to maintain the remaining valuation allowance until sufficient positive evidence exists to support a reversal of, or decrease in, the valuation allowance. During the three and six months ended June 30, 2020, there were no material changes to the total amount of unrecognized tax benefits.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments The Company’s principal commitments consist of future payment obligations under its convertible senior notes, finance leases to finance data centers and other computer and networking equipment purchases, operating leases for office facilities, and agreements with third parties to provide co-location hosting, telecommunication usage and equipment maintenance services. These commitments as of December 31, 2019 are disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, and did not change materially during the six months ended June 30, 2020, except for certain hosting and telecommunications agreements and the future payment obligations associated with the 2025 convertible senior notes, which were issued in May and June 2020, offset in part by the repurchase of a portion of the 2023 convertible senior notes in May 2020. As of June 30, 2020, the Company’s commitment under various hosting and telecommunications agreements totaled $7.4 million for terms ranging up to 36 months. These agreements require the Company to make monthly payments over the service term in exchange for certain network services. As of June 30, 2020, $825.2 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. 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	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Geographical Information	Geographical Information The following table summarizes revenues by geographic region based on client billing address and has been estimated based on the amounts billed to clients during the periods indicated (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 United States $ 91,784 $ 71,349 $ 179,215 $ 140,232 International 8,008 6,087 15,665 11,742 Total revenue $ 99,792 $ 77,436 $ 194,880 $ 151,974 The following table summarizes total property and equipment, net in the respective locations (in thousands): June 30, 2020 December 31, 2019 United States $ 35,152 $ 29,246 International 4,647 3,944 Property and equipment, net $ 39,799 $ 33,190

Leases

Leases	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Leases	Leases The Company has leases for offices, data centers and computer and networking equipment that expire at various dates through 2024. The Company’s leases have remaining terms of one three The components of lease expenses were as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Operating lease cost $ 1,515 $ 1,237 $ 3,031 $ 2,340 Finance lease cost: Amortization of right-of-use assets $ 982 $ 1,905 $ 2,120 $ 3,360 Interest on finance lease liabilities 63 187 145 423 Total finance lease cost $ 1,045 $ 2,092 $ 2,265 $ 3,783 Supplemental cash flow information related to leases was as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash used in operating leases $ (1,607) $ (1,265) $ (3,190) $ (2,409) Financing cash used in finance leases (966) (1,808) (2,195) (3,702) Right of use assets obtained in exchange for lease obligations: Operating leases 364 4,619 4,256 4,619 Finance leases — — — — Supplemental balance sheet information related to leases was as follows (in thousands): June 30, 2020 December 31, 2019 Operating leases Operating lease right-of-use assets $ 10,006 $ 8,746 Operating lease liabilities $ 5,247 $ 5,064 Operating lease liabilities — less current portion 5,249 4,329 Total operating lease liabilities $ 10,496 $ 9,393 Finance leases Property and equipment, gross $ 46,520 $ 46,671 Less: accumulated depreciation and amortization (41,539) (39,190) Property and equipment, net $ 4,981 $ 7,481 Finance lease liabilities: Finance leases $ 2,032 $ 3,518 Finance lease liabilities — less current portion 100 809 Total finance lease liabilities $ 2,132 $ 4,327 Weighted average remaining terms were as follows (in years): June 30, 2020 December 31, 2019 Weighted average remaining lease term Operating leases 2.6 2.7 Finance leases 1.0 1.1 Weighted average discount rates were as follows: June 30, 2020 December 31, 2019 Weighted average discount rate Operating leases 4.6 % 4.7 % Finance leases 7.5 % 7.5 % Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases Remaining 2020 $ 3,285 $ 1,440 2021 3,451 787 2022 2,420 — 2023 1,288 — 2024 678 — Total future minimum lease payments 11,122 2,227 Less: imputed interest (626) (95) Total $ 10,496 $ 2,132

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions 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, 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 preliminary pending finalization of valuation analyses pertaining to intangible assets acquired, liabilities assumed and tax liabilities assumed including calculation of deferred tax assets and liabilities. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. The measurement period will end no later than one year from the acquisition date. The following table presents the preliminary 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 5 years, 5 years, and 2 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 $0.6 million and $0.8 million that have been expensed as incurred and included in general and administrative expenses in the condensed consolidated statements of operations during the three and six months ended June 30, 2020, respectively, and expensed an additional $0.3 million in fiscal 2019. The results of operations of this acquisition are included in the accompanying condensed consolidated statements of operations from the date of acquisition. Whendu LLC In November 2019, the Company acquired certain assets from Whendu, including its integration platform as a service ("iPaaS") platform, which the Company has determined to be an asset acquisition. The purchase price, including the Company’s transaction costs, was approximately $15.9 million, of which $15.4 million was allocated to the Whendu iPaaS platform and $0.5 million was allocated to an assembled workforce, on a relative fair value basis. The assets are amortized on a straight-line basis over their useful lives of four

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent EventOn July 29, 2020, the Company entered into the Bishop Ranch Building Lease (the “Lease”) with 2600 CR, LLC, a Delaware limited liability company (the “Landlord”). Pursuant to the Lease, the Company will lease from the Landlord approximately 104,253 square feet of office space located at 3001 Bishop Drive, Suites 250 and 350, San Ramon, CA (the “Premises”). The Company expects to use the Premises as its new corporate headquarters. The Lease will commence on February 1, 2021 and will continue for a period of 120 months. The initial monthly base rent will be approximately $0.4 million, with periodic increases in accordance with the terms of the Lease, with eight months of rent abatement. In addition, the Company will be required to pay its proportionate share of building operating costs. As part of the Lease, the Company must provide a security deposit of approximately $0.5 million. The Landlord will provide the Company with a tenant improvement allowance of approximately $4.2 million.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed 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 interim financial reporting. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Therefore, these condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. In the opinion of management, the condensed consolidated financial statements reflect all adjustments, which are normal and recurring in nature, necessary for fair financial statement presentation. All intercompany transactions and balances have been eliminated in consolidation.
Reclassification	Certain prior period amounts included in the condensed consolidated financial statements have been reclassified to conform to the current period presentation.
Use of Estimates	Use of Estimates The preparation of condensed 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 condensed 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. Management periodically evaluates such estimates and they are adjusted prospectively based upon such periodic evaluation. Actual results could differ from those estimates.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires measurement and recognition of expected credit losses for financial assets held at amortized cost, including trade receivables. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model that requires the forward-looking information to calculate credit loss estimates. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in more timely recognition of credit losses. The Company adopted ASU 2016-13 using the modified retrospective method on January 1, 2020. The adoption of ASU 2016-13 did not have a material impact on the Company’s consolidated financial position, operating results or cash flows. See Notes 3 and 4 for further information on the impact of this adoption. Recent Accounting Pronouncements Not Yet Effective 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 provisions, removing exceptions to certain general principles in Topic 740, Income Taxes. The standard will be effective for the Company beginning in the first quarter of 2021, with early adoption permitted. The Company is currently evaluating the impact that the adoption of ASU 2019-12 will have on its consolidated financial statements. The Company has reviewed or is in the process of evaluating all other 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 cash flows.
Receivables	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	Deferred contract acquisition costs are recorded when incurred and are amortized over a customer benefit period of five years.
Revenue	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.

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Contract Balances	The following table provides information about accounts receivable, net, deferred contract acquisition costs, contract assets and contract liabilities from contracts with customers (in thousands): June 30, 2020 December 31, 2019 Accounts receivable, net $ 39,607 $ 37,655 Deferred contract acquisition costs: Current $ 16,151 $ 13,014 Non-current 39,366 30,655 Total deferred contract acquisition costs $ 55,517 $ 43,669 Contract assets and contract liabilities: Contract assets (included in prepaid expenses and other current assets) $ 771 $ 825 Contract liabilities (deferred revenue) 26,306 24,681 Contract liabilities (deferred revenue) (included in other long-term liabilities) 3,701 1,550 Net contract liabilities $ (29,236) $ (25,406)

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020 and December 31, 2019 were as follows (in thousands): June 30, 2020 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term Marketable Investments: Certificates of deposit $ 3,976 $ 1 $ — $ 3,977 U.S. treasury 283,830 217 (9) 284,038 U.S. agency securities 136,087 275 (3) 136,359 Commercial paper 5,387 — — 5,387 Municipal bonds 7,454 4 — 7,458 Corporate bonds 15,483 14 (8) 15,489 Total $ 452,217 $ 511 $ (20) $ 452,708 Long-term Marketable Investments: U.S. treasury $ 40,005 $ — $ (8) $ 39,997 U.S. agency securities 40,273 9 — 40,282 Corporate bonds 1,783 2 — 1,785 Total $ 82,061 $ 11 $ (8) $ 82,064 December 31, 2019 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term Marketable Investments: Certificates of deposit $ 161 $ 1 $ — $ 162 U.S. treasury 31,933 8 (1) 31,940 U.S. agency securities 177,629 110 (9) 177,730 Commercial paper 15,240 — — 15,240 Municipal bonds 3,014 1 — 3,015 Corporate bonds 13,876 10 — 13,886 Total $ 241,853 $ 130 $ (10) $ 241,973
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 June 30, 2020 and December 31, 2019 (in thousands): June 30, 2020 December 31, 2019 Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value U.S. treasury $ (17) $ 174,600 $ (1) $ 12,926 U.S. agency securities (4) 56,328 (9) 36,322 Municipal bonds (1) 512 Corporate bonds (8) 5,127 — 251 Total $ (30) $ 236,567 $ (10) $ 49,499
Schedule of Marketable Investments by Contractual Maturity	The amortized cost and fair value of the Company’s marketable investments by contractual maturity as of June 30, 2020 were as follows: Cost Fair Value Due within one year $ 452,217 $ 452,708 Due after one year through two years 82,061 82,064 Total $ 534,278 $ 534,772
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): June 30, 2020 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 54,325 $ — $ — $ 54,325 U.S. treasury 110,979 — — 110,979 Municipal bonds — 1,457 — 1,457 Total cash equivalents $ 165,304 $ 1,457 $ — $ 166,761 Marketable investments (Short and Long-term) Certificates of deposit $ — $ 3,977 $ — $ 3,977 U.S. treasury 324,036 — — 324,036 U.S. agency securities — 176,640 — 176,640 Commercial paper — 5,387 — 5,387 Municipal bonds — 7,458 — 7,458 Corporate bonds — 17,274 — 17,274 Total marketable investments $ 324,036 $ 210,736 $ — $ 534,772 December 31, 2019 Level 1 Level 2 Level 3 Total Assets Cash equivalents Money market funds $ 2,179 $ — $ — $ 2,179 Commercial paper — 2,697 — 2,697 Total cash equivalents $ 2,179 $ 2,697 $ — $ 4,876 Marketable investments Certificates of deposit $ — $ 162 $ — $ 162 U.S. treasury 31,940 — — 31,940 U.S. agency securities — 177,730 — 177,730 Commercial paper — 15,240 — 15,240 Municipal bonds — 3,015 — 3,015 Corporate bonds — 13,886 — 13,886 Total marketable investments $ 31,940 $ 210,033 $ — $ 241,973

Financial Statement Components

Financial Statement Components (Tables)	6 Months Ended
	Jun. 30, 2020
Financial Statement Components [Abstract]
Schedule of Cash and Cash Equivalents	Cash and cash equivalents consisted of the following (in thousands): June 30, 2020 December 31, 2019 Cash $ 66,474 $ 73,100 Money market funds 54,325 2,179 U.S. treasury 110,979 — Commercial paper — 2,697 Municipal bonds 1,457 — Total cash and cash equivalents $ 233,235 $ 77,976
Schedule of Accounts Receivable	Accounts receivable, net consisted of the following (in thousands): June 30, 2020 December 31, 2019 Trade accounts receivable $ 35,887 $ 34,591 Unbilled trade accounts receivable, net of advance client deposits 3,835 3,075 Allowance for doubtful accounts (115) (11) Accounts receivable, net $ 39,607 $ 37,655
Changes in Allowance for Doubtful Accounts	The following table presents the change in the allowance for doubtful accounts, including consideration of expected credit losses, for the three and six months ended June 30, 2020 (in thousands): Three Months Ended Six Months June 30, 2020 June 30, 2020 Balance, beginning of period $ (168) $ (11) Add: Bad debt expense (excluding expected credit loss portion) (23) (45) Add: Bad debt expense (expected credit loss portion) (74) (307) Less: Write-offs, net of recoveries (excluding expected credit loss portion) 18 29 Less: Write-offs, net of recoveries (expected credit loss portion) $ 132 $ 219 Balance, end of period $ (115) $ (115)
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2020 December 31, 2019 Prepaid expenses $ 10,071 $ 4,901 Other current assets 6,687 4,930 Contract assets 771 825 Prepaid expenses and other current assets $ 17,529 $ 10,656
Schedule of Property and Equipment	Property and equipment, net consisted of the following (in thousands): June 30, 2020 December 31, 2019 Computer and network equipment $ 77,828 $ 67,378 Computer software 18,301 14,157 Internal-use software development costs 500 500 Furniture and fixtures 2,869 2,918 Leasehold improvements 2,090 2,264 Property and equipment 101,588 87,217 Accumulated depreciation and amortization (61,789) (54,027) Property and equipment, net $ 39,799 $ 33,190 Property and equipment capitalized under finance lease obligations consists primarily of computer and network equipment and was as follows (in thousands): June 30, 2020 December 31, 2019 Gross $ 46,520 $ 46,671 Less: accumulated depreciation and amortization (41,539) (39,190) Total $ 4,981 $ 7,481
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): June 30, 2020 December 31, 2019 Accrued compensation and benefits $ 24,974 $ 14,233 Accrued expenses 9,843 4,152 Accrued and other current liabilities $ 34,817 $ 18,385

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill Activity	The following table summarizes the activity in the Company's goodwill and intangible asset balances during the six months ended June 30, 2020 (in thousands): Goodwill Intangible Assets Beginning of the period, December 31, 2019 $ 11,798 $ 15,533 Addition (Virtual Observer) 22,646 12,800 Addition (Whendu) — 100 Amortization — (2,828) End of the period, June 30, 2020 $ 34,444 $ 25,605
Intangible Assets Activity	The following table summarizes the activity in the Company's goodwill and intangible asset balances during the six months ended June 30, 2020 (in thousands): Goodwill Intangible Assets Beginning of the period, December 31, 2019 $ 11,798 $ 15,533 Addition (Virtual Observer) 22,646 12,800 Addition (Whendu) — 100 Amortization — (2,828) End of the period, June 30, 2020 $ 34,444 $ 25,605
Schedule of Intangible Assets	The components of intangible assets were as follows (in thousands): June 30, 2020 December 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Amortization period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Remaining Amortization period (Years) Developed technology $ 30,075 $ (5,404) $ 24,671 4.0 $ 17,777 $ (2,690) $ 15,087 3.9 Acquired workforce 470 (99) 371 2.4 467 (21) 446 2.9 Customer relationships 500 (25) 475 4.8 — — — Trademarks 100 (12) 88 1.8 — — — Total $ 31,145 $ (5,540) $ 25,605 4.0 $ 18,244 $ (2,711) $ 15,533 3.8
Schedule of Expected Future Amortization Expense of Intangible Assets	As of June 30, 2020, the expected future amortization expense for intangible assets was as follows (in thousands): Period Expected Future Amortization Expense Remaining 2020 $ 3,404 2021 6,600 2022 6,542 2023 5,883 2024 2,540 Thereafter 636 Total $ 25,605

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2020
Debt Instrument [Line Items]
Schedule of Net Impact on Equity Components from Issuance of Notes	The net impact to the Company's stockholders' equity as of June 30, 2020, included in additional paid-in capital, relating to the issuance of the 2025 convertible senior notes was as follows (in thousands): June 30, 2020 Conversion option $ 158,321 Payments for capped call transactions (90,448) Issuance costs (3,958) Total $ 63,915
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 liability component of the 2025 convertible senior notes was as follows (in thousands): June 30, 2020 Principal $ 747,500 Unamortized debt discount (155,792) Unamortized issuance costs (14,494) Net carrying amount $ 577,214 The net carrying amount of the equity component of the 2025 convertible senior notes was as follows (in thousands): June 30, 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): Three Months Ended June 30, 2020 Contractual interest expense $ 362 Amortization of debt discount 2,528 Amortization of issuance costs 235 Total interest expense $ 3,125
Schedule of Maturities of Debt	Maturity of the Company’s 2025 convertible senior notes as of June 30, 2020 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 liability component of the 2023 convertible senior notes was as follows (in thousands): June 30, 2020 December 31, 2019 Principal $ 77,745 $ 258,750 Unamortized debt discount (11,649) (44,881) Unamortized issuance costs (1,107) (4,265) Net carrying amount $ 64,989 $ 209,604 The net carrying amount of the equity component of the 2023 convertible senior notes continued to meet the conditions for equity classification as presented below (in thousands): June 30, 2020 December 31, 2019 Equity component $ 19,158 $ 63,756 Issuance costs (600) (1,998) Net carrying amount $ 18,558 $ 61,758
Schedule of Interest Expense Related to the Notes	Interest expense related to the 2023 convertible senior notes was as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Contractual interest expense $ 60 $ 81 $ 141 $ 162 Amortization of debt discount 2,272 2,888 5,304 5,698 Amortization of issuance costs 216 267 504 536 Total interest expense $ 2,548 $ 3,236 $ 5,949 $ 6,396
Schedule of Maturities of Debt	Maturity of the Company’s 2023 convertible senior notes as of June 30, 2020 was as follows (in thousands): Period Amount to Mature 2023 (Maturity date of May 1, 2023) $ 77,745 Total $ 77,745

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2020
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 were as follows (in thousands): June 30, 2020 Stock options outstanding 2,431 Restricted stock units outstanding 2,753 Shares available for future grant under 2014 Plan 11,684 Shares available for future issuance under ESPP 2,598 Total shares of common stock reserved 19,466
Schedule of Stock Option Activity	A summary of the Company’s stock option activity during the six months ended June 30, 2020 is as follows (in thousands, except years and per share data): Number of Weighted Weighted Aggregate Outstanding as of December 31, 2019 2,530 $ 19.38 Options granted (weighted average grant date fair value of $33.39 per share) 227 73.25 Options exercised (322) 18.91 Options forfeited or expired (4) 36.70 Outstanding as of June 30, 2020 2,431 $ 24.45 5.9 $ 209,602
Schedule of RSU Activity	A summary of the Company’s restricted stock unit, or RSU, activity during the six months ended June 30, 2020 is as follows (in thousands, except per share data): Number of Shares Weighted Average Grant Date Fair Value Per Share Outstanding as of December 31, 2019 2,372 $ 41.32 RSUs granted 1,050 73.26 RSUs vested and released (604) 37.97 RSUs forfeited (65) 48.56 Outstanding as of June 30, 2020 2,753 $ 54.54
Schedule of Stock-based Compensation Expense	Stock-based compensation expenses were as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Cost of revenue $ 2,499 $ 1,658 $ 4,488 $ 2,887 Research and development 3,684 1,907 6,491 3,377 Sales and marketing 5,265 2,749 9,371 4,998 General and administrative 5,343 4,122 10,235 7,860 Total stock-based compensation $ 16,791 $ 10,436 $ 30,585 $ 19,122
Schedule of Unrecognized Compensation Expense	As of June 30, 2020, 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 $ 17,414 $ 141,383 $ 2,506 Weighted-average amortization period 2.9 years 3.1 years 0.4 years
Schedule of Valuation Assumptions, Stock Option	The weighted-average assumptions used to value stock options granted during the periods presented were as follows: Stock Options Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Expected term (years) 6.0 6.1 6.0 6.1 Volatility 48 % 46 % 47 % 46 % Risk-free interest rate 0.4 % 2.4 % 1.1 % 2.5 % Dividend yield (1) — — — — (1) 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.

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
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): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Net loss $ (16,052) $ (1,860) $ (23,489) $ (3,784) Weighted-average shares of common stock outstanding 63,282 60,058 62,494 59,714 Basic and diluted net loss per share $ (0.25) $ (0.03) $ (0.38) $ (0.06)
Schedule of Antidilutive Securities Excluded from Computation of 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): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Stock options 2,431 2,693 2,431 2,693 Restricted stock units 2,753 2,598 2,753 2,598 Convertible senior notes 1,106 1,241 984 1,245 Total 6,290 6,532 6,168 6,536

Geographical Information (Table

Geographical Information (Tables)	6 Months Ended
	Jun. 30, 2020
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 and has been estimated based on the amounts billed to clients during the periods indicated (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 United States $ 91,784 $ 71,349 $ 179,215 $ 140,232 International 8,008 6,087 15,665 11,742 Total revenue $ 99,792 $ 77,436 $ 194,880 $ 151,974 The following table summarizes total property and equipment, net in the respective locations (in thousands): June 30, 2020 December 31, 2019 United States $ 35,152 $ 29,246 International 4,647 3,944 Property and equipment, net $ 39,799 $ 33,190

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2020
Leases [Abstract]
Schedule of lease expenses	The components of lease expenses were as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Operating lease cost $ 1,515 $ 1,237 $ 3,031 $ 2,340 Finance lease cost: Amortization of right-of-use assets $ 982 $ 1,905 $ 2,120 $ 3,360 Interest on finance lease liabilities 63 187 145 423 Total finance lease cost $ 1,045 $ 2,092 $ 2,265 $ 3,783 Supplemental cash flow information related to leases was as follows (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2019 June 30, 2020 June 30, 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash used in operating leases $ (1,607) $ (1,265) $ (3,190) $ (2,409) Financing cash used in finance leases (966) (1,808) (2,195) (3,702) Right of use assets obtained in exchange for lease obligations: Operating leases 364 4,619 4,256 4,619 Finance leases — — — — Weighted average remaining terms were as follows (in years): June 30, 2020 December 31, 2019 Weighted average remaining lease term Operating leases 2.6 2.7 Finance leases 1.0 1.1 Weighted average discount rates were as follows: June 30, 2020 December 31, 2019 Weighted average discount rate Operating leases 4.6 % 4.7 % Finance leases 7.5 % 7.5 %
Schedule of balance sheet information related to leases	Supplemental balance sheet information related to leases was as follows (in thousands): June 30, 2020 December 31, 2019 Operating leases Operating lease right-of-use assets $ 10,006 $ 8,746 Operating lease liabilities $ 5,247 $ 5,064 Operating lease liabilities — less current portion 5,249 4,329 Total operating lease liabilities $ 10,496 $ 9,393 Finance leases Property and equipment, gross $ 46,520 $ 46,671 Less: accumulated depreciation and amortization (41,539) (39,190) Property and equipment, net $ 4,981 $ 7,481 Finance lease liabilities: Finance leases $ 2,032 $ 3,518 Finance lease liabilities — less current portion 100 809 Total finance lease liabilities $ 2,132 $ 4,327
Schedule of operating lease maturities	Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases Remaining 2020 $ 3,285 $ 1,440 2021 3,451 787 2022 2,420 — 2023 1,288 — 2024 678 — Total future minimum lease payments 11,122 2,227 Less: imputed interest (626) (95) Total $ 10,496 $ 2,132
Schedule of finance lease maturities	Maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Operating Leases Finance Leases Remaining 2020 $ 3,285 $ 1,440 2021 3,451 787 2022 2,420 — 2023 1,288 — 2024 678 — Total future minimum lease payments 11,122 2,227 Less: imputed interest (626) (95) Total $ 10,496 $ 2,132

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2020
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table presents the preliminary 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

Revenue - Contract Balances (De

Revenue - Contract Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 39,607	$ 37,655
Deferred contract acquisition costs, current	16,151	13,014
Deferred contract acquisition costs, non-current	39,366	30,655
Total deferred contract acquisition costs	55,517	43,669
Contract assets (included in prepaid expenses and other current assets)	771	825
Contract liabilities (deferred revenue)	26,306	24,681
Contract liabilities (deferred revenue) (included in other long-term liabilities)	3,701	1,550
Net contract liabilities	$ (29,236)	$ (25,406)

Revenue - Narrative (Details)

Revenue - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2020USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract revenue recognized	$ 4	$ 20
Contract acquisition costs
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Amortization period of capitalized contract cost	5 years	5 years

Revenue - Remaining Performance

Revenue - Remaining Performance Obligations (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Performance obligation	$ 242
Performance obligation, description of timing	The Company expects to recognize revenue on approximately four-fifths of the remaining performance obligation 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]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation expected to be recognized (percent)	80.00%
Performance obligation satisfaction period	24 months

Investments and Fair Value Me_3

Investments and Fair Value Measurements - Schedule of Marketable Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	$ 452,217
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	511
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	(20)
Debt Securities, Available-for-sale, Current	452,708	$ 241,973
Debt Securities, Available-for-sale, Amortized Cost, Noncurrent	82,061
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Noncurrent	11
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Noncurrent	(8)
Debt Securities, Available-for-sale, Noncurrent	82,064
Available-for-sale debt securities, Total Amortized Cost	534,278	241,853
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		130
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		(10)
Debt Securities, Available-for-sale	534,772	241,973
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	3,976
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	0
Debt Securities, Available-for-sale, Current	3,977
Available-for-sale debt securities, Total Amortized Cost		161
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		0
Debt Securities, Available-for-sale	3,977	162
U.S. treasury
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	283,830
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	217
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	(9)
Debt Securities, Available-for-sale, Current	284,038
Debt Securities, Available-for-sale, Amortized Cost, Noncurrent	40,005
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Noncurrent	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Noncurrent	(8)
Debt Securities, Available-for-sale, Noncurrent	39,997
Available-for-sale debt securities, Total Amortized Cost		31,933
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		8
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		(1)
Debt Securities, Available-for-sale	324,036	31,940
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	136,087
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	275
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	(3)
Debt Securities, Available-for-sale, Current	136,359
Debt Securities, Available-for-sale, Amortized Cost, Noncurrent	40,273
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Noncurrent	9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Noncurrent	0
Debt Securities, Available-for-sale, Noncurrent	40,282
Available-for-sale debt securities, Total Amortized Cost		177,629
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		110
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		(9)
Debt Securities, Available-for-sale	176,640	177,730
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	5,387
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	0
Debt Securities, Available-for-sale, Current	5,387
Available-for-sale debt securities, Total Amortized Cost		15,240
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		0
Debt Securities, Available-for-sale	5,387	15,240
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	7,454
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	4
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	0
Debt Securities, Available-for-sale, Current	7,458
Available-for-sale debt securities, Total Amortized Cost		3,014
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		0
Debt Securities, Available-for-sale	7,458	3,015
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost, Current	15,483
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Current	14
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Current	(8)
Debt Securities, Available-for-sale, Current	15,489
Debt Securities, Available-for-sale, Amortized Cost, Noncurrent	1,783
Debt Securities. Available-for-sale, Accumulated Gross Unrealized Gain, Noncurrent	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax, Noncurrent	0
Debt Securities, Available-for-sale, Noncurrent	1,785
Available-for-sale debt securities, Total Amortized Cost		13,876
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain		10
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss		0
Debt Securities, Available-for-sale	$ 17,274	$ 13,886

Investments and Fair Value Me_4

Investments and Fair Value Measurements - Schedule of Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, gross unrealized losses	$ (30)	$ (10)
Less than 12 months, fair value	236,567	49,499
U.S. treasury
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, gross unrealized losses	(17)	(1)
Less than 12 months, fair value	174,600	12,926
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, gross unrealized losses	(4)	(9)
Less than 12 months, fair value	56,328	36,322
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, gross unrealized losses	(1)
Less than 12 months, fair value	512
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, gross unrealized losses	(8)	0
Less than 12 months, fair value	$ 5,127	$ 251

Investments and Fair Value Me_5

Investments and Fair Value Measurements - Schedule of Marketable Investments by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Available-for-sale debt securities, amortized cost, due within one year	$ 452,217
Available-for-sale debt securities, amortized cost, due after one year through two years	82,061
Available-for-sale debt securities, Total Amortized Cost	534,278	$ 241,853
Available-for-sale debt securities, fair value, due within one year	452,708
Available-for-sale debt securities, fair value, due after one year through two years	82,064
Available-for-sale debt securities, Total Fair Value	$ 534,772	$ 241,973

Investments and Fair Value Me_6

Investments and Fair Value Measurements - Schedule of Assets Carried at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Cash equivalents	$ 166,761	$ 4,876
Marketable investments (Short and Long-term)	534,772	241,973
Level 1
Assets
Cash equivalents	165,304	2,179
Marketable investments (Short and Long-term)	324,036	31,940
Level 2
Assets
Cash equivalents	1,457	2,697
Marketable investments (Short and Long-term)	210,736	210,033
Level 3
Assets
Cash equivalents	0	0
Marketable investments (Short and Long-term)	0	0
Certificates of deposit
Assets
Marketable investments (Short and Long-term)	3,977	162
Certificates of deposit | Level 1
Assets
Marketable investments (Short and Long-term)	0	0
Certificates of deposit | Level 2
Assets
Marketable investments (Short and Long-term)		162
Certificates of deposit | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
U.S. treasury
Assets
Marketable investments (Short and Long-term)	324,036	31,940
U.S. treasury | Level 1
Assets
Marketable investments (Short and Long-term)	324,036	31,940
U.S. treasury | Level 2
Assets
Marketable investments (Short and Long-term)	0	0
U.S. treasury | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
U.S. agency securities
Assets
Marketable investments (Short and Long-term)	176,640	177,730
U.S. agency securities | Level 1
Assets
Marketable investments (Short and Long-term)	0	0
U.S. agency securities | Level 2
Assets
Marketable investments (Short and Long-term)	176,640	177,730
U.S. agency securities | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
Commercial paper
Assets
Marketable investments (Short and Long-term)	5,387	15,240
Commercial paper | Level 1
Assets
Marketable investments (Short and Long-term)	0	0
Commercial paper | Level 2
Assets
Marketable investments (Short and Long-term)	5,387	15,240
Commercial paper | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
Municipal bonds
Assets
Marketable investments (Short and Long-term)	7,458	3,015
Municipal bonds | Level 1
Assets
Marketable investments (Short and Long-term)	0	0
Municipal bonds | Level 2
Assets
Marketable investments (Short and Long-term)	7,458	3,015
Municipal bonds | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
Corporate bonds
Assets
Marketable investments (Short and Long-term)	17,274	13,886
Corporate bonds | Level 1
Assets
Marketable investments (Short and Long-term)	0	0
Corporate bonds | Level 2
Assets
Marketable investments (Short and Long-term)	17,274	13,886
Corporate bonds | Level 3
Assets
Marketable investments (Short and Long-term)	0	0
Money market funds
Assets
Cash equivalents	54,325	2,179
Money market funds | Level 1
Assets
Cash equivalents	54,325	2,179
Money market funds | Level 2
Assets
Cash equivalents	0	0
Money market funds | Level 3
Assets
Cash equivalents	0	0
U.S. treasury
Assets
Cash equivalents	110,979
U.S. treasury | Level 1
Assets
Cash equivalents	110,979
U.S. treasury | Level 2
Assets
Cash equivalents	0
U.S. treasury | Level 3
Assets
Cash equivalents	0
Commercial paper
Assets
Cash equivalents		2,697
Commercial paper | Level 1
Assets
Cash equivalents		0
Commercial paper | Level 2
Assets
Cash equivalents		2,697
Commercial paper | Level 3
Assets
Cash equivalents		$ 0
Municipal bonds
Assets
Cash equivalents	1,457
Municipal bonds | Level 1
Assets
Cash equivalents	0
Municipal bonds | Level 2
Assets
Cash equivalents	1,457
Municipal bonds | Level 3
Assets
Cash equivalents	$ 0

Investments and Fair Value Me_7

Investments and Fair Value Measurements - Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	May 31, 2018
Debt Instrument [Line Items]
Impairment loss on available-for-sale debt securities	$ 0
Nonrecurring
Debt Instrument [Line Items]
Assets measured at fair value on nonrecurring basis	0	$ 0
Liabilities measured at fair value on nonrecurring basis	$ 0	$ 0
Convertible Senior Notes, Due 2023 | Convertible debt
Debt Instrument [Line Items]
Stated interest rate on debt (percent)	0.125%	0.125%	0.125%
Convertible Senior Notes, Due 2023 | Level 2 | Convertible debt
Debt Instrument [Line Items]
Fair value of long-term debt	$ 210,700,000	$ 437,000,000
Convertible Senior Notes, Due 2025 | Convertible debt
Debt Instrument [Line Items]
Stated interest rate on debt (percent)	0.50%
Convertible Senior Notes, Due 2025 | Level 2 | Convertible debt
Debt Instrument [Line Items]
Fair value of long-term debt	$ 802,400,000

Financial Statement Component_2

Financial Statement Components - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 233,235	$ 77,976
Cash
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	66,474	73,100
Money market funds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	54,325	2,179
U.S. treasury
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	110,979	0
Commercial paper
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	0	2,697
Municipal bonds
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 1,457	$ 0

Financial Statement Component_3

Financial Statement Components - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounts Receivable [Line Items]
Allowance for doubtful accounts	$ (115)	$ (168)	$ (11)
Accounts receivable, net	39,607		37,655
Trade accounts receivable
Accounts Receivable [Line Items]
Trade accounts receivable	35,887		34,591
Unbilled trade accounts receivable, net of advance client deposits
Accounts Receivable [Line Items]
Trade accounts receivable	$ 3,835		$ 3,075

Financial Statement Component_4

Financial Statement Components - Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Jun. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ (168)	$ (11)	$ (11)
Add: Bad debt expense			(353)	$ (30)
Balance, end of period	(115)	(168)	(115)
Excluding expected credit loss portion
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Add: Bad debt expense	(23)		(45)
Less: Write-offs, net of recoveries	18		29
Expected credit loss portion
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Add: Bad debt expense	(74)	$ (100)	(307)
Less: Write-offs, net of recoveries	$ 132		$ 219

Financial Statement Component_5

Financial Statement Components - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Statement Components [Abstract]
Prepaid expenses	$ 10,071	$ 4,901
Other current assets	6,687	4,930
Contract assets	771	825
Prepaid expenses and other current assets	$ 17,529	$ 10,656

Financial Statement Component_6

Financial Statement Components - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment	$ 101,588		$ 101,588		$ 87,217
Accumulated depreciation and amortization	(61,789)		(61,789)		(54,027)
Property and equipment, net	39,799		39,799		33,190
Depreciation expense	4,500	$ 3,300	8,400	$ 6,400
Computer and network equipment
Property, Plant and Equipment [Line Items]
Computer and network equipment	77,828		77,828		67,378
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment	18,301		18,301		14,157
Internal-use software development costs
Property, Plant and Equipment [Line Items]
Property and equipment	500		500		500
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	2,869		2,869		2,918
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 2,090		$ 2,090		$ 2,264

Financial Statement Component_7

Financial Statement Components - Schedule of Capital Leased Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Statement Components [Abstract]
Gross	$ 46,520	$ 46,671
Less: accumulated depreciation and amortization	(41,539)	(39,190)
Property and equipment, net	$ 4,981	$ 7,481

Financial Statement Component_8

Financial Statement Components - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Statement Components [Abstract]
Accrued compensation and benefits	$ 24,974	$ 14,233
Accrued expenses	9,843	4,152
Accrued and other current liabilities	$ 34,817	$ 18,385

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Apr. 30, 2020	Apr. 01, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets
Goodwill	$ 34,444		$ 34,444				$ 11,798
Amortization of Intangible Assets	$ 1,700	$ 100	$ 2,828	$ 200
Virtual Observer, formerly known as Coordinated Systems, Inc.
Acquired Finite-Lived Intangible Assets
Goodwill					$ 22,600	$ 22,646
Finite-lived intangibles acquired					$ 12,800

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Goodwill and Intangible Asset Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Goodwill [Roll Forward]
Goodwill, Beginning Balance			$ 11,798
Goodwill, Ending Balance	$ 34,444		34,444
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Net, Beginning Balance			15,533
Amortization of Intangible Assets	(1,700)	$ (100)	(2,828)	$ (200)
Finite-Lived Intangible Assets, Net, Ending Balance	$ 25,605		25,605
Whendu
Goodwill [Roll Forward]
Goodwill, Period Increase (Decrease)			0
Finite-lived Intangible Assets [Roll Forward]
Finite-lived Intangible Assets Acquired			100
Virtual Observer, formerly known as Coordinated Systems, Inc.
Goodwill [Roll Forward]
Goodwill, Period Increase (Decrease)			22,646
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Period Increase (Decrease)			$ 12,800

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 31,145	$ 18,244
Accumulated Amortization	(5,540)	(2,711)
Total	$ 25,605	$ 15,533
Weighted Average Remaining Amortization period (Years)	4 years	3 years 9 months 18 days
Developed technology
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 30,075	$ 17,777
Accumulated Amortization	(5,404)	(2,690)
Total	$ 24,671	$ 15,087
Weighted Average Remaining Amortization period (Years)	4 years	3 years 10 months 24 days
Acquired workforce
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 470	$ 467
Accumulated Amortization	(99)	(21)
Total	$ 371	$ 446
Weighted Average Remaining Amortization period (Years)	2 years 4 months 24 days	2 years 10 months 24 days
Customer relationships
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 500	$ 0
Accumulated Amortization	(25)	0
Total	$ 475	$ 0
Weighted Average Remaining Amortization period (Years)	4 years 9 months 18 days
Trademarks
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 100	$ 0
Accumulated Amortization	(12)	0
Total	$ 88	$ 0
Weighted Average Remaining Amortization period (Years)	1 year 9 months 18 days

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Future Amortization Expense (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining 2020	$ 3,404
2021	6,600
2022	6,542
2023	5,883
2024	2,540
Thereafter	636
Total	$ 25,605	$ 15,533

Debt - Convertible Senior Notes

Debt - Convertible Senior Notes and Capped Call (Details)	1 Months Ended			2 Months Ended	3 Months Ended		6 Months Ended
	Aug. 03, 2020USD ($)	May 31, 2020USD ($)shares	May 31, 2018USD ($)$ / shares	Jun. 30, 2020USD ($)$ / sharesshares	Jun. 30, 2020USD ($)dayconversion_election$ / sharesshares	Mar. 31, 2020USD ($)conversion_electionday$ / shares	Jun. 30, 2020USD ($)day$ / sharesRateshares	Jun. 30, 2019USD ($)	May 21, 2020$ / shares	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Purchase of capped calls related to the 2025 convertible senior notes					$ 90,448,000		$ 90,448,000
Cash Consideration to Repurchase Note							181,462,000	$ 0
Loss on early extinguishment of debt							$ (5,794,000)	$ 0
Common Stock
Debt Instrument [Line Items]
Equity component from partial repurchase of 2023 convertible senior notes (in shares) | shares					2,724,000		2,724,000
Convertible debt
Debt Instrument [Line Items]
Debt balance				$ 825,200,000	$ 825,200,000		$ 825,200,000
Convertible debt | Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Stated interest rate on debt (percent)			0.125%	0.125%	0.125%		0.125%			0.125%
Proceeds from issuance of debt			$ 250,800,000
Multiple of principle amount					$ 1,000	$ 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	$ 40.82
Sinking fund payment							$ 0
Equity component				$ 19,158,000	$ 19,158,000		$ 19,158,000			$ 63,756,000
Effective interest rate on debt (percent)		5.32%		6.39%	6.39%		6.39%
Payment on debt issuance cost			8,000,000
Debt issuance costs			$ 6,000,000	$ 1,107,000	$ 1,107,000		$ 1,107,000			4,265,000
Cap price of the Capped Call Transactions (in dollars per share) | $ / shares			$ 62.80
Debt Instrument, Repurchase Amount		$ 181,000,000
Aggregate Consideration to Repurchase Note		449,600,000
Cash Consideration to Repurchase Note		$ 181,000,000
Equity component from partial repurchase of 2023 convertible senior notes (in shares) | shares		2,723,581
Debt Instrument, Convertible, Carrying Amount of Debt Component		$ 155,800,000
Debt Instrument, Convertible, Carrying Amount of Equity Component		293,800,000		18,558,000	18,558,000		18,558,000			61,758,000
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)
Debt balance				77,745,000	77,745,000		77,745,000			$ 258,750,000
Debt Issuance Costs, Gross, within Extinguishment of Debt				$ 2,700,000	$ 2,700,000		$ 2,700,000
Number of conversion features triggered | conversion_election					1	1
Conversion price per share, requiring conversion of instrument (in USD per share) | $ / shares				$ 53.07	$ 53.07	$ 53.07	$ 53.07
Debt Instrument, Conversion Multiple of Aggregate Principal Amount							$ 5,000
Conversion of aggregate principal amount, term 1							$ 5,002,000
Number of shares covered in the Capped Call Transactions (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
Convertible debt | Convertible Senior Notes, Due 2023 | Subsequent Event
Debt Instrument [Line Items]
Conversion of aggregate principal amount, term 1	$ 13,652,000
Convertible debt | Convertible Senior Notes, Due 2023 | Common Stock
Debt Instrument [Line Items]
Equity component from partial repurchase of 2023 convertible senior notes (in shares) | shares		2,723,581
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 2025
Debt Instrument [Line Items]
Stated interest rate on debt (percent)				0.50%	0.50%		0.50%
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				110.67	110.67		110.67		$ 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		$ 158,321,000
Effective interest rate on debt (percent)				5.76%	5.76%		5.76%
Payment on debt issuance cost				$ 18,700,000
Debt issuance costs		$ 14,700,000		$ 14,494,000	$ 14,494,000		$ 14,494,000
Cap price of the Capped Call Transactions (in dollars per share) | $ / shares				$ 206.68
Purchase of capped calls related to the 2025 convertible senior notes				$ 90,500,000
Debt Instrument, Convertible, Carrying Amount of Equity Component				154,363,000	154,363,000		154,363,000
Debt balance				$ 747,500,000	$ 747,500,000		$ 747,500,000
Number of shares covered in the Capped Call Transactions (shares) | shares				5,600,000	5,600,000		5,600,000
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%
Number of trading days preceding notice of redemption | day							2
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	$ 747,500,000	$ 747,500,000		$ 747,500,000
Option to Purchase Additional Debt through Private Offering				$ 97,500,000	$ 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) - Convertible debt - USD ($) $ in Thousands	Jun. 30, 2020	May 31, 2020	Dec. 31, 2019	May 31, 2018
Debt Instrument [Line Items]
Principal	$ 825,200
Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
Principal	747,500
Unamortized debt discount	(155,792)
Unamortized issuance costs	(14,494)	$ (14,700)
Total debt, net carrying value	577,214
Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
Principal	77,745		$ 258,750
Unamortized debt discount	(11,649)		(44,881)
Unamortized issuance costs	(1,107)		(4,265)	$ (6,000)
Total debt, net carrying value	$ 64,989		$ 209,604

Debt - Schedule of Equity Compo

Debt - Schedule of Equity Component of Debt (Details) - Convertible debt - USD ($) $ in Thousands	Jun. 30, 2020	May 31, 2020	Dec. 31, 2019
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	19,158		$ 63,756
Issuance costs	(600)		(1,998)
Net carrying amount	$ 18,558	$ 293,800	$ 61,758

Debt - Schedule of Interest Exp

Debt - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Debt Instrument [Line Items]
Interest Expense	$ 5,734	$ 3,406	$ 9,218	$ 6,802
Convertible Senior Notes, Due 2025 | Convertible debt
Debt Instrument [Line Items]
Contractual interest expense	362
Amortization of debt discount	2,528
Amortization of issuance costs	235
Interest Expense	3,125
Convertible Senior Notes, Due 2023 | Convertible debt
Debt Instrument [Line Items]
Contractual interest expense	60	81	141	162
Amortization of debt discount	2,272	2,888	5,304	5,698
Amortization of issuance costs	216	267	504	536
Interest Expense	$ 2,548	$ 3,236	$ 5,949	$ 6,396

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Debt (Details) - Convertible debt - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total	$ 825,200
Convertible Senior Notes, Due 2025
Debt Instrument [Line Items]
2025 (Maturity date of June 1, 2025)	747,500
Total	747,500
Convertible Senior Notes, Due 2023
Debt Instrument [Line Items]
2023 (Maturity date of May 1, 2023)	77,745
Total	$ 77,745	$ 258,750

Debt - Net Impact to Stockholde

Debt - Net Impact to Stockholders Equity (Details) - Convertible Senior Notes, Due 2025 - Convertible debt $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature	$ 63,915
Conversion Option
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature	158,321
Payments for Capped Call Transaction
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature	(90,448)
Issuance Costs
Debt Instrument [Line Items]
Adjustments to Additional Paid in Capital, Convertible Debt with Conversion Feature	$ (3,958)

Stockholders' Equity - Capital

Stockholders' Equity - Capital Structure (Details) - $ / shares	1 Months Ended
	May 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Stockholders' Equity Capital Structure [Line Items]
Common Stock, Shares Authorized		450,000,000
Common Stock, Par or Stated Value Per Share		$ 0.001
Common Stock, Shares, Issued		65,295,611	61,543,634
Common Stock, Shares, Outstanding		65,295,611	61,543,634
Preferred Stock, Shares Authorized		5,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.001
Preferred Stock, Shares Issued		0	0
Preferred Stock, Shares Outstanding		0	0
Convertible Senior Notes, Due 2023 | Convertible debt
Stockholders' Equity Capital Structure [Line Items]
Equity component from partial repurchase of 2023 convertible senior notes (in shares)	2,723,581

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) shares in Thousands	Jun. 30, 2020shares
Class of Stock
Common stock reserved for future issuance (in shares)	19,466
Stock options
Class of Stock
Common stock reserved for future issuance (in shares)	2,431
Restricted stock units
Class of Stock
Common stock reserved for future issuance (in shares)	2,753
ESPP
Class of Stock
Common stock reserved for future issuance (in shares)	2,598
2014 Plan
Class of Stock
Common stock reserved for future issuance (in shares)	11,684

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares
Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Closing market price of common stock (in USD per share)	$ 110.67
Stock options
Options Outstanding [Roll Forward]
Outstanding, beginning balance (in shares) | shares	2,530
Options granted (weighted average grant date fair value of $33.04 per share) (in shares) | shares	227
Options exercised (in shares) | shares	(322)
Options forfeited or expired (in shares) | shares	(4)
Outstanding, ending balance (in shares) | shares	2,431
Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning balance, weighted average exercise price (in USD per share)	$ 19.38
Options granted, weighted average exercise price (in USD per share)	73.25
Options exercised, weighted average exercise price (in USD per share)	18.91
Options forfeited or expired, weighted average exercise price (in USD per share)	36.70
Outstanding, ending balance, weighted average exercise price (in USD per share)	$ 24.45
Outstanding, ending balance, weighted average remaining contractual life	5 years 10 months 24 days
Outstanding, ending balance, aggregate intrinsic value | $	$ 209,602
Weighted average grant date fair value, options granted (in USD per share)	$ 33.39

Stockholders' Equity - RSU Acti

Stockholders' Equity - RSU Activity (Details) - Restricted stock units shares in Thousands	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Number of Shares
Outstanding, beginning balance (in shares) | shares	2,372
RSUs granted (in shares) | shares	1,050
RSUs vested and released (in shares) | shares	(604)
RSUs forfeited (in shares) | shares	(65)
Outstanding, ending balance (in shares) | shares	2,753
Weighted Average Grant Date Fair Value Per Share
Outstanding, beginning balance, weighted-average grant date fair value per share (in USD per share) | $ / shares	$ 41.32
RSUs granted, weighted average grant date fair value (in USD per share) | $ / shares	73.26
RSUs vested and released, weighted average grant date fair value (in USD per share) | $ / shares	37.97
RSUs forfeited, weighted average grant date fair value (in USD per share) | $ / shares	48.56
Outstanding, ending balance, weighted-average grant date fair value per share (in USD per share) | $ / shares	$ 54.54

Stockholders' Equity - Stock-ba

Stockholders' Equity - Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-based Compensation Expense
Stock-based compensation expense	$ 16,791	$ 10,436	$ 30,585	$ 19,122
Stock options
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	17,414		$ 17,414
Weighted-average amortization period			2 years 10 months 24 days
Restricted stock units
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	141,383		$ 141,383
Weighted-average amortization period			3 years 1 month 6 days
ESPP
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	2,506		$ 2,506
Weighted-average amortization period			4 months 24 days
Cost of revenue
Stock-based Compensation Expense
Stock-based compensation expense	2,499	1,658	$ 4,488	2,887
Research and development
Stock-based Compensation Expense
Stock-based compensation expense	3,684	1,907	6,491	3,377
Sales and marketing
Stock-based Compensation Expense
Stock-based compensation expense	5,265	2,749	9,371	4,998
General and administrative
Stock-based Compensation Expense
Stock-based compensation expense	$ 5,343	$ 4,122	$ 10,235	$ 7,860

Stockholders' Equity - Valuatio

Stockholders' Equity - Valuation Assumptions (Details) - Stock options	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Class of Stock
Expected term (years)	6 years	6 years 1 month 6 days	6 years	6 years 1 month 6 days
Volatility (percent)	48.00%	46.00%	47.00%	46.00%
Risk-free interest rate (percent)	0.40%	2.40%	1.10%	2.50%
Dividend yield (percent)	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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ (16,052)	$ (1,860)	$ (23,489)	$ (3,784)
Weighted-average shares of common stock outstanding (in shares)	63,282	60,058	62,494	59,714
Basic and diluted net loss per share (in usd per share)	$ (0.25)	$ (0.03)	$ (0.38)	$ (0.06)

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	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (shares)	6,290	6,532	6,168	6,536
Convertible Senior Notes, Due 2023 | Convertible debt
Antidilutive Securities Excluded from Computation of Earnings Per Share
Conversion price on convertible debt (in USD per share)	$ 40.82		$ 40.82		$ 40.82
Convertible Senior Notes, Due 2025 | Convertible debt
Antidilutive Securities Excluded from Computation of Earnings Per Share
Conversion price on convertible debt (in USD per share)	$ 134.34		$ 134.34
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (shares)	2,431	2,693	2,431	2,693
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (shares)	2,753	2,598	2,753	2,598
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share (shares)	1,106	1,241	984	1,245

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes	$ (2,876)	$ 29	$ (2,807)	$ (20)

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Hosting and telecommunications agreement
Other Commitments [Line Items]
Total commitments under agreements	$ 7,400
Maximum | Hosting and telecommunications agreement
Other Commitments [Line Items]
Period for various agreements	36 months
Convertible debt
Other Commitments [Line Items]
Debt balance	$ 825,200

Geographical Information - Sche

Geographical Information - Schedule of Revenue and Property and Equipment by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets
Revenue	$ 99,792	$ 77,436	$ 194,880	$ 151,974
Property and equipment, net	39,799		39,799		$ 33,190
United States
Revenues from External Customers and Long-Lived Assets
Revenue	91,784	71,349	179,215	140,232
Property and equipment, net	35,152		35,152		29,246
International
Revenues from External Customers and Long-Lived Assets
Revenue	8,008	$ 6,087	15,665	$ 11,742
Property and equipment, net	$ 4,647		$ 4,647		$ 3,944

Leases - Narrative (Details)

Leases - Narrative (Details)	6 Months Ended
	Jun. 30, 2020
Lessee, Lease, Description [Line Items]
Operating lease termination notice, period	30 days
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	1 year
Operating lease, extension term	3 years
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, term of contract (in years)	5 years
Operating lease, extension term	5 years

Leases - Lease Cost and Supplem

Leases - Lease Cost and Supplemental Cash Flow (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 1,515	$ 1,237	$ 3,031	$ 2,340
Finance lease cost:
Amortization of right-of-use assets	982	1,905	2,120	3,360
Interest on finance lease liabilities	63	187	145	423
Total finance lease cost	1,045	2,092	2,265	3,783
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash used in operating leases	(1,607)	(1,265)	(3,190)	(2,409)
Financing cash used in finance leases	(966)	(1,808)	(2,195)	(3,702)
Right-of-use assets obtained in exchange for new operating leases	364	4,619	4,256	4,619
Right of use assets obtained in exchange for new finance leases	$ 0	$ 0	$ 0	$ 0

Leases - Balance Sheet Disclosu

Leases - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 10,006	$ 8,746
Operating lease liabilities	5,247	5,064
Operating lease liabilities — less current portion	5,249	4,329
Total operating lease liabilities	10,496	9,393
Property and equipment, gross	46,520	46,671
Less: accumulated depreciation and amortization	(41,539)	(39,190)
Property and equipment, net	4,981	7,481
Finance lease liabilities	2,032	3,518
Finance lease liabilities — less current portion	100	809
Total finance lease liabilities	$ 2,132	$ 4,327

Leases - Weighted Average Remai

Leases - Weighted Average Remaining Terms and Discount Rates (Details)	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Weighted average remaining lease term, Operating leases (in years)	2 years 7 months 6 days	2 years 8 months 12 days
Weighted average remaining lease term, Finance leases (in years)	1 year	1 year 1 month 6 days
Weighted average discount rate, Operating leases (percent)	4.60%	4.70%
Weighted average discount rate, Finance leases (percent)	7.50%	7.50%

Leases - Lease Maturities (Deta

Leases - Lease Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Operating Leases
Remaining 2020	$ 3,285
2021	3,451
2022	2,420
2023	1,288
2024	678
Total future minimum lease payments	11,122
Less: imputed interest	(626)
Total	10,496	$ 9,393
Finance Leases
Remaining 2020	1,440
2021	787
2022	0
2023	0
2024	0
Total future minimum lease payments	2,227
Less: imputed interest	(95)
Total	$ 2,132	$ 4,327

Acquisitions - Virtual Observer

Acquisitions - Virtual Observer Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2020	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Apr. 30, 2020
Business Acquisition [Line Items]
Cash paid to acquire Virtual Observer			$ 28,313	$ 0
Goodwill		$ 34,444	34,444		$ 11,798
Virtual Observer, formerly known as Coordinated Systems, Inc.
Business Acquisition [Line Items]
Cash paid to acquire Virtual Observer	$ 32,200
Goodwill	$ 22,646					$ 22,600
Business Combination, Acquisition Related Costs					$ 300
Virtual Observer, formerly known as Coordinated Systems, Inc. | Trade names and trademarks
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Years)	2 years
Business Combination, Acquisition Related Costs		800	800
Virtual Observer, formerly known as Coordinated Systems, Inc. | Developed technology
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Years)	5 years
Virtual Observer, formerly known as Coordinated Systems, Inc. | Customer-related intangible assets
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Years)	5 years
Business Combination, Acquisition Related Costs		$ 600	$ 600

Acquisitions - Virtual Observ_2

Acquisitions - Virtual Observer Table (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Apr. 30, 2020	Apr. 01, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 34,444			$ 11,798
Deferred tax liability			$ (2,910)
Virtual Observer, formerly known as Coordinated Systems, Inc.
Business Acquisition [Line Items]
Cash			168
Tangible assets acquired			200
Finite-lived intangibles acquired		$ 12,800
Goodwill		$ 22,600	22,646
Total assets acquired			35,814
Liabilities assumed			(682)
Total			32,222
Virtual Observer, formerly known as Coordinated Systems, Inc. | Developed technology rights
Business Acquisition [Line Items]
Finite-lived intangibles acquired			12,200
Virtual Observer, formerly known as Coordinated Systems, Inc. | Customer-related intangible assets
Business Acquisition [Line Items]
Finite-lived intangibles acquired			500
Virtual Observer, formerly known as Coordinated Systems, Inc. | Trade names and trademarks
Business Acquisition [Line Items]
Finite-lived intangibles acquired			$ 100

Acquisitions - Whendu LLC (Deta

Acquisitions - Whendu LLC (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended	12 Months Ended
	Nov. 30, 2019	Jun. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Amortization period (Years)		4 years	3 years 9 months 18 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Amortization period (Years)		4 years	3 years 10 months 24 days
Acquired workforce
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Amortization period (Years)		2 years 4 months 24 days	2 years 10 months 24 days
Whendu
Finite-Lived Intangible Assets [Line Items]
Payments to Acquire Intangible Assets	$ 15.9
Whendu | Developed technology
Finite-Lived Intangible Assets [Line Items]
Payments to Acquire Intangible Assets	$ 15.4
Weighted Average Remaining Amortization period (Years)	4 years
Whendu | Acquired workforce
Finite-Lived Intangible Assets [Line Items]
Payments to Acquire Intangible Assets	$ 0.5
Weighted Average Remaining Amortization period (Years)	3 years

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event - Bishop Ranch Building $ in Millions	Jul. 29, 2020USD ($)ft²
Subsequent Event [Line Items]
Rental space (in square feet) | ft²	104,253
Operating lease, term of contract (in months)	120 months
Operating lease, monthly rent expense	$ 0.4
Rent abatement period (in months)	8 months
Security deposit	$ 0.5
Tenant improvement allowance	$ 4.2