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	$ (58,881)	$ (36,820)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense	22,113	13,160
Non-cash operating lease costs	9,332	0
Amortization of deferred contract acquisition costs	7,462	4,904
Stock-based compensation expense	25,346	2,101
Net accretion of discounts and amortization of premiums on available-for-sale securities	(367)	(852)
Amortization of debt discount and issuance costs	4,303	0
Deferred income taxes	(2,621)	0
Provision for bad debt	2,493	451
Change in fair value of redeemable convertible preferred stock warrant liability	0	327
Other	(95)	9
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable, net	(12,272)	(5,222)
Contract assets	(161)	(153)
Deferred contract acquisition costs	(16,158)	(8,446)
Prepaid expenses and other current assets	(171)	(314)
Other noncurrent assets	(894)	(1,373)
Accounts payable	4,333	4,887
Accrued expenses and other current liabilities	4,179	920
Operating lease liabilities	(10,205)	0
Deferred revenue	13,371	10,727
Other noncurrent liabilities	(1,396)	3,137
Net cash used in operating activities	(10,289)	(12,557)
Cash Flows From Investing Activities
Purchases of property and equipment	(30,605)	(18,990)
Capitalized internal-use software	(9,863)	(7,471)
Cash paid for acquisitions, net of cash acquired	(13,691)	0
Purchases of available-for-sale securities	(579,437)	(45,143)
Sales of available-for-sale securities	0	1,978
Maturities of available-for-sale securities	323,832	97,448
Other investing activities	223	25
Net cash provided by (used in) investing activities	(309,541)	27,847
Cash Flows From Financing Activities
Gross proceeds from issuance of convertible senior notes	575,000	0
Purchases of capped calls related to convertible senior notes	(67,333)	0
Cash paid for issuance costs on convertible senior notes	(12,520)	0
Proceeds from the exercise of stock options	4,335	1,067
Proceeds from the early exercise of stock options	80	2,174
Repurchases of unvested common stock	(101)	(88)
Payments on note payable	(200)	(182)
Proceeds from the issuance of common stock for employee stock purchase plan	5,447	0
Proceeds from build-to-suit lease financing obligation drawdown	0	47
Payments of deferred offering costs	0	(969)
Net cash provided by financing activities	497,024	2,049
Net increase (decrease) in cash, cash equivalents, and restricted cash	177,194	17,339
Cash, cash equivalents, and restricted cash, beginning of period	145,636	31,426
Cash, cash equivalents, and restricted cash, end of period	322,830	48,765
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest	34	289
Cash paid for income taxes, net of refunds	30	916
Cash paid for operating lease liabilities	9,944	0
Supplemental Disclosure of Non-cash Investing and Financing Activities:
Stock-based compensation capitalized for software development	1,632	143
Accounts payable and accrued expenses related to property and equipment additions	4,651	2,229
Vesting of early exercised stock options	2,511	1,438
Deferred offering costs, accrued but not paid	0	1,958
Indemnity holdback consideration associated with business combinations	2,188	0
Issuance of common stock related to an acquisition	1,821	0
Operating lease right-of-use assets obtained in exchange for operating lease liabilities	4,607	0
Derecognition of build-to-suit lease	9,886	0
Restricted Stock Units (RSUs)
Cash Flows From Financing Activities
Payment of tax withholding obligation	(7,308)	0
Shares issuable pursuant to the ESPP
Cash Flows From Financing Activities
Payment of tax withholding obligation	$ (376)	$ 0