CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities
Net loss	$ (85,349)	$ (77,673)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization expense	35,029	20,923
Non-cash operating lease costs	14,134	0
Amortization of deferred contract acquisition costs	12,085	7,722
Stock-based compensation expense	40,091	25,012
Amortization of debt discount and issuance costs	12,865	0
Net accretion of discounts and amortization of premiums on available-for-sale securities	248	(1,137)
Deferred income taxes	(6,808)	0
Provision for bad debt	2,794	861
Change in fair value of redeemable convertible preferred stock warrant liability	0	1,517
Other	(73)	27
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable, net	(17,710)	(7,911)
Contract assets	(23)	82
Deferred contract acquisition costs	(24,615)	(12,923)
Prepaid expenses and other current assets	(6,131)	(7,525)
Other noncurrent assets	(930)	(1,686)
Accounts payable	4,648	(994)
Accrued expenses and other current liabilities	8,545	5,652
Operating lease liabilities	(15,131)	0
Deferred revenue	18,425	13,614
Other noncurrent liabilities	(410)	4,096
Net cash used in operating activities	(8,316)	(30,343)
Cash Flows From Investing Activities
Purchases of property and equipment	(45,962)	(30,981)
Capitalized internal-use software	(14,333)	(11,332)
Cash paid for acquisitions, net of cash acquired	(13,691)	0
Purchases of available-for-sale securities	(956,147)	(157,075)
Sales of available-for-sale securities	0	1,978
Maturities of available-for-sale securities	515,044	132,398
Other investing activities	395	30
Net cash used in investing activities	(514,694)	(64,982)
Cash Flows From Financing Activities
Proceeds from initial public offering, net of underwriting discounts and commissions	0	570,544
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	(12,542)	0
Proceeds from the exercise of stock options	5,724	2,899
Proceeds from the early exercise of stock options	180	2,871
Repurchases of unvested common stock	(113)	(155)
Payments on note payable	(200)	(218)
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	58
Payments of deferred offering costs	0	(3,734)
Net cash provided by financing activities	498,180	572,265
Net increase (decrease) in cash, cash equivalents, and restricted cash	(24,830)	476,940
Cash, cash equivalents, and restricted cash, beginning of period	145,636	31,426
Cash, cash equivalents, and restricted cash, end of period	120,806	508,366
Supplemental Disclosure of Cash Flow Information:
Cash paid for interest	34	573
Cash paid for income taxes, net of refunds	623	1,013
Cash paid for operating lease liabilities	15,256	0
Supplemental Disclosure of Non-cash Investing and Financing Activities:
Stock-based compensation capitalized for software development	2,560	1,428
Accounts payable and accrued expenses related to property and equipment additions	4,076	1,291
Vesting of early exercised stock options	3,651	2,389
Deferred offering costs, accrued but not paid	0	1,770
Indemnity holdback consideration associated with business combinations	2,187	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	7,975	0
Derecognition of build-to-suit lease	9,886	0
Conversion of redeemable convertible preferred stock to common stock	0	331,521
Conversion of redeemable convertible preferred stock warrant liability reclassified to additional paid-in capital	0	3,135
Restricted Stock Units (RSUs)
Cash Flows From Financing Activities
Payment of tax withholding obligation	(7,607)	0
Shares issuable pursuant to the ESPP
Cash Flows From Financing Activities
Payment of tax withholding obligation	$ (376)	$ 0