Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (94,010)	$ (78,764)	$ (28,578)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	9,903	6,321	4,156
Stock-based compensation	68,585	46,139	34,961
Amortization of deferred commissions	13,106	13,630	13,185
Noncash operating lease costs	8,737	9,023
Amortization of debt discount and issuance costs	4,096	0	0
Capital loss (gain) from sale of fixed assets	0	45	(27)
Changes in assets and liabilities:
Trade receivables	(19,075)	8,173	(7,627)
Prepaid expenses and other current assets	(543)	(1,225)	(1,932)
Deferred commissions	(19,131)	(19,132)	(15,308)
Other long-term assets	1,436	81	(270)
Trade payables	(328)	(1,623)	1,985
Accrued expenses and other short-term liabilities	16,058	(886)	9,910
Deferred revenues	(169)	7,219	14,115
Other long-term liabilities	5,493	316	(1,025)
Net cash provided by (used in) operating activities	(5,842)	(10,683)	23,545
Cash flows from investing activities:
Decrease (increase) in short-term deposits	(20,071)	60,466	(30,280)
Decrease (increase) in marketable securities	7,414	(1,761)	(39)
Increase in long-term deposits	(2,606)	(21)	(313)
Acquisition, net of cash acquired	(29,369)	0	0
Proceeds from sale of property and equipment	0	11	27
Purchases of property and equipment	(10,116)	(25,392)	(9,583)
Net cash provided by (used in) investing activities	(54,748)	33,303	(40,188)
Cash flows from financing activities:
Proceeds from issuance of convertible senior notes, net of issuance costs	245,308	0	0
Purchases of capped calls	(29,348)	0	0
Proceeds (withholdings) from employee stock plans, net	9,793		8,114
Proceeds (withholdings) from employee stock plans, net		(2,398)
Net cash provided by (used in) financing activities	225,753	(2,398)	8,114
Increase (decrease) in cash and cash equivalents	165,163	20,222	(8,529)
Cash and cash equivalents at beginning of period	68,929	48,707	57,236
Cash and cash equivalents at end of period	234,092	68,929	48,707
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,342	3,955	$ 710
Net lease liabilities arising from obtaining right-of-use assets	$ 6,256	$ 10,252