CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - 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	$ 99,721	$ 67,424	$ 190,971	$ 129,151
Cost of revenue	24,164	14,832	44,985	29,192
Gross profit	75,557	52,592	145,986	99,959
Operating expenses:
Sales and marketing	51,376	35,836	98,341	66,653
Research and development	28,131	18,868	61,485	36,517
General and administrative	20,754	17,659	46,935	33,707
Total operating expenses	100,261	72,363	206,761	136,877
Loss from operations	(24,704)	(19,771)	(60,775)	(36,918)
Non-operating income (expense):
Interest income	1,857	830	4,426	1,743
Interest expense	(5,007)	(290)	(5,074)	(563)
Other income (expense), net	(219)	(86)	266	(379)
Total non-operating income (expense), net	(3,369)	454	(382)	801
Loss before income taxes	(28,073)	(19,317)	(61,157)	(36,117)
Provision for (benefit from) income taxes	(1,938)	389	(2,276)	703
Net loss	$ (26,135)	$ (19,706)	$ (58,881)	$ (36,820)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.09)	$ (0.23)	$ (0.20)	$ (0.43)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	299,321	85,683	297,392	85,382