CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 114,162	$ 73,941	$ 305,133	$ 203,092
Cost of revenue	27,005	16,033	71,990	45,225
Gross profit	87,157	57,908	233,143	157,867
Operating expenses:
Sales and marketing	55,982	45,538	154,323	112,191
Research and development	30,902	27,863	92,387	64,380
General and administrative	21,525	25,593	68,460	59,300
Total operating expenses	108,409	98,994	315,170	235,871
Loss from operations	(21,252)	(41,086)	(82,027)	(78,004)
Non-operating income (expense):
Interest income	1,316	1,079	5,742	2,822
Interest expense	(9,828)	(407)	(14,902)	(970)
Other income (expense), net	(208)	(651)	58	(1,030)
Total non-operating income (expense), net	(8,720)	21	(9,102)	822
Loss before income taxes	(29,972)	(41,065)	(91,129)	(77,182)
Provision for (benefit from) income taxes	(3,504)	(212)	(5,780)	491
Net loss	$ (26,468)	$ (40,853)	$ (85,349)	$ (77,673)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.09)	$ (0.35)	$ (0.29)	$ (0.81)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	301,689	118,056	298,628	96,393