CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenue	$ 96,614	$ 66,187	$ 265,542	$ 176,658
Cost of revenue	22,236	13,163	57,632	37,020
Gross profit	74,378	53,024	207,910	139,638
Operating expense:
Research and development	57,087	13,249	91,377	53,062
Sales and marketing	96,785	34,164	188,155	95,348
General and administrative	60,759	5,558	76,785	43,953
Total operating expenses	214,631	52,971	356,317	192,363
(Loss) income from operations	(140,253)	53	(148,407)	(52,725)
Interest and other income, net	22,923	1,239	23,428	862
(Loss) income before income taxes	(117,330)	1,292	(124,979)	(51,863)
(Benefit from) provision for income taxes	(9,915)	(95)	(7,720)	3,896
Net (loss) income	(107,415)	1,387	(117,259)	(55,759)
Accretion of redeemable convertible preferred stock	(2,264,838)	(269,358)	(2,646,662)	(371,522)
Net loss attributable to common stockholders - basic and diluted
Net loss attributable to common stockholders - basic	(2,372,253)	(267,971)	(2,763,921)	(427,281)
Net loss attributable to common stockholders - diluted	$ (2,372,253)	$ (267,971)	$ (2,763,921)	$ (427,281)
Net loss attributable to common stockholders - basic and diluted
Basic (in dollars per share)	$ (24.72)	$ (3.49)	$ (32.96)	$ (5.56)
Diluted (in dollars per share)	$ (24.72)	$ (3.49)	$ (32.96)	$ (5.56)
Weighted average shares used in computing net loss per share attributable to common stockholders - basic and diluted
Weighted-average shares used in computing net loss per share attributable to common stockholders - diluted (in shares)	95,930	76,880	83,860	76,846
Weighted-average shares used in computing net loss per share attributable to common stockholders - basic (in shares)	95,930	76,880	83,860	76,846