CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 371,022	$ 249,659	$ 172,377
Cost of revenue	78,030	52,492	36,462
Gross profit	292,992	197,167	135,915
Operating expense:
Research and development	120,407	69,210	38,559
Sales and marketing	260,345	133,277	111,115
General and administrative	117,022	50,792	15,911
Total operating expenses	497,774	253,279	165,585
Loss from operations	(204,782)	(56,112)	(29,670)
Interest and other income, net	23,303	2,833	2,180
Loss before income taxes	(181,479)	(53,279)	(27,490)
Provision for income taxes	10,516	4,015	3,635
Net loss	(191,995)	(57,294)	(31,125)
Accretion of redeemable convertible preferred stock	(2,646,662)	(1,560,524)	(553,339)
Deemed dividend distribution	0	0	(40,071)
Net loss attributable to common stockholders - basic and diluted
Net loss attributable to common stockholders - basic	(2,838,657)	(1,617,818)	(624,535)
Net loss attributable to common stockholders - diluted	$ (2,838,657)	$ (1,617,818)	$ (624,535)
Net loss attributable to common stockholders - basic and diluted
Basic (in dollars per share)	$ (21.73)	$ (21.03)	$ (8.21)
Diluted (in dollars per share)	$ (21.73)	$ (21.03)	$ (8.21)
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)	130,652	76,945	76,029
Weighted-average shares used in computing net loss per share attributable to common stockholders - basic (in shares)	130,652	76,945	76,029