Net Loss per Share - Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss	$ (323,977)	$ (518,601)	$ (295,033)	$ (172,999)	$ (102,050)	$ (105,353)	$ (1,137,611)	$ (380,402)
Less: premium on repurchase of redeemable convertible preferred units	0			0			0	(92,734)
Net loss attributable to Class A and Class B common stockholders	$ (323,977)			$ (172,999)			$ (1,137,611)	$ (473,136)
Denominator:
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, basic (in shares)	1,747,255			29,284			1,313,234	27,085
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders, diluted (in shares)	1,747,255			29,284			1,313,234	27,085
Earnings Per Share, Basic and Diluted [Abstract]
Net loss attributable to Class A and Class B common stockholders per share, basic (in dollars per share)	$ (0.19)			$ (5.91)			$ (0.87)	$ (17.47)
Net loss attributable to Class A and Class B common stockholders per share, diluted (in dollars per share)	$ (0.19)			$ (5.91)			$ (0.87)	$ (17.47)