Net Loss Per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
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	(2,838,657)	(1,617,818)	(624,535)
Net loss attributable to common stockholders - diluted	$ (2,838,657)	$ (1,617,818)	$ (624,535)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders - basic (in shares)	130,652	76,945	76,029
Weighted-average shares used in computing net loss per share attributable to common stockholders - diluted (in shares)	130,652	76,945	76,029
Net loss per share attributable to Class A and Class B 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)
Common Stock
Numerator:
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)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders - basic (in shares)	130,652	76,945	76,029
Weighted-average shares used in computing net loss per share attributable to common stockholders - diluted (in shares)	130,652	76,945	76,029
Net loss per share attributable to Class A and Class B 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)