Net Loss per Share - Schedule of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Earnings Per Share [Abstract]
Net loss attributable to Class A and Class B common stockholders	$ (539,102)	$ (348,535)	$ (178,028)
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders - basic and diluted (in shares)	141,613,196	44,847,442	38,162,228
Net loss per share attributable to Class A and Class B common stockholders - basic and diluted (in dollars per share)	$ (3.81)	$ (7.77)	$ (4.67)