Net Loss per Share - Schedule of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Earnings Per Share [Abstract]
Net loss attributable to Class A and Class B common stockholders	$ (168,889)	$ (88,057)	$ (340,167)	$ (265,281)
Weighted-average shares used in computing net loss per share attributable to Class A and Class B common stockholders - basic and diluted (in shares)	166,868,200	45,911,449	93,763,599	43,113,683
Net loss per share attributable to Class A and Class B common stockholders - basic and diluted (in dollars per share)	$ (1.01)	$ (1.92)	$ (3.63)	$ (6.15)