Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Numerator:
Net loss	$ (72,764)	$ (63,495)	$ (190,526)	$ (158,441)
Denominator:
Weighted-average shares outstanding , basic and diluted (in shares)	128,813	118,976	126,222	115,598
Net loss per share, basic and diluted (in dollars per share)	$ (0.56)	$ (0.53)	$ (1.51)	$ (1.37)
Class A Common Stock
Numerator:
Net loss	$ (68,146)	$ (58,761)	$ (177,887)	$ (145,139)
Denominator:
Weighted-average shares outstanding , basic and diluted (in shares)	120,637	110,105	117,849	105,893
Net loss per share, basic and diluted (in dollars per share)	$ (0.56)	$ (0.53)	$ (1.51)	$ (1.37)
Class B Common Stock
Numerator:
Net loss	$ (4,618)	$ (4,734)	$ (12,639)	$ (13,302)
Denominator:
Weighted-average shares outstanding , basic and diluted (in shares)	8,176	8,871	8,373	9,705
Net loss per share, basic and diluted (in dollars per share)	$ (0.56)	$ (0.53)	$ (1.51)	$ (1.37)