Net Loss per Share - Summary of Computation 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	Jul. 31, 2020	Apr. 30, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Oct. 31, 2020	Oct. 31, 2019
Numerator:
Net loss	$ (5,284)	$ (7,656)	$ (25,550)	$ (40,896)	$ (36,234)	$ (36,828)	$ (38,490)	$ (113,958)
Denominator:
Weighted-average number of shares outstanding—basic and diluted	157,465			148,555			154,734	146,997
Net loss per share—basic and diluted	$ (0.03)			$ (0.28)			$ (0.25)	$ (0.78)