Stockholders’ Equity and Equity Incentive Plans - Summary of Stock-based Compensation Expense by Line Item (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 56,855	$ 18,075	$ 85,632	$ 24,737
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	7,727	1,902	10,976	2,732
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	10,010	2,510	15,234	3,674
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	32,398	10,439	49,521	13,066
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 6,720	$ 3,224	$ 9,901	$ 5,265