Equity Incentive Plans - Summary of Stock-Based Compensation Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 210,645	$ 150,673	$ 116,668
Cost of revenue—product
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	2,951	1,630	601
Cost of revenue—support subscription
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	12,378	9,050	5,639
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	92,484	71,229	63,495
Sales and marketing
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	66,350	47,687	34,317
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 36,482	$ 21,077	$ 12,616