Equity Incentive Plans and Employee Stock Purchase Plan - Stock-based Compensation Expense Recognized in Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 9,009	$ 4,917	$ 16,586	$ 9,371
Cost of revenue—subscription
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	489	170	848	321
Cost of revenue—services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	281	98	465	170
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,129	1,482	4,347	2,697
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,904	1,322	5,110	2,567
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 3,206	$ 1,845	$ 5,816	$ 3,616