Share-Based Compensation - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 9,086	$ 4,098	$ 15,383	$ 5,940
Cost of subscription revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	356	84	591	118
Cost of professional services revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	298	150	515	197
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	3,317	1,378	5,589	2,043
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	3,276	1,370	5,385	1,884
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation	$ 1,839	$ 1,116	$ 3,303	$ 1,698