Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 21,740	$ 8,310	$ 4,267
Cost of revenue | Subscription
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	828	370	149
Cost of revenue | Professional services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	376	122	69
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	9,080	3,074	1,739
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,950	1,223	781
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,506	$ 3,521	$ 1,529