Income Taxes - Components of Net Loss, Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Income Tax Disclosure [Abstract]
Domestic	$ (58,407)	$ (69,887)	$ (33,868)
Foreign	3,415	889	788
Net loss before provision for income taxes	$ (54,992)	$ (68,998)	$ (33,080)