Unrecognized Tax Benefits - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Apr. 30, 2020
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 10,825		$ 8,907
Unrecognized tax benefits that would impact effective tax rate	8,552
Accrued interest and penalties related to unrecognized tax benefits	530		$ 354
Net interest and penalties included in income tax expense	176	$ 183
Expected decrease in unrecognized tax benefits	$ 1,800