Unrecognized Tax Benefits - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Apr. 30, 2020
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 10,548		$ 8,907
Unrecognized tax benefits that would impact effective tax rate	8,333
Accrued interest and penalties related to unrecognized tax benefits	460		$ 354
Net interest and penalties included in income tax expense	106	$ 119
Expected decrease in unrecognized tax benefits	$ 1,800