Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Apr. 30, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 9,844		$ 7,287
Unrecognized tax benefits that would impact effective tax rate	7,799
Accrued interest and penalties related to unrecognized tax benefits	425		$ 242
Net interest and penalties included in income tax expense	183	$ 127
Expected decrease in unrecognized tax benefits	$ 1,100