Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Apr. 30, 2018
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 8,331		$ 6,421
Unrecognized tax benefits that would impact effective tax rate	6,604
Accrued interest and penalties related to unrecognized tax benefits	318		$ 191
Net interest and penalties included in income tax expense	127	$ 113
Expected decrease in unrecognized tax benefits	$ 1,300