Income Taxes - Changes in Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning of year	$ 6,037	$ 7,794	$ 3,674
Settlement with tax authority		(1,767)	(1,771)
Additions based on tax positions related to the current year	1,716	10	1,775
Additions based on tax positions related to prior years	2,201		4,116
Unrecognized tax benefits, end of year	$ 9,954	$ 6,037	$ 7,794