Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Statement Of Financial Position [Abstract]
Allowance for credit losses	$ 36	$ 107
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	74,641,439	74,222,127
Common stock, shares outstanding	45,601,069	49,937,329
Treasury stock, shares	29,040,370	24,284,798