Common Stock Repurchase Program (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2021	Aug. 01, 2021	Oct. 30, 2022	Oct. 31, 2021	Mar. 31, 2020
Stockholders Equity Note [Line Items]
Cost of common stock repurchase	$ 1,029,000	$ 723,000		$ 1,800,000
Common Stock [Member]
Stockholders Equity Note [Line Items]
Common stock repurchased	73,002	48,686	0	121,688
Cost of common stock repurchase	$ 3,000	$ 2,000
Remaining authorized repurchase amount			$ 3,200,000
Stock Repurchase Program March 2020 [Member] | Common Stock [Member]
Stockholders Equity Note [Line Items]
Authorization amount for repurchase of common stock					$ 5,000,000.0