Common Stock Repurchase Program (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Feb. 02, 2020	Jan. 31, 2021	Feb. 02, 2020	Mar. 31, 2020
Stockholders Equity Note [Line Items]
Cost of common stock repurchase	$ 728,000
Common Stock [Member]
Stockholders Equity Note [Line Items]
Common stock repurchased	55,750	0
Cost of common stock repurchase	$ 3,000
Remaining authorized repurchase amount		$ 5,000,000.0
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
Stock Repurchase Program September 5, 2019 [Member] | Common Stock [Member]
Stockholders Equity Note [Line Items]
Common stock repurchased			55,750
Cost of common stock repurchase			$ 728,000