Note 10 - Stock-based Compensation - Summary of Stock Option Activity (Details) - $ / shares		12 Months Ended
		Apr. 30, 2022	May 01, 2021	May 02, 2020
Options outstanding, beginning of year (in shares)		561,100
Options outstanding, beginning of year (in dollars per share)	[1]	$ 17.74
Granted (in shares)		30,000	266,500	0
Granted (in dollars per share)	[1]	$ 44.73
Exercised (in shares)		(36,500)
Exercised (in dollars per share)	[1]	$ 9.19
Cancelled (in shares)		(18,000)
Cancelled (in dollars per share)	[1]	$ 33.01
Options outstanding, end of year (in shares)		536,600	561,100
Options outstanding, end of year (in dollars per share)	[1]	$ 18.97	$ 17.74
Options exercisable, end of year (in shares)		303,740
Options exercisable, end of year (in dollars per share)	[1]	$ 4.46

[1] Weighted average exercise price.