Note 6 - Leases (Details Textual) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 30, 2021	Jan. 25, 2020	Jan. 30, 2021	Jan. 25, 2020	May 02, 2020
Operating Lease, Cost	$ 3.5	$ 4.0	$ 10.8	$ 10.7
Operating Lease, Weighted Average Remaining Lease Term (Year)	3 years 10 months 24 days		3 years 10 months 24 days		4 years 3 months 18 days
Operating Lease, Weighted Average Discount Rate, Percent	3.10%		3.10%		3.38%
Operating Lease, Payments	$ 3.3	$ 3.3	$ 10.3	$ 9.9