Note 6 - Leases (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jan. 25, 2020	Jan. 25, 2020	Apr. 28, 2019	Apr. 27, 2019
Operating Lease, Liability, Total	$ 47,485	$ 47,485
Operating Lease, Weighted Average Remaining Lease Term	3 years 9 months	3 years 9 months
Operating Lease, Weighted Average Discount Rate, Percent	3.38%	3.38%
Operating Lease, Expense	$ 4,000	$ 10,700
Short-term Lease, Cost	5,000	1,500
Operating Lease, Payments		10,800
Operating Lease, Right-of-Use Asset	$ 47,549	$ 47,549		$ 0
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total			$ 55,500
Operating Lease, Right-of-Use Asset			$ 55,500