Note 1 - Organization, Basis of Presentation, and Summary of Significant Accounting Policies - Revenue Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 25, 2018	Feb. 26, 2017	Feb. 25, 2018	Feb. 26, 2017
Revenue	$ 149,323	$ 136,568	$ 409,137	$ 404,827
Revenue Recorded Upon Shipment [Member]
Revenue	141,575	125,765	373,486	339,917
Revenue Recorded Upon Acceptance in Foreign Port [Member]
Revenue	4,414	7,276	25,982	56,316
Revenue from Multiple Element Arrangements [Member]
Revenue	1,528	2,624	5,230	5,892
Revenue from License Fees, R&D Contracts and Royalties/Profit Sharing [Member]
Revenue	$ 1,806	$ 903	$ 4,439	$ 2,702