Note 1 - Organization, Basis of Presentation, and Summary of Significant Accounting Policies - Summary of Stock-based Compensation by Income Statement Line Item (Details) - USD ($) $ in Thousands	12 Months Ended
	May 28, 2017	May 29, 2016	May 31, 2015
Stock-based compensation expense	$ 3,964	$ 3,465	$ 1,577
Cost of Sales [Member]
Stock-based compensation expense	485	405	142
Research and Development Expense [Member]
Stock-based compensation expense	83	90	16
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense	3,396	2,970	1,419
Employee Stock Option [Member]
Stock-based compensation expense	1,230	1,352	561
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense	$ 2,734	$ 2,113	$ 1,016