Note 5 - Diluted Net Income Per Share - Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 25, 2018	Feb. 26, 2017	Feb. 25, 2018	Feb. 26, 2017
Numerator:
Net income applicable to Common Stockholders	$ 16,088	$ 3,500	$ 18,721	$ 8,138
Denominator:
Weighted average shares for basic net income per share (in shares)	27,547	27,286	27,524	27,252
Effect of dilutive securities:
Stock options and restricted stock units (in shares)	371	396	360	356
Weighted average shares for diluted net income per share (in shares)	27,918	27,682	27,884	27,608
Diluted net income per share (in dollars per share)	$ 0.58	$ 0.13	$ 0.67	$ 0.29