Note 8 - Income Taxes - Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	May 28, 2017	May 29, 2016	May 31, 2015
Unrecognized tax benefits – beginning of the period	$ 842,000	$ 987,000	$ 1,035,000
Gross increases – tax positions in prior period	11,000	1,000	17,000
Gross decreases – tax positions in prior period	(90,000)	(223,000)	(141,000)
Gross increases – current-period tax positions	93,000	77,000	76,000
Lapse of statute of limitations	(319,000)
Unrecognized tax benefits – end of the period	$ 537,000	$ 842,000	$ 987,000