Note 9 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 28, 2017	Mar. 01, 2016	Feb. 28, 2017	Mar. 01, 2016	May 31, 2016
Deferred Tax Assets, Valuation Allowance	$ 131,300		$ 131,300		$ 89,900
Income Tax Expense (Benefit)	(84)	$ (483)	(1,742)	$ (1,686)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	10,300		44,100
Unrecognized Tax Benefits	3,800		3,800		4,500
Unrecognized Tax Benefit Reclassified Against Deferred Tax Assets			3,300		3,700
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	2,400		2,400		2,300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	400		400		$ 400
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 0		$ 0