Note 4 - Financial Instruments and Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Aug. 26, 2017	Nov. 26, 2016
Short-term Investments	$ 23,125	$ 23,125
Maximum [Member]
Interest Rate of Certificates of Deposit	1.50%
Certificates of Deposit Terms	270 days
Minimum [Member]
Interest Rate of Certificates of Deposit	0.10%
Weighted Average [Member]
Interest Rate of Certificates of Deposit	1.13%
Certificates of Deposit Terms	180 days