Note 9 - Bank Credit Facility (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Jun. 15, 2020	Nov. 28, 2020	Nov. 30, 2019	Nov. 24, 2018	Jan. 01, 2021
Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total		$ 49	$ 7	$ 166
Bank One [Member]
Line of Credit Facility, Maximum Borrowing Capacity		50,000
Letters of Credit Outstanding, Amount		2,881
Line of Credit Facility, Remaining Borrowing Capacity		47,119
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.25%
Bank One [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	1.90%
Bank One [Member] | Subsequent Event [Member]
Line of Credit Facility, Maximum Borrowing Capacity					$ 25,000
Bank Two [Member]
Letters of Credit Outstanding, Amount		$ 325