Note 2 - Certain Significant Estimates - Inventory Valuation Reserves (Details) - SEC Schedule, 12-09, Reserve, Inventory [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2021	Dec. 26, 2020	Dec. 28, 2019
Beginning balance	$ 697	$ 786	$ 456
Additions	446	831	756
Deductions	(395)	(920)	(426)
Ending balance	$ 748	$ 697	$ 786