Note 10 - Provision for Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2021	Dec. 26, 2020	Dec. 28, 2019
Balance at beginning of year	$ 61	$ 0	$ 0
Increases related to current year tax positions	0	61	0
Balance at end of year	$ 61	$ 61	$ 0