Note 7 - Stock Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 30, 2022
Stock-based compensation expense	$ 445	$ 306
The 2012 Director Stock Incentive Plan [Member]
Stock-based compensation expense	114	109
The 2012 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	141	165
The 2022 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	156	0
The 2002 Employee Stock Purchase Plan [Member]
Stock-based compensation expense	$ 34	$ 32