Note 7 - Stock Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Stock-based compensation expense	$ 258	$ 333	$ 977	$ 860
The 2012 Director Stock Incentive Plan [Member]
Stock-based compensation expense	126	170	497	339
The 2012 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	132	163	447	477
The 2022 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	0	0	1	0
The 2002 Employee Stock Purchase Plan [Member]
Stock-based compensation expense	$ 0	$ 0	$ 32	$ 44