Note 7 - Stock Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Stock-based compensation expense	$ 339	$ 518	$ 798	$ 963
The 2012 Director Stock Incentive Plan [Member]
Stock-based compensation expense	60	173	139	287
The 2012 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	61	118	149	259
The 2022 Omnibus Stock Incentive Plan [Member]
Stock-based compensation expense	218	227	384	383
The 2002 Employee Stock Purchase Plan [Member]
Stock-based compensation expense	$ 0	$ 0	$ 126	$ 34