Note 7 - Stock Plans - Unrecognized Stock-based Compensation Expense (Details) $ in Thousands	Mar. 31, 2023 USD ($)
Unrecognized stock-based compensation expense	$ 2,939
The 2012 Director Stock Incentive Plan [Member]
Unrecognized stock-based compensation expense	658
The 2012 Omnibus Stock Incentive Plan [Member]
Unrecognized stock-based compensation expense	670
The 2022 Omnibus Stock Incentive Plan [Member]
Unrecognized stock-based compensation expense	$ 1,611