Note 7 - Stock-based Compensation (Details Textual) - Incentive Compensation Plan [Member] - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		2,580,000		2,580,000
Share-Based Payment Arrangement, Expense	$ 72,000	$ 96,000	$ 159,000	$ 203,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 10,000		$ 10,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)			3 years