Note 3 - Stock-based Compensation (Details Textual) - USD ($)	9 Months Ended	16 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Restricted Stock [Member]
Share-based Payment Arrangement, Expense	$ 83,000	$ 0
Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense	155,000	$ 274,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 71,000		$ 71,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	7 months 9 days
Incentive Plan 2020 [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	15,140	0	24,052
The2004 Plan Member
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	0
Incentive Plan 2020 [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	1,800,000		1,800,000

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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