Note 3 - Stock-based Compensation (Details Textual) - Incentive Plan 2006 [Member] shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2022 USD ($) shares	Sep. 30, 2022 USD ($) shares
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)	176	176
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	1,136	1,136
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total \| $	$ 1,200	$ 1,200
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 10 months 24 days
Director [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Accelerated Vesting, Number (in shares)	19	35
Share-Based Payment Arrangement, Accelerated Cost \| $	$ 118	$ 230

Aggregate number of common shares reserved for future issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of additional cost recognized for award under share-based payment arrangement from occurrence of event accelerating recognition of cost.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Number of shares for which recognition of cost was accelerated for award under share-based payment arrangement.

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