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Note 12 - Stock-based Compensation (Details Textual) - The 2018 Equity Incentive Plan [Member] - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | May 17, 2018
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) |  |  |  |  | 1,300,000
Share-Based Payment Arrangement, Expense | $ 389,000 | $ 364,000 | $ 784,000 | $ 1,000,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expected Contractual Term Forfeiture Rate |  |  | 3.10% |  |
Share-Based Payment Arrangement, Tranche One [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 1 year |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term (Year) |  |  | 5 years 6 months |  |
Share-Based Payment Arrangement, Tranche Four [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 5 years |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term (Year) |  |  | 6 years 6 months |  |
Restricted Stock [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) |  |  |  |  | 326,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 80,622 |  | 80,622 |  |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) |  |  | 3 years |  |
Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount | $ 2,000,000 |  | $ 2,000,000 |  |
Restricted Stock [Member] | Director [Member] | Minimum [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 1 year |  |
Restricted Stock [Member] | Officers And Employees [Member] | Maximum [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 5 years |  |
Share-Based Payment Arrangement, Option [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | 265,532 |  | 265,532 |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) |  |  | 10 years |  |
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount | $ 1,300,000 |  | $ 1,300,000 |  |
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) |  |  | 3 years |  |
Share-Based Payment Arrangement, Option [Member] | Maximum [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) |  |  | 10 years |  |
Share-Based Payment Arrangement, Option [Member] | Director [Member] | Minimum [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 1 year |  |
Share-Based Payment Arrangement, Option [Member] | Officers And Employees [Member] | Share-Based Payment Arrangement, Tranche One [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage |  |  | 20.00% |  |
Share-Based Payment Arrangement, Option [Member] | Officers And Employees [Member] | Maximum [Member] |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) |  |  | 5 years |  |

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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479830/718-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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