Note 7 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2023	Mar. 31, 2024
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 6,700,000	$ 6,700,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 389,000	389,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued		$ 0
Domestic Tax Jurisdiction [Member]
Open Tax Year	2020 2021 2022 2023
State and Local Jurisdiction [Member]
Open Tax Year	2019 2020 2021 2022 2023

Tax year that remains open to examination under enacted tax laws, in YYYY format.

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Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return.

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Amount of interest expense accrued for an underpayment of income taxes.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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