Note 8 - Stock Based Compensation - Summary of Intrinsic Value (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Outstanding, number of shares underling options (in shares)	13	13	13
Outstanding, weighted average exercise price per share (in dollars per share)	$ 5.47	$ 5.47	$ 5.47
Outstanding, weighted average remaining contractual life (Year)	4 years 2 months 23 days
Outstanding, aggregate intrinsic value	$ 128
Exercisable, number of shares underling options (in shares)	13
Exercisable, weighted average exercise price per share (in dollars per share)	$ 5.47
Exercisable, weighted average remaining contractual life (Year)	4 years 2 months 23 days
Exercisable, aggregate intrinsic value	$ 128

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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