Note 10 - Stockholders' Equity and Stock-based Compensation - Summary of Options Issued to Employees and Directors (Details) - Share-Based Payment Arrangement, Option [Member] - $ / shares	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Balance (in shares)	237,985
Balance, weighted average exercise price (in dollars per share)	$ 6.14
Balance, weighted average remaining contract life (Year)	7 months 17 days	1 year 4 months 28 days
Exercised (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Expired (in shares)	(40,098)
Expired (in dollars per share)	$ 4.56
Balance (in shares)	197,887	237,985
Balance, weighted average exercise price (in dollars per share)	$ 6.46	$ 6.14
Exercisable (in shares)	197,887
Exercisable, weighted average exercise price (in dollars per share)	$ 6.46
Exercisable, weighted average remaining contract life (Year)	7 months 17 days

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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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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Number of share options (or share units) exercised during the current period.

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