Note 16 - Shareholders' Equity and Stock Plans - Stock Option Activity (Details) - $ / shares	12 Months Ended	24 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Options outstanding (in shares)	97,400		97,400
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.02		$ 5.02
Options outstanding, weighted average remaining contractual term (Year)	3 years 1 month 2 days	4 years 1 month 9 days	2 years 1 month 2 days
Exercised (in shares)	(11,000)
Exercised, weighted average exercise price (in dollars per share)	$ 4.70
Options outstanding (in shares)	86,400	97,400	86,400
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.06	$ 5.02	$ 5.06
Exercisable (in shares)	86,400		86,400
Exercisable, weighted average exercise price (in dollars per share)	$ 5.06		$ 5.06
Exercisable, weighted average remaining contractual term (Year) (Year)	3 years 1 month 2 days		2 years 1 month 2 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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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 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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