Note 10 - Stock Options and Stock Purchase Warrants - Summary of Option Activity (Details) - $ / shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Outstanding (in shares)	460,000	460,000
Outstanding (in dollars per share)	$ 7.34	$ 7.34
Granted (in shares)
Granted (in dollars per share)
Exercised (in shares)
Exercised (in dollars per share)
Forfeited or expired (in shares)
Forfeited or expired (in dollars per share)
Outstanding (in shares)	460,000	460,000
Outstanding (in dollars per share)	$ 7.34	$ 7.34

For presentations that combine terminations, 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 or that expired.

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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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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 per share amount at which grantees can acquire shares of common stock by exercise of options.

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

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