Note 10 - Stock Options and Stock Purchase Warrants - Summary of Option Activity (Details) - $ / shares	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Outstanding (in shares)	60,000	460,000
Outstanding (in dollars per share)	$ 6.93	$ 7.34
Granted (in shares)	120,000	0
Granted (in dollars per share)	$ 5.43	$ 0
Exercised (in shares)	0	0
Exercised (in dollars per share)	$ 0	$ 0
Forfeited or expired (in shares)	0	(400,000)
Forfeited or expired (in dollars per share)	$ 0	$ (7.40)
Outstanding (in shares)	180,000	60,000
Outstanding (in dollars per share)	$ 5.93	$ 6.93

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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