Note 7 - Stock Options - Changes in Options (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Options outstanding (in shares)	5,415,000	5,315,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.5	$ 0.49
Options outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0
Granted, options (in shares)		100,000
Granted, weighted average exercise price (in dollars per share)		$ 0.8
Granted, aggregate intrinsic value (in dollars per share)		$ 0
Expired, options (in shares)	(3,600,000)
Expired, weighted average exercise price (in dollars per share)	$ 0.35
Expired, aggregate intrinsic value (in dollars per share)	$ 0
Options outstanding (in shares)	1,815,000	5,415,000
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.8	$ 0.5

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The combined weighted average of the accumulated differences between the fair values on underlying shares and exercises prices to acquire such shares as of the grant date on options that were either forfeited or lapsed.

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The grant-date intrinsic value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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

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- Definition

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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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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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