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Stock Options - Options (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Apr. 05, 2012
Stock option details |  |  |  |  |
Number of rights issued |  |  | 8,000 |  |
Base value of units issued (per unit) |  |  | $ 53.91 |  |
Employee Stock Option |  |  |  |  |
Stock Options, Aggregate intrinsic value |  |  |  |  |
Stock-based compensation expense | $ 47,000 | $ 76,000 | $ 169,000 | $ 255,000 |
Employee Stock Option | 2012 Plan |  |  |  |  |
Stock option details |  |  |  |  |
Shares available for future grants |  |  |  |  | 800,000
Maximum exercisable period for granted share-based compensation |  |  | 10 years |  |
Stock option activity |  |  |  |  |
Options outstanding at the beginning of the period (in shares) |  |  | 383,865 |  |
Less: |  |  |  |  |
Options exercised (in shares) |  |  | (135,899) |  |
Options forfeited (in shares) |  |  | (20,937) |  |
Options outstanding at the end of the period (in shares) | 227,029 |  | 227,029 |  |
Options fully vested and exercisable at the end of the period (in shares) | 133,519 |  | 133,519 |  |
Stock Options, Weighted average exercise price |  |  |  |  |
Options outstanding at the beginning, weighted average exercise price (in dollars per share) |  |  | $ 30.65 |  |
Less: |  |  |  |  |
Options exercised, weighted average exercise price (in dollars per share) |  |  | 24.26 |  |
Options forfeited, weighted average exercise price (in dollars per share) |  |  | 23.27 |  |
Options outstanding at the end, weighted average exercise price (in dollars per share) | $ 35.15 |  | 35.15 |  |
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share) | $ 35.60 |  | $ 35.60 |  |
Stock Options, Weighted average remaining contractual term (years) |  |  |  |  |
Options outstanding at the end, weighted average remaining contractual term (years) |  |  | 4 years 3 months 10 days |  |
Options fully vested and exercisable at the end, weighted average remaining contractual term (years) |  |  | 3 years 5 months 19 days |  |
Stock Options, Aggregate intrinsic value |  |  |  |  |
Options outstanding at the end, aggregate intrinsic value | $ 5,594,000 |  | $ 5,594,000 |  |
Options fully vested and exercisable at the end, aggregate intrinsic value | 3,230,000 |  | 3,230,000 |  |
Stock-based compensation cost, unrecognized | $ 263,000 |  | $ 263,000 |  |
Stock-based compensation cost, unrecognized, weighted-average period of recognition |  |  | 1 year 4 months 24 days |  |
Incentive Stock Options to 10 Percent Shareholders | 2012 Plan |  |  |  |  |
Stock option details |  |  |  |  |
Maximum exercisable period for granted share-based compensation |  |  | 5 years |  |

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