Note 2 - Stock Based Compensation - Options Currently Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
Sep. 30, 2022 |
Sep. 30, 2021 |
Sep. 30, 2020 |
Sep. 30, 2019 |
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| Number outstanding (in shares) | 236,509 | 301,514 | 337,100 | 290,750 |
| Weighted average remaining contractual life (Year) | 3 years 3 months 18 days | 3 years 2 months 19 days | 3 years 5 months 4 days | |
| Weighted average exercise price (in dollars per share) | $ 31.30 | $ 16.25 | $ 12.48 | $ 11.86 |
| Aggregate intrinsic value | $ 17,343 | $ 8,412 | $ 721 | |
| X | ||||||||||
- Definition Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of options outstanding, including both vested and non-vested options. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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