Note 9 - Stock Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	9 Months Ended	12 Months Ended
Jun. 30, 2024	Sep. 30, 2023
Outstanding (in shares)	41,765
Outstanding, weighted average exercise price (in dollars per share)	$ 144.43
Outstanding, weighted average remaining contractual term (Year)	3 years 4 months 9 days	3 years 7 months 24 days
Granted (in shares)	8,000
Granted, weighted average exercise price (in dollars per share)	$ 0
Exercised (in shares)	0
Exercised, weighted average exercise price (in dollars per share)	$ 0
Forfeited (in shares)	(2,447)
Forfeited, weighted average exercise price (in dollars per share)	$ 166.06
Outstanding (in shares)	47,318	41,765
Outstanding, weighted average exercise price (in dollars per share)	$ 119	$ 144.43
Exercisable (in shares)	45,651
Exercisable, weighted average exercise price (in dollars per share)	$ 122.98
Exercisable at September 30, 2022 (Year)	3 years 4 months 20 days

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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.

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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 option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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.

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

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