Note 15 - Share-based Compensation - Stock Option Activity (Details) - $ / shares	6 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Outstanding September 30, 2022 (in shares)	3,940,899
Outstanding September 30, 2022 (in dollars per share)	$ 3.31
Granted (in shares)	1,806,500	302,000
Granted (in dollars per share)	$ 2.93
Forfeited/expired (in shares)	(1,476,612)
Forfeited/cancelled (in dollars per share)	$ 3.99
Exercised (in shares)	(83,765)
Exercised (in dollars per share)	$ 1.60
Outstanding March 31, 2023 (in shares)	4,187,022
Outstanding March 31, 2023 (in dollars per share)	$ 2.94
Exerciseable March 31, 2023 (in shares)	1,698,888
Exerciseable March 31, 2023 (in dollars per share)	$ 2.59

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

No definition available.

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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- Definition

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.

+ References

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- Definition

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.

+ References

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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- Definition

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

+ References

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

+ References

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

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