Note 12 - Commitments and Contingencies (Details Textual) $ in Millions	12 Months Ended
	Sep. 30, 2023 USD ($)
Severance Benefit, Ratio of Base Compensation Received if Other Key Members of Management Termination Within Two Years	1
Severance Benefit, Ratio of Average Bonus Received if Other Key Members of Management Termination Within Two Years	1
Chief Executive Officer [Member]
Severance Agreement, Initial Term (Year)	2 years
Severance Agreement, Renewal Term (Year)	1 year
Termination Benefit, Ratio of Annual Base Salary Received on Termination Date	1.5
Termination Benefit, Continuation Term for Health and Welfare Benefit (Month)	18 months
Severance Benefit, Ratio of Base Compensation Received if Termination Within Two Years	2
Severance Benefit, Ratio of Average Bonus Received if CEO Termination Within Two Years	2
Severance Benefit Received Term for the Prior Years if CEO Termination Within Two Years (Year)	3 years
Severance Benefits Continuation of Health and Welfare Benefits Term if CEO Termination Within Two Years (Year)	2 years
Key Members of Management [Member]
Control Agreement, Initial Term (Year)	2 years
Control Agreement, Automatically Renewal Term (Year)	1 year
Severance Benefit Received Term for the Prior Years if Other Members of Management Termination Within Two Years (Year)	3 years
Severance Benefits Continuation of Health and Welfare Benefits Term if Other Members of Management Termination Within Two Years (Year)	1 year
Non-cancelable Purchase Commitment for Raw Material [Member]
Purchase Commitment, Remaining Minimum Amount Committed	$ 51.6
Non-cancelable Purchase Commitment Term (Day)	90 days
Purchase Commitment for Equipment [Member]
Purchase Commitment, Remaining Minimum Amount Committed	$ 15.3