Note 5 - Fair Value Measurement and Fair Value of Financial Instruments - Warrant Liabilities Inputs and Assumptions (Details)	Sep. 30, 2023	Sep. 30, 2022
Montage Warrant [Member] | Measurement Input, Price Volatility [Member]
Volatility	0.607	0.82
Montage Warrant [Member] | Measurement Input, Risk Free Interest Rate [Member]
Volatility	0.05	0.042
Montage Warrant [Member] | Measurement Input, Share Price [Member]
Volatility	0.83	1.31
Series C Warrants [Member] | Measurement Input, Price Volatility [Member]
Volatility	0.517	0.839
Series C Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]
Volatility	0.055	0.042
Series C Warrants [Member] | Measurement Input, Share Price [Member]
Volatility	0.83	1.31
Series D Warrants [Member] | Measurement Input, Price Volatility [Member]
Volatility	0.736	0.847
Series D Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]
Volatility	0.048	0.041
Series D Warrants [Member] | Measurement Input, Share Price [Member]
Volatility	0.83	1.31