Note 4 - Fair Value Measurement and Fair Value of Financial Instruments - Warrant Liabilities Inputs and Assumptions (Details)	Mar. 31, 2020	Sep. 30, 2019
Montage Warrant [Member] | Measurement Input, Price Volatility [Member]
Volatility	0.8	0.71
Montage Warrant [Member] | Measurement Input, Risk Free Interest Rate [Member]
Volatility	0.0042	0.0159
Montage Warrant [Member] | Measurement Input, Share Price [Member]
Volatility	0.67	1.91
Series C Warrants [Member] | Measurement Input, Price Volatility [Member]
Volatility	0.834	0.809
Series C Warrants [Member] | Measurement Input, Risk Free Interest Rate [Member]
Volatility	0.003	0.0159
Series C Warrants [Member] | Measurement Input, Share Price [Member]
Volatility	0.67	1.91