Fair Value Measurements - Assumptions (Details)	Jun. 30, 2022 $ / shares Y	Sep. 30, 2021 Y $ / shares
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant inputs	2.96	0.62
Remaining contractual term of warrant
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant inputs | Y	2.6	3.4
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant inputs	100.3	124.7
Annual dividend yield
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant inputs	0	0
Fair value of common stock
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warrant inputs | $ / shares	1.02	2.17