Stockholders' Equity - Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended	9 Months Ended		30 Months Ended
	Jul. 13, 2020	Apr. 07, 2020	Mar. 04, 2019	Nov. 30, 2018	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022
April 2020 Private Placement Second Closing
Class of Stock
Ownership percentage		19.99%
"At-The-Market" Equity Program
Class of Stock
Stock issued (in shares)					0	5,117,357
Percentage of fixed commission expense of gross proceeds of shares sold in ATM agreement				3.00%
Net proceeds from offering of common stock				$ 50.0		$ 15.3
Maximum value of shares that are permitted to be sold, subject to certain limitations					$ 19.5
Lincoln Park Capital Fund, LLC ("Investor")
Class of Stock
Value of shares which may be sold			$ 35.0
Duration over which common stock purchase agreement may be sold			36 months
Stock issued (in shares)			269,749			800,000
Stock issued (per share)			$ 2.84
Net proceeds from offering of common stock						$ 4.2
April 2020 Private Placement
Class of Stock
Stock issued (in shares)		3,039,514
Warrant exercised price (per share)		$ 2.28
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any		$ 5.0
Combined purchase price (per share)		$ 1.645
Stock price underlying warrants (per share)		$ 0.125
Shares of common stock that may be purchased upon exercise of warrants		3,039,514
April 2020 Private Placement Second Closing
Class of Stock
Stock issued (in shares)		2,747,252
Warrant exercised price (per share)		$ 2.71
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any		$ 5.0
Stock price (in dollars per share)		$ 0.01
Shares of common stock that may be purchased upon exercise of warrants		1,373,626
April 2020 Private Placement and April 2020 Private Placement Second Closing in Aggregate
Class of Stock
Net proceeds from offering of common stock							$ 9.8
July 2020 Private Placement Second Closing
Class of Stock
Gross proceeds from sale of common stock and warrants excluding the proceeds from exercise of the warrants, if any	$ 5.1
July 2020 Private Placement Second Closing | Pre-funded Warrants
Class of Stock
Stock issued (in shares)	784,615
Stock price (in dollars per share)	$ 0.01
July 2020 Private Placement Second Closing | Warrants
Class of Stock
Warrant exercised price (per share)	$ 9.75
Shares of common stock that may be purchased upon exercise of warrants	274,615