Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation - Additional Information (Details)

Basis of Presentation - Additional Information (Details)					3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 09, 2024 USD ($) $ / shares shares	Oct. 07, 2022 USD ($) $ / shares	Sep. 08, 2020 USD ($) Debtinstrument	Jan. 21, 2020 USD ($) Debtinstrument	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($) $ / shares	Dec. 31, 2023 USD ($) $ / shares	May 03, 2023 $ / shares	Oct. 17, 2022 USD ($)	Feb. 10, 2021 $ / shares	Feb. 08, 2021 $ / shares	Oct. 31, 2020 $ / shares	Oct. 27, 2020 $ / shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Net losses					$ 6,094,000	$ 3,877,000	$ 18,192,000	$ 26,009,000	$ 38,371,000
Accumulated deficit					479,490,000		479,490,000		461,298,000
Cash and cash equivalents					$ 13,406,000		$ 13,406,000		$ 6,071,000
Ordinary shares, par value \| $ / shares					$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Maximum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Value of shares and securities may offer and sell											$ 100,000,000
Sales Agreement with H.C. Wainwright & Co., L.L.C
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Ordinary shares, par value \| $ / shares		$ 0.01
Sales Agreement with H.C. Wainwright & Co., L.L.C \| Maximum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
May offer and sell ordinary shares for aggregate gross sales proceeds		$ 16,000,000
2024 Rights Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of units sold \| shares	6,121,965
Subscription price per whole unit \| $ / shares	$ 1.21
Unit description							(a) one ordinary share, (b) a warrant to purchase 0.50 ordinary shares, at an exercise price of $1.21 per whole ordinary share from the date of issuance through its expiration one year from the date of issuance ("1-year warrants") and (c) a warrant to purchase one ordinary share, at an exercise price of $1.21 per whole ordinary share from the date of issuance through its expiration five years from the date of issuance ("5-year warrants" and, together with the 1-year warrants, the “warrants”).
Warrants to purchase ordinary shares, exercise price \| $ / shares	$ 1.21
Aggregate net proceeds from rights offering	$ 5,400,000
2024 Rights Offering \| 1-Year Warrant
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares that can be purchased with each warrant \| shares	0.5
Warrants to purchase ordinary shares, exercise price \| $ / shares	$ 1.21				1.21		$ 1.21
2024 Rights Offering \| 5-Year Warrants
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Warrants to purchase ordinary shares, exercise price \| $ / shares	$ 1.21				$ 1.21		$ 1.21
October Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Warrants to purchase ordinary shares, exercise price \| $ / shares														$ 12.1875	$ 9.75
February Underwritten Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Warrants to purchase ordinary shares, exercise price \| $ / shares												$ 21.5625	$ 21.5625
2025 Exchangeable Notes
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate principal amount				$ 9,891,000	$ 11,117,000		$ 11,117,000
2025 Exchangeable Notes \| Private Placement and Rights Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate principal amount			$ 51,800,000
Debt instrument interest rate				6.50%
2025 Exchangeable Notes \| Private Placement
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate principal amount				$ 51,588,000
Debt instrument price per unit				1,000
RLNs \| Private Placement and Rights Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate principal amount			$ 500	100,000
RLNs \| Private Placement
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate principal amount				$ 103,000
Number of debt instruments within each notes \| Debtinstrument			50	50