Quarterly report pursuant to Section 13 or 15(d)

Debt - Additional Information (Details)

v3.24.3
Debt - Additional Information (Details)
3 Months Ended 9 Months Ended 12 Months Ended 44 Months Ended
Sep. 08, 2020
USD ($)
Debtinstrument
$ / shares
shares
Jan. 21, 2020
USD ($)
Debtinstrument
$ / shares
shares
Apr. 27, 2018
USD ($)
$ / shares
shares
Sep. 30, 2024
USD ($)
Sep. 30, 2023
USD ($)
Sep. 30, 2024
USD ($)
$ / shares
shares
Sep. 30, 2023
USD ($)
Dec. 31, 2020
USD ($)
Sep. 30, 2024
USD ($)
shares
Debt Instrument [Line Items]                  
Accretion of debt discounts and deferred financing costs           $ 1,713,000 $ 1,753,000    
Aggregate principal amount of exchangeable notes                 $ 40,691,000
Issuance of ordinary shares on conversion of exchangeable notes (in shares) | shares                 3,760,155
Loan and Security Agreement | Silicon Valley Bank (SVB)                  
Debt Instrument [Line Items]                  
Loan and security agreement entered date     Apr. 27, 2018            
Funded amount under agreement     $ 15,000,000            
Remaining borrowing facility available date     Oct. 31, 2019            
Maximum amount available under agreement     $ 30,000,000            
Final interest rate payment on outstanding principal     4.20%            
Principal and interest payment, maturity date     Mar. 01, 2022            
Loan and Security Agreement | Silicon Valley Bank (SVB) | Maximum                  
Debt Instrument [Line Items]                  
Maximum amount available under second draw     $ 15,000,000            
Silicon Valley Bank and Life Sciences Fund II LLC | Ordinary Shares                  
Debt Instrument [Line Items]                  
Number of warrants to purchase ordinary shares | shares     1,326            
Silicon Valley Bank and Life Sciences Fund II LLC | Series B Convertible Preferred Shares                  
Debt Instrument [Line Items]                  
Number of warrants to purchase ordinary shares | shares     19,890            
Warrants to purchase preferred shares, exercise price | $ / shares     $ 282.75            
2025 Exchangeable Notes                  
Debt Instrument [Line Items]                  
Interest expense       $ 181,000 $ 205,000 542,000 615,000    
Accretion of debt discounts and deferred financing costs       575,000 $ 591,000 1,713,000 $ 1,753,000    
Aggregate principal amount   $ 9,891,000   11,117,000   11,117,000     $ 11,117,000
Debt instrument, outstanding principal       $ 11,117,000   $ 11,117,000     $ 11,117,000
Debt instrument, payment terms           The Company will be required to pay each holder of the Exchangeable Notes the greater of three times the outstanding principal amount of such Exchangeable Note and the consideration that would be received by the holder of such Exchangeable Note in connection with such Fundamental Change if the holder had exchanged its note for ordinary shares immediately prior to the consummation of such Fundamental Change, plus any accrued and unpaid interest.      
Fair value of derivative liability   27,038,000              
Financing transaction costs               $ 2,848,000  
Financing transaction costs, capitalized               $ 2,814,000  
2025 Exchangeable Notes | Private Placement                  
Debt Instrument [Line Items]                  
Aggregate principal amount   51,588,000              
Debt instrument price per unit   $ 1,000              
2025 Exchangeable Notes | Private Placement and Rights Offering                  
Debt Instrument [Line Items]                  
Aggregate principal amount $ 51,800,000                
Debt instrument interest rate   6.50%              
2025 Exchangeable Notes | Rights Offering                  
Debt Instrument [Line Items]                  
Aggregate principal amount 220,000                
2020 Rights Offering                  
Debt Instrument [Line Items]                  
Fair value of derivative liability related to rights offering 82,000                
2020 Rights Offering | Private Placement                  
Debt Instrument [Line Items]                  
Debt instrument price per unit 1,000                
2020 Rights Offering | Rights Offering                  
Debt Instrument [Line Items]                  
Aggregate principal amount $ 220,000                
RLNs | Private Placement                  
Debt Instrument [Line Items]                  
Aggregate principal amount   $ 103,000              
Number of debt instruments within each notes | Debtinstrument 50 50              
RLNs | Private Placement and Rights Offering                  
Debt Instrument [Line Items]                  
Aggregate principal amount $ 500 $ 100,000              
RLNs | Rights Offering                  
Debt Instrument [Line Items]                  
Aggregate principal amount 440                
Securities | Private Placement                  
Debt Instrument [Line Items]                  
Debt instrument price per unit $ 1,000 $ 1,000              
Debt instrument, shares embedded within each unit, shares | shares 66.666 66.666       175.2191      
Debt instrument, shares embedded within each unit, value $ 1,000 $ 1,000       $ 1,000      
Debt instrument, shares embedded within each unit, exchange price | $ / shares $ 15 $ 15       $ 5.707