Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation - Additional Information (Details)

v3.21.2
Basis of Presentation - Additional Information (Details)
1 Months Ended 3 Months Ended 8 Months Ended 9 Months Ended 12 Months Ended
Feb. 10, 2021
USD ($)
$ / shares
shares
Feb. 09, 2021
USD ($)
$ / shares
shares
Feb. 08, 2021
$ / shares
shares
Feb. 03, 2021
$ / shares
shares
Nov. 02, 2020
USD ($)
$ / shares
shares
Oct. 31, 2020
$ / shares
shares
Oct. 27, 2020
USD ($)
$ / shares
shares
Jul. 02, 2020
$ / shares
shares
Jun. 05, 2020
$ / shares
shares
Jun. 03, 2020
USD ($)
$ / shares
shares
Apr. 30, 2020
USD ($)
Jan. 21, 2020
USD ($)
Debtinstrument
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Nov. 30, 2020
USD ($)
Oct. 31, 2020
$ / shares
shares
Jun. 30, 2020
USD ($)
$ / shares
shares
Sep. 30, 2021
USD ($)
$ / shares
shares
Sep. 30, 2020
USD ($)
Sep. 30, 2021
USD ($)
$ / shares
shares
Sep. 30, 2021
USD ($)
$ / shares
shares
Sep. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
$ / shares
shares
Jan. 28, 2021
$ / shares
Sep. 08, 2020
USD ($)
Jun. 10, 2020
$ / shares
Jul. 16, 2019
USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Description of deferring payment on US payroll taxes                                       In April 2020, the Company began deferring payment on its share of U.S. payroll taxes owed, as allowed by the Coronavirus Aid, Relief and Economic Security Act (CARES Act) through December 31, 2020. The Company is able to defer half of its share of U.S. payroll taxes owed until December 31, 2021, with the remaining half due on December 31, 2022.            
Ordinary shares, shares issued | shares                         49,431,028       182,775,282   182,775,282 182,775,282   49,431,028        
Ordinary shares, par value | $ / shares                         $ 0.01       $ 0.01   $ 0.01 $ 0.01   $ 0.01 $ 0.01   $ 0.01  
Proceeds from registered direct offerings, net of transaction costs                                       $ 500,000            
Number of warrants to purchase ordinary shares | shares                                 380,000   380,000 380,000            
Net losses                                 $ (3,741,000) $ 12,199,000   $ 87,382,000 $ 40,820,000 $ 52,006,000        
Accumulated deficit                         $ 286,929,000       374,311,000   $ 374,311,000 374,311,000   286,929,000        
Cash and cash equivalents                         14,508,000       35,982,000   35,982,000 35,982,000   14,508,000        
Short-term investments                                 $ 49,729,000   $ 49,729,000 $ 49,729,000            
June 3 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, par value | $ / shares                                 $ 0.01   $ 0.01 $ 0.01            
June 30 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, par value | $ / shares                                 $ 0.01   $ 0.01 $ 0.01            
February SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares   17,500,000                                                
Ordinary shares, par value | $ / shares   $ 0.01                                                
Offering price per share | $ / shares   $ 2.00                                                
Aggregate gross proceeds from ordinary shares   $ 35,000,000.0                                                
Proceeds from registered direct offerings, net of transaction costs   $ 32,200,000                                                
Percentage of ordinary shares issued to purchase warrants   7.00%                                                
Offering closing date   Feb. 12, 2021                                                
February SPA | Warrant                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares   1,225,000                                                
Warrants to purchase ordinary shares, exercise price | $ / shares   $ 2.50                                                
Warrants expiry date   Feb. 09, 2026                                                
Iterum Therapeutics US Limited | Silicon Valley Bank (SVB) | Paycheck Protection Program                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                     $ 744,000                              
Debt instrument interest rate                     1.00%                              
Debt instrument maturity period                     2 years                              
Debt instrument, description                     Under the terms of the agreement, there shall be no payments due by the Company until the SBA remits the forgiveness amount to the Borrower or 10 months after the end of the six-month period beginning April 30, 2020 (the Deferral Period). Following the Deferral Period, equal monthly repayments of principal and interest will be due to fully amortize the principal amount outstanding on the PPP loan by the maturity date.                 Under the terms of the agreement, there shall be no payments due by the Company until the SBA remits the forgiveness amount to the Borrower or until after the Deferral Period. Following the Deferral Period, equal monthly repayments of principal and interest will be due to fully amortize the principal amount outstanding on the PPP loan by the maturity date.            
Debt instrument, forgiveness loan                           $ 340,000                        
Debt instrument, remaining amount amortized                         $ 404,000                          
Maximum                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate initial offering price of securities authorized to issue                                                   $ 150,000,000.0
2025 Exchangeable Notes                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                                 $ 12,600,000   $ 12,600,000 $ 12,600,000            
Private Placement and Rights Offering | 2025 Exchangeable Notes                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                       $ 51,800,000                            
Debt instrument interest rate                       6.50%                            
Private Placement and Rights Offering | RLNs                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                       $ 100,000                            
Private Placement | June 3 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares                 208,023                                  
Warrants to purchase ordinary shares, exercise price | $ / shares                 $ 2.1031 $ 1.62                                
Warrants expiry date                 Jun. 03, 2025 Dec. 05, 2025                                
Warrants closing date                   Jun. 05, 2020                                
Percentage of ordinary shares issued to purchase warrants                 7.00%                                  
Private Placement | June 30 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares               236,088                                    
Warrants to purchase ordinary shares, exercise price | $ / shares               $ 1.8531               $ 1.42                    
Warrants expiry date               Jun. 30, 2025               Jan. 02, 2026                    
Warrants closing date                               Jul. 02, 2020                    
Percentage of ordinary shares issued to purchase warrants               7.00%                                    
Private Placement | Maximum | June 3 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares                   1,485,885                                
Private Placement | Maximum | June 30 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares                               1,686,343                    
Private Placement | 2025 Exchangeable Notes                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                       51,600,000                            
Debt instrument price per unit                       1,000                            
Private Placement | RLNs                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                       $ 100,000                            
Number of debt instruments within each notes | Debtinstrument                       50                            
Debt instrument, aggregate potential payment capped rate                       4,000 times                            
Private Placement | Securities                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Debt instrument, shares embedded within each unit, shares | shares         1,286.1845             1,000                            
Debt instrument, shares embedded within each unit, value         $ 1,000             $ 1,000                            
Rights Offering in Connection with Private Placement                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Maximum subscription units to be accepted | shares                       220                            
Rights Offering in Connection with Private Placement | 2025 Exchangeable Notes                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                                 $ 12,600,000   12,600,000 $ 12,600,000       $ 200,000    
Debt instrument price per unit                       $ 1,000                            
Debt instrument price per unit                       $ 1,000                            
Debt instrument, shares embedded within each unit, shares | shares         1,286.1845             1,000                            
Debt instrument, shares embedded within each unit, value         $ 1,000             $ 1,000                            
Debt instrument, shares embedded within each unit, exchange price | $ / shares         $ 0.7775             $ 1.00                            
Aggregate principal amount of exchangeable notes                                     $ 39,200,000              
Debt instrument, aggregate number of shares exchanged | shares                                     53,888,331              
Rights Offering in Connection with Private Placement | RLNs                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Aggregate principal amount                                               $ 20,000.00    
Number of debt instruments within each notes | Debtinstrument                       50                            
Aggregate amount payable per unit                       $ 160.00                            
Debt instrument, aggregate potential payment capped rate                       4,000 times                            
Rights Offering in Connection with Private Placement | RLNs | Minimum                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Debt instrument, percentage of net revenue from domestic sale for potential aggregate payments                       15.00%                            
Rights Offering in Connection with Private Placement | RLNs | Maximum                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Debt instrument, percentage of net revenue from domestic sale for potential aggregate payments                       20.00%                            
Rights Offering in Connection with Private Placement | Securities                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Proceeds from sale of securities                       $ 45,000,000.0                            
Direct Offering | June 3 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares                   2,971,770                                
Ordinary shares, par value | $ / shares                   $ 0.01                                
Offering price per share | $ / shares                   $ 1.6825                                
Aggregate gross proceeds from ordinary shares                   $ 5,000,000.0                                
Proceeds from registered direct offerings, net of transaction costs                   $ 4,300,000                                
Direct Offering | June 30 SPA                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares                               3,372,686                    
Ordinary shares, par value | $ / shares                               $ 0.01                    
Offering price per share | $ / shares                               $ 1.4825                    
Aggregate gross proceeds from ordinary shares                               $ 5,000,000.0                    
Proceeds from registered direct offerings, net of transaction costs                               $ 4,200,000                    
October Offering                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares             15,511,537                                      
Ordinary shares, par value | $ / shares             $ 0.01                   $ 0.01   $ 0.01 $ 0.01            
Aggregate gross proceeds from ordinary shares             $ 17,400,000                                      
Proceeds from registered direct offerings, net of transaction costs             $ 15,500,000                         $ 13,900,000            
Number of warrants to purchase ordinary shares | shares           1,884,615                 1,884,615   20,890,516   20,890,516 20,890,516            
Warrants to purchase ordinary shares, exercise price | $ / shares           $ 0.8125 $ 0.65               $ 0.8125                      
Warrants expiry date           Oct. 22, 2025 Oct. 27, 2025                                      
Percentage of ordinary shares issued to purchase warrants           7.00%                                        
October Offering | Pre-Funded Warrants                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Offering price per share | $ / shares             $ 0.01                                      
Proceeds from registered direct offerings, net of transaction costs                                           $ 110,000        
Number of warrants to purchase ordinary shares | shares             11,411,539                                      
Warrants to purchase ordinary shares, exercise price | $ / shares             $ 0.64                                      
Percentage of ordinary share at election of purchaser             9.99%                                      
October Offering | Warrant                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Offering price per share | $ / shares             $ 0.65                                      
Number of warrants to purchase ordinary shares | shares             20,192,307                                      
Warrants to purchase ordinary shares, exercise price | $ / shares             $ 0.65                                      
October Offering | Purchase Agreement                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares           1,884,615                 1,884,615                      
Warrants to purchase ordinary shares, exercise price | $ / shares           $ 0.8125                 $ 0.8125                      
Warrants expiry date                             Oct. 22, 2025                      
Percentage of ordinary shares issued to purchase warrants                             7.00%                      
Description of purchase agreement                                       In connection with the October Offering, the Company entered into a Securities Purchase Agreement (the Purchase Agreement) on October 22, 2020 with certain institutional investors. The Purchase Agreement contains customary representations and warranties of the Company, termination rights of the parties, and certain indemnification obligations of the Company.            
October Offering | Minimum | Pre-Funded Warrants                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Percentage of beneficial ownership that certain purchasers didn't want to exceed             4.99%                                      
October Offering | Maximum                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares             20,192,307                                      
February Underwritten Offering                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Warrants to purchase ordinary shares, exercise price | $ / shares $ 1.4375   $ 1.4375                                              
Warrants expiry date Feb. 03, 2026   Feb. 03, 2026                                              
Percentage of ordinary shares issued to purchase warrants 7.00%   7.00%                                              
Offering closing date Feb. 10, 2021   Feb. 08, 2021                                              
Additional ordinary shares that can be purchased by underwriter | shares 5,217,391                                                  
February Underwritten Offering | Underwriting Agreement                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares       34,782,609                                            
Ordinary shares, par value | $ / shares       $ 0.01                                            
Offering price per share | $ / shares       $ 1.15                                            
Offering closing date       Feb. 08, 2021                                            
February Underwritten Offering | Pursuant to the Underwriting Agreement                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Ordinary shares, shares issued | shares 40,000,000                                                  
Aggregate gross proceeds from ordinary shares $ 46,000,000.0                                                  
Proceeds from registered direct offerings, net of transaction costs $ 42,100,000                                                  
Percentage of ordinary shares issued to purchase warrants 7.00%                                                  
Additional ordinary shares that can be purchased by underwriter | shares 5,217,391                                                  
February Underwritten Offering | Pursuant to the Underwriting Agreement | Warrant                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares 2,800,000                                                  
Warrants to purchase ordinary shares, exercise price | $ / shares $ 1.4375                                                  
Warrants expiry date Feb. 03, 2026                                                  
February Underwritten Offering | Maximum                                                    
Organization Consolidation And Presentation Of Financial Statements [Line Items]                                                    
Number of warrants to purchase ordinary shares | shares 365,217   2,434,783