Iterum Therapeutics (ITRM) 10-Q 14 Nov 24 2024 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2024	Nov. 04, 2024
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Trading Symbol	ITRM
Entity Registrant Name	Iterum Therapeutics plc
Entity Central Index Key	0001659323
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		27,515,926
Entity File Number	001-38503
Entity Tax Identification Number	98-1283148
Entity Address, Address Line One	Fitzwilliam Court 1st Floor
Entity Address, Address Line Two	Leeson Close
Entity Address, City or Town	Dublin 2
Entity Address, Country	IE
Entity Address, Postal Zip Code	Not applicable
City Area Code	+353
Local Phone Number	1 669-4820
Entity Interactive Data Current	Yes
Title of 12(b) Security	Ordinary Shares, $0.01 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	L2
Document Quarterly Report	true
Document Transition Report	false

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 13,406	$ 6,071
Short-term investments	1,096	17,859
Income taxes receivable	208	38
Prepaid expenses and other current assets	1,144	1,628
Total current assets	15,854	25,596
Property and equipment, net	30	51
Restricted cash	34	34
Other assets	6	578
Total assets	15,924	26,259
Current liabilities:
Accounts payable	835	4,996
Accrued expenses	3,492	7,761
Exchangeable notes	13,708
Other current liabilities	668	761
Total current liabilities	18,703	13,518
Exchangeable notes		11,453
Royalty-linked notes	8,728	7,503
Other liabilities		188
Total liabilities	27,431	32,662
Commitments and contingencies (Note 14)
Shareholders' deficit
Undesignated preferred shares, $0.01 par value per share: 100,000,000 shares authorized at September 30, 2024 and December 31, 2023; no shares issued at September 30, 2024 and December 31, 2023
Ordinary shares, $0.01 par value per share: 80,000,000 shares authorized at September 30, 2024 and December 31, 2023, 22,705,994 shares issued at September 30, 2024; 13,499,003 shares issued at December 31, 2023	227	135
Additional paid-in capital	467,754	454,759
Accumulated deficit	(479,490)	(461,298)
Accumulated other comprehensive income	2	1
Total shareholders' deficit	(11,507)	(6,403)
Total liabilities and shareholders' deficit	$ 15,924	$ 26,259

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	May 03, 2023
Statement of Financial Position [Abstract]
Undesignated preferred shares, par value	$ 0.01	$ 0.01
Undesignated preferred shares, authorized	100,000,000	100,000,000
Undesignated preferred shares issued	0	0
Ordinary shares, par value	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Ordinary shares, shares authorized	80,000,000	80,000,000
Ordinary shares, shares issued	22,705,994	13,499,003

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses:
Research and development	$ (3,107)	$ (14,852)	$ (9,159)	$ (30,248)
General and administrative	(1,780)	(1,833)	(5,867)	(5,789)
Total operating expenses	(4,887)	(16,685)	(15,026)	(36,037)
Operating loss	(4,887)	(16,685)	(15,026)	(36,037)
Interest expense, net	(590)	(300)	(1,648)	(1,023)
Adjustments to fair value of derivatives	(433)	13,199	(1,226)	11,361
Other (expense) / income, net	(48)	70	(77)	161
Total other (expense) / income	(1,071)	12,969	(2,951)	10,499
Loss before income taxes	(5,958)	(3,716)	(17,977)	(25,538)
Income tax expense	(136)	(161)	(215)	(471)
Net loss	$ (6,094)	$ (3,877)	$ (18,192)	$ (26,009)
Net loss per share - basic	$ (0.3)	$ (0.3)	$ (1.05)	$ (2.02)
Net loss per share - diluted	$ (0.3)	$ (0.3)	$ (1.05)	$ (2.02)
Weighted average ordinary shares outstanding - basic	20,044,270	13,039,437	17,352,918	12,888,869
Weighted average ordinary shares outstanding - diluted	20,044,270	13,039,437	17,352,918	12,888,869
Other comprehensive income:
Net loss	$ (6,094)	$ (3,877)	$ (18,192)	$ (26,009)
Unrealized gain on marketable securities	3	29	1	353
Comprehensive loss	$ (6,091)	$ (3,848)	$ (18,191)	$ (25,656)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (18,192)	$ (26,009)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	23	23
Amortization of intangible asset		1,287
Share-based compensation expense	274	645
Interest on short-term investments	1	55
Lease termination adjustments		473
Amortization of debt discount and deferred financing costs	1,713	1,753
Financing transaction costs included in financing activities	1,977
Adjustments to fair value of derivatives	1,226	(11,361)
Other	1,233	974
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,575)	(2,560)
Accounts payable	(4,161)	2,741
Accrued expenses	(4,270)	4,778
Income taxes	(4)	355
Other liabilities	(301)	(256)
Net cash used in operating activities	(22,514)	(26,487)
Cash flows from investing activities:
Purchases of property, plant and equipment	(2)	(13)
Purchases of short-term investments	(12,390)	(36,002)
Proceeds from sale of short-term investments	29,500	45,828
Net cash provided by investing activities	17,108	9,813
Cash flows from financing activities:
Proceeds from issuance of ordinary shares, net of transaction costs	12,814	445
Net cash provided by financing activities	12,814	445
Effect of exchange rates on cash and cash equivalents	(73)	(47)
Net increase / (decrease) in cash, cash equivalents and restricted cash	7,335	(16,276)
Cash, cash equivalents and restricted cash, at beginning of period	6,105	21,126
Cash, cash equivalents and restricted cash, at end of period	13,440	4,850
Supplemental Disclosure of Cash Flow Information:
Income taxes paid - U.S	220	120
Exchangeable Notes
Adjustments to reconcile net loss to cash used in operating activities:
Interest on exchangeable notes - non-cash	$ 542	$ 615

Condensed Consolidated Statemen

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2022	$ 27,999	$ 126	$ 451,150	$ (422,927)	$ (350)
Beginning balance (in shares) at Dec. 31, 2022		12,598,641
Issuance of ordinary shares, net	444	$ 4	440
Issuance of ordinary shares, net (in shares)		442,400
Share-based compensation expense	645		645
Net loss	(26,009)			(26,009)
Unrealized gain on available-for-sale securities	353				353
Ending balance at Sep. 30, 2023	3,432	$ 130	452,235	(448,936)	3
Ending balance (in shares) at Sep. 30, 2023		13,041,041
Beginning balance at Dec. 31, 2022	27,999	$ 126	451,150	(422,927)	(350)
Beginning balance (in shares) at Dec. 31, 2022		12,598,641
Net loss	(38,371)
Ending balance at Dec. 31, 2023	(6,403)	$ 135	454,759	(461,298)	1
Ending balance (in shares) at Dec. 31, 2023		13,499,003
Beginning balance at Jun. 30, 2023	7,129	$ 130	452,084	(445,059)	(26)
Beginning balance (in shares) at Jun. 30, 2023		13,028,403
Issuance of ordinary shares, net (in shares)		12,638
Share-based compensation expense	151		151
Net loss	(3,877)			(3,877)
Unrealized gain on available-for-sale securities	29				29
Ending balance at Sep. 30, 2023	3,432	$ 130	452,235	(448,936)	3
Ending balance (in shares) at Sep. 30, 2023		13,041,041
Beginning balance at Dec. 31, 2023	(6,403)	$ 135	454,759	(461,298)	1
Beginning balance (in shares) at Dec. 31, 2023		13,499,003
Issuance of ordinary shares, net	10,066	$ 92	9,974
Issuance of ordinary shares, net (in shares)		9,177,847
Issuance of warrants for ordinary shares, net	2,718		2,718
Exercise of share options	$ 29		29
Exercise of share options, (in shares)	29,144	29,144
Share-based compensation expense	$ 274		274
Net loss	(18,192)			(18,192)
Unrealized gain on available-for-sale securities	1				1
Ending balance at Sep. 30, 2024	(11,507)	$ 227	467,754	(479,490)	2
Ending balance (in shares) at Sep. 30, 2024		22,705,994
Beginning balance at Jun. 30, 2024	(10,913)	$ 166	462,318	(473,396)	(1)
Beginning balance (in shares) at Jun. 30, 2024		16,584,029
Issuance of ordinary shares, net	2,712	$ 61	2,651
Issuance of ordinary shares, net (in shares)		6,121,965
Issuance of warrants for ordinary shares, net	2,718		2,718
Share-based compensation expense	67		67
Net loss	(6,094)			(6,094)
Unrealized gain on available-for-sale securities	3				3
Ending balance at Sep. 30, 2024	$ (11,507)	$ 227	$ 467,754	$ (479,490)	$ 2
Ending balance (in shares) at Sep. 30, 2024		22,705,994

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (6,094)	$ (3,877)	$ (18,192)	$ (26,009)	$ (38,371)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation Description of Business Iterum Therapeutics plc (the Company) was incorporated under the laws of the Republic of Ireland in June 2015 as a limited company and re-registered as a public limited company on March 20, 2018. The Company maintains its registered office at Fitzwilliam Court, 1 st Floor, Leeson Close, Dublin 2, Ireland. The Company commenced operations in November 2015. The Company licensed global rights to its novel anti-infective compound, sulopenem, from Pfizer Inc. (Pfizer). The Company is focused on delivering differentiated anti-infectives aimed at combating the global crisis of multi-drug resistant pathogens to significantly improve the lives of people affected by serious and life-threatening diseases around the world. The Company is advancing the development of its first compound, sulopenem, a novel penem anti-infective compound, with an oral formulation and IV formulation. Liquidity and Going Concern Since inception, the Company has devoted substantially all of its efforts to research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of ordinary and convertible preferred shares, debt raised under a financing arrangement with Silicon Valley Bank (SVB) including the Paycheck Protection Program loan (PPP loan), a sub-award from the Trustees of Boston University under the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (CARB-X) program and the proceeds of a private placement (Private Placement) and subsequent rights offering (the 2020 Rights Offering) pursuant to which its wholly owned subsidiary, Iterum Therapeutics Bermuda Limited (Iterum Bermuda) issued and sold approximately $ 51.8 million aggregate principal amount of 6.500 % Exchangeable Senior Subordinated Notes due 2025 (Exchangeable Notes) and $ 0.1 million aggregate principal amount of Limited Recourse Royalty-Linked Subordinated Notes (the RLNs and, together with the Exchangeable Notes, the Securities), which Securities were sold in units consisting of an Exchangeable Note in the original principal amount of $ 1,000 and 50 RLNs (the Units). The Company has not generated any product revenue. The Company is subject to risks and uncertainties common to early-stage companies in the pharmaceutical industry, including, but not limited to, the ability to secure additional capital to fund operations, failure to successfully develop and commercialize its product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology and compliance with government regulations. Even with receipt of FDA approval, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of the Company and its subsidiaries. The Company file d a universal shelf registration statement on Form S-3 with the SEC, which was declared effective on October 17, 2022 (File No. 333-267795), and pursuant to which the Company registered for sale up to $ 100.0 million of any combination of debt securities, ordinary shares, preferred shares, subscription rights, purchase contracts, units and/or warrants from time to time and at prices and on terms that the Company may determine. On October 7, 2022, the Company entered into a sales agreement with H.C. Wainwright & Co., LLC (HC Wainwright), as agent, pursuant to which the Company may offer and sell ordinary shares, nominal value $ 0.01 per share, for aggregate gross sales proceeds of up to $ 16.0 million (subject to the availability of ordinary shares), from time to time through HC Wainwright by any method permitted that is deemed to be an "at the market offering" as defined in Rule 415 (a)(4) promulgated under the Securities Act of 1933, as amended (the "Sales Agreement"). On August 9, 2024, the Company completed a rights offering (the 2024 Rights Offering) in which it sold an aggregate of 6,121,965 units ("Units") at a subscription price of $ 1.21 per whole Unit, consisting of (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 (the "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 (the "5-year warrants" and, together with the 1-year warrants, the “warrants”). The Company's net proceeds from the 2024 Rights Offering, after deducting placement agent fees and other offering expenses payable by the Company, were approximately $ 5.4 million. The warrants are exercisable upon issuance at a price of $ 1.21 per ordinary share. The 1-year warrants expire on August 9, 2025 and the 5-year warrants expire on August 9, 2029. In accordance with Accounting Standards Update (ASU) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) , the Company has evaluated whether there are conditions and events, considered in aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year of the date of issue of these quarterly condensed consolidated financial statements. The Company has funded its operations to date primarily with proceeds from the sale of preferred shares and ordinary shares, warrants, debt raised under its financing arrangement with SVB including the PPP loan (both of which have been repaid), payments received under the CARB-X program and proceeds of the Private Placement and 2020 Rights Offering. The Company has incurred operating losses since inception, including net losses of $ 18,192 and $ 26,009 for the nine months ended September 30, 2024 and 2023, respectively, and a net loss of $ 38,371 for the year ended December 31, 2023. The Company had an accumulated deficit of $ 479,490 as of September 30, 2024 and expects to continue to incur net losses for the foreseeable future. The Company’s future cash flows are dependent on key variables such as its ability to secure additional sources of funding in the form of public or private financing of debt or equity or collaboration agreements. Based on its available cash, cash equivalents and short-term investments, including amounts raised subsequent to the period-end under the "at-the market"agreement (see Note 16 – Subsequent Events), the Company does not have cash on hand to fund its current operations and capital expenditure requirements for the next 12 months from the date of this Quarterly Report on Form 10-Q. This condition raises substantial doubt about the Company’s ability to continue as a going concern for one year from the date these condensed consolidated financial statements are issued. The Company plans to address this condition by raising funding through the possible sale of the Company’s equity or debt through public or private equity financings. Although management intends to pursue plans to obtain additional funding to finance its operations, and the Company has successfully raised capital in the past, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. In addition, in parallel, the Company is evaluating its corporate, strategic, financial and financing alternatives, with the goal of maximizing value for its stakeholders. These alternatives could potentially include the licensing, sale or divestiture of the Company’s assets or proprietary technologies or another strategic transaction involving the Company. The evaluation of corporate, strategic, financial and financing alternatives may not result in any particular action or any transaction being pursued, entered into or consummated, and there is no assurance as to the timing, sequence or outcome of any action or transaction or series of actions or transactions. If the Company is unable to obtain funding, it could be forced to significantly delay, scale back or discontinue the development and commercialization of its sulopenem program, or otherwise change its strategy, which could adversely affect its business prospects, or the Company may be unable to continue operations. Based on the Company’s operating losses since inception, the expectation of continued operating losses for the foreseeable future, and the need to raise additional capital to finance its future operations, management has concluded there is substantial doubt about the Company’s ability to continue as a going concern within one year from the date these condensed consolidated financial statements are issued. The accompanying condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Interim Financial Information The condensed consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed consolidated financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 28, 2024. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2024, and results of operations for the three and nine months ended September 30, 2024 and 2023, and cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 .

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of expenses during the reporting period and the assessment of the Company’s ability to continue as a going concern. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the valuation of the RLNs. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results could differ materially from those estimates. Specifically, management has estimated variables used to calculate the discounted cash flow analysis (DCF) to value the RLN liability (see Note 3 – Fair Value of Financial Assets and Liabilities). Cash and Cash Equivalents The Company’s cash and cash equivalents consist of cash balances and highly liquid investments with maturities of three months or less at the date of purchase. Accounts held at U.S. financial institutions are insured by the Federal Deposit Insurance Corporation up to $ 250 , while accounts held at Irish financial institutions are insured under the Deposit Guarantee Scheme up to $ 111 (€ 100 ). Cash accounts with any type of restriction are classified as restricted cash. If restrictions are expected to be lifted in the next twelve months, the restricted cash account is classified as current. Included within restricted cash on the Company’s condensed consolidated balance sheet is $ 17 as of September 30, 2024 relating to the warrants issued on June 5, 2020 pursuant to the securities purchase agreement (June 3, 2020 SPA) from the June 3, 2020 registered direct offering (June 3, 2020 Offering), $ 6 as of September 30, 2024 relating to the warrants issued on July 2, 2020 pursuant to the securities purchase agreement (June 30, 2020 SPA) from the June 30, 2020 registered direct offering (June 30, 2020 Offering) and $ 11 as of September 30, 2024 relating to warrants issued in the underwritten offering in October 2020 (October 2020 Offering). These restricted cash amounts are unchanged from December 31, 2023 . On the closing date of each of the registered direct offerings in June 2020 (June 3 Offering) and July 2020 (June 30 Offering) and the underwritten offering in the October 2020 Offering, each investor deposited $ 0.01 per warrant issued being the nominal value of the underlying ordinary share represented by each warrant. This amount will be held in trust by the Company pending a decision by the relevant investor to exercise the warrant by means of a “cashless exercise” pursuant to the terms of the warrant, in which case the $ 0.01 will be used to pay up the nominal value of the ordinary share issued pursuant to the warrant. Upon the exercise of the warrants other than by means of a "cashless exercise", the amount held in trust will be returned to the relevant investor in accordance with the terms of the applicable purchase agreement or prospectus. Concentration of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company has most of its cash, cash equivalents and short-term investments at three accredited financial institutions in the United States and Ireland, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. Net Loss Per Ordinary Share Basic and diluted net loss per ordinary share is determined by dividing net loss attributable to ordinary shareholders by the weighted-average ordinary shares outstanding during the period in accordance with Accounting Standard Codification (ASC) 260, Earnings per Share . For the periods presented, the following ordinary shares underlying the options, unvested restricted share units, warrants and the Exchangeable Notes have been excluded from the calculation because they would be anti-dilutive. Three and Nine Months Ended September 30, 2024 September 30, 2023 Options to purchase ordinary shares 913,988 1,108,988 Unvested restricted share units — 33,965 Warrants 9,663,125 480,186 Exchangeable Notes 2,541,786 1,404,721 Total 13,118,899 3,027,860 Segment and Other Information The Company determines and presents operating segments based on the information that is internally provided to the Chief Executive Officer and Chief Financial Officer, who together are considered the Company’s chief operating decision maker, in accordance with ASC 280, Segment Reporting . The Company has determined that it operates as a single business segment, which is the development and commercialization of innovative treatments for drug resistant bacterial infections. The distribution of total operating expenses by geographical area was as follows: Three Months Ended September 30, Nine Months Ended September 30, Operating expenses 2024 2023 2024 2023 Ireland $ 4,072 $ 15,201 $ 11,602 $ 31,754 U.S. 815 1,484 3,390 4,260 Bermuda — — 34 23 Total $ 4,887 $ 16,685 $ 15,026 $ 36,037 The distribution of long-lived assets by geographical area was as follows: Long-lived assets September 30, 2024 December 31, 2023 Ireland $ 15 $ 342 U.S. 21 287 Total $ 36 $ 629 Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. On November 27, 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which enhances segment disclosures and requires additional disclosures of segment expenses. This ASU is effective for annual periods in fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. Early adoption is permitted. ASU 2023-07 is not expected to have a material impact on the consolidated financial statements. On October 9, 2023, the FASB issued ASU No. 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative, or ASU 2023-06, which incorporates into the Codification several disclosures and presentation requirements currently residing in SEC Regulations S-X and S-K. For entities subject to the existing SEC disclosure requirements, including those preparing for sale or issuance of securities, the effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. For all other entities, the amendments will be effective two years later, with early adoption permitted. ASU 2023-06 is not expected to have a material impact on the consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , or ASU 2023-09, which enhances the annual income tax disclosures for the effective tax rate reconciliation and income taxes paid. The amendments are effective for public business entities, for annual periods beginning after December 15, 2024 and for annual periods beginning after December 15, 2025 for all other entities. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. The ASU applies on a prospective basis to annual financial statements for periods beginning after the effective date. However, retrospective application in all prior periods presented is permitted. The Company is assessing what impact ASU 2023-09 will have on the condensed consolidated financial statements.

Fair Value of Financial Assets

Fair Value of Financial Assets and Liabilities	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities	3. Fair Value of Financial Assets and Liabilities The following table presents information about the Company’s financial assets that were carried at fair value on a recurring basis on the condensed consolidated balance sheet as of September 30, 2024 and December 31, 2023 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value. September 30, 2024 Assets Total Level 1 Level 2 Level 3 Short-term investments: U.S. Treasury bonds $ 1,096 $ — $ 1,096 $ — $ 1,096 $ — $ 1,096 $ — December 31, 2023 Assets Total Level 1 Level 2 Level 3 Short-term investments: Corporate bonds $ 1,179 $ — $ 1,179 $ — Commercial paper 3,287 — 3,287 — U.S. Treasury bonds 13,393 — 13,393 — $ 17,859 $ — $ 17,859 $ — See Note 4 for details on the short-term investments. The carrying amounts reported in the condensed consolidated balance sheets for prepaid expenses and other current assets, accounts payable, accrued expenses and other current liabilities approximate their fair value based on the short-term maturity of these instruments. The following table presents information about the Company’s Exchangeable Notes and RLNs and indicates the fair value hierarchy of the valuation inputs utilized to determine the approximate fair value: September 30, 2024 Book Approximate Short-term Liabilities Value Fair Value Level 1 Level 2 Level 3 Exchangeable Notes Exchangeable note $ 13,708 $ 13,744 $ — $ 13,744 $ — Total short-term liabilities $ 13,708 $ 13,744 $ — $ 13,744 $ — Long-term Liabilities Revenue Futures Royalty-linked notes 8,728 8,728 — — 8,728 Total long-term liabilities $ 8,728 $ 8,728 $ — $ — $ 8,728 December 31, 2023 Book Approximate Long-term Liabilities Value Fair Value Level 1 Level 2 Level 3 Exchangeable Notes Long-term exchangeable note $ 11,453 $ 11,645 $ — $ 11,645 $ — Revenue Futures Royalty-linked notes 7,503 7,503 — — 7,503 Total long-term liabilities $ 18,956 $ 19,148 $ — $ 11,645 $ 7,503 The fair value of Exchangeable Notes was determined using DCF analysis using the fixed interest rate outlined in the indenture governing the Exchangeable Notes (Exchangeable Notes Indenture), without consideration of transaction costs, which represents a Level 2 basis of fair value measurement. The Level 3 liabilities held as of September 30, 2024 consist of a separate financial instrument, that was issued as part of the Units, the RLNs (see Note 10 – Royalty-Linked Notes). At any time on or after January 21, 2021, subject to specified limitations, the Exchangeable Notes are exchangeable for the Company’s ordinary shares, cash or a combination of ordinary shares and cash, at an exchange rate of 175.2191 shares per $ 1,000 of principal and interest on the Exchangeable Notes (equivalent to an exchange price of approximately $ 5.707 per ordinary share) as of September 30, 2024 , which was adjusted from an initial exchange rate of 66.666 shares per $ 1,000 principal and interest on the Exchangeable Notes (equivalent to an initial exchange price of $ 15.00 per ordinary share) and is subject to further adjustment pursuant to the terms of the Exchangeable Notes Indenture. Beginning on January 21, 2021 to September 30, 2024, certain noteholders of $ 40,691 aggregate principal amount of Exchangeable Notes have exchanged their notes for an aggreg ate of 3,760,155 of the Company’s ordinary shares, which included accrued and unpaid interest relating to such notes. The aggregate principal amount of Exchangeable Notes outstanding as of September 30, 2024 was $ 11,117 . The fair value of the exchange option at September 30, 2024 was $ 0 . The RLN liability is carried at fair value on the condensed consolidated balance sheet (see Note 10 – Royalty-Linked Notes). The total fair value of $ 8,728 was determined using DCF analysis, without consideration of transaction costs, which represents a Level 3 basis of fair value measurement. The key inputs to valuing the RLNs were the terms of the indenture governing the RLNs (the RLN Indenture), the expected cash flows to be received by holders of the RLNs based on management’s revenue forecasts of U.S. sulopenem sales and a risk-adjusted discount rate to derive the net present value of expected cash flows. The RLNs will be subject to a maximum return amount, including all principal and payments and certain default interest in respect of uncurable defaults, of $ 160.00 (or 4,000 times the principal amount of such note). The discount rate applied to the model was 22 %. Fair value measurements are highly sensitive to changes in these inputs and significant changes in these inputs could result in a significantly higher or lower fair value. There have been no transfers of assets or liabilities between the fair value measurement levels.

Short-term Investments

Short-term Investments	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Short-term Investments	4. Short-term Investments The Company classifies its short-term investments as available-for-sale. Short-term investments comprise highly liquid investments with minimum “A-” rated securities and as at quarter end consist of corporate bonds, commercial paper and U.S. Treasury bonds with maturities of more than three months at the date of purchase. Short-term investments as of September 30, 2024 have a weighted average maturity of 0.08 years. The investments are reported at fair value with unrealized gains or losses recorded in the condensed consolidated statements of operations and comprehensive loss. Any differences between the amortized cost and fair value of investments are represented by unrealized gains or losses. The fair value of corporate bonds, commercial paper and U.S. Treasury bonds are represented by Level 2 fair value measurements - quoted price for a similar asset, or other observable inputs such as interest rates or yield curves. The following table represents the Company’s available for sale short-term investments by major security type as of September 30, 2024 and December 31, 2023: September 30, 2024 Maturity by period Amortized Unrealized Unrealized Fair Value Less than 1 Available-for-sale Cost Gains (Losses) Total Year 1 to 5 Years U.S. Treasury bonds $ 1,095 $ 1 $ — $ 1,096 $ 1,096 $ — December 31, 2023 Maturity by period Amortized Unrealized Unrealized Fair Value Less than 1 Available-for-sale Cost Gains (Losses) Total Year 1 to 5 Years Corporate bonds $ 1,179 $ 1 $ — $ 1,180 $ 1,180 $ — Commercial paper 3,288 — ( 1 ) 3,287 3,287 — U.S. Treasury bonds 13,391 3 ( 2 ) 13,392 13,392 — Total $ 17,858 $ 4 $ ( 3 ) $ 17,859 $ 17,859 $ — For the three and nine months ended September 30, 2024 and 2023, no allowance was recorded for credit losses. Unrealized gains and losses are reported as a component of accumulated other comprehensive income in shareholders’ deficit.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2024
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid Expenses and Other Current Assets	5. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following: September 30, December 31, Prepaid insurance $ 551 $ 472 Right of use assets, net 264 — Other prepaid assets 213 89 Research and development tax credit receivable 66 195 Prepaid research and development expenses 50 872 Total $ 1,144 $ 1,628

Property and Equipment, Net

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	6. Property and Equipment, net Property and equipment and related accumulated depreciation are as follows: September 30, December 31, Leasehold improvements $ 148 $ 148 Furniture and fixtures 120 120 Computer equipment 95 98 363 366 Less: accumulated depreciation ( 333 ) ( 315 ) $ 30 $ 51 Depreciation expense for the nine months ended September 30, 2024 and 2023 was $ 23 and $ 23 , respectively. In addition, accumulated depreciation decreased by $ 5 due to the removal of fully depreciated computer equipment during the nine months ended September 30, 2024 .

Leases

Leases	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Leases	7. Leases The Company has entered into a number of operating leases, primarily for office space and commercial property. These leases have remaining terms which ra nge from 0.2 years to 0.8 years. Th e renewal option on one lease was exercised in February 2022 for an additional period of three years , extending this lease term to June 2025. A Deed of Assignment was signed in August 2023 in relation to a commercial property lease and accordingly the related Right of Use asset and lease liability were derecognized. In September 2020, the Company entered into a sublease agreement for a commercial unit. This sublease agreement was assigned with the related lease in August 2023. In November 2021, the Company entered into a 12-month lease, with a rolling extension, for office space, and in May 2022, the Company entered into a 6-month lease for office space, which was extended to November 2023, and elected not to apply the measurement and recognition requirements of ASC 842 to these short-term leases as any renewal term exercised or considered reasonably certain of exercise by the Company did not extend more than 12 months from the end of the previously determined lease term. In August 2023, the Company extended the lease agreements for a further nine months, with a rolling extension, and twelve months, respectively. While neither of the extended agreements extend more than 12 months from the end of the previously determined lease term, it is considered to be reasonably certain that these lease arrangements will be extended beyond a period of more than 12 months. Accordingly, the Company has applied the measurement and recognition requirements of ASC 842 to these lease arrangements. In September 2024, the Company notified the landlord of its intention to terminate the twelve month lease on November 30, 2024 and the related Right of Use asset and lease liability has accordingly been reduced. Certain leases contain variable lease payments, including payments based on an index or rate. Variable lease payments based on an index or rate are initially measured using the index or rate in effect at lease commencement. Certain agreements contain both lease and non-lease components. The Company has elected to separately account for these components in determining the lease liabilities and right-of-use assets. The Company’s lease agreements generally do not provide an implicit borrowing rate; therefore, an internal incremental borrowing rate was determined based on information available at lease commencement date for the purposes of determining the present value of lease payments. The Company used the incremental borrowing rate on January 1, 2019 for all leases that commenced prior to that date. All operating lease expenses are recognized on a straight-line basis over the lease term. The Company recognized $ 101 and $ 299 of operating lease costs for right-of-use assets during the three and nine months ended September 30, 2024, respectively, and $ 51 and $ 265 of operating lease costs for right-of-use assets during the three and nine months ended September 30, 2023 , respectively. No rental expense on short-term leases was recognized during the three and nine months ended September 30, 2024, and $ 49 and $ 194 of rental expense was recognized on short-term leases during the three and nine months ended September 30, 2023 , respectively. No sublease income was recognized during the three and nine months ended September 30, 2024 and $ 48 and $ 199 of sublease income was recognized during the three and nine months ended September 30, 2023, respectively. Information related to the Company’s right-of-use assets and related lease liabilities is as follows: Three Months Ended Three Months Ended Nine Months Ended Nine Months Ended September 30, 2024 September 30, 2023 September 30, 2024 September 30, 2023 Cash paid for operating lease liabilities $ 101 $ 52 $ 301 $ 256 September 30, 2024 December 31, Weighted-average remaining lease term 0.73 years 1.46 years Weighted-average discount rate 12.9 % 12.9 % Right-of-use assets and lease liabilities for the Company’s operating leases were recorded in the condensed consolidated balance sheet as follows, representing the Company’s right to use the underlying asset for the lease term ("Prepaid expenses and other current assets" and “Other assets”) and the Company’s obligation to make lease payments (“Other current liabilities” and “Other liabilities”): September 30, 2024 December 31, Prepaid expenses and other current assets $ 264 $ — Other assets — 549 Total lease assets $ 264 $ 549 Other current liabilities $ 268 $ 365 Other liabilities — 188 Total lease liabilities $ 268 $ 553 Future lease payments included in the measurement of lease liabilities on the condensed consolidated balance sheet as of September 30, 2024 for the following five fiscal years and thereafter were as follows: Due in 12 month period ended September 30, 2025 $ 279 2026 — 2027 — 2028 — 2029 — Thereafter — $ 279 Less imputed interest ( 11 ) Total lease liabilities $ 268

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses	8. Accrued Expenses Accrued expenses consist of the following: September 30, December 31, Accrued payroll and bonus expenses $ 1,770 $ 2,742 Accrued manufacturing expenses 1,484 71 Accrued other expenses 111 76 Accrued professional fees 108 37 Accrued clinical trial costs 19 4,835 Total $ 3,492 $ 7,761

Debt

Debt	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Debt	9. Debt Secured Credit Facility On April 27, 2018 , the Company’s subsidiaries, Iterum Therapeutics International Limited, Iterum Therapeutics US Holding Limited and Iterum Therapeutics US Limited (the Borrowers), entered into a loan and security agreement (Loan and Security Agreement) with SVB pursuant to which SVB agreed to lend the Borrowers up to $ 30,000 in two term loans. $ 15,000 of the secured credit facility was funded on closing. A second draw of up to $ 15,000 was available to the Company through October 31, 2019 , upon satisfaction of either of the following: (i) the achievement by the Company of both non-inferiority and superiority primary endpoints from its Phase 3 uncomplicated urinary tract infection (uUTI) trial, as well as reporting satisfactory safety data from the trial, or (ii) the achievement of non-inferiority primary endpoints from both its Phase 3 uUTI and complicated urinary tract infection trials, as well as reporting satisfactory safety data from the trials. The Company did not satisfy the conditions for the second draw above before the deadline of October 31, 2019. All outstanding principal, plus a 4.20 % final interest payment, were due and paid on March 1, 2022 (the maturity date), effectively terminating the Loan and Security Agreement. In connection with the initial $ 15,000 draw, the Company issued SVB and Life Sciences Fund II LLC (LSF) warrants to purchase an aggregate of 19,890 Series B convertible preferred shares (which converted into warrants to purchase 1,326 ordinary shares upon the Company’s initial public offering (IPO)) at an exercise price of $ 282.75 per share. These warrants will expire on April 27, 2028. In connection with the Private Placement, Iterum Bermuda was joined as a party to the Loan and Security Agreement as a borrower and the Loan and Security Agreement was amended on January 16, 2020 to, among other things, modify the definition of subordinated debt to include the RLNs and Exchangeable Notes. 2025 Exchangeable Notes On January 21, 2020, the Company completed a Private Placement pursuant to which its wholly owned subsidiary, Iterum Bermuda issued and sold $ 51,588 aggregate principal amount of Exchangeable Notes and $ 103 aggregate principal amount of RLNs, to a group of accredited investors. On September 8, 2020, the Company completed a rights offering (the 2020 Rights Offering) pursuant to which Iterum Bermuda issued and sold $ 220 aggregate principal amount of Exchangeable Notes and $ 0.5 aggregate principal amount of RLNs, to existing shareholders. The Securities were sold in Units with each Unit consisting of an Exchangeable Note in the original principal amount of $ 1,000 and 50 RLNs. The Units were sold at a price of $ 1,000 per Unit. At any time on or after January 21, 2021, subject to specified limitations, the Exchangeable Notes are exchangeable for the Company’s ordinary shares, cash or a combination of ordinary shares and cash, at the Company’s election, at an exchange rate of 175.2191 shares per $ 1,000 principal and interest on the Exchangeable Notes (equivalent to an exchange price of approximately $ 5.707 per ordinary share) as of September 30, 2024 , which exchange rate was adjusted from an initial exchange rate of 66.666 shares per $ 1,000 principal and interest on the Exchangeable Notes (equivalent to an initial exchange price of $ 15.00 per ordinary share) and is subject to further adjustment pursuant to the terms of the Exchangeable Notes Indenture. Any accrued and unpaid interest being exchanged will be calculated to include all interest accrued on the Exchangeable Notes being exchanged to, but excluding, the exchange settlement date. Beginning on January 21, 2021 to September 30, 2024, certain noteholders of $ 40,691 aggregate principal amount of Exchangeable Notes have completed a non-cash exchange of their notes for an aggregate of 3,760,155 of the Company’s ordinary shares, which included accrued and unpaid interest relating to such notes. The aggregate principal amount of Exchangeable Notes outstanding as of September 30, 2024 was $ 11,117 . In addition, the Exchangeable Notes will become due and payable by the Company upon the occurrence of a Fundamental Change as defined in the Exchangeable Notes Indenture. 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. The Company evaluates its debt and equity issuances to determine if those contracts, or embedded components of those contracts, qualify as derivatives under ASC 815-15, Derivatives and Hedging , requiring separate recognition in the Company’s financial statements. The Company evaluated the accounting for the issuance of the Exchangeable Notes and concluded that the embedded exchange option and change of control feature are considered a derivative liability under ASC 815-15 requiring bifurcation, from the Exchangeable Notes, as it does not qualify for the scope exceptions for contracts in an entity’s own equity given the terms of the Exchangeable Notes. The exchange option and change of control feature are accounted for as a derivative liability, under ASC 815-15, and are required to be separated and recorded as a single liability, which is revalued at each reporting period with the resulting change in fair value reflected in adjustments to fair value of derivatives in the condensed consolidated statements of operations and comprehensive loss. The fair value of the derivative liability related to the Private Placement on January 21, 2020 was $ 27,038 , and the fair value of the derivative liability related to the 2020 Rights Offering on September 8, 2020 was $ 82 , both of which were recorded as a reduction to the book value of the host debt contract. This debt discount is being amortized to interest expense over the term of the debt using the effective interest method. Transaction costs amounting to $ 2,848 were allocated to the exchange option. These costs were reflected in financing transaction costs in the consolidated statements of operations and comprehensive loss for the year ended December 31, 2020. Transaction costs amounting to $ 2,814 were allocated to the debt host and capitalized in the host debt book value. In circumstances where the embedded exchange option in a convertible instrument is required to be bifurcated, and there are other embedded derivative instruments in the convertible instrument that are required to be bifurcated, the derivative instruments are accounted for as a single, compound derivative instrument. The classification of derivative instruments, including whether such instruments should be recorded as liabilities or as equity, is reassessed at the end of each reporting period. Derivative instrument liabilities are classified in the balance sheet as current or non-current based on whether or not settlement of the derivative instrument is expected within twelve months of the balance sheet date. The Company determined that all other features of the Exchangeable Notes were clearly and closely associated with a debt host and did not require bifurcation as a derivative liability. The initial value of the Exchangeable Notes on inception, net of transaction costs, was $ 9,891 . The Company recognized $ 181 and $ 542 of interest expense related to the Exchangeable Notes during the three and nine months ended September 30, 2024, respectively, and $ 205 and $ 615 of interest expense related to the Exchangeable Notes during the three and nine months ended September 30, 2023, respectively. The Company recognized $ 575 and $ 1,713 related to the amortization of the debt discounts and deferred financing costs during the three and nine months ended September 30, 2024, respectively, and $ 591 and $ 1,753 related to the amortization of the debt discounts and deferred financing costs during the three and nine months ended September 30, 2023, respectively. These amounts are recorded in interest expense, net in the condensed consolidated statements of operations and comprehensive loss . The balance of the Exchangeable Notes as of September 30, 2024 is as follows: September 30, 2024 Principal Accrued Interest January 2020 $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) $ 51,588 $ 6,397 September 2020 $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) 220 34 Conversion of $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) ( 40,691 ) ( 3,071 ) 2025 Exchangeable Notes, net 11,117 3,360 Unamortized discount and debt issuance costs ( 769 ) — 2025 Exchangeable Notes, net $ 10,348 $ 3,360 Scheduled principal payments on outstanding debt, including principal amounts owed to RLN holders (see Note 10 – Royalty-Linked Notes), as of September 30, 2024 , for the following five fiscal years and thereafter were as follows: Year Ending September 30, 2025 $ 11,117 2026 — 2027 — 2028 — 2029 — Thereafter 104 Total $ 11,221

Royalty-Linked Notes

Royalty-Linked Notes	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Royalty-Linked Notes	10. Royalty-Linked Notes Liability Related to Sale of Future Royalties On January 21, 2020, as part of the Private Placement, the Company issued 2,579,400 RLNs to a group of accredited investors. On September 8, 2020, as part of the 2020 Rights Offering, the Company issued 11,000 RLNs to existing shareholders. The RLNs will entitle the holders thereof to payments, at the applicable payment rate, based solely on a percentage of the Company’s net revenues from U.S. sales of specified sulopenem products earned through December 31, 2045, but will not entitle the holders thereof to any payments unless the Company receives approval from the U.S. Food and Drug Administration (FDA) for one or more specified sulopenem products prior to December 31, 2025 and the Company earns net revenues on such product. If any portion of the principal amount of the outstanding RLNs, equal to $ 0.04 per RLN, has not been paid as of the end date on December 31, 2045 (or December 31, 2025, in the event that the Company has not yet received FDA approval with respect to one or more specified sulopenem products by such date), Iterum Bermuda must pay the unpaid portion of the principal amount. The RLNs will earn default interest if the Company breaches certain obligations under the RLN Indenture (but do not otherwise bear interest) and will be subject to a maximum return amount, including all principal and payments and certain default interest in respect of uncurable defaults, of $ 160.00 (or 4,000 times the principal amount of such note). The RLNs will be redeemable at the Company’s option, subject to the terms of the RLN Indenture. In accordance with exceptions allowed under ASC 815-10, Derivatives and Hedging , this transaction was initially accounted for as a debt liability under ASC 470, Debt . Subsequent to the listing of the RLNs on the Bermuda Stock Exchange in January 2021, the RLNs are accounted for as a derivative and are remeasured to fair value at each reporting date. In accordance with ASC 815, the fair value of the RLNs is determined using DCF analysis, without consideration of transaction costs, which represents a Level 3 basis of fair value measurement. Fair value measurements are highly sensitive to changes in inputs and significant changes to inputs can result in a significantly higher or lower fair value. The Company periodically assesses the revenue forecasts of the specified sulopenem products and the related payments. The Company has no obligation to pay any amount to the noteholders until the net revenue of the specified products are earned. The balance of the RLNs at each reporting date is as follows: September 30, Total liability related to the sale of future royalties, on inception $ 10,990 Liability related to the sale of future royalties, arising from the 2020 Rights Offering 51 Amortization of discount and debt issuance costs 3,666 Adjustments to fair value ( 5,979 ) Total liability related to the sale of future royalties at June 30, 2024 $ 8,728 Current Portion — Long-term Portion $ 8,728 December 31, 2023 Total liability related to the sale of future royalties, on inception $ 10,990 Liability related to the sale of future royalties, arising from the 2020 Rights Offering 51 Amortization of discount and debt issuance costs 3,666 Adjustments to fair value ( 7,204 ) Total liability related to the sale of future royalties at December 31, 2023 $ 7,503 Current Portion — Long-term Portion $ 7,503

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Shareholders' Equity	11. Shareholders’ Equity The Company’s capital structure consists of ordinary shares and undesignated preferred shares. Under Irish law, the Company is prohibited from allotting shares without consideration. Accordingly, at least the nominal value of the shares issued underlying any warrant, pre-funded warrant, restricted share award, restricted share unit, performance share award, bonus share or any other share-based grant must be paid pursuant to the Irish Companies Act 2014 (Irish Companies Act). Ordinary Shares On August 9, 2024, the Company completed a rights offering (2024 Rights Offering) in which it sold an aggregate of 6,121,965 units ("Units") at a subscription price of $ 1.21 per whole Unit, consisting of (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”). Aggregate gross proceeds to the Company's from the 2024 Rights Offering were $ 7.4 million and net proceeds were $ 5.4 million after deducting fees payable to the placement agent fees and other offering expenses payable by the Company. At the Company’ s annual general meeting of shareholders on May 3, 2023, the Company’s shareholders approved an increase of 60,000,000 ordinary shares of $ 0.01 par value each to the number of authorized ordinary shares and the Company’s Articles of Association were amended accordingly. The Company has authorized ordinary shares of 80,000,000 ordinary shares of $ 0.01 par value each as of September 30, 2024 . The holders of ordinary shares are entitled to one vote for each share held. There are no redemption or sinking fund provisions with respect to the authorized ordinary shares. The Company filed a universal shelf registration statement on Form S-3 with the SEC, which was declared effective on October 17, 2022 (File No. 333-267795), and pursuant to which the Company registered for sale up to $ 100.0 million of any combination of debt securities, ordinary shares, preferred shares, subscription rights, purchase contracts, units and/or warrants from time to time and at prices and on terms that the Company may determine. On October 7, 2022, the Company entered into an “at the market offering” agreement (the Sales Agreement) with H.C. Wainwright & Co., LLC (HC Wainwright) , as agent, pursuant to which the Company may offer and sell ordinary shares, nominal value $ 0.01 per share, for aggregate gross sales proceeds of up to $ 16.0 million (subject to the availability of ordinary shares), from time to time through HC Wainwright by any method permitted that is deemed to be an "at the market offering" as defined in Rule 415 (a)(4) promulgated under the Securities Act of 1933, as amended. During the nine months ended September 30, 2024 , the Company sold 3,055,882 ordinary shares under the “at the market” agreement at an average price of $ 2.49 per share for net proceeds of $ 7.4 million. Beginning on January 21, 2021 to September 30, 2024, certain noteholders of $ 40,691 aggregate principal amount of Exchangeable Notes have exchanged their notes for an aggregate of 3,760,155 of the Company’s ordinary shares, which included accrued and unpaid interest relating to such notes. The aggregate principal amount of Exchangeable Notes outstanding as of September 30, 2024 was $ 11,117 . Warrants to purchase Ordinary Shares In connection with the initial drawdown under the Loan and Security Agreement, the Company issued SVB and LSF warrants to purchase an aggregate of 19,890 Series B convertible preferred shares (which converted into warrants to purchase 1,326 ordinary shares upon the Company’s IPO) at an exercise price of $ 282.75 per share. These warrants will expire on April 27, 2028 . No warrants had been exercised as of September 30, 2024. In connection with the June 3, 2020 Offering completed on June 5, 2020, pursuant to the June 3, 2020 SPA, in a concurrent private placement, the Company issued and sold to institutional investors warrants to purchase up to 99,057 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $ 24.30 per ordinary share, subject to adjustment in certain circumstances, and will expire on December 5, 2025 . Warrants to purchase 13,868 ordinary shares, amounting to 7 % of the ordinary shares issued under the June 3, 2020 SPA, were issued to designees of the placement agent on the closing of the June 3, 2020 Offering. Upon closing, the warrants issued to such designees were exercisable immediately at an exercise price of $ 31.5465 per ordinary share and will expire on June 3, 2025 . No warrants had been exercised as of September 30, 2024. In connection with the June 30, 2020 Offering completed on July 2, 2020, pursuant to the June 30, 2020 SPA, in a concurrent private placement, the Company has also issued and sold to institutional investors warrants to purchase up to 112,422 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $ 21.30 per ordinary share, subject to adjustment in certain circumstances, and will expire on January 2, 2026 . Warrants to purchase 15,739 ordinary shares, amounting to 7 % of the ordinary shares issued under the June 30, 2020 SPA, were issued to designees of the placement agent on closing of the June 30, 2020 Offering. Upon closing, the warrants issued to such designees were exercisable immediately at an exercise price of $ 27.7965 per ordinary share and will expire on June 30, 2025 . As of September 30, 2024, warrants issued in connection with the June 30, 2020 Offering had been exercised for 84,317 ordinary shares, for net proceeds of $ 1,796 . In connection with the October 2020 Offering, the Company issued and sold warrants to purchase up to 1,346,153 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $ 9.75 per ordinary share, subject to adjustment in certain circumstances, and will expire on October 27, 2025 . Warrants to purchase 125,641 ordinary shares, which represents a number of ordinary shares equal to 7.0 % of the aggregate number of ordinary shares and pre-funded warrants sold in the October 2020 Offering, were issued to designees of the placement agent on closing of the October 2020 Offering. Upon closing, the warrants issued to such designees became exercisable immediately at an exercise price of $ 12.1875 per ordinary share and expire on October 22, 2025 . As of September 30, 2024, warrants issued in connection with the October 2020 Offering had been exercised for 1,392,701 ordinary shares, for net proceeds of $ 13,885 . In connection with the February 2021 Underwritten Offering, the Company issued to the underwriter’s designees warrants to purchase 162,318 ordinary shares, amounting to 7.0 % of the aggregate number of ordinary shares sold in the February 2021 Underwritten Offering which closed on February 8, 2021 . The warrants issued to such designees have an exercise price of $ 21.5625 per ordinary share, were exercisable upon issuance and will expire on February 3, 2026 . As of September 30, 2024, warrants issued in connection with the February 2021 Underwritten Offering had been exercised for 25,333 ordinary shares, for net proceeds of $ 546 . In connection with the February 2021 Underwritten Offering, the Company granted the underwriter an option for a period of 30 days to purchase an additional 347,826 ordinary shares. Upon the underwriter’s exercise of its option, on February 10, 2021 , the Company issued warrants to purchase an additional 24,347 ordinary shares to the underwriter’s designees, amounting to 7.0 % of the aggregate number of additional ordinary shares sold pursuant to the underwriter’s option. The warrants issued to such designees have an exercise price of $ 21.5625 per ordinary share, were exercisable upon issuance and will expire on February 3, 2026 . No warrants had been exercised as of September 30, 2024. In connection with the February 2021 Registered Direct Offering which closed on February 12, 2021 , warrants to purchase 81,666 ordinary shares, amounting to 7.0 % of the aggregate number of ordinary shares issued under the securities purchase agreement, were issued to designees of the placement agent upon closing. The warrants issued to such designees were exercisable upon issuance at an exercise price of $ 37.50 per ordinary share and will expire on February 9, 2026 . No warrants had been exercised as of September 30, 2024. In connection with the 2024 Rights Offering, which closed on August 9, 2024, the Company iss ued and sold 1-year warrants to purchase up to 3,060,982 ordinary shares and 5-year warrants to purchase up to 6,121,965 ordinary shares. Upon closing, the warrants became exercisable immediately at an exercise price of $ 1.21 per ordinary share and will expire on August 9, 2025 and August 9, 2029, respectively. No warrants had been exercised as of September 30, 2024. The Company has classified the warrants as equity in accordance with ASC 815. Accordingly, the proceeds were allocated between ordinary shares, the 1-year warrants and the 5-year warrants based on the relative fair value of the individual components. The fair value of the warrants were determined using a Black-Scholes option pricing model and the ordinary shares based on the closing date share price and were recorded in additional paid-in capital within shareholders' deficit on the condensed consolidated balance sheets. The following assumptions were used in the Black-Scholes option pricing model: August 9, 2024 1-year warrants 5-year warrants Volatility 109 % 109 % Expected term in years 1.00 5.00 Dividend rate 0 % 0 % Risk-free interest rate 4.50 % 3.80 % Share price $ 1.18 $ 1.18 Strike price $ 1.21 $ 1.21 Fair value of warrants issued $ 0.50 $ 0.94 Undesignated Preferred Shares The Company has authorized 100,000,000 undesignated preferred shares of $ 0.01 par value each as of September 30, 2024 . The Company’s Board of Directors is authorized by the Company’s Articles of Association to determine the rights attaching to the undesignated preferred shares including rights of redemption, rights as to dividends, rights on winding up and conversion rights. There were no designated preferred shares in issue as of September 30, 2024 or December 31, 2023 .

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	12. Share-Based Compensation On November 18, 2015, the Company’s Board of Directors adopted and approved the 2015 Equity Incentive Plan (the 2015 Plan), which authorized the Company to grant up to 14,895 ordinary shares in the form of incentive share options, nonstatutory share options, share appreciation rights, restricted share awards, restricted share units and other share awards. The types of share-based awards, including the rights, amount, terms, and exercisability provisions of grants are determined by the Company’s Board of Directors. The purpose of the 2015 Plan was to provide the Company with the flexibility to issue share-based awards as part of an overall compensation package to attract and retain qualified personnel. On May 18, 2017, the Company amended the 2015 Plan to increase the number of ordinary shares available for issuance under the 2015 Plan by 14,640 shares to 29,535 shares. On March 14, 2018, the Company’s Board of Directors adopted and approved the 2018 Equity Incentive Plan (the 2018 Plan), which became effective upon the execution and delivery of the underwriting agreement related to the Company’s IPO in May 2018. Since adopting the 2018 Plan, no further grants will be made under the 2015 Plan. The ordinary shares underlying any options that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2015 Plan will not be added back to the ordinary shares available for issuance. The 2018 Plan originally authorized the Company to grant up to 67,897 ordinary shares in the form of incentive share options, nonstatutory share options, share appreciation rights, restricted share awards, restricted share units, performance share awards, performance cash awards and other share awards. The types of share-based awards, including the amount, terms, and exercisability provisions of grants are determined by the Company’s Board of Directors. The ordinary shares underlying any options that are forfeited, cancelled, repurchased or are otherwise terminated by the Company under the 2018 Plan are added back to the ordinary shares available for issuance under the 2018 Plan. On December 5, 2018, pursuant to powers delegated to it by the Board of Directors of the Company, the Compensation Committee approved an increase in the number of ordinary shares available to be granted pursuant to the 2018 Plan by 4 % of the total number of shares of the Company’s issued share capital on December 31, 2018, being 38,272 ordinary shares. On February 14, 2020, pursuant to powers delegated to it by the Board of Directors of the Company, the Compensation Committee approved, by written resolution, an increase of 39,650 ordinary shares to the number of ordinary shares available to be granted pursuant to the 2018 Plan, being just under 4 % of the total number of the Company’s ordinary shares outstanding on December 31, 2019, in accordance with the terms of the 2018 Plan. On June 10, 2020, at the Company’s annual general meeting of shareholders, the shareholders approved and adopted an amended and restated 2018 Plan which, among other things included an increase of 150,000 ordinary shares to the number of ordinary shares reserved for issuance under the 2018 Plan. On June 23, 2021, at the Company’s annual general meeting of shareholders, the shareholders approved an amendment to the amended and restated 2018 Plan to increase the number of ordinary shares reserved for issuance under the amended and restated 2018 Plan by 1,000,000 ordinary shares to 1,295,819 ordinary shares. On November 24, 2021, the Company’s Board of Directors adopted and approved the 2021 Inducement Equity Incentive Plan (the 2021 Inducement Plan) reserving 333,333 of its ordinary shares to be used exclusively for grants of awards to individuals that were not previously employees or directors of the Company (or following such individuals’ bona fide period of non-employment with the company), as a material inducement to such individuals’ entry into employment with the company within the meaning of Rule 5635(c)(4) of the Nasdaq Listing Rules. The terms and conditions of the 2021 Inducement Plan are substantially similar to the 2018 Plan. Share Options Unless specified otherwise in an individual option agreement, share options granted under the 2015 Plan, the 2018 Plan and the 2021 Inducement Plan generally have a ten year term and a four year vesting period for employees and a one year vesting period for directors. The vesting requirement is conditioned upon a grantee’s continued service with the Company during the vesting period. Once vested, all awards are exercisable from the date of grant until they expire. The option grants are non-transferable. Vested options generally remain exercisable for 90 days subsequent to the termination of the option holder’s service with the Company. In the event of an option holder’s disability or death while employed by or providing service to the Company, the exercisable period extends to twelve months or eighteen months, respectively. The fair value of options granted are estimated using the Black-Scholes option-pricing model. The inputs for the Black-Scholes model require significant management assumptions. The risk-free interest rate is based on a normalized estimate of the 7-year U.S. treasury yield. The Company has estimated the expected term utilizing the “simplified” method for awards that qualify as “plain vanilla”. The Company does not have sufficient company-specific historical and implied volatility information and it therefore estimates its expected share volatility based on historical volatility information of reasonably comparable guideline public companies and itself. The Company expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded share price. Expected dividend yield is based on the fact that the Company has never paid cash dividends and the Company’s future ability to pay cash dividends on its shares may be limited by the terms of any future debt or preferred securities. The Company has elected to account for forfeitures as they occur. The Company did no t grant any share options to employees and directors during the nine months ended September 30, 2024 and 857,500 share options were granted to employees during the nine months ended September 30, 2023. There were 398,824 and 939,290 unvested employee and director share options outstanding as of September 30, 2024 and September 30, 2023, respectively. Total expense recognized related to employee share options was $ 68 and $ 279 for the three and nine months ended September 30, 2024, respectively, and $ 123 and $ 344 for the three and nine months ended September 30, 2023, respectively. Total unamortized compensation expense related to employee share options was $ 364 and $ 1,124 as of September 30, 2024 and September 30, 2023, respectively, which is expected to be recognized over a remaining weighted average vesting period of 1.49 years and 2.33 years as of September 30, 2024 and September 30, 2023, respectively. The range of assumptions that the Company used to determine the grant date fair value of employee and director options granted were as follows: Nine Months Ended September 30, 2023 Volatility 100 % Expected term in years 6.00 - 6.25 Dividend rate 0 % Risk-free interest rate 3.55 % - 3.67 % Share price $ 1.00 - $ 1.04 Fair value of option on grant date $ 0.80 - $ 0.84 The following table summarizes total share option activity for all Company plans: Equity Plans Inducement Plan Total Options outstanding December 31, 2023 984,155 124,833 1,108,988 Granted — — — Exercised ( 29,144 ) — ( 29,144 ) Forfeited ( 45,856 ) ( 120,000 ) ( 165,856 ) Options outstanding September 30, 2024 909,155 4,833 913,988 The following table summarizes the number of options outstanding and the weighted-average exercise price as of September 30, 2024: Number of Weighted Weighted Aggregate Options outstanding December 31, 2023 1,108,988 $ 2.73 8.94 $ 832 Granted — Exercised ( 29,144 ) $ 1.00 Forfeited ( 165,856 ) $ 5.54 Options outstanding September 30, 2024 913,988 $ 2.28 8.31 $ 70 Exercisable at September 30, 2024 515,164 $ 3.17 8.18 $ 35 Restricted Share Units (RSUs) The Company did no t grant any RSUs to employees and directors during the nine months ended September 30, 2024 and 2023, respectively. The following table summarizes the number of RSUs granted covering an equal number of the Company’s ordinary shares for all of Company plans: Equity Plans Inducement Plan Total RSUs outstanding December 31, 2023 — 16,666 16,666 Granted — — — Shares vested — — — Forfeited — ( 16,666 ) ( 16,666 ) RSUs outstanding September 30, 2024 — — — The table below shows the number of RSUs outstanding covering an equal number of the Company’s ordinary shares and the weighted-average grant date fair value of the RSUs outstanding as of September 30, 2024: Number of Weighted Average RSUs outstanding December 31, 2023 16,666 $ 7.26 Granted — Shares vested — Forfeited ( 16,666 ) $ 7.26 RSUs outstanding September 30, 2024 — The fair value of the RSUs is determined on the date of grant based on the market price of the Company’s ordinary shares on that date. The fair value of RSUs is expensed ratably over the vesting period, which is gener ally one year for directors and two years for employees under the 2018 Plan and four years for employees under the 2021 Inducement Plan. No amount was recognized relating to the RSUs for the three months ended September 30, 2024 and total benefit recognized related to the RSUs was $ 5 for the nine months ended September 30, 2024, and total expense recognized related to the RSUs was $ 19 and $ 301 for the three and nine months ended September 30, 2023, respectively. There was no unamortized compensation expense related to the RSUs as of September 30, 2024 and total unamortized expense related to the RSUs was $ 131 as of September 30, 2023, which was expected to be recognized over a remaining average vesting period of 2.17 years as of September 30, 2023. The Company’s share-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development expense $ 25 $ 96 $ 147 $ 315 General and administrative expense 43 46 127 330 There was a total of $ 364 and $ 1,255 unamortized share-based compensation expense for options and RSUs as of September 30, 2024 and September 30, 2023 , respectively, which is expected to be recognized over a remaining average vesting period of 1.49 years and 2.32 years as of September 30, 2024 and September 30, 2023 , respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes In accordance with ASC 270, Interim Reporting, and ASC 740, Income Taxes, at the end of each interim period, the Company is required to determine the best estimate of its annual effective tax rate and then apply that rate in providing for income taxes on a current year-to-date (interim period) basis. The Company recorded an income tax expense of $ 136 and $ 215 , for the three and nine months ended September 30, 2024, respectively and $ 161 and $ 471 , for the three and nine months ended September 30, 2023, respectively. Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax bases of assets and liabilities using statutory rates. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, including the Company’s history of losses and determined that it is more-likely-than-not that these net deferred tax assets will not be realized. As of September 30, 2024 and December 31, 2023, the Company has net operating loss carryforwards in Ireland which result in tax benefits of approximately $ 44,057 and $ 41,525 , respectively, for which a full valuation allowance has been recognized. The net operating loss carryforwards do not expire, but are carried forward indefinitely. Realization of these deferred tax assets is dependent on the generation of sufficient taxable income. If the Company demonstrates consistent profitability in the future, the evaluation of the recoverability of these deferred tax assets may change and the remaining valuation allowance may be released in part or in whole. While management expects to realize the deferred tax assets, net of valuation allowances, changes in estimates of future taxable income or in tax laws may alter this expectation.

Commitment and Contingencies

Commitment and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies License Agreement On November 18, 2015, the Company and Iterum Therapeutics International Limited (ITIL), a wholly owned subsidiary of the Company, entered into a license agreement with Pfizer for the worldwide exclusive rights to research, develop, manufacture and commercialize sulopenem (the Pfizer License). Under the Pfizer License, ITIL agreed to make certain regulatory and sales milestone payments, including a regulatory milestone payment of $ 20 million to Pfizer upon approval of oral sulopenem for commercial sale in the United States by the FDA. The Company deferred this payment for a two-year period, at an annual rate of eight percent on a daily compounded basis until paid in full, as was permitted pursuant to the terms of the Pfizer License. See Note 16 – Subsequent Events . The Company is obligated to make a potential one-time payment related to sublicensing income that exceeds a certain threshold. The Company is also obligated to pay Pfizer sales milestones upon achievement of net sales ranging from $ 250.0 million to $ 1.0 billion for each product type, as well as royalties ranging from a single-digit to mid-teens percentage based on marginal net sales of each licensed product. Royalty-Linked Notes On January 21, 2020, as part of the Private Placement, the Company issued 2,579,400 RLNs to a group of accredited investors. On September 8, 2020, as part of the 2020 Rights Offering, the Company issued 11,000 RLNs to existing shareholders. The RLNs will entitle the holders thereof to payments, at the applicable payment rate, based solely on a percentage of the Company’s net revenues from U.S. sales of specified sulopenem products earned through December 31, 2045, but will not entitle the holders thereof to any payments unless the Company receives FDA approval for one or more specified sulopenem products prior to December 31, 2025 and the Company earns net revenues on such product. If any portion of the principal amount of the outstanding RLNs, equal to $ 0.04 per RLN, has not been paid as of the end date on December 31, 2045 (or December 31, 2025, in the event that the Company has not yet received FDA approval with respect to one or more specified sulopenem products by such date), Iterum Bermuda must pay the unpaid portion of the principal amount. The RLNs will earn default interest if the Company breaches certain obligations under the RLN Indenture (but do not otherwise bear interest) and will be subject to a maximum return amount, including all principal and payments and certain default interest in respect of uncurable defaults, of $ 160.00 (or 4,000 times the principal amount of such note). The RLNs will be redeemable at the Company’s option, subject to the terms of the RLN Indenture. Other Contingencies Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. At each reporting date the Company evaluates whether or not a potential loss amount or a potential loss range is probable and reasonably estimable under the provisions of the authoritative guidelines that address accounting for contingencies. The Company expenses costs as incurred in relation to such legal proceedings. The Company has no contingent liabilities in respect of legal claims arising in the ordinary course of business. Under the terms of their respective employment agreements, each of the named executive officers is eligible to receive severance payments and benefits upon a termination without “cause” (other than due to death or disability) or upon “resignation for good reason”, contingent upon the named executive officer’s continued performance for the Company. Under the terms of the Employee Severance Plan approved by the Compensation Committee in January 2022, an employee, who is not an executive officer of the Company, is entitled to severance pay and benefits on a "qualifying termination", that is termination at any time during the period beginning on the date that is 30 days prior to and ending on the date that is 12 months following a change of control without "cause" (other than due to death or disability) based on the employee's level/salary grade.

Condensed Consolidating Financi

Condensed Consolidating Financial Statements	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Financial Statements	15. Condensed Consolidating Financial Statements On January 21, 2020, the Company completed a Private Placement pursuant to which its wholly owned subsidiary, Iterum Bermuda, issued and sold $ 51,588 aggregate principal amount of Exchangeable Notes and $ 103 aggregate principal amount of RLNs to a group of accredited investors. On September 8, 2020, the Company completed a Rights Offering pursuant to which Iterum Bermuda issued and sold $ 220 aggregate principal amount of Exchangeable Notes and $ 0.44 aggregate principal amount of RLNs to existing shareholders. The Securities were sold in Units with each Unit consisting of an Exchangeable Note in the original principal amount of $ 1,000 and 50 RLNs. As of September 30, 2024, $ 11,117 aggregate principal amount of Exchangeable Notes and all RLNs remained outstanding. The Units were issued by Iterum Bermuda, which was formed on November 6, 2019 and is a 100 % owned “finance subsidiary” of the Company under Rule 3-10 of Regulation S-X with no independent function and no assets or operations other than those related to the issuance, administration and repayment of the Exchangeable Notes and RLNs. Iterum Therapeutics plc, as the parent company, has no independent assets or operations, and its operations are conducted solely through its subsidiaries. The assets, liabilities and results of operations of the Company, Iterum Bermuda and Iterum Therapeutics International Limited, Iterum Therapeutics US Holding Limited and Iterum Therapeutics US Limited (the Subsidiary Guarantors) are not materially different than the corresponding amounts presented in the condensed consolidated financial statements of this Quarterly Report on Form 10-Q. The Company and the Subsidiary Guarantors have provided a full and unconditional guarantee of Iterum Bermuda’s obligations under the Exchangeable Notes and the RLNs, and each of the guarantees constitutes the joint and several obligations of the applicable guarantor. The Subsidiary Guarantors are 100 % directly or indirectly owned subsidiaries of the Company. There are no significant restrictions upon the Company’s or the Subsidiary Guarantors’ ability to obtain funds from their subsidiaries by dividend or loan. None of the assets of Iterum Bermuda or the Subsidiary Guarantors represent restricted net assets pursuant to Rule 4-08(e)(3) of Regulation S-X.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events Regulatory Milestone Payment On November 18, 2015, the Company and Iterum Therapeutics International Limited (ITIL), a wholly owned subsidiary of the Company, entered into a license agreement with Pfizer for the worldwide exclusive rights to research, develop, manufacture and commercialize sulopenem (the Pfizer License). Under the Pfizer License, ITIL agreed to make certain regulatory and sales milestone payments, including a regulatory milestone payment of $ 20 million to Pfizer upon approval of oral sulopenem for commercial sale in the United States by the FDA. On October 25, 2024, the Company received FDA approval for ORLYNVAH™ (sulopenem etzadroxil and probenecid) for the treatment of uncomplicated urinary tract infections caused by the designated microorganisms Escherichia coli, Klebsiella pneumoniae , or Proteus mirabilis in adult women who have limited or no alternative oral antibacterial treatment options. On October 28, 2024, the Company notified Pfizer that it was electing to defer payment of the milestone payment for two year s, or until October 25, 2026 (the Deferral Period), and delivered a promissory note (the Note) issued by ITIL in the amount of the milestone payment to Pfizer, as permitted pursuant to the terms of the Pfizer License. The Note bears interest at an annual rate of eight percent ( 8 %) on a daily compounded basis until paid in full and matures on October 25, 2026. ITIL has the right to prepay the unpaid principal balance of the Note together with accrued and unpaid interest at any time without premium or penalty. Pursuant to the terms of the Note, ITIL may (i) assign the Note to an affiliate of ITIL; (ii) designate one of its affiliates to perform its obligations thereunder; or (iii) assign the Note in the event of a change of control, provided that in the case of clauses (i) and (ii) ITIL is not relieved of any liability thereunder. Pursuant to the terms of the Pfizer License, if a change of control of ITIL or the Company occurs during the Deferral Period, Pfizer may, in its sole discretion and at its sole option, declare the Milestone Payment to be immediately due and payable together with all interest accrued under the Note. The Company has guaranteed all of the amounts payable by ITIL under the terms of the Pfizer License, including the amounts owed under the Note, pursuant to the guarantee entered into by ITIL, the Company and Pfizer on November 18, 2015 in connection with the Pfizer License On October 25, 2024, the Company received FDA approval for ORLYNVAH™ (sulopenem etzadroxil and probenecid) for the treatment of uncomplicated urinary tract infections caused by the designated microorganisms Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis in adult women who have limited or no alternative oral antibacterial treatment options. On October 28, 2024, the Company notified Pfizer that it was electing to defer payment of the milestone payment for two year s, or until October 25, 2026 (the Deferral Period), and delivered the Note to Pfizer. Equity Offerings Subsequent to September 30, 2024, through November 4, 2024, the Company sold 4.5 million ordinary shares under the Sales Agreement, with HC Wainwright as agent, at an average price of $ 1.55 per share for net proceeds of $ 6.7 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Description of Business	Description of Business Iterum Therapeutics plc (the Company) was incorporated under the laws of the Republic of Ireland in June 2015 as a limited company and re-registered as a public limited company on March 20, 2018. The Company maintains its registered office at Fitzwilliam Court, 1 st Floor, Leeson Close, Dublin 2, Ireland. The Company commenced operations in November 2015. The Company licensed global rights to its novel anti-infective compound, sulopenem, from Pfizer Inc. (Pfizer). The Company is focused on delivering differentiated anti-infectives aimed at combating the global crisis of multi-drug resistant pathogens to significantly improve the lives of people affected by serious and life-threatening diseases around the world. The Company is advancing the development of its first compound, sulopenem, a novel penem anti-infective compound, with an oral formulation and IV formulation.
Liquidity and Going Concern	Liquidity and Going Concern Since inception, the Company has devoted substantially all of its efforts to research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of ordinary and convertible preferred shares, debt raised under a financing arrangement with Silicon Valley Bank (SVB) including the Paycheck Protection Program loan (PPP loan), a sub-award from the Trustees of Boston University under the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (CARB-X) program and the proceeds of a private placement (Private Placement) and subsequent rights offering (the 2020 Rights Offering) pursuant to which its wholly owned subsidiary, Iterum Therapeutics Bermuda Limited (Iterum Bermuda) issued and sold approximately $ 51.8 million aggregate principal amount of 6.500 % Exchangeable Senior Subordinated Notes due 2025 (Exchangeable Notes) and $ 0.1 million aggregate principal amount of Limited Recourse Royalty-Linked Subordinated Notes (the RLNs and, together with the Exchangeable Notes, the Securities), which Securities were sold in units consisting of an Exchangeable Note in the original principal amount of $ 1,000 and 50 RLNs (the Units). The Company has not generated any product revenue. The Company is subject to risks and uncertainties common to early-stage companies in the pharmaceutical industry, including, but not limited to, the ability to secure additional capital to fund operations, failure to successfully develop and commercialize its product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology and compliance with government regulations. Even with receipt of FDA approval, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and include the accounts of the Company and its subsidiaries. The Company file d a universal shelf registration statement on Form S-3 with the SEC, which was declared effective on October 17, 2022 (File No. 333-267795), and pursuant to which the Company registered for sale up to $ 100.0 million of any combination of debt securities, ordinary shares, preferred shares, subscription rights, purchase contracts, units and/or warrants from time to time and at prices and on terms that the Company may determine. On October 7, 2022, the Company entered into a sales agreement with H.C. Wainwright & Co., LLC (HC Wainwright), as agent, pursuant to which the Company may offer and sell ordinary shares, nominal value $ 0.01 per share, for aggregate gross sales proceeds of up to $ 16.0 million (subject to the availability of ordinary shares), from time to time through HC Wainwright by any method permitted that is deemed to be an "at the market offering" as defined in Rule 415 (a)(4) promulgated under the Securities Act of 1933, as amended (the "Sales Agreement"). On August 9, 2024, the Company completed a rights offering (the 2024 Rights Offering) in which it sold an aggregate of 6,121,965 units ("Units") at a subscription price of $ 1.21 per whole Unit, consisting of (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 (the "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 (the "5-year warrants" and, together with the 1-year warrants, the “warrants”). The Company's net proceeds from the 2024 Rights Offering, after deducting placement agent fees and other offering expenses payable by the Company, were approximately $ 5.4 million. The warrants are exercisable upon issuance at a price of $ 1.21 per ordinary share. The 1-year warrants expire on August 9, 2025 and the 5-year warrants expire on August 9, 2029. In accordance with Accounting Standards Update (ASU) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40) , the Company has evaluated whether there are conditions and events, considered in aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year of the date of issue of these quarterly condensed consolidated financial statements. The Company has funded its operations to date primarily with proceeds from the sale of preferred shares and ordinary shares, warrants, debt raised under its financing arrangement with SVB including the PPP loan (both of which have been repaid), payments received under the CARB-X program and proceeds of the Private Placement and 2020 Rights Offering. The Company has incurred operating losses since inception, including net losses of $ 18,192 and $ 26,009 for the nine months ended September 30, 2024 and 2023, respectively, and a net loss of $ 38,371 for the year ended December 31, 2023. The Company had an accumulated deficit of $ 479,490 as of September 30, 2024 and expects to continue to incur net losses for the foreseeable future. The Company’s future cash flows are dependent on key variables such as its ability to secure additional sources of funding in the form of public or private financing of debt or equity or collaboration agreements. Based on its available cash, cash equivalents and short-term investments, including amounts raised subsequent to the period-end under the "at-the market"agreement (see Note 16 – Subsequent Events), the Company does not have cash on hand to fund its current operations and capital expenditure requirements for the next 12 months from the date of this Quarterly Report on Form 10-Q. This condition raises substantial doubt about the Company’s ability to continue as a going concern for one year from the date these condensed consolidated financial statements are issued. The Company plans to address this condition by raising funding through the possible sale of the Company’s equity or debt through public or private equity financings. Although management intends to pursue plans to obtain additional funding to finance its operations, and the Company has successfully raised capital in the past, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. In addition, in parallel, the Company is evaluating its corporate, strategic, financial and financing alternatives, with the goal of maximizing value for its stakeholders. These alternatives could potentially include the licensing, sale or divestiture of the Company’s assets or proprietary technologies or another strategic transaction involving the Company. The evaluation of corporate, strategic, financial and financing alternatives may not result in any particular action or any transaction being pursued, entered into or consummated, and there is no assurance as to the timing, sequence or outcome of any action or transaction or series of actions or transactions. If the Company is unable to obtain funding, it could be forced to significantly delay, scale back or discontinue the development and commercialization of its sulopenem program, or otherwise change its strategy, which could adversely affect its business prospects, or the Company may be unable to continue operations. Based on the Company’s operating losses since inception, the expectation of continued operating losses for the foreseeable future, and the need to raise additional capital to finance its future operations, management has concluded there is substantial doubt about the Company’s ability to continue as a going concern within one year from the date these condensed consolidated financial statements are issued. The accompanying condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the condensed consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and which contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business.
Interim Financial Information	Interim Financial Information The condensed consolidated balance sheet at December 31, 2023 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed consolidated financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2023, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 28, 2024. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s financial position as of September 30, 2024, and results of operations for the three and nine months ended September 30, 2024 and 2023, and cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024 .
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of expenses during the reporting period and the assessment of the Company’s ability to continue as a going concern. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the valuation of the RLNs. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates as there are changes in circumstances, facts and experience. Actual results could differ materially from those estimates. Specifically, management has estimated variables used to calculate the discounted cash flow analysis (DCF) to value the RLN liability (see Note 3 – Fair Value of Financial Assets and Liabilities).
Cash and Cash Equivalents	Cash and Cash Equivalents The Company’s cash and cash equivalents consist of cash balances and highly liquid investments with maturities of three months or less at the date of purchase. Accounts held at U.S. financial institutions are insured by the Federal Deposit Insurance Corporation up to $ 250 , while accounts held at Irish financial institutions are insured under the Deposit Guarantee Scheme up to $ 111 (€ 100 ). Cash accounts with any type of restriction are classified as restricted cash. If restrictions are expected to be lifted in the next twelve months, the restricted cash account is classified as current. Included within restricted cash on the Company’s condensed consolidated balance sheet is $ 17 as of September 30, 2024 relating to the warrants issued on June 5, 2020 pursuant to the securities purchase agreement (June 3, 2020 SPA) from the June 3, 2020 registered direct offering (June 3, 2020 Offering), $ 6 as of September 30, 2024 relating to the warrants issued on July 2, 2020 pursuant to the securities purchase agreement (June 30, 2020 SPA) from the June 30, 2020 registered direct offering (June 30, 2020 Offering) and $ 11 as of September 30, 2024 relating to warrants issued in the underwritten offering in October 2020 (October 2020 Offering). These restricted cash amounts are unchanged from December 31, 2023 . On the closing date of each of the registered direct offerings in June 2020 (June 3 Offering) and July 2020 (June 30 Offering) and the underwritten offering in the October 2020 Offering, each investor deposited $ 0.01 per warrant issued being the nominal value of the underlying ordinary share represented by each warrant. This amount will be held in trust by the Company pending a decision by the relevant investor to exercise the warrant by means of a “cashless exercise” pursuant to the terms of the warrant, in which case the $ 0.01 will be used to pay up the nominal value of the ordinary share issued pursuant to the warrant. Upon the exercise of the warrants other than by means of a "cashless exercise", the amount held in trust will be returned to the relevant investor in accordance with the terms of the applicable purchase agreement or prospectus.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company has most of its cash, cash equivalents and short-term investments at three accredited financial institutions in the United States and Ireland, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.
Net Loss Per Ordinary Share	Net Loss Per Ordinary Share Basic and diluted net loss per ordinary share is determined by dividing net loss attributable to ordinary shareholders by the weighted-average ordinary shares outstanding during the period in accordance with Accounting Standard Codification (ASC) 260, Earnings per Share . For the periods presented, the following ordinary shares underlying the options, unvested restricted share units, warrants and the Exchangeable Notes have been excluded from the calculation because they would be anti-dilutive. Three and Nine Months Ended September 30, 2024 September 30, 2023 Options to purchase ordinary shares 913,988 1,108,988 Unvested restricted share units — 33,965 Warrants 9,663,125 480,186 Exchangeable Notes 2,541,786 1,404,721 Total 13,118,899 3,027,860
Segment and Other Information	Segment and Other Information The Company determines and presents operating segments based on the information that is internally provided to the Chief Executive Officer and Chief Financial Officer, who together are considered the Company’s chief operating decision maker, in accordance with ASC 280, Segment Reporting . The Company has determined that it operates as a single business segment, which is the development and commercialization of innovative treatments for drug resistant bacterial infections. The distribution of total operating expenses by geographical area was as follows: Three Months Ended September 30, Nine Months Ended September 30, Operating expenses 2024 2023 2024 2023 Ireland $ 4,072 $ 15,201 $ 11,602 $ 31,754 U.S. 815 1,484 3,390 4,260 Bermuda — — 34 23 Total $ 4,887 $ 16,685 $ 15,026 $ 36,037 The distribution of long-lived assets by geographical area was as follows: Long-lived assets September 30, 2024 December 31, 2023 Ireland $ 15 $ 342 U.S. 21 287 Total $ 36 $ 629
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. On November 27, 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which enhances segment disclosures and requires additional disclosures of segment expenses. This ASU is effective for annual periods in fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. Early adoption is permitted. ASU 2023-07 is not expected to have a material impact on the consolidated financial statements. On October 9, 2023, the FASB issued ASU No. 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative, or ASU 2023-06, which incorporates into the Codification several disclosures and presentation requirements currently residing in SEC Regulations S-X and S-K. For entities subject to the existing SEC disclosure requirements, including those preparing for sale or issuance of securities, the effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. For all other entities, the amendments will be effective two years later, with early adoption permitted. ASU 2023-06 is not expected to have a material impact on the consolidated financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures , or ASU 2023-09, which enhances the annual income tax disclosures for the effective tax rate reconciliation and income taxes paid. The amendments are effective for public business entities, for annual periods beginning after December 15, 2024 and for annual periods beginning after December 15, 2025 for all other entities. Early adoption is permitted for annual financial statements that have not yet been issued or made available for issuance. The ASU applies on a prospective basis to annual financial statements for periods beginning after the effective date. However, retrospective application in all prior periods presented is permitted. The Company is assessing what impact ASU 2023-09 will have on the condensed consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding	For the periods presented, the following ordinary shares underlying the options, unvested restricted share units, warrants and the Exchangeable Notes have been excluded from the calculation because they would be anti-dilutive. Three and Nine Months Ended September 30, 2024 September 30, 2023 Options to purchase ordinary shares 913,988 1,108,988 Unvested restricted share units — 33,965 Warrants 9,663,125 480,186 Exchangeable Notes 2,541,786 1,404,721 Total 13,118,899 3,027,860
Schedule of Distribution of Total Operating Expenses by Geographical Area	The distribution of total operating expenses by geographical area was as follows: Three Months Ended September 30, Nine Months Ended September 30, Operating expenses 2024 2023 2024 2023 Ireland $ 4,072 $ 15,201 $ 11,602 $ 31,754 U.S. 815 1,484 3,390 4,260 Bermuda — — 34 23 Total $ 4,887 $ 16,685 $ 15,026 $ 36,037
Schedule of Distribution of Long-Lived Assets by Geographical Area	The distribution of long-lived assets by geographical area was as follows: Long-lived assets September 30, 2024 December 31, 2023 Ireland $ 15 $ 342 U.S. 21 287 Total $ 36 $ 629

Fair Value of Financial Asset_2

Fair Value of Financial Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2024
Schedule of Financial Assets Measured at Fair Value	The following table presents information about the Company’s financial assets that were carried at fair value on a recurring basis on the condensed consolidated balance sheet as of September 30, 2024 and December 31, 2023 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value. September 30, 2024 Assets Total Level 1 Level 2 Level 3 Short-term investments: U.S. Treasury bonds $ 1,096 $ — $ 1,096 $ — $ 1,096 $ — $ 1,096 $ — December 31, 2023 Assets Total Level 1 Level 2 Level 3 Short-term investments: Corporate bonds $ 1,179 $ — $ 1,179 $ — Commercial paper 3,287 — 3,287 — U.S. Treasury bonds 13,393 — 13,393 — $ 17,859 $ — $ 17,859 $ —
Summary of Long Term And Short Term Debt at Fair Value Hierarchy of Valuation Inputs Utilized to Determine Fair Value	The following table presents information about the Company’s Exchangeable Notes and RLNs and indicates the fair value hierarchy of the valuation inputs utilized to determine the approximate fair value: September 30, 2024 Book Approximate Short-term Liabilities Value Fair Value Level 1 Level 2 Level 3 Exchangeable Notes Exchangeable note $ 13,708 $ 13,744 $ — $ 13,744 $ — Total short-term liabilities $ 13,708 $ 13,744 $ — $ 13,744 $ — Long-term Liabilities Revenue Futures Royalty-linked notes 8,728 8,728 — — 8,728 Total long-term liabilities $ 8,728 $ 8,728 $ — $ — $ 8,728 December 31, 2023 Book Approximate Long-term Liabilities Value Fair Value Level 1 Level 2 Level 3 Exchangeable Notes Long-term exchangeable note $ 11,453 $ 11,645 $ — $ 11,645 $ — Revenue Futures Royalty-linked notes 7,503 7,503 — — 7,503 Total long-term liabilities $ 18,956 $ 19,148 $ — $ 11,645 $ 7,503

Short-term Investments (Tables)

Short-term Investments (Tables)	9 Months Ended
	Sep. 30, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of Available for Sale Short-term Investments by Major Security Type	The following table represents the Company’s available for sale short-term investments by major security type as of September 30, 2024 and December 31, 2023: September 30, 2024 Maturity by period Amortized Unrealized Unrealized Fair Value Less than 1 Available-for-sale Cost Gains (Losses) Total Year 1 to 5 Years U.S. Treasury bonds $ 1,095 $ 1 $ — $ 1,096 $ 1,096 $ — December 31, 2023 Maturity by period Amortized Unrealized Unrealized Fair Value Less than 1 Available-for-sale Cost Gains (Losses) Total Year 1 to 5 Years Corporate bonds $ 1,179 $ 1 $ — $ 1,180 $ 1,180 $ — Commercial paper 3,288 — ( 1 ) 3,287 3,287 — U.S. Treasury bonds 13,391 3 ( 2 ) 13,392 13,392 — Total $ 17,858 $ 4 $ ( 3 ) $ 17,859 $ 17,859 $ — For the three and nine months ended September 30, 2024 and 2023, no allowance was recorded for credit losses. Unrealized gains and losses are reported as a component of accumulated other comprehensive income in shareholders’ deficit.

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2024
Prepaid Expense and Other Assets, Current [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following: September 30, December 31, Prepaid insurance $ 551 $ 472 Right of use assets, net 264 — Other prepaid assets 213 89 Research and development tax credit receivable 66 195 Prepaid research and development expenses 50 872 Total $ 1,144 $ 1,628

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment and Related Accumulated Depreciation	Property and equipment and related accumulated depreciation are as follows: September 30, December 31, Leasehold improvements $ 148 $ 148 Furniture and fixtures 120 120 Computer equipment 95 98 363 366 Less: accumulated depreciation ( 333 ) ( 315 ) $ 30 $ 51

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Summary of Right-of-Use Assets and Lease Liabilities	Information related to the Company’s right-of-use assets and related lease liabilities is as follows: Three Months Ended Three Months Ended Nine Months Ended Nine Months Ended September 30, 2024 September 30, 2023 September 30, 2024 September 30, 2023 Cash paid for operating lease liabilities $ 101 $ 52 $ 301 $ 256 September 30, 2024 December 31, Weighted-average remaining lease term 0.73 years 1.46 years Weighted-average discount rate 12.9 % 12.9 % Right-of-use assets and lease liabilities for the Company’s operating leases were recorded in the condensed consolidated balance sheet as follows, representing the Company’s right to use the underlying asset for the lease term ("Prepaid expenses and other current assets" and “Other assets”) and the Company’s obligation to make lease payments (“Other current liabilities” and “Other liabilities”): September 30, 2024 December 31, Prepaid expenses and other current assets $ 264 $ — Other assets — 549 Total lease assets $ 264 $ 549 Other current liabilities $ 268 $ 365 Other liabilities — 188 Total lease liabilities $ 268 $ 553
Schedule of Future Lease Payments Included in Measurement of Lease Liabilities on Condensed Consolidated Balance Sheet	Future lease payments included in the measurement of lease liabilities on the condensed consolidated balance sheet as of September 30, 2024 for the following five fiscal years and thereafter were as follows: Due in 12 month period ended September 30, 2025 $ 279 2026 — 2027 — 2028 — 2029 — Thereafter — $ 279 Less imputed interest ( 11 ) Total lease liabilities $ 268

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following: September 30, December 31, Accrued payroll and bonus expenses $ 1,770 $ 2,742 Accrued manufacturing expenses 1,484 71 Accrued other expenses 111 76 Accrued professional fees 108 37 Accrued clinical trial costs 19 4,835 Total $ 3,492 $ 7,761

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2024
Schedule of Principal Payments on Outstanding Debt, Including Principal Amounts owed to RLN Holders	Scheduled principal payments on outstanding debt, including principal amounts owed to RLN holders (see Note 10 – Royalty-Linked Notes), as of September 30, 2024 , for the following five fiscal years and thereafter were as follows: Year Ending September 30, 2025 $ 11,117 2026 — 2027 — 2028 — 2029 — Thereafter 104 Total $ 11,221
2025 Exchangeable Notes
Summary of Balance of Exchangeable Notes	The balance of the Exchangeable Notes as of September 30, 2024 is as follows: September 30, 2024 Principal Accrued Interest January 2020 $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) $ 51,588 $ 6,397 September 2020 $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) 220 34 Conversion of $ 1,000 Exchangeable Notes, 6.5 % interest, due January 31, 2025 (2025 Exchangeable Notes) ( 40,691 ) ( 3,071 ) 2025 Exchangeable Notes, net 11,117 3,360 Unamortized discount and debt issuance costs ( 769 ) — 2025 Exchangeable Notes, net $ 10,348 $ 3,360

Royalty-Linked Notes (Tables)

Royalty-Linked Notes (Tables)	9 Months Ended
	Sep. 30, 2024
Royalty Linked Notes [Abstract]
Summary of Royalty-Linked Notes	The balance of the RLNs at each reporting date is as follows: September 30, Total liability related to the sale of future royalties, on inception $ 10,990 Liability related to the sale of future royalties, arising from the 2020 Rights Offering 51 Amortization of discount and debt issuance costs 3,666 Adjustments to fair value ( 5,979 ) Total liability related to the sale of future royalties at June 30, 2024 $ 8,728 Current Portion — Long-term Portion $ 8,728 December 31, 2023 Total liability related to the sale of future royalties, on inception $ 10,990 Liability related to the sale of future royalties, arising from the 2020 Rights Offering 51 Amortization of discount and debt issuance costs 3,666 Adjustments to fair value ( 7,204 ) Total liability related to the sale of future royalties at December 31, 2023 $ 7,503 Current Portion — Long-term Portion $ 7,503

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Summary of Assumptions Used to Determine Fair Value of Warrants	The following assumptions were used in the Black-Scholes option pricing model: August 9, 2024 1-year warrants 5-year warrants Volatility 109 % 109 % Expected term in years 1.00 5.00 Dividend rate 0 % 0 % Risk-free interest rate 4.50 % 3.80 % Share price $ 1.18 $ 1.18 Strike price $ 1.21 $ 1.21 Fair value of warrants issued $ 0.50 $ 0.94

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Summary of Assumptions Used to Determine Fair Value of Options	The range of assumptions that the Company used to determine the grant date fair value of employee and director options granted were as follows: Nine Months Ended September 30, 2023 Volatility 100 % Expected term in years 6.00 - 6.25 Dividend rate 0 % Risk-free interest rate 3.55 % - 3.67 % Share price $ 1.00 - $ 1.04 Fair value of option on grant date $ 0.80 - $ 0.84
Summary of Stock Options Activity	The following table summarizes total share option activity for all Company plans: Equity Plans Inducement Plan Total Options outstanding December 31, 2023 984,155 124,833 1,108,988 Granted — — — Exercised ( 29,144 ) — ( 29,144 ) Forfeited ( 45,856 ) ( 120,000 ) ( 165,856 ) Options outstanding September 30, 2024 909,155 4,833 913,988 The following table summarizes the number of options outstanding and the weighted-average exercise price as of September 30, 2024: Number of Weighted Weighted Aggregate Options outstanding December 31, 2023 1,108,988 $ 2.73 8.94 $ 832 Granted — Exercised ( 29,144 ) $ 1.00 Forfeited ( 165,856 ) $ 5.54 Options outstanding September 30, 2024 913,988 $ 2.28 8.31 $ 70 Exercisable at September 30, 2024 515,164 $ 3.17 8.18 $ 35
Summary of Restricted Share Units (RSUs)	The following table summarizes the number of RSUs granted covering an equal number of the Company’s ordinary shares for all of Company plans: Equity Plans Inducement Plan Total RSUs outstanding December 31, 2023 — 16,666 16,666 Granted — — — Shares vested — — — Forfeited — ( 16,666 ) ( 16,666 ) RSUs outstanding September 30, 2024 — — — The table below shows the number of RSUs outstanding covering an equal number of the Company’s ordinary shares and the weighted-average grant date fair value of the RSUs outstanding as of September 30, 2024: Number of Weighted Average RSUs outstanding December 31, 2023 16,666 $ 7.26 Granted — Shares vested — Forfeited ( 16,666 ) $ 7.26 RSUs outstanding September 30, 2024 —
Summary of Share-based Compensation Expense	The Company’s share-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows: Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Research and development expense $ 25 $ 96 $ 147 $ 315 General and administrative expense 43 46 127 330

Basis of Presentation - Additio

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

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, € in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) Segment $ / shares	Sep. 30, 2024 EUR (€)	Dec. 31, 2023 $ / shares	Sep. 30, 2023 $ / shares	May 03, 2023 $ / shares
Accounting Policies [Line Items]
Ordinary shares, par value | $ / shares	$ 0.01		$ 0.01	$ 0.01	$ 0.01
Number of business segments | Segment	1
October 2020 Offering
Accounting Policies [Line Items]
Ordinary shares, par value | $ / shares	$ 0.01			0.01
June 3, 2020 SPA
Accounting Policies [Line Items]
Ordinary shares, par value | $ / shares	0.01			0.01
June 30, 2020 SPA
Accounting Policies [Line Items]
Ordinary shares, par value | $ / shares	$ 0.01			$ 0.01
Warrants Issued | October 2020 Offering
Accounting Policies [Line Items]
Restricted cash | $	$ 11
Warrants Issued | June 3, 2020 SPA
Accounting Policies [Line Items]
Restricted cash | $	17
Warrants Issued | June 30, 2020 SPA
Accounting Policies [Line Items]
Restricted cash | $	6
Maximum
Accounting Policies [Line Items]
Cash, Federal Deposit Isurance Corporation insured amount | $	250
Cash, DGS insured amount	$ 111	€ 100

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	13,118,899	3,027,860
Options to Purchase Ordinary Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	913,988	1,108,988
Unvested Restricted Share Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding		33,965
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	9,663,125	480,186
Exchangeable Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	2,541,786	1,404,721

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Distribution of Total Operating Expenses by Geographical Area (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Operating expenses	$ 4,887	$ 16,685	$ 15,026	$ 36,037
Ireland
Segment Reporting Information [Line Items]
Operating expenses	4,072	15,201	11,602	31,754
U.S.
Segment Reporting Information [Line Items]
Operating expenses	$ 815	$ 1,484	3,390	4,260
Bermuda
Segment Reporting Information [Line Items]
Operating expenses			$ 34	$ 23

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Distribution of Long-Lived Assets by Geographical Area (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]
Long lived assets	$ 36	$ 629
Ireland
Revenues from External Customers and Long-Lived Assets [Line Items]
Long lived assets	15	342
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Long lived assets	$ 21	$ 287

Fair Value of Financial Asset_3

Fair Value of Financial Assets and Liabilities (Schedule of Financial Assets Measured at Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 1,096	$ 17,859
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		1,179
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		3,287
U.S. Treasury Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	1,096	13,393
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	1,096	17,859
Level 2 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		1,179
Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		3,287
Level 2 | U.S. Treasury Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 1,096	$ 13,393

Fair Value of Financial Asset_4

Fair Value of Financial Assets and Liabilities - Summary of Long Term And Short Term Debt at Fair Value Hierarchy of Valuation Inputs Utilized to Determine Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Book Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term exchangeable note		$ 11,453
Short-term Liabilities, Exchangeable note	$ 13,708
Total short-term liabilities	13,708
Long-term Liabilities, Royalty-linked notes	8,728	7,503
Total long-term liabilities	8,728	18,956
Approximate Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total short-term liabilities	13,744
Long-term exchangeable note		11,645
Short-term Liabilities, Exchangeable note	13,744
Long-term Liabilities, Royalty-linked notes	8,728	7,503
Total long-term liabilities	8,728	19,148
Level 2 | Approximate Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total short-term liabilities	13,744
Long-term exchangeable note		11,645
Short-term Liabilities, Exchangeable note	13,744
Total long-term liabilities		11,645
Level 3 | Approximate Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term Liabilities, Royalty-linked notes	8,728	7,503
Total long-term liabilities	$ 8,728	$ 7,503

Fair Value of Financial Asset_5

Fair Value of Financial Assets and Liabilities - Additional Information (Details) - USD ($)		9 Months Ended	44 Months Ended
	Jan. 21, 2020	Sep. 30, 2024	Sep. 30, 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative liability for the exchange option, fair value		$ 0	$ 0
Aggregate principal amount of exchangeable notes			40,691,000
RLNs liability		8,728,000	8,728,000
Fair value, asset Level 3 transfers amount		0
Fair value, liabilities Level 3 transfers amount		0
Exchangeable Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal amount of exchangeable notes			40,691,000
Private Placement | Exchangeable Notes
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Aggregate principal amount of exchangeable notes			$ 40,691,000
Debt instrument, aggregate number of shares exchanged			3,760,155
Debt instrument, outstanding principal		$ 11,117,000	$ 11,117,000
Private Placement | Securities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument price per ordinary share	$ 15	$ 5.707
Debt instrument, shares embedded within each unit, shares	66.666	175.2191
Debt instrument, shares embedded within each unit, value	$ 1,000	$ 1,000
Private Placement | RLNs
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, aggregate potential payment capped value	160.00
Debt instrument, aggregate potential payment capped rate	4,000 times
Debt instrument, discount rate applied for royalty linked notes	22%

Short-term Investments - Additi

Short-term Investments - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Average maturity period	29 days
Allowance recorded for credit losses	$ 0	$ 0

Short-term Investments - Schedu

Short-term Investments - Schedule of Available for Sale Short-term Investments by Major Security Type (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		$ 17,858
Unrealized Gains		4
Unrealized (Losses)		(3)
Fair Value Total		17,859
Maturity by period Less than 1 Year		17,859
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		1,179
Unrealized Gains		1
Fair Value Total		1,180
Maturity by period Less than 1 Year		1,180
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost		3,288
Unrealized (Losses)		(1)
Fair Value Total		3,287
Maturity by period Less than 1 Year		3,287
U.S. Treasury Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 1,095	13,391
Unrealized Gains	1	3
Unrealized (Losses)		(2)
Fair Value Total	1,096	13,392
Maturity by period Less than 1 Year	$ 1,096	$ 13,392

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid insurance	$ 551	$ 472
Right of use assets, net	264	549
Other prepaid assets	213	89
Research and development tax credit receivable	66	195
Prepaid research and development expenses	50	872
Total	$ 1,144	$ 1,628

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment and Related Accumulated Depreciation (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 363	$ 366
Less: accumulated depreciation	(333)	(315)
Property and equipment, net	30	51
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	148	148
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	120	120
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 95	$ 98

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 23	$ 23
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation decreased amount	$ 5

Leases - Additional Information

Leases - Additional Information (Details) - Office Space and Commercial Property - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating Leased Assets [Line Items]
Lessee, operating lease, description			These leases have remaining terms which range from 0.2 years to 0.8 years.
Lessee, operating lease, option to extend			The renewal option on one lease was exercised in February 2022 for an additional period of three years, extending this lease term to June 2025.
Lessee, operating lease, renewal term	3 years		3 years
Operating lease cost for right - of - use assets	$ 101,000	$ 51,000	$ 299,000	$ 265,000
Operating lease, rental expenses	0	49,000	0	194,000
Sublease Income	$ 0	$ 48,000	$ 0	$ 199,000
Minimum
Operating Leased Assets [Line Items]
Lessee, operating lease, remaining lease term	2 months 12 days		2 months 12 days
Maximum
Operating Leased Assets [Line Items]
Lessee, operating lease, remaining lease term	9 months 18 days		9 months 18 days

Leases - Summary of Right-of-Us

Leases - Summary of Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Leases [Abstract]
Cash paid for operating lease liabilities	$ 101	$ 52	$ 301	$ 256
Weighted-average remaining lease term	8 months 23 days		8 months 23 days		1 year 5 months 15 days
Weighted-average discount rate	12.90%		12.90%		12.90%

Leases - Summary of Right-of-_2

Leases - Summary of Right-of-Use Assets and Lease Liabilities for Operating Leases Recorded in Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule Of Lease Assets And Liabilities [Abstract]
Prepaid expenses and other current assets	$ 264
Operating Lease, Right-of-Use Asset, Current, Statement of Financial Position [Extensible Enumeration]	Prepaid Expense and Other Assets, Current
Other assets		$ 549
Operating Lease, Right-of-Use Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Other Assets, Noncurrent
Total lease assets	$ 264	$ 549
Other current liabilities	$ 268	$ 365
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Other liabilities		$ 188
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Total lease liabilities	$ 268	$ 553

Leases - Schedule of Future Lea

Leases - Schedule of Future Lease Payments Included in Measurement of Lease Liabilities on Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Leases [Abstract]
2025	$ 279
Total	279
Less imputed interest	(11)
Total lease liabilities	$ 268	$ 553

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued payroll and bonus expenses	$ 1,770	$ 2,742
Accrued manufacturing expenses	1,484	71
Accrued other expenses	111	76
Accrued professional fees	108	37
Accrued clinical trial costs	19	4,835
Total	$ 3,492	$ 7,761

Debt - Additional Information (

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

Debt - Summary of Balances of E

Debt - Summary of Balances of Exchangeable Notes (Details) $ in Thousands	9 Months Ended	44 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
Exchangeable Notes, Conversion		$ (40,691)
Exchangeable Notes, net	$ 11,221	11,221
January 2020 $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Exchangeable Notes	51,588	51,588
Exchangeable Notes, Accrued Interest	6,397	6,397
September 2020 $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Exchangeable Notes	220	220
Exchangeable Notes, Accrued Interest	34	34
Conversion of $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Exchangeable Notes, Conversion	(40,691)
Exchangeable Notes, Accrued Interest Conversion	(3,071)	(3,071)
2025 Exchangeable Notes
Debt Instrument [Line Items]
Exchangeable Notes	11,117	11,117
Unamortized discount and debt issuance costs	(769)	(769)
Exchangeable Notes, net	10,348	10,348
Exchangeable Notes, Accrued Interest	$ 3,360	$ 3,360

Debt - Summary of Balances of_2

Debt - Summary of Balances of Exchangeable Notes (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2024 USD ($)
January 2020 $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Debt instrument price per unit	$ 1,000
Debt instrument interest rate	6.50%
Debt instrument maturity date	Jan. 31, 2025
September 2020 $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Debt instrument price per unit	$ 1,000
Debt instrument interest rate	6.50%
Debt instrument maturity date	Jan. 31, 2025
Conversion of $1,000 Exchangeable Notes due January 31, 2025
Debt Instrument [Line Items]
Debt instrument price per unit	$ 1,000
Debt instrument interest rate	6.50%
Debt instrument maturity date	Jan. 31, 2025

Debt - Schedule of Principal Pa

Debt - Schedule of Principal Payments on Outstanding Debt, Including Principal Amounts owed to RLN Holders (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Debt Disclosure [Abstract]
2025	$ 11,117
Thereafter	104
Total	$ 11,221

Royalty-Linked Notes - Addition

Royalty-Linked Notes - Additional Information (Details) - Royalty-Linked Notes			9 Months Ended
	Sep. 08, 2020 Debtinstrument	Jan. 21, 2020 Debtinstrument	Sep. 30, 2024 USD ($) UsdRln
Debt Instrument [Line Items]
Debt instrument maturity date			Dec. 31, 2045
Debt instrument outstanding portion | UsdRln			0.04
Aggregate amount payable per unit | $			$ 160
Debt instrument, aggregate potential payment capped rate			4,000
Private Placement
Debt Instrument [Line Items]
Number of debt instruments issued		2,579,400
2020 Rights Offering
Debt Instrument [Line Items]
Number of debt instruments issued	11,000

Royalty Linked Notes - Summary

Royalty Linked Notes - Summary of Royalty-Linked Notes (Details) - USD ($) $ in Thousands	47 Months Ended	56 Months Ended
	Dec. 31, 2023	Sep. 30, 2024	Sep. 08, 2020
Royalty Linked Notes [Abstract]
Total liability related to the sale of future royalties, on inception	$ 10,990	$ 10,990
Liability related to the sale of future royalties, arising from the Rights Offering			$ 51
Amortization of discount and debt issuance costs	3,666	3,666
Adjustments to fair value	(7,204)	(5,979)
Total liability related to the sale of future royalties	7,503	8,728
Long-term Portion	$ 7,503	$ 8,728

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Details)

1 Months Ended

9 Months Ended

44 Months Ended

Aug. 09, 2024 USD ($) $ / shares shares

Oct. 17, 2022 USD ($)

Oct. 07, 2022 USD ($) $ / shares

Feb. 12, 2021 $ / shares shares

Feb. 10, 2021 $ / shares shares

Feb. 08, 2021 $ / shares shares

Oct. 31, 2020 $ / shares shares

Oct. 27, 2020 $ / shares shares

Jul. 02, 2020 $ / shares shares

Jun. 05, 2020 $ / shares shares

Jun. 03, 2020 $ / shares shares

Apr. 27, 2018 $ / shares shares

Nov. 04, 2024 USD ($) $ / shares shares

Jun. 30, 2020 $ / shares shares

Sep. 30, 2024 USD ($) Vote $ / shares shares

Sep. 30, 2023 USD ($) $ / shares

Sep. 30, 2024 USD ($) $ / shares shares

Dec. 31, 2023 USD ($) $ / shares shares

May 03, 2023 $ / shares shares

Class Of Stock [Line Items]

Increase to authorized ordinary shares

60,000,000

Ordinary shares, par value | $ / shares

$ 0.01

$ 0.01

$ 0.01

$ 0.01

$ 0.01

Aggregate offering price of shares | $

$ 227,000

$ 227,000

$ 135,000

Ordinary shares, shares authorized

80,000,000

80,000,000

80,000,000

Number of vote per common share | Vote

1

Common stock rights and preferences

There are no redemption or sinking fund provisions with respect to the authorized ordinary shares.

Authorized amount for sale of stock | $

$ 100,000,000

Ordinary shares, shares issued

22,705,994

22,705,994

13,499,003

Proceeds from registered direct offerings, net of transaction costs | $

$ 12,814,000

$ 445,000

Aggregate principal amount of exchangeable notes | $

$ 40,691,000

Undesignated preferred shares, par value | $ / shares

$ 0.01

$ 0.01

$ 0.01

Undesignated preferred shares, authorized

100,000,000

100,000,000

100,000,000

Undesignated preferred shares issued

0

0

0

Sales Agreement With H.C. Wainwright

Class Of Stock [Line Items]

Ordinary shares, par value | $ / shares

$ 0.01

Subsequent Events | Sales Agreement With H.C. Wainwright

Class Of Stock [Line Items]

Number of ordinary shares sold

4,500,000

Offering price per share | $ / shares

$ 1.55

Proceeds from registered direct offerings, net of transaction costs | $

$ 6,700,000

Maximum | Sales Agreement With H.C. Wainwright

Class Of Stock [Line Items]

May offer and sell ordinary shares for aggregate gross sales proceeds | $

$ 16,000,000

2024 Rights Offering

Class Of Stock [Line Items]

Subscription price per whole unit | $ / shares

$ 1.21

Aggregate gross proceeds from rights offering | $

$ 7,400,000

Aggregate net proceeds from rights offering | $

$ 5,400,000

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”).

Number of units sold

6,121,965

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 1.21

Private Placement | Securities Purchase Agreement

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

13,868

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 31.5465

$ 24.3

Warrants expiry date

Jun. 03, 2025

Dec. 05, 2025

Warrants exercisable date

Jun. 03, 2020

Percentage of ordinary shares issued to purchase warrants

7%

Private Placement | Securities Purchase Agreement | Maximum

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

99,057

Private Placement | June 30 SPA

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

15,739

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 27.7965

$ 21.3

Warrants expiry date

Jun. 30, 2025

Jan. 02, 2026

Percentage of ordinary shares issued to purchase warrants

7%

Proceeds from exercise of warrants related to registered direct offering | $

$ 1,796,000

Warrants exercised

84,317

84,317

Private Placement | June 30 SPA | Maximum

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

112,422

October Offering

Class Of Stock [Line Items]

Proceeds from registered direct offerings, net of transaction costs | $

$ 13,885,000

Number of warrants to purchase ordinary shares

125,641

Number of warrants exercised for ordinary shares

1,392,701

1,392,701

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 12.1875

$ 9.75

Warrants expiry date

Oct. 22, 2025

Oct. 27, 2025

Percentage of ordinary shares issued to purchase warrants

7%

October Offering | Maximum

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

1,346,153

February Underwritten Offering

Class Of Stock [Line Items]

Offering closing date

Feb. 10, 2021

Feb. 08, 2021

Additional ordinary shares that can be purchased by underwriter

347,826

Number of warrants exercised for ordinary shares

25,333

25,333

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 21.5625

$ 21.5625

Warrants expiry date

Feb. 03, 2026

Feb. 03, 2026

Percentage of ordinary shares issued to purchase warrants

7%

7%

Proceeds from warrants connected to registered direct offerings | $

$ 546,000

February Underwritten Offering | Maximum

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

24,347

162,318

At-the-market agreement

Class Of Stock [Line Items]

Number of ordinary shares sold

3,055,882

Offering price per share | $ / shares

$ 2.49

$ 2.49

Proceeds from registered direct offerings, net of transaction costs | $

$ 7,400,000

February Registered Direct Offering

Class Of Stock [Line Items]

Offering closing date

Feb. 12, 2021

Number of warrants to purchase ordinary shares

81,666

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 37.5

Warrants expiry date

Feb. 09, 2026

Percentage of ordinary shares issued to purchase warrants

7%

Warrants to Purchase 19,890 Ordinary Shares | Silicon Valley Bank and Life Sciences Fund II LLC

Class Of Stock [Line Items]

Warrants expiry date

Apr. 27, 2028

1-Year Warrant | 2024 Rights Offering

Class Of Stock [Line Items]

Number of shares that can be purchased with each warrant

0.5

Number of warrants to purchase ordinary shares

3,060,982

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 1.21

$ 1.21

1.21

5-Year Warrants | 2024 Rights Offering

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

6,121,965

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 1.21

1.21

1.21

Series B Convertible Preferred Shares | Silicon Valley Bank and Life Sciences Fund II LLC

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

19,890

Warrants to purchase ordinary shares, exercise price | $ / shares

$ 282.75

Undesignated Preferred Shares

Class Of Stock [Line Items]

Undesignated preferred shares, par value | $ / shares

$ 0.01

$ 0.01

Undesignated preferred shares, authorized

100,000,000

100,000,000

Designated Preferred Shares

Class Of Stock [Line Items]

Undesignated preferred shares issued

0

0

0

Ordinary Shares | Silicon Valley Bank and Life Sciences Fund II LLC

Class Of Stock [Line Items]

Number of warrants to purchase ordinary shares

1,326

Exchangeable Notes

Class Of Stock [Line Items]

Ordinary shares, shares issued

3,760,155

3,760,155

Aggregate principal amount of exchangeable notes | $

$ 40,691,000

Aggregate principal amount | $

$ 11,117,000

11,117,000

Exchangeable Notes | Private Placement

Class Of Stock [Line Items]

Aggregate principal amount of exchangeable notes | $

$ 40,691,000

Shareholders' Equity - Summary

Shareholders' Equity - Summary of Assumptions Used to Determine Fair Value of Warrants (Details)	Aug. 09, 2024 $ / shares
1-Year Warrant
Class of Warrant or Right [Line Items]
Volatility	109%
Expected term in years	1 year
Dividend rate	0%
Risk-free interest rate	4.50%
Share price	$ 1.18
Strike price	1.21
Fair value of warrants issued	$ 0.5
5-Year Warrants
Class of Warrant or Right [Line Items]
Volatility	109%
Expected term in years	5 years
Dividend rate	0%
Risk-free interest rate	3.80%
Share price	$ 1.18
Strike price	1.21
Fair value of warrants issued	$ 0.94

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)

3 Months Ended

9 Months Ended

Nov. 24, 2021

Jun. 23, 2021

Jun. 10, 2020

Feb. 14, 2020

Dec. 05, 2018

May 18, 2017

Sep. 30, 2024

Sep. 30, 2023

Sep. 30, 2024

Sep. 30, 2023

Mar. 14, 2018

Nov. 18, 2015

Employees and Directors

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Share options granted

0

857,500

Unvested employee options outstanding

398,824

939,290

398,824

939,290

Employee Stock Option

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Expense recognized

$ 68,000

$ 123,000

$ 279,000

$ 344,000

Unamortized compensation expense share options

364,000

1,124,000

$ 364,000

$ 1,124,000

Vesting period

1 year 5 months 26 days

2 years 3 months 29 days

Risk-free interest rate based on estimate of U.S. treasury yield

7 years

Restricted Share Units (RSUs)

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Benefit recognized related to share based compensation

0

$ 5,000

Expense recognized

19,000

$ 301,000

Unamortized compensation expense

0

131,000

$ 0

$ 131,000

Stock-based compensation expense, expected weighted average period for recognition

2 years 2 months 1 day

Restricted Share Units (RSUs) | Employees and Directors

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares, granted/awarded

0

0

Restricted Share Units (RSUs) | Director

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

1 year

Options and Restricted Share Units

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

1 year 5 months 26 days

2 years 3 months 25 days

Unamortized compensation expense

$ 364,000

$ 1,255,000

$ 364,000

$ 1,255,000

2015 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares authorized

29,535

14,895

Increase in number of ordinary shares available for issuance

14,640

2018 Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares authorized

1,295,819

67,897

Increase in number of ordinary shares available to be granted, percentage

4%

4%

Increase in number of ordinary shares available to be granted

1,000,000

150,000

39,650

38,272

2018 Plan | Restricted Share Units (RSUs) | Employees

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

2 years

2021 Inducement Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Increase in number of ordinary shares available to be granted

333,333

2021 Inducement Plan | Restricted Share Units (RSUs) | Employees

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

4 years

2015 Plan, 2018 Plan and 2021 Inducement Plan | Employee Stock Option

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

4 years

Vesting rights

The vesting requirement is conditioned upon a grantee’s continued service with the Company during the vesting period. Once vested, all awards are exercisable from the date of grant until they expire. The option grants are non-transferable. Vested options generally remain exercisable for 90 days subsequent to the termination of the option holder’s service with the Company. In the event of an option holder’s disability or death while employed by or providing service to the Company, the exercisable period extends to twelve months or eighteen months, respectively.

Share option granted term

10 years

2015 Plan, 2018 Plan and 2021 Inducement Plan | Employee Stock Option | Director

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Vesting period

1 year

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee and Director Options Granted (Details)	9 Months Ended
	Sep. 30, 2023 $ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	100%
Dividend rate	0%
Risk-free interest rate, minimum	3.55%
Risk-free interest rate, maximum	3.67%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term in years	6 years
Share price	$ 1
Fair value of option on grant date	$ 0.8
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term in years	6 years 3 months
Share price	$ 1.04
Fair value of option on grant date	$ 0.84

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity (Details)	9 Months Ended
	Sep. 30, 2024 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Options outstanding Beginning Balance	1,108,988
Number of Shares, Exercised	(29,144)
Number of Shares, Forfeited	(165,856)
Number of Shares, Options outstanding Ending Balance	913,988
2015 Plan and 2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Options outstanding Beginning Balance	984,155
Number of Shares, Exercised	(29,144)
Number of Shares, Forfeited	(45,856)
Number of Shares, Options outstanding Ending Balance	909,155
Two Thousand Twenty One Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Options outstanding Beginning Balance	124,833
Number of Shares, Forfeited	(120,000)
Number of Shares, Options outstanding Ending Balance	4,833
2015 Plan, 2018 Plan and 2021 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Options outstanding Beginning Balance	1,108,988
Number of Shares, Exercised	(29,144)
Number of Shares, Forfeited	(165,856)
Number of Shares, Options outstanding Ending Balance	913,988

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Compensation Related Costs [Abstract]
Number of Shares, Options outstanding Beginning Balance	1,108,988
Number of Shares, Exercised	(29,144)
Number of Shares, Forfeited	(165,856)
Number of Shares, Options outstanding Ending Balance	913,988	1,108,988
Number of Shares, Exercisable at September 30, 2024	515,164
Weighted Average Exercise Price, Options outstanding Beginning Balance	$ 2.73
Weighted Average Exercise Price, Exercised	1
Weighted Average Exercise Price, Forfeited	5.54
Weighted Average Exercise Price, Options outstanding Ending Balance	2.28	$ 2.73
Weighted Average Exercise Price, Exercisable at September 30, 2024	$ 3.17
Weighted Average Remaining Contractual Life in Years, Options outstanding	8 years 3 months 21 days	8 years 11 months 8 days
Weighted Average Remaining Contractual Life in Years, Exercisable at September 30, 2024	8 years 2 months 4 days
Aggregate Intrinsic Value, Options outstanding	$ 832
Aggregate Intrinsic Value, Options outstanding	70	$ 832
Aggregate Intrinsic Value, Exercisable at September 30, 2024	$ 35

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Number of RSUs Granted (Details) - Restricted Share Units (RSUs)	9 Months Ended
	Sep. 30, 2024 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, outstanding Beginning Balance	16,666
Number of Shares, Forfeited	(16,666)
Two Thousand Twenty One Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, outstanding Beginning Balance	16,666
Number of Shares, Forfeited	(16,666)
2015 Plan, 2018 Plan and 2021 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, outstanding Beginning Balance	16,666
Number of Shares, Forfeited	(16,666)

Share-Based Compensation - Su_4

Share-Based Compensation - Summary of Number of RSUs Outstanding and Weighted-average Grant Date Fair Value of RSUs (Details) - Restricted Share Units (RSUs)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, outstanding Beginning Balance | shares	16,666
Number of Shares, Forfeited | shares	(16,666)
Weighted average grant date fair value per share, outstanding Beginning Balance | $ / shares	$ 7.26
Weighted Average grant date fair value per share, Forfeited | $ / shares	$ 7.26

Share-Based Compensation - Su_5

Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 25	$ 96	$ 147	$ 315
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 43	$ 46	$ 127	$ 330

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Income Tax [Line Items]
Income tax expense	$ 136	$ 161	$ 215	$ 471
Ireland
Income Tax [Line Items]
Net operating loss carryforwards	$ 44,057		$ 44,057		$ 41,525

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Details)				9 Months Ended
	Sep. 08, 2020 Debtinstrument	Jan. 21, 2020 Debtinstrument	Nov. 18, 2015 USD ($)	Sep. 30, 2024 USD ($) UsdRln
Royalty-Linked Notes
Other Commitments [Line Items]
Debt instrument outstanding portion | UsdRln				0.04
Debt instrument maturity date				Dec. 31, 2045
Debt instrument price per unit				$ 160
Debt instrument, aggregate potential payment capped rate				4,000
Royalty-Linked Notes | Private Placement
Other Commitments [Line Items]
Number of debt instruments issued | Debtinstrument		2,579,400
Royalty-Linked Notes | 2020 Rights Offering
Other Commitments [Line Items]
Number of debt instruments issued | Debtinstrument	11,000
Pfizer License Agreement
Other Commitments [Line Items]
Regulatory milestone payments upon approval of product			$ 20,000,000
Regulatory and sales milestone deferred payment period			2 years
Pfizer License Agreement | Minimum
Other Commitments [Line Items]
Regulatory and sales milestone payments upon achievement of net sales.			$ 250,000,000
Pfizer License Agreement | Maximum
Other Commitments [Line Items]
Regulatory and sales milestone payments upon achievement of net sales.			$ 1,000,000,000

Condensed Consolidating Finan_2

Condensed Consolidating Financial Statements - Additional Information (Details)	Sep. 08, 2020 USD ($) Debtinstrument	Jan. 21, 2020 USD ($) Debtinstrument	Sep. 30, 2024 USD ($)
Iterum Therapeutics Bermuda Limited
Condensed Financial Statements Captions [Line Items]
Ownership percentage		100%
Subsidiary Guarantors
Condensed Financial Statements Captions [Line Items]
Ownership percentage		100%
2025 Exchangeable Notes
Condensed Financial Statements Captions [Line Items]
Aggregate principal amount		$ 9,891,000	$ 11,117,000
Private Placement | 2025 Exchangeable Notes
Condensed Financial Statements Captions [Line Items]
Aggregate principal amount		51,588,000
Debt instrument price per unit		1,000
Private Placement | RLNs
Condensed Financial Statements Captions [Line Items]
Aggregate principal amount		$ 103,000
Number of debt instruments within each notes | Debtinstrument	50	50
Rights Offering | 2025 Exchangeable Notes
Condensed Financial Statements Captions [Line Items]
Aggregate principal amount	$ 220,000
Rights Offering | RLNs
Condensed Financial Statements Captions [Line Items]
Aggregate principal amount	$ 440

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	9 Months Ended
	Oct. 28, 2024	Nov. 18, 2015	Nov. 04, 2024	Sep. 30, 2024	Sep. 30, 2023
Subsequent Event [Line Items]
Proceeds from issuance of ordinary shares, net of transaction costs				$ 12,814	$ 445
Pfizer License Agreement
Subsequent Event [Line Items]
Regulatory milestone payments upon approval of product		$ 20,000
Regulatory and sales milestone deferred payment annual rate		8%
Subsequent Events | Pfizer License Agreement
Subsequent Event [Line Items]
Regulatory milestone deferred/intends to defer payment period	2 years
Subsequent Events | Sales Agreement With H.C. Wainwright
Subsequent Event [Line Items]
Number of ordinary shares sold			4,500,000
Offering price per share			$ 1.55
Proceeds from issuance of ordinary shares, net of transaction costs			$ 6,700