Iterum Therapeutics (ITRM) 10-Q 14 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	ITRM
Entity Registrant Name	Iterum Therapeutics plc
Entity Central Index Key	1,659,323
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		14,159,423

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 84,901	$ 8,485
Short-term investments	50,370	30,731
Prepaid expenses and other current assets	6,442	4,957
Total current assets	141,713	44,173
Property and equipment, net	735	747
Restricted cash	120
Other assets	2,902	1,837
Total assets	145,470	46,757
Current liabilities:
Accounts payable	8,169	3,152
Accrued expenses	4,121	3,974
Total current liabilities	12,290	7,126
Long-term debt	14,505
Other liabilities	145	80
Total liabilities	26,940	7,206
Commitments and contingencies (Note 11)
Shareholders’ equity:
Ordinary shares, $0.01 par value per share: 44,557,606 shares authorized, 14,159,423 shares issued at June 30,2018; 7,956,715 shares authorized 413,110 shares issued at December 31, 2017	142	4
Additional paid-in capital	201,018	94,227
Accumulated deficit	(82,630)	(54,737)
Total shareholders' equity	118,530	39,494
Total liabilities, convertible preferred shares and shareholders’ equity	$ 145,470	46,757
Series A Convertible Preferred Shares
Current liabilities:
Convertible preferred shares		30
Series B Convertible Preferred Shares
Current liabilities:
Convertible preferred shares		$ 27

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Ordinary shares, par value	$ 0.01	$ 0.01
Ordinary shares, shares authorized	44,557,606	7,956,715
Ordinary shares, shares issued	14,159,423	413,110
Series A Convertible Preferred Shares
Temporary equity, par value	$ 0.01	$ 0.01
Temporary equity, shares authorized	3,032,463	3,032,463
Temporary equity, shares issued	0	3,032,457
Series B Convertible Preferred Shares
Temporary equity, par value	$ 0.01	$ 0.01
Temporary equity, shares authorized	4,801,493	3,696,943
Temporary equity, shares issued	0	2,654,206

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 185		$ 376
Operating expenses:
Research and development	(13,725)	$ (5,290)	(24,604)	$ (9,824)
General and administrative	(1,886)	(1,123)	(3,401)	(2,131)
Total operating expenses	(15,611)	(6,413)	(28,005)	(11,955)
Operating loss	(15,426)	(6,413)	(27,629)	(11,955)
Interest (expense) / income, net	(76)	46	9	46
Other (expense) / income, net	(177)	165	(116)	97
Total other (expense) / income	(253)	211	(107)	143
Loss before income taxes	(15,679)	(6,202)	(27,736)	(11,812)
Income tax expense	(68)	(78)	(157)	(305)
Net loss and comprehensive loss	(15,747)	(6,280)	(27,893)	(12,117)
Net loss attributable to ordinary shareholders	$ (15,747)	$ (6,280)	$ (27,893)	$ (12,117)
Net loss per share attributable to ordinary shareholders – basic and diluted	$ (2.22)	$ (39.44)	$ (6.72)	$ (82.82)
Weighted average ordinary shares outstanding – basic and diluted	7,085,655	159,221	4,148,535	146,311

Consolidated Statements of Cash

Consolidated Statements of Cash flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (27,893)	$ (12,117)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	64	14	$ 65
Share-based compensation expense	404	180
Non-cash (loss) / gain on short term investments	(62)	20
Interest on short-term investments	(71)	(97)
Amortization of debt discount and deferred financing costs	138
Other	245
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,563)	(3,165)
Other assets	(1,065)	(584)
Accounts payable	5,014	624
Accrued expenses	94	(242)
Income taxes	60	239
Other liabilities	65	84
Net cash used in operating activities	(24,570)	(15,044)
Cash flows from investing activities:
Purchases of property and equipment	(53)	(612)
Purchases of short-term investments	(53,727)	(33,785)
Proceeds from sale of short-term investments	34,150
Net cash used in investing activities	(19,630)	(34,397)
Cash flows from financing activities:
Proceeds from issuance of debt, net of debt issuance costs	14,507
Proceeds from issuance of ordinary shares, net of issuance costs	74,155
Net cash provided by financing activities	120,835	45,867
Effect of exchange rates on cash and cash equivalents	(99)
Net increase / (decrease) in cash, cash equivalents and restricted cash	76,536	(3,574)
Cash, cash equivalents and restricted cash, at beginning of period	8,485	24,809	24,809
Cash, cash equivalents and restricted cash, at end of period	85,021	21,235	$ 8,485
Series B Convertible Preferred Shares
Cash flows from financing activities:
Proceeds from issuance of Series B convertible preferred shares	$ 32,173	$ 45,867

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation Iterum Therapeutics plc (the “Company”) was incorporated under the laws of the state of Ireland in June 2015 as a limited company and reregistered as a public limited company on March 20, 2018. The Company maintains its registered office at Block 2 Floor 3, Harcourt Centre, Harcourt Street, 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 a clinical-stage pharmaceutical company dedicated to developing and commercializing sulopenem to be the first and only oral and intravenous (“IV”) branded penem available globally. 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”) and a sub-award from the Trustees of Boston University under the Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (“CARB-X”) program . 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, failure to successfully develop and commercialize its product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval prior to commercialization. Even if the Company’s product development efforts are successful, 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. On May 15, 2018, the Company’s shareholders approved a consolidation of its ordinary shares and convertible preferred shares at a 1-for-15.71 ratio (the “Reverse Share Split”), effective on that date. Fractional entitlements to ordinary shares and convertible preferred shares arising as a result of the Reverse Share Split were rounded down to the nearest whole number for each holder of ordinary shares and convertible preferred shares. Those fractional entitlements were aggregated and surrendered to the Company for cancellation. Immediately following the Reverse Share Split, the Company redenominated its ordinary shares and convertible preferred shares from $0.01571 (the nominal value resulting from the Reverse Share Split) per share to $0.01 per share (the “Renominalisation”). All issued and outstanding ordinary shares, convertible preferred shares, options for ordinary shares, restricted stock awards, warrants and per share amounts have been retroactively adjusted to reflect this Reverse Share Split and Renominalisation for all periods presented. On May 30, 2018, the Company completed an initial public offering (“IPO”) of its ordinary shares, and issued and sold 6,150,000 ordinary shares at a public offering price of $13.00 per share, resulting in net proceeds of $71.8 million after deducting underwriting discounts and commissions and offering costs payable by the Company. On June 26, 2018, the Company issued and sold an additional 200,000 ordinary shares at the IPO price of $13.00 per share pursuant to the underwriters’ partial exercise of their option to purchase additional ordinary shares, resulting in additional net proceeds of $2.4 million after deducting underwriting discounts and commissions and costs payable by the Company. Aggregate net proceeds from the IPO totaled $74.2 million after deducting underwriting discounts and commissions and offering costs. 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 incurred operating losses since inception, including net losses of $27,893 and $12,117 for the six month periods ended June 30, 2018 and June 30, 2017, respectively, and a net loss of $29,406 for the year ended December 31, 2017. The Company had an accumulated deficit of $82,630 as of June 30, 2018. The Company expects to continue to incur net losses for the next several years and is highly dependent on its ability to find additional sources of funding in the form of debt or equity financing to fund its operations. Management believe that its cash and cash equivalents balance of $84,901 and short-term investments balance of $50,370 at June 30, 2018, are sufficient to fund operations through the fourth quarter of 2019. In making this assessment management have considered the Company’s available cash resources, the $15.0 million available under the secured credit facility with SVB, future financing options available to the Company, the planned operations of the Company and the ability to adjust its plans if required. The Company will then seek additional funding through public or private financing of debt or equity or collaboration agreements. There can be no assurances, however, that the current operating plan will be achieved or that additional funding will be available on terms acceptable to the Company, or at all. Interim Financial Information The condensed consolidated balance sheet at December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed consolidated financial statements as of June 30, 2018, and for six months ended June 30, 2018 and 2017, 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, 2017, included in the Company’s final prospectus for its initial public offering filed pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended (the “Securities Act”) with the SEC on May 25, 2018. 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 June 30, 2018, and results of operations for the six months ended June 30, 2018 and 2017, and cash flows for the six months ended June 30, 2018 and 2017 have been made. The results of operations for the six months ended June 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies 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 and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual for research and development expenses, revenue from grant awards, the valuation of restricted ordinary shares and the valuation of share-based compensation awards. 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. 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 The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding as they would be anti-dilutive: Six months ended June 30, 2018 June 30, 2017 Options to purchase ordinary shares 696,112 66,832 Preferred shares convertible into ordinary shares — 5,686,667 Unvested restricted ordinary shares 143,076 246,282 Unvested restricted stock units 36,924 — Warrants 19,890 — Total 896,002 5,999,781 Segment Information The Company determines and presents operating segments based on the information that is internally provided to the Chief Executive Officer, Chief Scientific Officer, Chief Financial Officer and Chief Commercial Officer, who together are considered the Company’s chief operating decision maker, in accordance with ASC 280, Segment Reporting The distribution of total operating expenses by geographical area was as follows: Three months ended June 30, Six months ended June 30, Operating expenses 2018 2017 2018 2017 Ireland $ 12,811 $ 5,205 $ 22,775 $ 9,674 U.S. 2,800 1,208 5,230 2,281 Total $ 15,611 $ 6,413 $ 28,005 $ 11,955 The distribution of long-lived assets by geographical area was as follows: Long lived assets June 30, 2018 December 31, 2017 Ireland $ 3,388 $ 2,341 U.S. 369 243 Total $ 3,757 $ 2,584 Recent Accounting Pronouncements In July 2017, the Financial Accounting Standards Board ( Earnings Per Share Distinguishing Liabilities from Equity Derivatives and Hedging Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred shares that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within ASC Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. ASU 2017-11 is required to be adopted for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The adoption of ASU 2017-11 is not expected to have a significant impact on the consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases

Fair Value of Financial Assets

Fair Value of Financial Assets	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets	3. Fair Value of Financial Assets The following table presents information about the Company’s financial assets that have been measured at fair value at December 31, 2017 and June 30, 2018 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value. June 30, 2018 Assets Total Level 1 Level 2 Level 3 Short-term investments $ 50,370 $ 50,370 — — Other asset – advance payment to supplier 1,728 — — 1,728 Total $ 52,098 50,370 — 1,728 December 31, 2017 Assets Total Level 1 Level 2 Level 3 Short-term investments $ 30,731 30,731 — — Other asset – advance payment to supplier 1,472 — — 1,472 Total $ 32,203 30,731 — 1,472 See Note 4 for further details on the short-term investments held. The other asset above relates to advance payments made to a supplier that were recorded at fair value using the discounted cash flow model (DCF), as of December 31, 2017 and June 30, 2018. Key assumptions used in the DCF include a discount rate of 15% and the expected time to recovery of the payment. See Note 11—Payments to Supplier, for further details on these advance payments. As of June 30, 2018, the estimated fair value of our borrowings under our term loan with SVB was approximately equal to its book value based on the borrowing rates currently available for variable rate loans (Level 2).

Short Term Investments

Short Term Investments	6 Months Ended
	Jun. 30, 2018
Available For Sale 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 period-ends consist of U.S. Treasury and agency bonds and corporate entity commercial paper with maturities of more than three months but less than one year at the date of purchase. Short-term investments as of June 30, 2018 have an average maturity of 0.41 years. The investments are reported at fair value with unrealized gains or losses recorded in the consolidated statements of operations and comprehensive loss. Any differences between the cost and fair value of investments are represented by unrealized gains or losses. The fair value of short-term investments are represented by Level 1 fair value measurements – quoted prices in active markets for identical assets. The following table represents the Company’s available for sale short-term investments by major security type as of June 30, 2018 and December 31, 2017: June 30, 2018 Maturity by period Unrealized Unrealized Fair Value Less than 1 Available for sale Cost Total gains (losses) Total year 1 to 5 years Commercial paper $ 47,831 58 (3 ) 47,886 47,886 — U.S. Treasury and Agency Bonds 2,477 7 — 2,484 2,484 — Total $ 50,308 65 (3 ) 50,370 50,370 — December 31, 2017 Maturity by period Unrealized Unrealized Fair Value Less than 1 Available for sale Cost Total gains (losses) Total year 1 to 5 years Commercial paper $ 22,538 8 (27 ) 22,519 22,519 — U.S. Treasury and Agency Bonds 8,205 18 (11 ) 8,212 8,212 — Total $ 30,743 26 (38 ) 30,731 30,731 —

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	6 Months Ended
	Jun. 30, 2018
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: June 30, 2018 December 31, 2017 Prepaid research and development expenses $ 3,165 $ 2,289 Short-term deposits 1,195 1,346 Other prepaid assets 595 516 Value added tax receivable 592 281 Deferred IPO expenses - 180 Research and development tax credit receivable 130 133 Prepaid insurance 598 117 Interest receivable 167 95 Total $ 6,442 $ 4,957

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Property and Equipment	6. Property and Equipment Property and equipment and related accumulated depreciation are as follows: June 30, 2018 December 31, 2017 Leasehold improvements $ 592 $ 579 Furniture and fixtures 118 108 Laboratory equipment 81 81 Computer equipment 73 44 864 812 Less: accumulated depreciation (129 ) (65 ) $ 735 $ 747 Depreciation expense was $64 for the six month period ended June 30, 2018 and $65 for the year ended December 31, 2017.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2018
Payables And Accruals [Abstract]
Accrued Expenses	7. Accrued Expenses Accrued expenses consist of the following: June 30, 2018 December 31, 2017 Accrued clinical trial costs $ 2,025 $ 594 Accrued manufacturing expenses 851 2,031 Accrued payroll and bonus expenses 920 1,059 Accrued other expenses 325 290 Total $ 4,121 $ 3,974

Shareholders_ Equity

Shareholders’ Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Shareholders’ Equity	8. Shareholders’ Equity The following tables present a reconciliation of our beginning and ending balances in shareholders’ equity for the six months ended June 30, 2018 and 2017: Total Shareholders' Equity Shareholders' equity at January 1, 2018 $ 39,494 Issuance of Series B convertible preferred shares 32,159 Issuance of ordinary shares 74,153 Conversion of preferred shares to ordinary shares 74 Share-based compensation expense 404 Issuance of warrants 139 Net loss (27,893 ) Shareholders' equity at June 30, 2018 $ 118,530 Total Shareholders' Equity Shareholders' equity at January 1, 2017 $ 22,668 Issuance of Series B convertible preferred shares 45,840 Share-based compensation expense 180 Net loss (12,117 ) Shareholders' equity at June 30, 2017 $ 56,571

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	9. Share-Based Compensation The Company’s Board of Directors adopted and approved the 2015 Equity Incentive Plan in November 2015 (“the 2015 Plan”). The 2015 Plan was amended most recently in May 2017. The 2015 Plan provides for the grant of incentive stock options, nonstatutory stock options, restricted stock awards, restricted stock units, stock appreciation rights, and other stock awards to our employees, directors and consultants. On March 14, 2018, the Company’s Board of Directors adopted and approved the 2018 Equity Incentive Plan (the “2018 Plan”), which became effective on the execution and delivery of the underwriting agreement related to the IPO. The 2018 Plan authorizes the Company to grant up to 1,018,459 ordinary shares in the form of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, performance stock awards, performance cash awards and other stock awards. The types of share-based awards, including share purchase rights amount, terms, and exercisability provisions of grants are determined by the Company’s Board of Directors. Since Restricted Ordinary Shares In connection with the Company’s formation, 413,110 restricted ordinary shares were issued on October 14, 2015 to the Company’s founders at par value. These ordinary shares are subject to various restrictions pursuant to ordinary share purchase agreements between the Company and each founder, including restrictions on transfer and a Company right of repurchase. The restricted ordinary shares were 25% vested as of October 14, 2016 and 1/36th of the remaining restricted ordinary shares vest on a monthly basis thereafter (subject to acceleration of vesting in connection with certain change of control transactions). A change in status occurred on November 18, 2015 when the founders became employees of the Company. The grant date of these shares is now considered to be November 18, 2015 when the fair value was $3.14 per share. The Company recorded an expense of $165 and $165 for the restricted ordinary shares for the six month periods ended June 30, 2018 and June 30, 2017, respectively. Total unamortized compensation expense related to restricted ordinary shares was $428 and $761 as of June 30, 2018 and June 30, 2017, respectively, expected to be recognized over a weighted average period of 1.38 years and 2.38 years as of June 30, 2018 and June 30, 2017, respectively. The following table summarizes restricted ordinary shares activity for the six months ended June 30, 2018: Number of Weighted Average grant date fair Shares value per share Unvested at December 31, 2017 189,342 $ 3.14 Granted — Vested (46,266 ) $ 3.14 Forfeited — Unvested at June 30, 2018 (unaudited) 143,076 $ 3.14 Stock Options The Company awarded 447,984 stock options to employees and directors for the six month period ended June 30, 2018 under the 2018 Plan. The Company awarded 17,502 stock options to employees and directors during the six month period ended June 30, 2017 under the 2015 Plan. There were 663,916 and 56,596 unvested employee options outstanding as of June 30, 2018 and June 30, 2017, respectively. Total expense recognized related to the employee stock options was $189 and $15 for the six month periods ended June 30, 2018 and June 30, 2017, respectively. Total unamortized compensation expense related to employee stock options was $3,549 and $95 as of June 30, 2018 and June 30, 2017, respectively, which is expected to be recognized over a remaining average vesting period of 3.71 years and 3.28 years as of June 30, 2018 and June 30, 2017, respectively. The assumptions that the Company used to determine the grant date fair value of employee and director options granted were as follows, presented on a weighted average basis: Six months ended June 30, 2018 2017 Volatility 60 % 60 % Expected term in years 6.25 6.25 Dividend rate 0 % 0 % Risk-free interest rate 2.16 % 1.63 % Share price $12.20 - $13.00 $ 3.30 Fair value of option on grant date $7.03 - $7.49 $ 1.88 The following table summarizes the number of options outstanding and the weighted-average exercise price: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value (in thousands) Options outstanding December 31, 2017 248,128 $ 3.31 9.44 Granted 447,984 12.99 9.92 Exercised — Forfeited — Options outstanding June 30, 2018 696,112 $ 9.54 9.57 1,825 Vested at June 30, 2018 (unaudited) 32,196 Exercisable at June 30, 2018 (unaudited) 32,196 $ 3.17 8.15 766 Restricted stock units (RSUs) The Company granted 36,924 RSUs to directors for the six month period ended June 30, 2018. No RSUs were awarded for the six month period ended June 30, 2017. The table below shows the number of RSUs granted covering an equal number of our ordinary shares and the weighted-average grant date fair value of the RSUs granted: Number of Shares Weighted average grant date fair value per share RSUs outstanding December 31, 2017 — Granted 36,924 $ 13.00 Shares vested — Forfeited — RSUs outstanding June 30, 2018 36,924 $ 13.00 The fair value of the RSUs is determined on the date of grant based on the market price of our ordinary shares on that date. The fair value of RSUs is expensed ratably over the vesting period, which is generally one year for directors. Total expense recognized related to the RSUs was $50 for the period ended June 30, 2018. Total unamortized compensation expense related to RSUs was $431 as of June 30, 2018, which is expected to be recognized over a remaining average vesting period of 0.9 years as of June 30, 2018. The Company’s share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) Research and development expense $ 118 $ 42 $ 197 $ 85 General and administrative expense 149 48 207 95 There was a total of $4,408 and $856 unamortized share-based compensation expense for restricted ordinary shares, options and restricted stock units as of June 30, 2018 and June 30, 2017, respectively, which is expected to be recognized over a remaining average vesting period of 3.21 years and 2.48 years as of June 30, 2018 and June 30, 2017, respectively.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes In accordance with the FASB ASC Topic No. 270 “ Interim Reporting” “Income Taxes” (Topic No. 740) 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 June 30, 2018, and December 31, 2017, the company has net operating loss carryforwards in Ireland of approximately $8,886 and $5,409 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	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies Operating Leases In June 2018, the Company entered into an operating lease agreement for a commercial unit in Dublin for a period of 20 years with a 10 year break option, that commenced in June 2018. Annual lease payments are $321, subject to certain escalations at each five year interval. Under the terms of the lease, the Company provided a security deposit of $818 to the landlord, which is included in other assets in the accompanying balance sheet. In March 2018, the Company entered into an operating lease agreement for office space in Chicago for a period of five years that commenced in June 2018. Annual lease payments are $258, subject to certain escalations, with a renewal option to extend the lease for an additional five years. Under the terms of the lease, the Company provided a security deposit in the form of a letter of credit for the benefit of the landlord in the amount of $120 which amount will be reduced incrementally over the term of the lease. The letter of credit outstanding is collateralized with a certificate of deposit. In April 2017, the Company entered into an operating lease agreement for office space in Connecticut for a period of five years that commenced in July 2017. Annual lease payments are $131, subject to certain escalations, with a renewal option to extend the lease for an additional three years. Under the terms of the lease, the Company provided a security deposit of $17 to the landlord, which is included in other assets in the accompanying consolidated balance sheets. In December 2016, the Company entered into an operating lease agreement for office space in Dublin that commenced on December 1, 2016 and expires on December 1, 2026. The lease requires annual payments of $375 over the ten-year term with a renewal option to extend the lease for an additional five years. Under the terms of the lease, the Company provided a security deposit of $338 to the landlord, which is included in other assets in the accompanying consolidated balance sheets. The lease is subject to a review in December 2022. The following table summarizes the future minimum payments due under the operating leases as of June 30, 2018: Year Ending December 31, (unaudited) 2018 (remaining) $ 402 2019 962 2020 1,078 2021 1,088 2022 1,030 Thereafter 3,255 $ 7,815 License Agreement On November 18, 2015, the Company entered into a license agreement with Pfizer for the worldwide exclusive rights to research, develop, manufacture and commercialize sulopenem. As part of the license agreement, the Company is obligated to pay Pfizer potential future regulatory milestone payments, as well as sales milestones upon achievement of net sales ranging from $250.0 million to $1.0 billion for each product type. The Company is also obligated to pay Pfizer royalties ranging from a single-digit to mid-teens percentage based on marginal net sales of each licensed product. Payments to Supplier In June 2016, the Company entered into an agreement with a supplier whereby the Company would pay $2,923 to the supplier to acquire equipment which will be used solely to manufacture product for the Company. In June 2018, the Company entered into a supplemental agreement with this supplier whereby the Company would pay an additional $2,397 under the same terms as the original agreement. These payments will be offset against the price of the product to be supplied under a future supply agreement. $2,397 and $599 remained outstanding to the supplier as of June 30, 2018 and December 31, 2017, respectively. 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 is not currently involved in any legal matters arising in the normal 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” or due to “permanent disability”, or upon “resignation for good reason”, contingent upon the named executive officer’s delivery to the Company.

Debt

Debt	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt	12. Debt On April 27, 2018, the Company’s subsidiaries, Iterum Therapeutics International Limited, Iterum Therapeutics US Holding Limited and Iterum Therapeutics US Limited, entered into a Loan and Security Agreement with SVB and made an initial draw of $15,000 on closing. A second draw of up to $15,000 will be available to the Company through October 31, 2019, upon satisfaction of either (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 (cUTI) trials, as well as reporting satisfactory safety data from the trials. The initial draw requires monthly amortization payments commencing on November 1, 2019; however this will extend to April 1, 2020 if the second draw is funded. Interest will accrue at a floating per annum rate equal to the greater of (i) 8.31%; or (ii) 3.89% above the Wall Street Journal prime rate, and is payable monthly in arrears. All outstanding principal, plus a 4.2% final interest payment, will be due and payable on March 1, 2022. Voluntary prepayments will be permitted at any time, subject to a prepayment fee of 3% in the first year, 2% in the second year, and 1% thereafter. In connection with the initial $15,000 draw, the Company issued to SVB and Life Sciences Fund II LLC (LSF) warrants to purchase an aggregate of 19,890 Series B convertible preferred shares (which converted to ordinary shares upon the Company’s IPO) at an exercise price of $18.85 per share. On the funding date of the second term loan, each of SVB and LSF will be automatically entitled to purchase additional ordinary shares in an aggregate amount equal to 2.5% of the second term loan divided by the applicable exercise price. The loan proceeds were allocated based on the relative fair values of the debt instrument and the warrant instrument. The fair value of the warrants and the closing costs were recorded as debt discounts and are being amortized using the effective interest rate method over the term of the loan. Amortization of the debt discount was $138 for the six months ended June 30, 2018. Scheduled principal payments on outstanding debt, as of June 30, 2018, are as follows: Year Ending December 31, (unaudited) 2018 (remaining) — 2019 1,552 2020 6,207 2021 6,207 2022 1,034 $ 15,000

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events The Company initiated its Phase 3 uUTI clinical trial, known as SU R E

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Going concern	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 incurred operating losses since inception, including net losses of $27,893 and $12,117 for the six month periods ended June 30, 2018 and June 30, 2017, respectively, and a net loss of $29,406 for the year ended December 31, 2017. The Company had an accumulated deficit of $82,630 as of June 30, 2018. The Company expects to continue to incur net losses for the next several years and is highly dependent on its ability to find additional sources of funding in the form of debt or equity financing to fund its operations. Management believe that its cash and cash equivalents balance of $84,901 and short-term investments balance of $50,370 at June 30, 2018, are sufficient to fund operations through the fourth quarter of 2019. In making this assessment management have considered the Company’s available cash resources, the $15.0 million available under the secured credit facility with SVB, future financing options available to the Company, the planned operations of the Company and the ability to adjust its plans if required. The Company will then seek additional funding through public or private financing of debt or equity or collaboration agreements. There can be no assurances, however, that the current operating plan will be achieved or that additional funding will be available on terms acceptable to the Company, or at all.
Interim Financial Information	Interim Financial Information The condensed consolidated balance sheet at December 31, 2017 was derived from audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed consolidated financial statements as of June 30, 2018, and for six months ended June 30, 2018 and 2017, 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, 2017, included in the Company’s final prospectus for its initial public offering filed pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended (the “Securities Act”) with the SEC on May 25, 2018. 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 June 30, 2018, and results of operations for the six months ended June 30, 2018 and 2017, and cash flows for the six months ended June 30, 2018 and 2017 have been made. The results of operations for the six months ended June 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018.
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 and the reported amounts of expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual for research and development expenses, revenue from grant awards, the valuation of restricted ordinary shares and the valuation of share-based compensation awards. 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.
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 The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding as they would be anti-dilutive: Six months ended June 30, 2018 June 30, 2017 Options to purchase ordinary shares 696,112 66,832 Preferred shares convertible into ordinary shares — 5,686,667 Unvested restricted ordinary shares 143,076 246,282 Unvested restricted stock units 36,924 — Warrants 19,890 — Total 896,002 5,999,781
Segment Information	Segment Information The Company determines and presents operating segments based on the information that is internally provided to the Chief Executive Officer, Chief Scientific Officer, Chief Financial Officer and Chief Commercial Officer, who together are considered the Company’s chief operating decision maker, in accordance with ASC 280, Segment Reporting The distribution of total operating expenses by geographical area was as follows: Three months ended June 30, Six months ended June 30, Operating expenses 2018 2017 2018 2017 Ireland $ 12,811 $ 5,205 $ 22,775 $ 9,674 U.S. 2,800 1,208 5,230 2,281 Total $ 15,611 $ 6,413 $ 28,005 $ 11,955 The distribution of long-lived assets by geographical area was as follows: Long lived assets June 30, 2018 December 31, 2017 Ireland $ 3,388 $ 2,341 U.S. 369 243 Total $ 3,757 $ 2,584
Recent Accounting Pronouncements	Recent Accounting Pronouncements In July 2017, the Financial Accounting Standards Board ( Earnings Per Share Distinguishing Liabilities from Equity Derivatives and Hedging Part I applies to entities that issue financial instruments such as warrants, convertible debt or convertible preferred shares that contain down-round features. Part II replaces the indefinite deferral for certain mandatorily redeemable noncontrolling interests and mandatorily redeemable financial instruments of nonpublic entities contained within ASC Topic 480 with a scope exception and does not impact the accounting for these mandatorily redeemable instruments. ASU 2017-11 is required to be adopted for annual periods beginning after December 15, 2018, including interim periods within those fiscal years. The adoption of ASU 2017-11 is not expected to have a significant impact on the consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding	The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding as they would be anti-dilutive: Six months ended June 30, 2018 June 30, 2017 Options to purchase ordinary shares 696,112 66,832 Preferred shares convertible into ordinary shares — 5,686,667 Unvested restricted ordinary shares 143,076 246,282 Unvested restricted stock units 36,924 — Warrants 19,890 — Total 896,002 5,999,781
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 June 30, Six months ended June 30, Operating expenses 2018 2017 2018 2017 Ireland $ 12,811 $ 5,205 $ 22,775 $ 9,674 U.S. 2,800 1,208 5,230 2,281 Total $ 15,611 $ 6,413 $ 28,005 $ 11,955
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 June 30, 2018 December 31, 2017 Ireland $ 3,388 $ 2,341 U.S. 369 243 Total $ 3,757 $ 2,584

Fair Value of Financial Assets

Fair Value of Financial Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value	The following table presents information about the Company’s financial assets that have been measured at fair value at December 31, 2017 and June 30, 2018 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value. June 30, 2018 Assets Total Level 1 Level 2 Level 3 Short-term investments $ 50,370 $ 50,370 — — Other asset – advance payment to supplier 1,728 — — 1,728 Total $ 52,098 50,370 — 1,728 December 31, 2017 Assets Total Level 1 Level 2 Level 3 Short-term investments $ 30,731 30,731 — — Other asset – advance payment to supplier 1,472 — — 1,472 Total $ 32,203 30,731 — 1,472

Short Term Investments (Tables)

Short Term Investments (Tables)	6 Months Ended
	Jun. 30, 2018
Available For Sale Securities [Abstract]
Schedule of Available for Sale Short-term Investments by Major Security Types	The following table represents the Company’s available for sale short-term investments by major security type as of June 30, 2018 and December 31, 2017: June 30, 2018 Maturity by period Unrealized Unrealized Fair Value Less than 1 Available for sale Cost Total gains (losses) Total year 1 to 5 years Commercial paper $ 47,831 58 (3 ) 47,886 47,886 — U.S. Treasury and Agency Bonds 2,477 7 — 2,484 2,484 — Total $ 50,308 65 (3 ) 50,370 50,370 — December 31, 2017 Maturity by period Unrealized Unrealized Fair Value Less than 1 Available for sale Cost Total gains (losses) Total year 1 to 5 years Commercial paper $ 22,538 8 (27 ) 22,519 22,519 — U.S. Treasury and Agency Bonds 8,205 18 (11 ) 8,212 8,212 — Total $ 30,743 26 (38 ) 30,731 30,731 —

Prepaid Expenses and Other Cu23

Prepaid Expenses and Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2018
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: June 30, 2018 December 31, 2017 Prepaid research and development expenses $ 3,165 $ 2,289 Short-term deposits 1,195 1,346 Other prepaid assets 595 516 Value added tax receivable 592 281 Deferred IPO expenses - 180 Research and development tax credit receivable 130 133 Prepaid insurance 598 117 Interest receivable 167 95 Total $ 6,442 $ 4,957

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment and Related Accumulated Depreciation	Property and equipment and related accumulated depreciation are as follows: June 30, 2018 December 31, 2017 Leasehold improvements $ 592 $ 579 Furniture and fixtures 118 108 Laboratory equipment 81 81 Computer equipment 73 44 864 812 Less: accumulated depreciation (129 ) (65 ) $ 735 $ 747

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2018
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following: June 30, 2018 December 31, 2017 Accrued clinical trial costs $ 2,025 $ 594 Accrued manufacturing expenses 851 2,031 Accrued payroll and bonus expenses 920 1,059 Accrued other expenses 325 290 Total $ 4,121 $ 3,974

Shareholders_ Equity (Tables)

Shareholders’ Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Reconciliation of Beginning and Ending Balances in Shareholders' Equity	The following tables present a reconciliation of our beginning and ending balances in shareholders’ equity for the six months ended June 30, 2018 and 2017: Total Shareholders' Equity Shareholders' equity at January 1, 2018 $ 39,494 Issuance of Series B convertible preferred shares 32,159 Issuance of ordinary shares 74,153 Conversion of preferred shares to ordinary shares 74 Share-based compensation expense 404 Issuance of warrants 139 Net loss (27,893 ) Shareholders' equity at June 30, 2018 $ 118,530 Total Shareholders' Equity Shareholders' equity at January 1, 2017 $ 22,668 Issuance of Series B convertible preferred shares 45,840 Share-based compensation expense 180 Net loss (12,117 ) Shareholders' equity at June 30, 2017 $ 56,571

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Restricted Ordinary Shares Activity	The following table summarizes restricted ordinary shares activity for the six months ended June 30, 2018: Number of Weighted Average grant date fair Shares value per share Unvested at December 31, 2017 189,342 $ 3.14 Granted — Vested (46,266 ) $ 3.14 Forfeited — Unvested at June 30, 2018 (unaudited) 143,076 $ 3.14
Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee and Director Options Granted	The assumptions that the Company used to determine the grant date fair value of employee and director options granted were as follows, presented on a weighted average basis: Six months ended June 30, 2018 2017 Volatility 60 % 60 % Expected term in years 6.25 6.25 Dividend rate 0 % 0 % Risk-free interest rate 2.16 % 1.63 % Share price $12.20 - $13.00 $ 3.30 Fair value of option on grant date $7.03 - $7.49 $ 1.88
Summary of Number of Options Outstanding and Weighted-average Exercise Price	The following table summarizes the number of options outstanding and the weighted-average exercise price: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value (in thousands) Options outstanding December 31, 2017 248,128 $ 3.31 9.44 Granted 447,984 12.99 9.92 Exercised — Forfeited — Options outstanding June 30, 2018 696,112 $ 9.54 9.57 1,825 Vested at June 30, 2018 (unaudited) 32,196 Exercisable at June 30, 2018 (unaudited) 32,196 $ 3.17 8.15 766
Summary of Number of RSUs Granted and Weighted-average Grant Date Fair Value of RSUs	The Company granted 36,924 RSUs to directors for the six month period ended June 30, 2018. No RSUs were awarded for the six month period ended June 30, 2017. The table below shows the number of RSUs granted covering an equal number of our ordinary shares and the weighted-average grant date fair value of the RSUs granted: Number of Shares Weighted average grant date fair value per share RSUs outstanding December 31, 2017 — Granted 36,924 $ 13.00 Shares vested — Forfeited — RSUs outstanding June 30, 2018 36,924 $ 13.00
Summary of Share-based Compensation Expense	The Company’s share-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (unaudited) (unaudited) Research and development expense $ 118 $ 42 $ 197 $ 85 General and administrative expense 149 48 207 95

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Future Minimum Payments Due under Operating Leases	The following table summarizes the future minimum payments due under the operating leases as of June 30, 2018: Year Ending December 31, (unaudited) 2018 (remaining) $ 402 2019 962 2020 1,078 2021 1,088 2022 1,030 Thereafter 3,255 $ 7,815

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Principal Payments on Outstanding Debt	Scheduled principal payments on outstanding debt, as of June 30, 2018, are as follows: Year Ending December 31, (unaudited) 2018 (remaining) — 2019 1,552 2020 6,207 2021 6,207 2022 1,034 $ 15,000

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands	Jun. 26, 2018USD ($)$ / sharesshares	May 30, 2018USD ($)$ / sharesshares	May 15, 2018$ / shares	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Reverse share split			0.0636
Share consolidation basis nominal value per share | $ / shares			$ 0.01571
Share consolidation basis renominalisation value per share | $ / shares			$ 0.01
Net proceeds from issuance of stock after deducting underwriting discounts,commissions and offering cost	$ 2,400	$ 71,800				$ 74,155
Net losses				$ 15,747	$ 6,280	27,893	$ 12,117	$ 29,406
Accumulated deficit				82,630		82,630		54,737
Cash and cash equivalents				84,901		84,901		8,485
Short-term investments				50,370		50,370		$ 30,731
Cash resources available under the secured credit facility				$ 15,000		$ 15,000
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares	200,000	6,150,000
Offering price per share | $ / shares	$ 13	$ 13

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	896,002	5,999,781
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	696,112	66,832
Preferred Shares Convertible into 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		5,686,667
Unvested Restricted 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	143,076	246,282
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	36,924
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	19,890

Summary of Significant Accoun32

Summary of Significant Accounting Policies - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018Segment
Accounting Policies [Abstract]
Number of business segments	1

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Schedule of Distribution of Total Operating Expenses by Geographical Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Operating expenses	$ 15,611	$ 6,413	$ 28,005	$ 11,955
Ireland
Segment Reporting Information [Line Items]
Operating expenses	12,811	5,205	22,775	9,674
U.S.
Segment Reporting Information [Line Items]
Operating expenses	$ 2,800	$ 1,208	$ 5,230	$ 2,281

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Schedule of Distribution of Long-Lived Assets by Geographical Area (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Long lived assets	$ 3,757	$ 2,584
Ireland
Segment Reporting Information [Line Items]
Long lived assets	3,388	2,341
U.S.
Segment Reporting Information [Line Items]
Long lived assets	$ 369	$ 243

Fair Value of Financial Asset35

Fair Value of Financial Assets (Schedule of Financial Assets Measured at Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 50,370	$ 30,731
Other asset – advance payment to supplier	1,728	1,472
Total	52,098	32,203
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	50,370	30,731
Total	50,370	30,731
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other asset – advance payment to supplier	1,728	1,472
Total	$ 1,728	$ 1,472

Fair Value of Financial Asset36

Fair Value of Financial Assets - Additional Information (Details)	Jun. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Discounted cash flow include a discount rate	15.00%	15.00%

Short Term Investments - Additi

Short Term Investments - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018
Available For Sale Securities [Abstract]
Short term investments maturity period	4 months 28 days

Short Term Investments - Schedu

Short Term Investments - Schedule of Available for Sale Short-term Investments by Major Security Types (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Available for sale, Cost Total	$ 50,308	$ 30,743
Available for sale, Unrealized gains	65	26
Available for sale, Unrealized (losses)	(3)	(38)
Available for sale, Fair Value Total	50,370	30,731
Available for sale, Maturity by period Less than 1 year	50,370	30,731
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available for sale, Cost Total	47,831	22,538
Available for sale, Unrealized gains	58	8
Available for sale, Unrealized (losses)	(3)	(27)
Available for sale, Fair Value Total	47,886	22,519
Available for sale, Maturity by period Less than 1 year	47,886	22,519
U.S. Treasury and Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Available for sale, Cost Total	2,477	8,205
Available for sale, Unrealized gains	7	18
Available for sale, Unrealized (losses)		(11)
Available for sale, Fair Value Total	2,484	8,212
Available for sale, Maturity by period Less than 1 year	$ 2,484	$ 8,212

Prepaid Expenses and Other Cu39

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Prepaid Expense And Other Assets Current [Abstract]
Prepaid research and development expenses	$ 3,165	$ 2,289
Short-term deposits	1,195	1,346
Other prepaid assets	595	516
Value added tax receivable	592	281
Deferred IPO expenses		180
Research and development tax credit receivable	130	133
Prepaid insurance	598	117
Interest receivable	167	95
Total	$ 6,442	$ 4,957

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment and Related Accumulated Depreciation (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 864	$ 812
Less: accumulated depreciation	(129)	(65)
Property and equipment, net	735	747
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	592	579
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	118	108
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	81	81
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 73	$ 44

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property Plant And Equipment [Abstract]
Depreciation expense	$ 64	$ 14	$ 65

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued clinical trial costs	$ 2,025	$ 594
Accrued manufacturing expenses	851	2,031
Accrued payroll and bonus expenses	920	1,059
Accrued other expenses	325	290
Total	$ 4,121	$ 3,974

Shareholders' Equity - Reconcil

Shareholders' Equity - Reconciliation of Beginning and Ending Balances in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Class Of Stock [Line Items]
Shareholders' equity, Beginning Balance			$ 39,494	$ 22,668	$ 22,668
Conversion of preferred shares to ordinary shares			74
Share-based compensation expense			404	180
Issuance of warrants			139
Net loss	$ (15,747)	$ (6,280)	(27,893)	(12,117)	(29,406)
Shareholders' equity, Ending Balance	$ 118,530	$ 56,571	118,530	56,571	$ 39,494
Series B Convertible Preferred Shares
Class Of Stock [Line Items]
Issuance of shares			32,159	$ 45,840
Ordinary Shares
Class Of Stock [Line Items]
Issuance of shares			$ 74,153

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 14, 2016	Oct. 14, 2015	Jun. 30, 2018	Jun. 30, 2017	Mar. 14, 2018	Dec. 31, 2017	Nov. 18, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options awarded			447,984
Restricted Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued in the period		413,110
Percentage of remaining restricted ordinary shares vest on monthly basis	0.0278%
Grant date fair value			$ 3.14			$ 3.14	$ 3.14
Expense recognized			$ 165	$ 165
Unamortized stock compensation expense			$ 428	$ 761
Stock-based compensation expense, expected weighted average period for recognition			1 year 4 months 17 days	2 years 4 months 17 days
Restricted Ordinary Shares | Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of awards vested	25.00%
Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expense recognized			$ 189	$ 15
Unvested employee options outstanding			663,916	56,596
Unamortized compensation expense stock options			$ 3,549	$ 95
Vesting period			3 years 8 months 15 days	3 years 3 months 10 days
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value			$ 13
Expense recognized			$ 50
Unamortized stock compensation expense			$ 431
Stock-based compensation expense, expected weighted average period for recognition			10 months 24 days
Number of Shares, Granted			36,924	0
Restricted Stock Units (RSUs) | Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			1 year
Restricted Ordinary Shares, Options and Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years 2 months 15 days	2 years 5 months 23 days
Unamortized compensation expense			$ 4,408	$ 856
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized					1,018,459
2018 Plan | Employees and Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options awarded			447,984
2015 Plan | Employees and Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options awarded				17,502

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Restricted Ordinary Shares Activity (Details) - Restricted Ordinary Shares	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Number of Shares
Number of Shares, Unvested, Beginning balance | shares	189,342
Number of Shares, Vested | shares	(46,266)
Number of Shares, Unvested, Ending balance | shares	143,076
Weighted Average grant date fair value per share
Weighted Average grant date fair value per share, Unvested, Beginning balance | $ / shares	$ 3.14
Weighted Average grant date fair value per share, Vested | $ / shares	3.14
Weighted Average grant date fair value per share, Unvested, Ending balance | $ / shares	$ 3.14

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Assumptions Used to Determine Grant Date Fair Value of Employee and Director Options Granted (Details) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility	60.00%	60.00%
Expected term in years	6 years 3 months	6 years 3 months
Dividend rate	0.00%	0.00%
Risk-free interest rate	2.16%	1.63%
Share price		$ 3.30
Fair value of option on grant date		$ 1.88
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price	$ 12.20
Fair value of option on grant date	7.03
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price	13
Fair value of option on grant date	$ 7.49

Share-Based Compensation - Su47

Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Compensation Related Costs [Abstract]
Number of Shares, Options outstanding Beginning Balance	248,128
Number of Shares, Granted	447,984
Number of Shares, Options outstanding Ending Balance	696,112	248,128
Number of Shares, Vested at June 30, 2018 (unaudited)	32,196
Number of Shares, Exercisable at June 30, 2018 (unaudited)	32,196
Weighted Average Exercise Price, Options outstanding Beginning Balance	$ 3.31
Weighted Average Exercise Price, Granted	12.99
Weighted Average Exercise Price, Options outstanding Ending Balance	9.54	$ 3.31
Weighted Average Exercise Price, Exercisable at June 30, 2018 (unaudited)	$ 3.17
Weighted Average Remaining Contractual Life in Years, Options outstanding	9 years 6 months 25 days	9 years 5 months 8 days
Weighted Average Remaining Contractual Life in Years, Granted	9 years 11 months 1 day
Weighted Average Remaining Contractual Life in Years, Exercisable at June 30, 2018 (unaudited)	8 years 1 month 24 days
Aggregate Intrinsic Value, Options outstanding	$ 1,825
Aggregate Intrinsic Value, Exercisable at June 30, 2018 (unaudited)	$ 766

Share-Based Compensation - Su48

Share-Based Compensation - Summary of Number of RSUs Granted and Weighted-average Grant Date Fair Value of RSUs (Details) - Restricted Stock Units (RSUs) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted	36,924	0
Number of Shares, Unvested, Ending balance	36,924
Weighted Average grant date fair value per share, Granted	$ 13
Weighted Average grant date fair value per share, Unvested, Ending balance	$ 13

Share-Based Compensation - Su49

Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 118	$ 42	$ 197	$ 85
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 149	$ 48	$ 207	$ 95

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax [Line Items]
Income tax expense	$ 68	$ 78	$ 157	$ 305
Ireland
Income Tax [Line Items]
Net operating loss carryforwards	$ 8,886		$ 8,886		$ 5,409

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Apr. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Jun. 30, 2016	Nov. 18, 2015
Other Commitments [Line Items]
Purchase obligation	$ 2,397,000				$ 599,000	$ 2,923,000
Pfizer License Agreement | Minimum
Other Commitments [Line Items]
Potential future regulatory milestone and sales milestone payments upon achievement of net sales							$ 250,000,000
Pfizer License Agreement | Maximum
Other Commitments [Line Items]
Potential future regulatory milestone and sales milestone payments upon achievement of net sales							$ 1,000,000,000
Supplemental Agreement
Other Commitments [Line Items]
Purchase obligation	$ 2,397,000
Commercial Unit Lease Agreement | Dublin
Other Commitments [Line Items]
Operating lease agreement, term of contract	20 years
Operating lease agreement, break option term of contract	10 years
Operating lease agreement, commencement period	2018-06
Annual lease payments	$ 321,000
Operating lease agreement, rental review	5 years
Security deposit	$ 818,000
Office Space Lease Agreement | Dublin
Other Commitments [Line Items]
Operating lease agreement, term of contract				10 years
Annual lease payments				$ 375,000
Operating lease agreement, renewal term				5 years
Operating lease agreement, commencement date				Dec. 1, 2016
Operating lease agreement, expiration date				Dec. 1, 2026
Operating lease agreement, review period				2022-12
Office Space Lease Agreement | Dublin | Other Assets
Other Commitments [Line Items]
Security deposit				$ 338,000
Office Space Lease Agreement | Chicago
Other Commitments [Line Items]
Operating lease agreement, term of contract		5 years
Operating lease agreement, commencement period		2018-06
Annual lease payments		$ 258,000
Security deposit		$ 120,000
Operating lease agreement, renewal term		5 years
Office Space Lease Agreement | Connecticut
Other Commitments [Line Items]
Operating lease agreement, term of contract			5 years
Operating lease agreement, commencement period			2017-07
Annual lease payments			$ 131,000
Operating lease agreement, renewal term			3 years
Office Space Lease Agreement | Connecticut | Other Assets
Other Commitments [Line Items]
Security deposit			$ 17,000

Commitment and Contingencies 52

Commitment and Contingencies - Summary of Future Minimum Payments Due under Operating Leases (Details) $ in Thousands	Jun. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018 (remaining)	$ 402
2,019	962
2,020	1,078
2,021	1,088
2,022	1,030
Thereafter	3,255
Total	$ 7,815

Debt - Additional Information (

Debt - Additional Information (Details) - USD ($)	Apr. 27, 2018	Jun. 30, 2018
Debt Instrument [Line Items]
Maximum amount available under second draw		$ 15,000,000
Amortization of debt discount		$ 138,000
Loan and Security Agreement | Silicon Valley Bank (SVB)
Debt Instrument [Line Items]
Loan and security agreement entered date		Apr. 27, 2018
Initial draw amount under agreement	$ 15,000,000
Remaining borrowing facility available date	Oct. 31, 2019
Frequency of amortization payments		Monthly
Date of first required payment of initial draw	Nov. 1, 2019
Extended date of first required payment if second draw funded	Apr. 1, 2020
Minimum fixed interest rate per annum	8.31%
Final interest rate payment on outstanding principal	4.20%
Principal and interest payment date	Mar. 1, 2022
Voluntary prepayment fee in first year	3.00%
Voluntary prepayment fee in second year	2.00%
Voluntary prepayment fee thereafter	1.00%
Loan and Security Agreement | Silicon Valley Bank (SVB) | Wall Street Journal Prime Rate
Debt Instrument [Line Items]
Basis spread on interest rate	3.89%
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
Debt Instrument [Line Items]
Percentage of purchase additional ordinary shares equal to term loan divided by applicable exercise price	2.50%
Silicon Valley Bank and Life Sciences Fund II LLC | Series B Convertible Preferred Shares
Debt Instrument [Line Items]
Number of warrants to purchase convertible preferred shares	19,890
Warrants to purchase convertible preferred shares, exercise price	$ 18.85

Debt - Schedule of Principal Pa

Debt - Schedule of Principal Payments on Outstanding Debt (Details) $ in Thousands	Jun. 30, 2018USD ($)
Debt Disclosure [Abstract]
2,019	$ 1,552
2,020	6,207
2,021	6,207
2,022	1,034
Long-term Debt	$ 15,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ in Thousands	Aug. 14, 2018USD ($)
Pfizer License Agreement | SUlopenem for Resistant Enterobacteriaceae (SURE) 1 | Subsequent Event
Subsequent Event [Line Items]
Liability on achieving milestones	$ 7,500