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 valuation of share-based compensation awards, the valuation of the RLNs and the Derivative liabilities, which consist of embedded features in the Exchangeable Notes, and the accrual for research and development expenses. 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. The Company has contemplated the impact of COVID-19 within its financial statements and is not aware of any specific event or circumstance that would require the Company to update estimates or judgments or revise the carrying value of any assets or liabilities.

Specifically, management has estimated variables used to calculate the discounted cash flow analysis (DCF) to value derivative instruments (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 a certificate of deposit for $30 as of March 31, 2022 which is being held by a third party bank as collateral for the irrevocable letter of credit issued in March 2018 to secure an office lease. Also included within restricted cash on the Company’s condensed consolidated balance sheet is $17 as of March 31, 2022 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 March 31, 2022 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 March 31, 2022 relating to warrants issued in the underwritten offering in October 2020 (October 2020 Offering). These restricted cash amounts are unchanged from December 31, 2021. On the closing date of each of the June 3, 2020 Offering, June 30, 2020 Offering and 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 two 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, unvested performance restricted share units, warrants and the Exchangeable Notes have been excluded from the calculation because they would be anti-dilutive.

Segment and Other Information

The Company determines and presents operating segments based on the information that is internally provided to the Chief Executive Officer, Chief Financial Officer and Chief Medical 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.

On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was signed into law in the United States to provide certain relief as a result of the COVID-19 pandemic. In addition, governments around the world have enacted or implemented various forms of tax relief measures in response to the economic conditions in the wake of COVID-19. Neither the enactment of the CARES Act nor changes to income tax laws or regulations in other jurisdictions had a significant impact on the Company’s income tax provision for the three months ended March 31, 2022 and 2021, or to the Company’s net deferred tax assets as of March 31, 2022.

Recently Adopted Accounting Pronouncements

In August 2020, the Financial Accounting Standards Board (FASB) issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which reduces the number of accounting models for convertible instruments and allows more contracts to qualify for equity classification. The ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2021. The new standard became effective for the Company on January 1, 2022 and did not have a material impact on the Company’s condensed consolidated financial statements.

In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options, which clarifies an issuer’s accounting for modifications or exchanges of freestanding written call options that remain equity-classified after modification. The ASU 2021-04 is effective for all entities for interim and annual periods in fiscal years beginning after December 15, 2021. The new standard became effective for the Company on January 1, 2022 and did not have a material impact on the Company’s condensed consolidated financial statements.

In July 2021, the FASB issued ASU 2021-05, Leases (Topic 842): Lessors – Certain Leases with Variable Lease Payments, which requires a lessor to classify a lease with entirely or partially variable payments that do not depend on an index or rate as an operating lease if a different classification would result in a commencement date selling loss (Day 1 loss). For entities that have adopted ASU 2016-02, Leases, as of July 19, 2021, ASU 2021-05 is effective for annual and interim periods in fiscal years beginning after December 15, 2021 for public business entities and annual periods in fiscal years beginning after December 15, 2021 and interim periods in fiscal years beginning after December 15, 2022 for all other entities. The new standard became effective for the Company on January 1, 2022 and did not have a material impact on the Company’s condensed consolidated financial statements.