2. Summary of Significant Accounting Policies

There have been no material changes in the Company’s significant accounting policies, other than a change to the measurement method of the RLNs and the adoption of accounting pronouncements as described below, as compared to the significant accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.

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, the valuation of share-based compensation awards, and the valuation of the RLNs and the Derivative liabilities. 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, 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) and assumptions used in the Black-Scholes and binomial option pricing models 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 $117 (€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 $60 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 (see Note 7 - Leases). Also included within restricted cash on the Company’s condensed consolidated balance sheet is $17 relating to the warrants issued on June 5, 2020 pursuant to the June 3 SPA, $6 relating to the warrants issued on July 2, 2020 pursuant to the June 30 SPA and $17 relating to warrants issued in the October Offering. On the closing date of each of the June 3 Offering, June 30 Offering and October 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 and the warrants 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 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:

Royalty-Linked Notes

On recognition, the RLNs qualified as debt instruments under ASC 470, Debt, and were initially recorded at fair value, applying a DCF model, and then subsequently measured at amortized cost. In January 2021, the RLNs were exchange listed, and therefore, derivative accounting has been applied in accordance with ASC 815, Derivatives and Hedging, which establishes accounting and reporting standards for derivative instruments, including certain derivative instruments embedded in other financial instruments or contracts which require bifurcation and measurement at fair value for accounting purposes on the balance sheet date. Any liabilities recorded at fair value are revalued at each reporting period with the resulting change in fair value reflected in other income / (expense), net.

Income Taxes

The CARES Act lifts certain deduction limitations originally imposed by the Tax Cuts and Jobs Act of 2017 (2017 Tax Act). Corporate taxpayers may carryback net operating losses (NOLs) originating during 2018 through 2020 for up to five years, which was not previously allowed under the 2017 Tax Act. The CARES Act also eliminates the 80% of taxable income limitations by allowing corporate entities to fully utilize NOL carryforwards to offset taxable income in 2018, 2019 or 2020. Taxpayers may generally deduct interest up to the sum of 50% of adjusted taxable income plus business interest income (30% limit under the 2017 Tax Act) for tax years beginning January 1, 2019 and 2020. The CARES Act allows taxpayers with alternative minimum tax credits to claim a refund in 2020 for the entire amount of the credits instead of recovering the credits through refunds over a period of years, as originally enacted by the 2017 Tax Act. The enactment of the CARES Act did not result in any material adjustments to the Company’s income tax provision for the three months ended March 31, 2021, or to the Company’s net deferred tax assets as of March 31, 2021.

Recently Adopted Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The new guidance is intended to simplify the accounting for income taxes by removing certain exceptions and by updating accounting requirements around franchise taxes, goodwill recognized for tax purposes, the allocation of current and deferred tax expense among legal entities, among other minor changes. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The new standard became effective for the Company on January 1, 2021 and adoption did not have a material impact on the Company’s condensed consolidated financial statements.

In January 2020, the FASB issued ASU 2020-01, Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815. The amendments in ASU 2020-01 clarify the interaction of the accounting for equity securities under Topic 321 and investments accounted for under the equity method of accounting. ASU 2020-01 is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years. The new standard became effective for the Company on January 1, 2021 and adoption did not have a material impact on the Company’s condensed consolidated financial statements.

In October 2020, the FASB issued ASU 2020-10, Codification Improvements, which clarifies various topics in the Codification by providing consistency in codification wording and moving existing disclosure requirements to the relevant disclosure sections. ASU 2020-10 is effective for annual and interim periods in fiscal years beginning after December 15, 2020. This standard became effective for the Company on January 1, 2021, and did not have a material impact on the Company’s disclosures.

Recent Accounting Pronouncements

In August 2020, the 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. Early adoption is permitted, but no earlier than annual and interim periods in fiscal years beginning after December 15, 2020. The Company is assessing what impact ASU 2020-06 will have on the condensed consolidated financial statements.