2. Summary of Significant Accounting Policies

There have been no material changes in the Company’s significant accounting policies, other than the adoption of accounting pronouncements 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, 2018.

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 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. For the periods presented, the ordinary shares underlying the options, unvested restricted ordinary shares, unvested restricted share units, unvested performance restricted share units and the warrants have been excluded from the calculation because they would be anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted-average shares outstanding as they would be anti-dilutive:

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 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:

Recently Adopted Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-02, Leases (Topic 842) in order to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under prior GAAP. In July 2018, the FASB issued ASU 2018-11 Leases (Topic 842): Targeted Improvements which provides the option to adopt the standard retrospectively for each prior period presented, as initially set out in ASU 2016-02, or as of the adoption date with a cumulative-effect adjustment to the opening balance of retained earnings. In March 2019, the FASB issued ASU 2019-03 Leases (Topic 842): Codification Improvements amending the transition disclosures for Topic 842, in that all companies are exempt from certain interim period transition disclosure requirements.

ASU 2016-02 requires a lessee to recognize a liability to make lease payments (the lease liability) and a right-of-use asset, representing its right to use the underlying asset for the lease term, on the balance sheet. The Company adopted ASU 2016-02 in the first quarter of 2019 utilizing the modified retrospective transition method with an effective date as the date of initial application. Consequently, prior period balances and disclosures have not been restated. The adoption of ASU 2016-02 on January 1, 2019 resulted in the recognition of right-of-use assets of $7.6 million and operating lease liabilities of $7.8 million, however, the adoption of the standard did not have an impact on the Company’s beginning retained earnings, results from operations or cash flows. See Note 7 for further information regarding the impact of the adoption of ASU 2016-02 on the Company's financial statements.

In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815), I. Accounting for Certain Financial Instruments with Down Round Features, II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception.

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 did not have an impact on the condensed consolidated financial statements.