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Summary of significant accounting policies | 9 Months Ended
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Sep. 30, 2024
Accounting Policies [Abstract] |
Summary of significant accounting policies | Summary of significant accounting policies Principles of Consolidation The accompanying unaudited condensed consolidated financial statements include those of the Company and its wholly owned subsidiary, Mersana Securities Corp. All intercompany balances and transactions have been eliminated. Use of Estimates The preparation of the Company’s unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, the Company’s management evaluates its estimates which include, but are not limited to, management’s judgments with respect to the identification of performance obligations and standalone selling prices of those performance obligations within its revenue arrangements, accrued preclinical, manufacturing and clinical expenses, valuation of stock-based awards and income taxes. Actual results could differ from those estimates. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision-maker, or decision making group, in deciding how to allocate resources and assess performance. The Company views its operations and manages its business as a single operating segment, which is the business of discovering and developing ADCs. Summary of Accounting Policies The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and nine months ended September 30, 2024 are consistent with those discussed in Note 2, Summary of Significant Accounting Policies, in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on February 28, 2024. Fair Value Measurements Fair value is defined as the price that would be received upon sale of an asset or paid to transfer a liability between market participants at measurement dates. ASC 820, Fair Value Measurement, establishes a three-level valuation hierarchy for instruments measured at fair value. The hierarchy is based on the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows: Level 1—Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2—Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. Level 3—Inputs to the valuation methodology are unobservable and significant to the fair value measurement. Concentration of Credit Risk and Off-balance Sheet Risk Financial instruments that potentially subject the Company to concentrations of credit risk primarily consist of cash equivalents and marketable securities. Under its investment policy, the Company limits amounts invested in such securities by credit rating, maturity, industry group, investment type and issuer, except for securities issued by the U.S. government. The Company does not believe that it is subject to any significant concentrations of credit risk from these financial instruments. The Company has no financial instruments with off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Cash and Cash Equivalents The Company considers all highly-liquid investments with an original maturity, or a remaining maturity at the time of purchase, of three months or less to be cash equivalents. The Company invests excess cash primarily in money market funds, treasury securities, commercial paper and government agency securities, which are highly liquid and have strong credit ratings. These investments are subject to minimal credit and market risks. Cash and cash equivalents are stated at cost, which approximates market value. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies, and the Company adopts such pronouncements as of the specified effective date. Unless otherwise discussed below, the Company does not believe that the adoption of recently issued standards has had or may have a material impact on the Company's condensed consolidated financial statements or disclosures. In November 2023, the FASB issued Accounting Standard Update, or ASU, 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which is intended to improve reportable segment disclosure requirements, primarily through additional disclosures about significant segment expenses. The standard is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments should be applied retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating the impact ASU 2023-07 may have on the Company's consolidated financial statements. In December 2023, the FASB, issued ASU 2023-09, Improvements to Income Tax Disclosures, which requires entities to disclose disaggregated information about their effective tax rate reconciliation as well as expanded information on income taxes paid by jurisdiction. The disclosure requirements will be applied on a prospective basis, with the option to apply them retrospectively. The standard is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact ASU 2023-09 may have on the Company's consolidated financial statements.

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