Cash, Cash Equivalents, and Restricted Cash

The Company considers all highly liquid investments that are readily convertible into cash with original maturities of three months or less at the date of purchase to be cash equivalents. The Company invests excess cash primarily in overnight cash sweeps and money market funds which are highly liquid and have high credit ratings. Such investments are subject to minimal credit and market risks. The Company classifies all cash of which use is limited by contractual provisions as restricted cash. Restricted cash is recorded on the condensed consolidated balance sheet within other non-current assets and includes amounts held as a security deposit for a letter of credit in connection with leased facilities and its corporate card program.

Deferred Offering Costs

The Company capitalizes certain legal, professional, accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded as a reduction of the proceeds from the offering, either as a reduction of the carrying value of the convertible preferred stock or in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. Should the in-process equity financing be abandoned or delayed the deferred offering costs would be expensed immediately as a charge to operating expenses in the condensed consolidated statements of operations and comprehensive loss. The Company recorded deferred offering costs of $2.2 million and $1.2 million within other non-current assets as of March 31, 2026 and December 31, 2025.

Government Grants

The Company received an award to perform research activities by a United States government agency which provides the Company with payments to reimburse research and development expenses. The Company accounts for government awards under ASC 832, Government Assistance. For awards related to income, the Company recognizes amounts earned under government awards when it is deemed probable that the Company will comply with the conditions attached to the government award and the government award will be received. The Company recognizes amounts earned under government awards as a reduction of research and development expense as the qualifying research expense is incurred, and records a corresponding receivable within prepaid and other current assets on its condensed consolidated balance sheet.

Net Loss per Share

The Company applies the two-class method when computing net loss per share attributable to common stockholders as the Company has issued shares that meet the definition of participating securities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income (loss) available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to share in the undistributed earnings as if all income (loss) for the period had been distributed. The Company considers its convertible preferred stock to be participating securities as, in the event a dividend is paid on common stock, the holders of convertible preferred stock would be entitled to receive dividends on a basis consistent with the common stockholders. There is no allocation required under the two-class method during periods of loss since the participating securities do not have a contractual obligation to share in the losses.

Basic net loss per share is computed by dividing the net loss in each period by the weighted average number of shares of common stock outstanding during such period, excluding potentially dilutive common shares. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional shares of common stock that would have been outstanding if the potential shares of common stock had been issued and if the additional shares of common stock were dilutive.

Recently Adopted Accounting Pronouncements

In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, which adds guidance to ASC 832 on the recognition, measurement, and presentation of government grants. In developing the ASU’s recognition and measurement framework, the FASB largely leveraged the guidance in IAS 20, to which many for-profit entities that apply U.S. GAAP have historically analogized when accounting for government grants. The ASU is effective for fiscal years beginning after December 15, 2028, including interim periods within those fiscal years. Early adoption is permitted. The Company early adopted ASU 2025-10 prospectively on January 1, 2026. There was not a material impact on the Company’s condensed consolidated financial statements as a result of this adoption.

Recently Issued Accounting Standards Updates Not Yet Adopted

From time to time, new accounting pronouncements are issued by the FASB, or other standard-setting bodies that are adopted by Seaport as of the specified effective date. The Company qualifies as an ‘‘emerging growth company’’ as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to ‘‘opt out’’ of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and non-public companies, the Company can adopt the new or revised standard at the time non-public companies adopt the new or revised standard and can do so until such time that the Company either (i) irrevocably elects to ‘‘opt out’’ of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for non-public companies. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, or ASU 2024-03, which is intended to provide more detailed information about specified categories of expenses (purchases of inventory, employee compensation, depreciation, and amortization) included in certain expense captions presented on the statement of operations. The guidance in ASU 2024-03 is effective for fiscal years beginning after December 15, 2026. Early adoption is permitted. The amendments may be applied either (1) prospectively to financial statements issued for periods after the effective date of ASU 2024-03 or (2) retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating the impact that the adoption of ASU 2024-03 may have on its consolidated financial statements and disclosures for fiscal years beginning after December 15, 2026.