Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of Presentation The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The Company’s condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, T2 Biosystems Securities Corporation. All intercompany balances and transactions have been eliminated. On October 12, 2023, the Company effected a 1-for-100 reverse stock split. One share of common stock was issued for every 100 shares of issued and outstanding common stock , and fractional shares were settled in cash. All references to share and per share amounts (excluding authorized shares) in the condensed consolidated financial statements and accompanying notes have been retroactively restated to account for the reverse split. Unaudited Interim Financial Information Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. The accompanying interim condensed consolidated balance sheet as of June 30, 2024, the condensed consolidated statements of operations for the three and six months ended June 30, 2024 and 2023, the condensed consolidated statements of stockholders’ deficit for the three and six months ended June 30, 2024 and 2023, the condensed consolidated statements of cash flows for the six months ended June 30, 2024 and 2023 and the related financial data and other information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2024, and the results of its operations for the three and six months ended June 30, 2024 and 2023 and its cash flows for the six months ended June 30, 2024 and 2023. The results for the three and six months ended June 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 , any other interim periods, or any future year or period. 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 in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company views its operations and manages its business in one operating segment, which is the business of developing and, upon regulatory clearance, commercially launching its diagnostic products aimed at lowering mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier. Geographic Information The Company sells its products domestically and internationally. Total international sales were approximately $ 0.8 million, or 40 % of total revenue, and $ 1.0 million, or 50 % of total revenue, for the three months ended June 30, 2024 and 2023 , respectively. Total international sales were approximately $ 1.8 million, or 44 % of total revenue, and $ 1.7 million, or 43 % of total revenue, for the six months ended June 30, 2024 and 2023, respectively. International sales to Italy were approximately $ 0.2 million, or 13 % of total revenue, and $ 0.7 million, or 16 % of total revenue, for the three and six months ended June 30, 2024 , respectively. International sales to Italy were approximately $ 0.7 million, or 33 % of total revenue, and $ 1.0 million, or 26 % of total revenue, for the three and six months ended June 30, 2023 , respectively. International sales to Austria were approximately $ 0.2 million, or 11 % of total revenue, and $ 0.5 million, or 12 % of total revenue, for the three and six months ended June 30, 2024 , respectively. International sales to Austria did not exceed 10 % of total revenue for the three and six months ended June 30, 2023. The following table shows customers that represent greater than 10% of total revenue for the period presented: Three Months Ended Six Months Ended 2024 2023 2024 2023 Entity A — % — % — % 10 % Customer A 13 % 33 % 16 % 26 % Customer B 11 % — % 12 % — % Customer C 10 % 11 % — % — % Customer E 11 % — % — % — % Entity A is a U.S. government entity (BARDA). Customers A and B are international distributors. Customers C and E are U.S. hospitals. The following table shows customers that represent greater than 10% of the accounts receivable balance for the period presented: June 30, December 31, Customer A 12 % — % Customer B 13 % — % Customer C 11 % 13 % Customer D — % 16 % Customer E 15 % — % Customers A and B are international distributors. Customers C and E are U.S. hospitals. Customer D is a clinical laboratory company. As of June 30, 2024 and December 31, 2023 , the Company had outstanding receivables of $ 0.6 million and $ 0.3 million, respectively, from customers located outside of the U.S. Net Loss Per Share As discussed in Note 7, the Company issued 93,297 shares of Series B Convertible Preferred Stock on July 3, 2023 and 17,160.48 shares of Series A Convertible Preferred Stock on April 12, 2024. As of June 30, 2024 , no shares of Series B Convertible Preferred Stock or Series A Convertible Preferred Stock remain issued and outstanding. The Company reviewed the terms of the Series B Convertible Preferred Stock and the Series A Convertible Preferred Stock and noted that such stock had no preferential rights and that the liquidation preference for each would be on parity with that of the Company’s common shares. Because the Series B Convertible Preferred Stock and the Series A Convertible Preferred Stock had the same level of subordination and, in substance, the same characteristics as the Company’s common shares, the Company included the Series B Convertible Preferred Stock and Series A Convertible Preferred Stock, on an if-converted basis, in the basic and diluted net loss per share attributable to common stockholders calculation for all periods in which the Series B Convertible Preferred Stock and the Series A Convertible Preferred Stock remained issued and outstanding. The Company has also issued certain securities that are participating securities. Therefore, the Company must apply the two-class method to determine basic and diluted earnings per share. The two-class method is an earnings allocation method under which net loss per share is calculated for each class of common stock and participating security considering both dividends declared, if any, and participation rights in undistributed earnings as if all such earnings had been distributed for the period. The Company’s participating securities do not have an obligation to share in the losses of the Company; therefore, to the extent that the Company remains in a net loss position, the entire net loss will be allocated to common stockholders. Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, in-substance common stock, and potential common shares exercisable for little to no consideration, and does not consider other common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted-average number of shares outstanding, in-substance common stock, and potential common shares exercisable for little to no consideration used to compute basic earnings per share for the dilutive effect of other common stock equivalents that were outstanding during the period, determined using either the if-converted method or the treasury-stock method. Derivative Instruments The Company evaluates its financial instruments to determine if such instruments are derivatives or contain features that qualify as embedded derivatives requiring bifurcation in accordance with ASC Topic 815, Derivatives and Hedging . Derivative instruments are measured at fair value at issuance and at each reporting date in accordance with ASC 820 with changes in fair value recognized in the period of change in the condensed consolidated statements of operations. The Company determined that the warrant issued in conjunction with the Series A Redeemable Convertible Preferred Stock in August of 2022 and the Common Stock Warrants issued in February 2023 are derivative instruments. The warrant liabilities are classified on the condensed consolidated balance sheets as current because settlement of the warrant liability could be required by the holder within 12 months of the balance sheet date. Changes in fair value are recognized in change in fair value of warrant liabilities in the period of change in the condensed consolidated statements of operations. See Notes 3 and 8. The Company has identified a derivative liability related to its Term Loan Agreement with CRG that is classified as a current liability on the condensed consolidated balance sheets to match the classification of the related Term Loan Agreement. Changes in fair value are recognized in change in fair value of derivative related to Term Loan in the period of change in the condensed consolidated statements of operations. See Note 6. The Company does not designate its derivative instruments as hedging instruments. Guarantees As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while each such officer or director is, or was, serving at the Company’s request in such a capacity. The term of the indemnification is the officer’s or director’s lifetime. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ liability insurance coverage that limits its exposure and enables the Company to recover a portion of any future amounts paid. The Company leases office, laboratory and manufacturing space under noncancelable operating leases. The Company has standard indemnification arrangements under the leases that require it to indemnify the landlords against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation or nonperformance of any covenant or condition of the Company’s leases. See Note 14 for a discussion about the Billerica, Massachusetts lease. In the ordinary course of business, the Company enters into indemnification agreements with certain suppliers and business partners where the Company has certain indemnification obligations limited to the costs, expenses, fines, suits, claims, demands, liabilities and actions directly resulting from the Company’s gross negligence or willful misconduct, and in certain instances, breaches, violations or nonperformance of covenants or conditions under the agreements. As of June 30, 2024 and December 31, 2023 , the Company had not experienced any material losses related to these indemnification obligations, and no material claims with respect thereto were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Leases Lessee Pursuant to ASC Topic 842, Leases (“ASC 842”), at the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Leases with a term greater than one year are recognized on the balance sheet as right-of-use assets, lease liabilities and long-term lease liabilities. The Company has elected not to recognize on the balance sheet leases with terms of one year or less. The exercise of lease renewal options is at the Company’s discretion and the periods subject to renewal options are not included in the measurement of the Company’s right-of-use assets and lease liabilities as the renewal options are not reasonably certain of exercise. The Company will continue to evaluate the renewal options and when they are reasonably certain of exercise, the Company will include the renewal period in its lease term. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. However, certain adjustments to the right-of-use asset may be required for items such as prepaid or accrued lease payments. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rates, which are the rates incurred to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. In accordance with the guidance in ASC 842, components of a lease should be split into three categories: lease components (e.g., land, building, etc.), non-lease components (e.g., common area maintenance, consumables, etc.), and non-components (e.g., property taxes, insurance, etc.). Then the fixed and in-substance fixed contract consideration (including any related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. The Company made the policy election to not separate lease and associated non-lease components. Each lease component and the related non-lease components are accounted for together as a single component. Lessor The Company derives revenue from leasing its T2-owned instruments through reagent rental agreements (see the Revenue Recognition section below). Customers typically have the right to cancel every twelve months, resulting in a lease term of generally one year. These lease agreements impose no requirement on the customer to purchase the instrument, and the instrument is not transferred to the customer at the end of the lease term. The short-term nature of the lease agreements does not result in lease payments accumulating to an amount that exceeds substantially all of the fair value of the instrument nor is the lease term for the majority of the remaining economic life of the instrument. Instrument leases are generally classified as operating leases as they do not meet any of the sales-type lease or direct financing lease criteria per ASC 842 and are recognized ratably over the duration of the lease. In accordance with these contracts, customers only make payments when consumables are ordered and delivered thus making these payments variable by nature. The Company estimates the expected volume of consumables to be purchased by each customer over the lease term to measure and recognize rental and consumables revenue. Generally, lease arrangements include both lease and non-lease components. The lease component relates to the customer’s right-to-use the T2-owned instrument over the lease term. The non-lease components relate to (1) consumables and (2) maintenance services. Because the timing and pattern of transfer for the operating lease component, the T2-owned instrument, and maintenance components of a reagent rental agreement are recognized over the same time period and in the same pattern, the Company elected the practical expedient to aggregate non-lease components with the associated lease component and account for the combined component as an operating lease for all instrument leases. In the evaluation of whether the lease component (T2-owned instrument) or the non-lease component associated with the lease component (maintenance) is the predominant component, the Company determined that the lease component is predominant as we believe the customer would ascribe more value to the use of the T2-owned instrument than that of the maintenance services. The T2-owned instrument lease and maintenance service performance obligations are classified as a single category of instrument rental revenue within product revenue in the condensed consolidated statements of operations (see disaggregated revenue table below in Revenue Recognition section). The consumables non-lease component does not meet the requirements to elect the practical expedient because of its point-in-time pattern of transfer (versus over time for the combined lease component) and therefore must apply ASC Topic 606, Revenue from Contracts with Customers , as described below in the Revenue Recognition section. The Company considers the economic life of its T2-owned instruments to be five years. The Company believes five years is representative of the period during which the instrument is expected to be economically usable by one or more users, with normal service, for the purpose for which it is intended. The residual value is estimated to be the value at the end of the lease term based on the anticipated fair market value of the units. The Company mitigates residual value risk of its leased instrument by performing regular management and maintenance, as necessary. Revenue Recognition The Company generates revenue from the sale of instruments, consumable diagnostic tests, related services, reagent rental agreements and government contributions. For arrangements in the scope of ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”), the Company determines revenue recognition through the following steps: • Identification of a contract with a customer • Identification of the performance obligations in the contract • Determination of the transaction price • Allocation of the transaction price to the performance obligations • Recognition of revenue as a performance obligation is satisfied The amount of revenue recognized reflects the consideration the Company expects to be entitled to receive in exchange for these goods and services. Once a contract is determined to be within the scope of ASC 606 at contract inception, the Company reviews the contract to determine which performance obligations the Company must deliver and which of these performance obligations are distinct. The Company recognizes as revenues the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied. Generally, the Company’s performance obligations are transferred to customers either at a point in time, typically upon shipment, or over time, as services are performed. Contracts typically have net 30 payment terms in the U.S. and net 60 payment terms internationally. Most of the Company’s contracts with distributors in geographic regions outside the United States contain only a single performance obligation, whereas most of the Company’s contracts with direct sales customers in the United States contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis. Excluded from the transaction price are sales tax and other similar taxes which are presented on a net basis. Product revenue is generated by the sale of instruments and consumable diagnostic tests predominantly through the Company’s direct sales force in the United States and distributors in geographic regions outside the United States. The Company generally does not offer product returns or exchange rights (other than those relating to defective goods under warranty) or price protection allowances to its customers, including its distributors. Payment terms granted to distributors are the same as those granted to end-user customers and payments are not dependent upon the distributors’ receipt of payment from their end-user customers. The Company either sells instruments to customers and international distributors or retains title and places the instrument at the customer site pursuant to a reagent rental agreement. When an instrument is purchased by a customer or international distributor, the Company recognizes revenue when the related performance obligation is satisfied (i.e., when the control of an instrument has passed to the customer; typically, at shipping point). When the instrument is placed under a reagent rental agreement, the Company’s customers generally agree to fixed term agreements, which can be extended, and incremental charges on each consumable diagnostic test purchased. Revenue from the sale of consumable diagnostic tests (under a reagent rental agreement) is generally recognized upon shipment. The transaction price from consumables purchases is allocated between the lease and non-lease components when related performance obligations are satisfied, as a component of lease and product revenue, and is included as Instrument Rentals in the below table. Revenue associated with reagent rental consumables purchases is currently classified as variable consideration and constrained until a purchase order is received and related performance obligations have been satisfied. Revenue from the sale of consumable diagnostic tests (under instrument purchase agreements) is recognized when control has passed to the customer, typically at shipping point. Shipping and handling costs billed to customers in connection with a product sale are recorded as a component of the transaction price and allocated to product revenue in the condensed consolidated statements of operations as they are incurred by the Company in fulfilling its performance obligations. Direct sales of instruments include warranty, maintenance and technical support services typically for one year following the installation of the purchased instrument (“Maintenance Services”). Maintenance Services are separate performance obligations as they are service based warranties and are recognized on a straight-line basis over the service delivery period. After the completion of the initial Maintenance Services period, customers have the option to renew or extend the Maintenance Services typically for additional one-year periods in exchange for additional consideration. The extended Maintenance Services are also service based warranties that represent separate purchasing decisions. The Company recognizes revenue allocated to the extended Maintenance Services performance obligation on a straight-line basis over the service delivery period. Fees paid to member-owned group purchasing organizations (“GPOs”) are deducted from related product revenues. The Company warrants that consumable diagnostic tests will be free from defects, when handled according to product specifications, for the stated life of the product. To fulfill valid warranty claims, the Company provides replacement product free of charge. Warranty expense is recognized based on the estimated defect rates of the consumable diagnostic tests. Contribution Revenue The government contract with BARDA was considered a government grant and not considered a contract with a customer and thus not subject to ASC 606. Revenue under the government BARDA contract was earned under a cost-sharing arrangement in which the Company was reimbursed for direct costs incurred plus allowable indirect costs. The government contract revenue was recognized as the related reimbursable expenses were incurred. The cost reimbursement that was reported as revenue was presented gross of the related reimbursable expenses in the Company’s condensed consolidated statements of operations; the related reimbursable expenses were expensed as incurred as research and development expense. The Company accounted for these contracts as a government grant by analogy to International Accounting Standards 20 (“IAS 20”), Accounting for Government Grants and Disclosure of Government Assistance . The BARDA contract expired in September 2023. Disaggregation of Revenue The Company disaggregates revenue from contracts with customers by type of products and services, as it best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The following table disaggregates our revenue by major source (in thousands): Three Months Ended Six Months Ended 2024 2023 2024 2023 Product revenue Instruments 180 550 644 872 Consumables 1,597 1,238 3,002 2,415 Instrument rentals 43 49 106 104 Service 132 127 261 228 Total product revenue 1,952 1,964 4,013 3,619 Contribution revenue — 423 Total revenue $ 1,952 $ 1,964 $ 4,013 $ 4,042 Remaining Performance Obligations Under ASC 606, the Company is required to disclose the aggregate amount of the transaction price that is allocated to unsatisfied or partially satisfied performance obligations as of June 30, 2024 . However, the guidance provides certain practical expedients that limit this requirement, and therefore, the Company has elected to not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less. The nature of the excluded unsatisfied performance obligations pursuant to the practical expedient include consumable shipments, service contracts, warranties and installation services that will be performed within one year . The amount of the transaction price that is allocated to unsatisfied or partially satisfied performance obligations, that has not yet been recognized as revenue and that does not meet the elected practical expedient is $ 0.1 million as of June 30, 2024 . The Company expects to recognize 44 % of this amount as revenue within one year and the remainder within three years . Judgments Certain contracts with customers include promises to transfer multiple products and services to a customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment. Once the performance obligations are determined, the Company determines the transaction price, which includes estimating the amount of variable consideration, based on the most likely amount, to be included in the transaction price, if any. The Company then allocates the transaction price to each performance obligation in the contract based on a relative standalone selling price method. The corresponding revenue is recognized as the related performance obligations are satisfied as discussed in the revenue categories above. Judgment is required to determine the standalone selling price for each distinct performance obligation. The Company determines standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as a range of selling prices, market conditions and the expected costs and margin related to the performance obligations. Contract Assets and Liabilities The Company's contract assets represent revenue recognized for performance obligations in advance of invoicing at the contract level based on the transaction price allocated to the respective performance obligations. The opening and closing balances of the Company's contract assets were $ 0.1 million and $ 0.1 million for the six months ended June 30, 2024 , respectively, and $ 0.1 million and $ 0.2 million for the six months ended June 30, 2023, respectively. The Company’s contract liabilities consist of upfront payments for maintenance services on instrument sales. Contract liabilities are classified in deferred revenue as current or non-current based on the timing of when revenue is expected to be recognized. The opening and closing balances of the Company's contract liabilities were $ 0.3 million and $ 0.3 million for the six months ended June 30, 2024 , respectively, and $ 0.2 million and $ 0.3 million for the six months ended June 30, 2023, respectively. Revenue recognized during the six months ended June 30, 2024 relating to contract liabilities on December 31, 2023 was $ 0.2 million and related to straight-line revenue recognition associated with maintenance agreements. Accounts Receivable, Net The opening and closing balances of the Company's accounts receivable, net were $ 1.4 million and $ 1.3 million for the six months ended June 30, 2024 , respectively, and $ 2.2 million and $ 1.3 million for the six months ended June 30, 2023 , respectively. Cost of Product Revenue Cost of product revenue includes the cost of materials, direct labor and manufacturing overhead costs used in the manufacture of consumable diagnostic tests sold to customers, related warranty and license and royalty fees. Cost of product revenue also includes depreciation on T2-owned revenue generating T2Dx Instruments that have been placed with customers under reagent rental agreements; costs of materials, direct labor and manufacturing overhead costs on the T2Dx Instruments sold to customers; and other costs such as customer support costs, royalties and license fees, warranty and repair and maintenance expense on the T2Dx Instruments that have been placed with customers under reagent rental agreements. Research and Development Costs Costs incurred in the research and development of the Company’s product candidates are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including activities associated with delivering products or services associated with contribution revenue, clinical trials to evaluate the clinical utility of product candidates, and costs associated with the enhancements of developed products. These costs include salaries and benefits, stock compensation, research related facility and overhead costs, laboratory supplies, equipment, depreciation on T2Dx Instruments used for research and development activities and contract services. Selling, General and Administrative Expenses Selling, general and administrative expenses consist primarily of costs for the Company’s sales and marketing, finance, legal, human resources, business development and general management functions, as well as professional services, such as legal, consulting and accounting services. Other selling, general and administrative expenses include commercial support activity, facility-related costs, fees and expenses associated with obtaining and maintaining patents, clinical and economic studies and publications, marketing expenses, and travel expenses. The Company expenses the majority of selling, general and administrative expenses as incurred. Impairment of Long-lived Assets The Company reviews long‑lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Impairment is evaluated by comparing the carrying value of the long-lived assets with the estimated future net undiscounted cash flows expected to result from the use of the assets, including cash flows from disposition. Should the sum of the expected future net cash flows be less than the carrying value, the Company would recognize an impairment loss at that date. An impairment loss would be measured by comparing the amount by which the carrying value exceeds the fair value, or the estimated discounted future cash flows, of the long-lived assets. Recent Accounting Standards From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that its adoption of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations at the respective effective dates. Accounting Standards Issued, To Be Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). This ASU was issued to improve th |