Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2022

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated 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 GAAP as found in the Accounting Standards Codification ("ASC") or an Accounting Standards Update (“ASU”) issued by the Financial Accounting Standards Board (“FASB”).

Use of Estimates

The preparation of the consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the consolidated financial statements and the reported amount of expenses during the reporting period. Actual results could differ from those estimates. Management considers many factors in selecting appropriate financial accounting policies in developing the estimates and assumptions that are used in the preparation of the consolidated financial statements. Management must apply significant judgment in this process. Management’s estimation process often may yield a range of potentially reasonable estimates and management must select an amount that falls within that range of reasonable estimates. Estimates are used in the following areas, among others: estimating the

fair value of the Company’s common stock (prior to the IPO); accrued expenses and related research and development expenses.

Segments

Operating segments are defined as components of an enterprise for which separate and discrete information is available for evaluation by the chief operating decision-maker in deciding how to allocate resources and assess performance. The Company has one operating segment. The Company’s chief operating decision maker, its Chief Executive Officer, manages the Company’s operations on an aggregate basis for the purpose of allocating resources.

Cash and Cash Equivalents

The Company considers highly-liquid investments purchased with an original maturity date of ninety days or less from the date of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in money market funds. Cash equivalents are stated at cost, which approximates market value.

Investments

Investments in marketable debt securities are classified as available-for-sale. Investments with maturities beyond one year may be classified as short-term based on their highly liquid nature and because such securities represent an investment of cash that is available for current operations.

Available-for-sale investments are reported at fair value at each balance sheet date. Changes in the market value of available-for-sale investments, excluding other-than-temporary impairments, are reflected as other comprehensive loss, a component of stockholders’ equity. Realized gains and losses are determined using the specific identification method and are included in other income in our consolidated statements of operations and comprehensive loss.

Investments are evaluated for other-than-temporary impairment at the end of each reporting period. Impairment is evaluated considering numerous factors, and their relative significance varies depending on the situation. Factors considered include whether a decline in fair value below the amortized cost basis is due to credit-related factors or non-credit-related factors, the financial condition and near-term prospects of the issuer, and the Company's intent and ability to hold the investment to allow for an anticipated recovery in fair value. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income and a new cost basis in the investment is established.

Restricted Cash

The Company had $2.4 million of restricted cash in the form of a letter of credit related to a lease at December 31, 2022 and 2021.

Comprehensive loss

Comprehensive loss includes net loss, as well as other changes in stockholders’ equity (deficit) that result from transactions and economic events other than those with stockholders.

Concentrations of Credit Risk

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents, restricted cash equivalents and investments. The Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company deposits its cash in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

The Company’s investments consist of money market funds and marketable debt securities, including corporate bonds and U.S. Treasury securities. The Company’s investments may include commercial paper and other debt securities of U.S. government agencies, corporate entities, and banks. The Company’s investment policy limits instruments to investment grade securities with high credit quality issuers with the objective to preserve capital and to maintain liquidity until the funds can be used in business operations.

Measurement of Credit Losses

For financial assets measured at fair value through other comprehensive loss, the Company must record an allowance for credit losses at the end of each reporting period in the consolidated statement of operations. When developing an estimate of expected credit losses on financial assets, the Company will consider available information relevant to assessing the collectability of cash flows. This information may include internal information, external information, or a combination of both, relating to past events, current conditions, and reasonable and supportable forecasts for financial asset pools.

The Company’s investment in corporate bonds and U.S. treasury securities, reported as available-for-sale investments, and the associated accrued interest reported as other current assets on the consolidated balance sheets, is the only financial asset pool. The financial asset pool was determined by the type of financial asset instrument and its credit quality. Management does not expect a credit loss with this financial asset pool and determined an allowance was not required based on the issuers' current high quality credit ratings and the lack of default history on its obligations.

Fair Value Measurements

Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

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Level 1—Quoted prices in active markets for identical assets or liabilities.

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Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

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Level 3—Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Cloud Computing Arrangements

The Company capitalizes implementation costs for cloud computing arrangement service contracts. The Company’s cloud computing arrangements relate to its enterprise resource planning and manufacturing software. For such cloud computing service contracts, the Company capitalizes certain implementation costs as prepaid expenses in the consolidated balance sheets. The Company amortizes these capitalized cloud computing implementation costs into general and administrative expenses using the straight-line method over the fixed, non-cancellable term of the associated hosting arrangement, plus any reasonably certain renewal periods.

Property and Equipment, Net

Property and equipment, net is recorded at cost less accumulated depreciation. Depreciation expense is recorded using the straight-line method over the estimated useful life of the related asset, which are as follows:


	Estimated Useful Life
Computer equipment	3 years
Manufacturing equipment	5 years
Furniture and equipment	5 years
Laboratory equipment	5 years
Leasehold improvements	Shorter of remaining lease term or useful life

Purchased assets that are not yet in service are recorded to construction-in-process and no depreciation expense is recorded. Once they are placed in service, they are reclassified to the appropriate asset class. When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is reflected in the Company’s consolidated statements of operation and comprehensive loss. Expenditures for maintenance and repairs are expensed as incurred.

Impairment of Long-Lived Assets

Long-lived assets consist of property and equipment. The Company continually evaluates whether events or circumstances have occurred that indicate that the estimated remaining useful life of its long-lived assets may warrant revision or that the carrying value of these assets may not be recoverable. If circumstances require that a long-lived asset or asset group be tested for impairment, the Company first compares the estimated undiscounted future cash flows expected to result from the use or disposition of that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment loss would be recognized to the extent the carrying value exceeds its fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market prices and third-party independent appraisals, as considered necessary.

Leases

At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease. Leases with a term greater than one year are recognized on the consolidated balance sheet as a right-of-use (“ROU”) asset and current and non-current lease liabilities, as applicable. The Company has made an accounting policy election, known as the short-term lease recognition exemption, which allows the Company to not recognize ROU assets and lease liabilities that arise from short-term leases (12 months or less); The Company has applied this election to all classes of underlying assets. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew or options to cancel a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew or will not cancel, respectively. The Company monitors its material leases on a quarterly basis.

Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of future lease payments over the expected remaining lease term. Lease cost for operating leases is recognized on a straight-line basis over the lease term as an operating expense. Certain adjustments to the ROU asset may be required for items such as lease prepayments or incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment.

The Company has elected to account for the lease and non-lease components together for office, laboratory, and manufacturing real estate leases.

Research and Development

Research and development expenses include costs directly attributable to the conduct of the Company’s research and development programs.

Expenditures relating to research and development are expensed in the period incurred. Nonrefundable advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment

is made. The cost of materials for a research and development activity that have an alternative future use is capitalized when the materials are acquired and recognized as expense as consumed. The costs of materials that were acquired for a particular research and development activity and have no alternative future use are expensed in the period acquired.

Costs incurred in obtaining licenses are recognized as research and development expense as incurred if the license has no alternative use.

Accrued Research and Development Expenses

The Company has entered into various research and development related contracts, including contracts with third-party contract research organizations and contract manufacturing organizations. These agreements are cancelable, and related payments are recognized as research and development expenses as incurred. The Company records accrued liabilities for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes the progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. To date, the Company’s historical accrual estimates have not been materially different from the actual costs.

Stock-Based Compensation Expense

The Company accounts for stock-based compensation under the provisions of ASC 718-10, Compensation—Stock Compensation (“ASC 718-10”), which requires all share-based payments to employees, non-employees and directors, including grants of stock options and restricted stock, to be recognized in the consolidated statements of operations and comprehensive loss based on their fair values on the date of grant over the requisite service period, which is generally the vesting period of the respective award. Forfeitures are accounted for as they occur. Generally, the Company issues awards with only service-based vesting conditions and records the expense for these awards using the ratable method. The Company classifies stock-based compensation expense in the same manner in which the award recipient’s payroll or service provider’s costs are classified. Share-based payments that contain performance conditions are recognized when such conditions are probable of being achieved.

The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date.

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model, which requires inputs based on certain subjective assumptions, including the following:

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Fair Value of Common Stock—See the discussion below.

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Expected Term—The expected term represents the period that the stock-based awards are expected to be outstanding. The Company uses the simplified method to determine the expected term, which is based on the average of the time-to-vesting and the contractual life of the options.

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Expected Volatility—Because the Company does not have sufficient trading history for its common stock as of December 31, 2022, the expected volatility was estimated based on the average volatility for comparable publicly traded biotechnology companies over a period equal to the expected term of the stock option grants. The comparable companies were chosen based on the similar size, stage in life cycle or area of specialty. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

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Risk-Free Interest Rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the awards.

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Dividend Yield—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

The Company began to use the closing common stock price as reported on the Nasdaq Global Select Market exchange as the fair value of common stock on the date of a grant subsequent to its IPO. Prior to the Company's IPO the estimated fair value of common stock was determined by the Company’s board of directors as of the date of each option grant, with input from management, considering third-party valuations of its common stock as well as the Company’s board of directors’ assessment of additional objective and subjective factors that it believed were relevant and which may have changed from the date of the most recent third-party valuation through the date of the

grant. These objective and subjective factors include: (i) prices paid for the Company’s redeemable convertible preferred stock, and the rights, preferences, and privileges of the Company’s redeemable convertible preferred stock and common stock; (ii) the Company’s stage of development; (iii) the fact that the grants of stock-based awards related to illiquid securities in a private company; and (iv) the likelihood of achieving a liquidity event for the common stock underlying the stock-based awards, such as an initial public offering or sale of the Company, given prevailing market conditions. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately Held Company Equity Securities Issued as Compensation. Each valuation methodology includes estimates and assumptions that require the Company’s judgment. The methodology utilized to estimate the fair value of the Company’s common stock was the option-pricing method (“OPM”) to back-solve the estimated value of the Company’s equity and corresponding value of the Company’s common stock.

Income Taxes

The Company accounts for income taxes using the asset and liability approach. Deferred tax assets and liabilities represent future tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of assets and liabilities and for loss carryforwards using enacted tax rates expected to be in effect in the years in which the differences reverse. A valuation allowance is established to reduce deferred tax assets to the amounts expected to be realized. The Company also recognizes a tax benefit from uncertain tax positions only if it is “more likely than not” that the position is sustainable based on its technical merits. The Company accounts for interest or penalties related to uncertain tax positions as part of its provision for income taxes. To date, the Company has not incurred interest and penalties related to uncertain tax positions. Should such costs be incurred, they would be classified as a component of provision for income taxes.

Net Loss Per Share

Net loss attributable to common stockholders is equal to the net loss for the period, as adjusted for cumulative dividends on redeemable convertible preferred stock, for the respective period.

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the reporting period, without consideration for potentially dilutive securities. Diluted net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding during the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share attributable to common stockholders calculation, restricted stock and stock options considered to be potentially dilutive securities were excluded from the calculation of diluted net loss per share attributable to common stockholders because their effect would be anti-dilutive and therefore, basic and diluted net loss per share attributable to common stockholders were the same for all reporting periods presented.

Recent Accounting Pronouncements

From time to time, new accounting pronouncements are issued and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the “JOBS Act”), the Company meets the definition of an emerging growth company and has elected to take advantage of the extended transition period for complying with certain new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. As noted below, certain new or revised accounting standards were early adopted.

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which has been subsequently amended by ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-10, ASU 2019-11 and ASU 2020-03 (“ASU 2016-13”). This standard requires that credit losses be recorded using an expected losses model rather than the incurred losses model that was previously used and establishes additional credit risk disclosures associated with financial assets. The adoption of this standard on January 1, 2022, did not have a significant impact on the Company’s financial statements.