Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Basis of Consolidation	Basis of Consolidation The accompanying consolidated financial statements include us and our wholly-owned Australian subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. We operate in one reportable segment, and our functional and reporting currency is the U.S. dollar.
Use of Estimates	Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with U.S. GAAP requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. We base our estimates and assumptions on historical experience when available and on various factors that we believe to be reasonable under the circumstances. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation, and the liability related to the sale of future royalties. We evaluate our estimates and assumptions on an ongoing basis. Our actual results could differ from these estimates under different assumptions or conditions.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments with a maturity at date of purchase of three months or less to be cash equivalents. Cash equivalents consist primarily of money market and mutual funds with original maturities of 90 days or less.
Short Term and Long Term Investments	Short-Term and Long-Term Investments All investments have been classified as “available-for-sale” and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Investments with contractual maturities less than 12 months at the balance sheet date are considered short-term investments. Those investments with contractual maturities 12 months or greater at the balance sheet date are considered long-term investments. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). We review our portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss). No credit impairment losses have been recorded during the years ended December 31, 2023, 2022, or 2021.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject us to a concentration of credit risk consist of cash and cash equivalents and certain investments in money market funds, certificates of deposit, agency securities, commercial obligations and U.S. Treasury securities. Bank deposits are diversified between three financial institutions and these deposits may exceed insured limits. We are exposed to credit risk in the event of default by the financial institutions holding our cash and cash equivalents and issuers of investments that are recorded on our consolidated balance sheets. We mitigate our risk by investing in high-grade instruments and limiting the concentration in any one issuer, which limits our exposure.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, less accumulated depreciation. Expenditures for major additions and betterments are capitalized. Maintenance and repairs are charged to operations as incurred. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets, which range from three to seven years. Leasehold improvements are amortized using the straight-line method over the term of the lease. Upon sale or retirement of property and equipment, the related cost and accumulated depreciation are removed from the accounts and any gain or loss is reflected in operations.
Long Lived Assets	Long Lived Assets Long-lived assets, consisting of property and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted cash flows. If long-lived assets are impaired, an impairment loss is recognized and is measured as the amount by which the carrying value exceeds the estimated fair value of the assets.
Leases	Leases Our leases consist of a lease for office and lab space that is classified as an operating lease. We determine if an arrangement is a lease at inception. Rent expense is recognized on a straight-line basis. When an operating lease includes rent abatements or requires fixed escalations of the minimum lease payments, the aggregate rental expense is recognized on a straight-line basis over the term of the lease. When an operating lease includes lease incentives such as leasehold improvement allowances, the lease incentive is included in ROU asset. For leases that have greater than a 12-month lease term, the ROU assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term. For this purpose, we consider only payments that are fixed and determinable at the time of commencement. As our lease does not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. We account for fixed lease components separately from non-lease components. We elected the practical expedient to not record leases with an initial term of 12 months or less on the balance sheet and recognize the associated lease payments in the consolidated statements of operations on a straight-line basis over the lease term.
Liability Related to the Sale of Future Royalties	Liability Related to the Sale of Future Royalties We treat the liability related to the sale of future royalties as debt, amortized under the effective interest rate method over the estimated life of the Jemperli Royalty Monetization Agreement and the Zejula Royalty Monetization Agreement. See Note 5. The amortization of the liability related to the sale of future revenue is based on our current estimates of future royalty payments. Royalty and milestone revenue will be recognized as earned and the payments made will be recorded as a reduction of the liability when paid.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs related to a recognized debt liability are deferred and amortized over the term of the debt using the effective interest method. These costs are recorded as a direct reduction to the carrying value of the debt on the balance sheet and the amortization expense is included in non-cash interest expense in the statement of operations.
Non-Cash Interest Expense on the Liability Related to the Sale of Future Royalties	Non-Cash Interest Expense on the Liability Related to the Sale of Future Royalties The total threshold of royalties to be paid, less the net proceeds received will be recorded as non-cash interest expense over the life of the liability. We impute interest on the unamortized portion of the liability using the effective interest method and record expense based on the timing of payments received over the term of the Jemperli Royalty Monetization Agreement and the Zejula Royalty Monetization Agreement. Over the course of the agreement, the actual interest rate will be affected by the timing of royalty and milestone payments made and changes in the forecasted revenue.
Revenue Recognition	Revenue Recognition Revenue is recognized in accordance with revenue recognition accounting guidance, which utilizes five basic steps to determine whether revenue can be recognized and to what extent: (i) identify the contract with a customer; (ii) identify the performance obligation; (iii) determine the transaction price; (iv) allocate the transaction price; and (v) determine the recognition period. Performance Obligations. We evaluate deliverables on a contract-by-contract basis to determine whether each deliverable represents a good or service that is distinct or has the same pattern of transfer as other deliverables. A deliverable is considered distinct if the customer can benefit from the good or service independently of other goods/services either in the contract or that can be obtained elsewhere, without regard to contract exclusivity, and the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contact. If the deliverable is not considered distinct, we combine such deliverables and account for them as a single performance obligation. We allocate the consideration to each deliverable at the inception of the arrangement based on the transaction price. Our performance obligations may include the following: •License Arrangements. The performance obligations under our collaboration and license agreements generally include exclusive or nonexclusive licenses to one or more products generated using our technologies. Licenses for multiple antibodies within a single contract are generally combined as they have substantially the same pattern of transfer to the customer. Historically, our licenses have held no value to the customer, as the antibodies were in the discovery phase and required our expertise for further development. Accordingly, licenses are not considered distinct. •Research and Development Services. The performance obligations under our collaboration and license agreements generally include research and development services we perform on behalf of or with our collaborators. As discussed within license arrangements above, our licenses have historically held no value without the research and development services we provide. As we generally only provide research and development services for internally generated antibodies that require a license to be utilized by a third party, our research and development services are not considered distinct. •Steering Committee Meetings. The performance obligations under our collaboration and license agreements may also include our participation on steering committees, which allows us to direct the progression of our discovery programs. As these steering committees would not occur or benefit the customer without the use of our licenses, these are not considered distinct. We recognize consideration allocated to a performance obligation as the performance obligation is satisfied, and the determination as to whether consideration is recognized over time or at a point in time is made upon contract inception. For our collaboration agreements, this is generally over the period in which research and development services have been performed. There were no new agreements with performance obligations entered into during the year ended December 31, 2023. Transaction Price. Our collaboration and license agreements generally include both fixed and variable consideration. Fixed payments, such as those for upfront fees are included in the transaction price at contract value, while variable consideration such as reimbursement for research and development services, milestone and royalty payments are estimated and then evaluated for constraints upon inception of the contract and evaluated on a quarterly basis thereafter. Research and development services are updated for actual invoices. Given the nature of our agreements, milestones are estimated using the most likely amount and are evaluated on a quarterly basis. Upon commercialization, royalty payments will be recognized in the period incurred. Royalty Revenue We receive royalty revenue on sales by our partners of products covered by patents or contract rights that we own and net sales of their approved drugs, where we have concluded the license is the predominant item to which the royalties relate. We do not have future performance obligations under these license arrangements. We generally satisfy our obligation to grant intellectual property rights on the effective date of the contract. However, we apply the royalty recognition constraint required under the guidance for sales-based royalties, which requires a sales-based royalty to be recorded when the underlying sale occurs. Therefore, royalties on sales of products commercialized by our partners are recognized in the quarter the product is sold. Our partners generally report sales information to us on a quarter lag. Thus, we estimate the expected royalty proceeds based on an analysis of our partners’ historical experience including their publicly announced sales. Differences between actual and estimated royalty revenues are adjusted for in the period in which they become known, typically the following quarter. As of December 31, 2023, there have not been material differences between actual and estimated royalty revenues.
Research and Development Expenses	Research and Development Expenses Research and development costs primarily include third-party clinical and preclinical research and development services such as manufacturing, laboratory and related supplies, salaries and personnel-related costs, in-licensing fees, outside services, and an allocation of information technology, and facility overhead costs. Costs associated with research and development activities are expensed as incurred. We account for nonrefundable advance payments for goods and services that will be used in future research and development activities as expense when the service has been performed or when the goods have been received. We estimate research and development costs incurred during the period, which impacts the amount of accrued expenses and prepaid balances related to such costs as of each balance sheet date. This process involves reviewing open contracts and purchase orders, communicating with our personnel and service providers to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. The majority of our service providers invoice us monthly in arrears for services performed or when contractual milestones are met. We make estimates of our accrued expenses as of each balance sheet date based on facts and circumstances known to us at that time. We periodically confirm the accuracy of our estimates with the service providers and make adjustments if necessary. The significant estimates in our accrued research and development expenses include the costs incurred for services performed by our vendors in connection with research and development activities for which we have not yet been invoiced. Upfront and milestone payments incurred under our in-licensing agreements are expensed as acquired in-process research and development in the period in which they are incurred, provided that the technology or method has no alternative future use. Acquired In-process Research and Development Acquired in-process research and development costs consist of upfront payments incurred in connection with the acquisition of licensing of products or technologies that do not meet the definition of a business under the Accounting Standards of Codification Topic 805, Business Combinations.
Stock-Based Compensation	Stock-Based Compensation We recognize stock-based compensation expense using a fair-value-based method for costs related to all share-based payments, including stock options. Stock-based compensation cost for stock options granted to our employees and directors is measured at the grant date based on the fair-value of the award which is estimated using the Black-Scholes option-pricing model, and is recognized as expense over the requisite service period on a straight-line basis. We recognize forfeitures in the period in which forfeitures occur and record stock-based compensation expense as though all awards are expected to vest. We record the expense for stock-based compensation awards subject to performance-based milestone vesting over the requisite service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions at each reporting date. Each Restricted Stock Unit (“RSU”) represents one equivalent share of our common stock to be issued after satisfying the applicable continued service-based vesting criteria over a specified period. The fair value of these RSUs is based on the closing price of our common stock on the date of the grant. We measure compensation expense over the expected vesting period on a straight-line basis. No tax benefits for stock-based compensation have been recognized in the statements of changes in stockholders’ equity or cash flows. We have not recognized, and do not expect to recognize in the near future, any tax benefit related to stock-based compensation cost as a result of our full valuation allowance on net deferred tax assets and net operating loss carryforwards.
Income Taxes	Income Taxes We account for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to be recovered or settled. Realization of deferred tax assets is dependent upon future taxable income. A valuation allowance is recognized if it is more likely than not that some portion or all of a deferred tax asset will not be realized based on the weight of available evidence, including expected future earnings. We recognize an uncertain tax position in our consolidated financial statements when we conclude that a tax position is more likely than not to be sustained upon examination based solely on technical merits. Only after a tax position passes the first step of recognition will measurement be required. Under the measurement step, the tax benefit is measured as the largest amount of benefit that is more likely than not to be realized upon effective settlement. This is determined on a cumulative probability basis. The full impact of any change in recognition or measurement is reflected in the period in which such change occurs. We have elected to accrue any interest or penalties related to income taxes as part of our income tax expense.
Foreign Currency of Foreign Operations	Functional Currency of Foreign Operations Our Australian subsidiary operates in a U.S. dollar functional currency environment. Assets and liabilities of our foreign subsidiary that are not denominated in the functional currency are remeasured into U.S. dollars at foreign currency exchange rates in effect at the balance sheet date except for nonmonetary assets and capital accounts, which are remeasured at historical foreign currency exchange rates in effect at the date of transaction. Expenses are generally remeasured at monthly foreign currency exchange rates which approximate average rates in effect during each period. Net realized and unrealized gains and losses from foreign currency transactions and remeasurement are reported in other income (expense), net, in the consolidated statements of operations.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) represents all changes in stockholders’ equity except those resulting from distributions to stockholders. Our unrealized gain and losses on available for sale investments represent the only component of other comprehensive income (loss) that is excluded from the reported net income (loss).
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common equivalent shares outstanding for the period, as well as any dilutive effect from outstanding stock options and warrants using the treasury stock method. For each period presented, there is no difference in the number of shares used to calculate basic and diluted net loss per share.
Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements We have implemented all new accounting pronouncements that are in effect and may have an impact on our consolidated financial statements. Unless otherwise discussed, we believe the impact of any recently issued pronouncements, not yet effective will not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires enhanced disclosure of significant segment expenses on an annual and interim basis. The guidance will be effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning December 15, 2024, with early adoption permitted. Upon adoption, the guidance should be applied retrospectively to all prior periods presented in the financial statements. We are currently assessing the impact that this standard will have on our consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures Income Taxes, which improves the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This guidance will be effective for the annual periods beginning after December 15, 2024. Early adoption is permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. We are currently assessing the impact that this standard will have on our consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

The accompanying consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).

Basis of Consolidation

The accompanying consolidated financial statements include us and our wholly-owned Australian subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. We operate in one reportable segment, and our functional and reporting currency is the U.S. dollar.

Use of Estimates

The preparation of the accompanying consolidated financial statements in conformity with U.S. GAAP requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. We base our estimates and assumptions on historical experience when available and on various factors that we believe to be reasonable under the circumstances. Significant estimates relied upon in preparing these financial statements include estimates related to revenue recognition, accrued research and development expenses, stock-based compensation, and the liability related to the sale of future royalties. We evaluate our estimates and assumptions on an ongoing basis. Our actual results could differ from these estimates under different assumptions or conditions.

Cash and Cash Equivalents

We consider all highly liquid investments with a maturity at date of purchase of three months or less to be cash equivalents. Cash equivalents consist primarily of money market and mutual funds with original maturities of 90 days or less.

Short Term and Long Term Investments

Short-Term and Long-Term Investments

All investments have been classified as “available-for-sale” and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Investments with contractual maturities less than 12 months at the balance sheet date are considered short-term investments. Those investments with contractual maturities 12 months or greater at the balance sheet date are considered long-term investments. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold. Unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss). We review our portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss). No credit impairment losses have been recorded during the years ended December 31, 2023, 2022, or 2021.

Concentration of Credit Risk

Financial instruments that potentially subject us to a concentration of credit risk consist of cash and cash equivalents and certain investments in money market funds, certificates of deposit, agency securities, commercial obligations and U.S. Treasury securities. Bank deposits are diversified between three financial institutions and these deposits may exceed insured limits. We are exposed to credit risk in the event of default by the financial institutions holding our cash and cash equivalents and issuers of investments that are recorded on our consolidated balance sheets. We mitigate our risk by investing in high-grade instruments and limiting the concentration in any one issuer, which limits our exposure.

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation. Expenditures for major additions and betterments are capitalized. Maintenance and repairs are charged to operations as incurred. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the assets, which range from three to seven years. Leasehold improvements are amortized using the straight-line method over the term of the lease. Upon sale or retirement of property and equipment, the related cost and accumulated depreciation are removed from the accounts and any gain or loss is reflected in operations.

Long Lived Assets

Long-lived assets, consisting of property and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable based on undiscounted cash flows. If long-lived assets are impaired, an impairment loss is recognized and is measured as the amount by which the carrying value exceeds the estimated fair value of the assets.

Leases

Our leases consist of a lease for office and lab space that is classified as an operating lease. We determine if an arrangement is a lease at inception. Rent expense is recognized on a straight-line basis. When an operating lease includes rent abatements or requires fixed escalations of the minimum lease payments, the aggregate rental expense is recognized on a straight-line basis over the term of the lease. When an operating lease includes lease incentives such as leasehold improvement allowances, the lease incentive is included in ROU asset. For leases that have greater than a 12-month lease term, the ROU assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term. For this purpose, we consider only payments that are fixed and determinable at the time of commencement.

As our lease does not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. We account for fixed lease components separately from non-lease components.

We elected the practical expedient to not record leases with an initial term of 12 months or less on the balance sheet and recognize the associated lease payments in the consolidated statements of operations on a straight-line basis over the lease term.

We treat the liability related to the sale of future royalties as debt, amortized under the effective interest rate method over the estimated life of the Jemperli Royalty Monetization Agreement and the Zejula Royalty Monetization Agreement. See Note 5. The amortization of the liability related to the sale of future revenue is based on our current estimates of future royalty

payments. Royalty and milestone revenue will be recognized as earned and the payments made will be recorded as a reduction of the liability when paid.

Debt Issuance Costs

Debt issuance costs related to a recognized debt liability are deferred and amortized over the term of the debt using the effective interest method. These costs are recorded as a direct reduction to the carrying value of the debt on the balance sheet and the amortization expense is included in non-cash interest expense in the statement of operations.

Non-Cash Interest Expense on the Liability Related to the Sale of Future Royalties

The total threshold of royalties to be paid, less the net proceeds received will be recorded as non-cash interest expense over the life of the liability. We impute interest on the unamortized portion of the liability using the effective interest method and record expense based on the timing of payments received over the term of the Jemperli Royalty Monetization Agreement and the Zejula Royalty Monetization Agreement. Over the course of the agreement, the actual interest rate will be affected by the timing of royalty and milestone payments made and changes in the forecasted revenue.

Revenue Recognition

Revenue is recognized in accordance with revenue recognition accounting guidance, which utilizes five basic steps to determine whether revenue can be recognized and to what extent: (i) identify the contract with a customer; (ii) identify the performance obligation; (iii) determine the transaction price; (iv) allocate the transaction price; and (v) determine the recognition period.

Performance Obligations. We evaluate deliverables on a contract-by-contract basis to determine whether each deliverable represents a good or service that is distinct or has the same pattern of transfer as other deliverables. A deliverable is considered distinct if the customer can benefit from the good or service independently of other goods/services either in the contract or that can be obtained elsewhere, without regard to contract exclusivity, and the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contact. If the deliverable is not considered distinct, we combine such deliverables and account for them as a single performance obligation. We allocate the consideration to each deliverable at the inception of the arrangement based on the transaction price.

Our performance obligations may include the following:

•License Arrangements. The performance obligations under our collaboration and license agreements generally include exclusive or nonexclusive licenses to one or more products generated using our technologies. Licenses for multiple antibodies within a single contract are generally combined as they have substantially the same pattern of transfer to the customer. Historically, our licenses have held no value to the customer, as the antibodies were in the discovery phase and required our expertise for further development. Accordingly, licenses are not considered distinct.

•Research and Development Services. The performance obligations under our collaboration and license agreements generally include research and development services we perform on behalf of or with our collaborators. As discussed within license arrangements above, our licenses have historically held no value without the research and development services we provide. As we generally only provide research and development services for internally generated antibodies that require a license to be utilized by a third party, our research and development services are not considered distinct.

•Steering Committee Meetings. The performance obligations under our collaboration and license agreements may also include our participation on steering committees, which allows us to direct the progression of our discovery programs. As these steering committees would not occur or benefit the customer without the use of our licenses, these are not considered distinct.

We recognize consideration allocated to a performance obligation as the performance obligation is satisfied, and the determination as to whether consideration is recognized over time or at a point in time is made upon contract inception. For our collaboration agreements, this is generally over the period in which research and development services have been performed. There were no new agreements with performance obligations entered into during the year ended December 31, 2023.

Transaction Price. Our collaboration and license agreements generally include both fixed and variable consideration. Fixed payments, such as those for upfront fees are included in the transaction price at contract value, while variable consideration such as reimbursement for research and development services, milestone and royalty payments are estimated and then evaluated for constraints upon inception of the contract and evaluated on a quarterly basis thereafter. Research and development services are updated for actual invoices. Given the nature of our agreements, milestones are estimated using the most likely amount and are evaluated on a quarterly basis. Upon commercialization, royalty payments will be recognized in the period incurred.

Royalty Revenue

We receive royalty revenue on sales by our partners of products covered by patents or contract rights that we own and net sales of their approved drugs, where we have concluded the license is the predominant item to which the royalties relate. We do not have future performance obligations under these license arrangements. We generally satisfy our obligation to grant intellectual property rights on the effective date of the contract. However, we apply the royalty recognition constraint required under the guidance for sales-based royalties, which requires a sales-based royalty to be recorded when the underlying sale occurs. Therefore, royalties on sales of products commercialized by our partners are recognized in the quarter the product is sold. Our partners generally report sales information to us on a quarter lag. Thus, we estimate the expected royalty proceeds based on an analysis of our partners’ historical experience including their publicly announced sales. Differences between actual and estimated royalty revenues are adjusted for in the period in which they become known, typically the following quarter. As of December 31, 2023, there have not been material differences between actual and estimated royalty revenues.

Research and Development Expenses

Research and development costs primarily include third-party clinical and preclinical research and development services such as manufacturing, laboratory and related supplies, salaries and personnel-related costs, in-licensing fees, outside services, and an allocation of information technology, and facility overhead costs.

Costs associated with research and development activities are expensed as incurred. We account for nonrefundable advance payments for goods and services that will be used in future research and development activities as expense when the service has been performed or when the goods have been received. We estimate research and development costs incurred during the period, which impacts the amount of accrued expenses and prepaid balances related to such costs as of each balance sheet date. This process involves reviewing open contracts and purchase orders, communicating with our personnel and service providers to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. The majority of our service providers invoice us monthly in arrears for services performed or when contractual milestones are met. We make estimates of our accrued expenses as of each balance sheet date based on facts and circumstances known to us at that time. We periodically confirm the accuracy of our estimates with the service providers and make adjustments if necessary. The significant estimates in our accrued research and development expenses include the costs incurred for services performed by our vendors in connection with research and development activities for which we have not yet been invoiced.

Upfront and milestone payments incurred under our in-licensing agreements are expensed as acquired in-process research and development in the period in which they are incurred, provided that the technology or method has no alternative future use.

Acquired In-process Research and Development

Acquired in-process research and development costs consist of upfront payments incurred in connection with the acquisition of licensing of products or technologies that do not meet the definition of a business under the Accounting Standards of Codification Topic 805, Business Combinations.

Stock-Based Compensation

We recognize stock-based compensation expense using a fair-value-based method for costs related to all share-based payments, including stock options. Stock-based compensation cost for stock options granted to our employees and directors is measured at the grant date based on the fair-value of the award which is estimated using the Black-Scholes option-pricing model, and is recognized as expense over the requisite service period on a straight-line basis. We recognize forfeitures in the period in which forfeitures occur and record stock-based compensation expense as though all awards are expected to vest.

We record the expense for stock-based compensation awards subject to performance-based milestone vesting over the requisite service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions at each reporting date.

Each Restricted Stock Unit (“RSU”) represents one equivalent share of our common stock to be issued after satisfying the applicable continued service-based vesting criteria over a specified period. The fair value of these RSUs is based on the closing price of our common stock on the date of the grant. We measure compensation expense over the expected vesting period on a straight-line basis.

No tax benefits for stock-based compensation have been recognized in the statements of changes in stockholders’ equity or cash flows. We have not recognized, and do not expect to recognize in the near future, any tax benefit related to stock-based compensation cost as a result of our full valuation allowance on net deferred tax assets and net operating loss carryforwards.

Income Taxes

We account for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities and are measured using enacted tax rates and laws that are expected to be in effect when the differences are expected to be recovered or settled. Realization of deferred tax assets is dependent upon future taxable income. A valuation allowance is recognized if it is more likely than not that some portion or all of a deferred tax asset will not be realized based on the weight of available evidence, including expected future earnings.

We recognize an uncertain tax position in our consolidated financial statements when we conclude that a tax position is more likely than not to be sustained upon examination based solely on technical merits. Only after a tax position passes the first step of recognition will measurement be required. Under the measurement step, the tax benefit is measured as the largest amount of benefit that is more likely than not to be realized upon effective settlement. This is determined on a cumulative probability basis. The full impact of any change in recognition or measurement is reflected in the period in which such change occurs. We have elected to accrue any interest or penalties related to income taxes as part of our income tax expense.

Foreign Currency of Foreign Operations

Functional Currency of Foreign Operations

Our Australian subsidiary operates in a U.S. dollar functional currency environment. Assets and liabilities of our foreign subsidiary that are not denominated in the functional currency are remeasured into U.S. dollars at foreign currency exchange rates in effect at the balance sheet date except for nonmonetary assets and capital accounts, which are remeasured at historical foreign currency exchange rates in effect at the date of transaction. Expenses are generally remeasured at monthly foreign currency exchange rates which approximate average rates in effect during each period. Net realized and unrealized gains and losses from foreign currency transactions and remeasurement are reported in other income (expense), net, in the consolidated statements of operations.

Comprehensive Income (Loss)

Comprehensive income (loss) represents all changes in stockholders’ equity except those resulting from distributions to stockholders. Our unrealized gain and losses on available for sale investments represent the only component of other comprehensive income (loss) that is excluded from the reported net income (loss).

Net Loss Per Common Share

Basic net loss per common share is computed by dividing net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common equivalent shares outstanding for the period, as well as any dilutive effect from outstanding stock options and warrants using the treasury stock method. For each period presented, there is no difference in the number of shares used to calculate basic and diluted net loss per share.

Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Adopted

Accounting Pronouncements

We have implemented all new accounting pronouncements that are in effect and may have an impact on our consolidated financial statements. Unless otherwise discussed, we believe the impact of any recently issued pronouncements, not yet effective will not have a material impact on our consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which requires enhanced disclosure of significant segment expenses on an annual and interim basis. The guidance will be effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning December 15, 2024, with early adoption permitted. Upon adoption, the guidance should be applied retrospectively to all prior periods presented in the financial statements. We are currently assessing the impact that this standard will have on our consolidated financial statements.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures Income Taxes, which improves the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the effective tax rate reconciliation and income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. This guidance will be effective for the annual periods beginning after December 15, 2024. Early adoption is permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. We are currently assessing the impact that this standard will have on our consolidated financial statements.