Annual Report for Fiscal Year Ending December 31, 2024 (Form 10-K)

Management's Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis should be read in conjunction with the audited consolidated financial statements and related notes included elsewhere in this Annual Report. This discussion and analysis and other parts of this Annual Report contain forward-looking statements based upon current beliefs, plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and projections. Our actual results and the timing of selected events could differ materially from those anticipated in these forward-looking statements as a result of several factors, including those set forth under Part I, Item 1A, "Risk Factors" and elsewhere in this Annual Report. You should carefully read the "Risk Factors" section of this Annual Report to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements. Please also see the section titled "Special Note Regarding Forward-Looking Statements."

Overview

We are a clinical-stage biotechnology company developing precision therapies to treat solid tumors designed to preserve organ function. Our lead candidate bel-sar is in late-stage clinical development for the treatment of patients with primary choroidal melanoma and is also in clinical development for other ocular oncology indications and bladder cancer.

There is significant unmet need for novel treatments for patients with choroidal melanoma, given the limitations of the current standard of care, or SoC, and patient reluctance to undergo radiotherapy in the form of either plaque brachytherapy or proton beam therapy, both highly-invasive therapies that result in significant vision loss, and potential legal blindness in the treated eye. Enucleation, or surgical removal of the affected eye, is another treatment option for patients with choroidal melanoma, in which patients lose all vision without the possibility of vision restoration. We are evaluating the safety and efficacy of bel-sar as a potential vision-sparing therapy in our ongoing global Phase 3 CoMpass trial for the first-line treatment of adult patients with small choroidal melanoma and indeterminate lesions, or early-stage choroidal melanoma. Moreover, we intend to assess the safety and efficacy of bel-sar in treating a range of other solid tumors, beginning with metastases of the choroid and bladder cancer where bel-sar is in clinical development. We believe bel-sar, if approved, has the potential to change the current treatment paradigm for patients with ocular and urologic cancers and other solid tumors.

Bel-sar has shown clinical benefit and has been generally well-tolerated in clinical trials to date. In a Phase 2 study (ClinicalTrials.gov ID: NCT04417530) evaluating suprachoroidal administration of bel-sar for the first-line treatment of early-stage choroidal melanoma, patients were closely monitored over a twelve-month follow-up period to assess tumor control, visual acuity preservation, and tumor growth rate. A total of 22 patients were enrolled in the study. Bel-sar achieved an 80% tumor control rate (n=8/10) among Phase 3-eligible patients who received the therapeutic regimen, with complete cessation of growth following treatment among responders (post-treatment average growth rate of 0.011 mm/yr among responders compared to 0.351 mm/yr prior to study entry; p<0.0001). Visual acuity preservation was achieved in 90% of these ten patients. Importantly, 80% of these ten patients were at high risk for vision loss with tumors close to the fovea or optic disc, highlighting the potential for vision preservation with this novel class of drugs. The safety profile of bel-sar was highly favorable in all participants regardless of dose. We believe the Phase 2 results are a significant achievement considering the typically poor prognosis associated with choroidal melanoma, a rare and life-threatening ocular cancer, where there are no approved vision-preserving therapies to date. We believe bel-sar has the possibility to transform the field of ocular oncology beyond choroidal melanoma and we plan to expand clinical development in two additional indications: metastases to the choroid and cancers of the ocular surface. We have initiated a Phase 2 clinical trial in metastases to the choroid and have activated sites with patients in prescreening. We also plan to continue to advance our preclinical work designed to be IND-enabling in cancers of the ocular surface.

VDCs are a novel class of drugs with a dual mechanism of action that promote cancer cell death by both the delivery of the cytotoxic payload to generate acute necrosis and activation of a secondary immune mediated response. Bel-sar, our lead VDC candidate, consists of modified capsid proteins of the human papilloma virus, or HPV, conjugated to hundreds of light-activated molecules.

Light activation of bel-sar is designed to result in precise tumor cell killing with minimal damage to surrounding healthy tissues. In the absence of bel-sar activation or binding to the tumor cell membrane, there is no cytotoxic effect. Multiple light activations, following a single dose of bel-sar, increase antitumor activity because of the reoxygenation of the tumor and the photostability of bel-sar. Finally, acute necrosis triggers immunogenic cell death leading to the generation of an adaptive, long-term antitumor immune response. The tumor targeting specificity of

VDCs is driven by the selective binding of the VLPs to a subset of modified tumor associated glycosaminoglycans, or GAGs, that are part of the heparan sulphate chain of heparan sulfate proteoglycans or HSPGs, expressed on the tumor cell membrane. This targeting mechanism enables the delivery of multiple types of cytotoxic payloads directly to a wide range of solid tumors.

Beyond ocular cancers, bel-sar is in early-stage clinical development in bladder cancer. Bladder cancer is the ninth most common cancer worldwide and it is diagnosed early as non-muscle invasive bladder cancer, or NMIBC, with a prevalence of approximately 80,000 cases per year in the United States. Despite the early diagnosis, patients with NMIBC have a high risk of recurrence and progression with current SoC treatments. In March 2025, we announced positive data from our Phase 1 trial in NMIBC (NCT05483868).

We were incorporated as a Delaware corporation in 2009 and our headquarters are located in Boston, Massachusetts. Since our inception, we have focused our efforts on identifying and developing potential product candidates, conducting preclinical studies and clinical trials, organizing and staffing our company, business planning, establishing our intellectual property portfolio, raising capital, conducting discovery, research and development activities and providing general and administrative support for these operations. We do not have any product candidates approved for sale and have not generated any revenue to date. We have funded our operations primarily through the sale of convertible preferred stock, common stock, and warrants. From inception through December 31, 2024, we have raised an aggregate of approximately $419.9 million of gross proceeds primarily from private placements of our equity and convertible preferred stock as well as through the issuance of our common stock. On November 9, 2023, we issued and sold 11,000,000 shares of common stock at a price to the public of $9.00 per share for aggregate gross proceeds of $99.0 million, or the 2023 Follow-On Offering. We received approximately $92.6 million in net proceeds from the 2023 Follow-On Offering after deducting underwriting discounts and commissions and offering expenses. On December 5, 2022, we issued and sold 7,705,000 shares of common stock, including the full exercise of the underwriters' option to purchase additional shares at a price to the public of $12.00 per share, for aggregate gross proceeds of $92.5 million, or the 2022 Follow-On Offering. We received approximately $86.7 million in net proceeds from the 2022 Follow-On Offering after deducting underwriting discounts, commissions and offering expenses. On November 1, 2022, we filed a shelf registration statement on Form S-3, or the 2022 Shelf, with the SEC in relation to the registration of up to an aggregate offering price of $250.0 million of common stock, preferred stock, debt securities, warrants and units or any combination thereof. We also simultaneously entered into an Open Market Sale AgreementSM, or the Sales Agreement, with Jefferies LLC, or the Sales Agent, to provide for the offering, issuance and sale by us of up to an aggregate of $75.0 million of its common stock from time to time in "at-the-market" offerings, or the ATM, under the 2022 Shelf and subject to the limitations thereof. In connection with the 2023 Follow-On Offering, on November 6, 2023, we delivered written notice to Jefferies that we were suspending and terminating the prospectus related to the shares issuable in the ATM pursuant to the terms of the Sales Agreement. During the year ended December 31, 2023, we issued a total of 261,807 shares of common stock at an average price of $12.49 for aggregate gross proceeds of $3.3 million under the ATM. On March 27, 2024, we filed a new shelf registration statement on Form S-3, or the 2024 Shelf, with the SEC in relation to the registration of up to an aggregate offering price of $350.0 million of common stock, preferred stock, debt securities, warrants and units or any combination thereof, which superseded the 2022 Shelf. The 2024 Shelf included a prospectus supplement to provide for offerings in the ATM under the Sales Agreement. We did not issue any shares of common stock during the year ended December 31, 2024 under the ATM.

We have incurred significant operating losses in every year since our inception in 2009 and have not generated any revenue. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our ability to generate product revenue sufficient to achieve profitability will depend on the successful development and commercialization of one or more of our product candidates. Our net losses were $86.9 million and $76.4 million for the years ended December 31, 2024 and 2023, respectively. As of December 31, 2024, we had an accumulated deficit of $374.2 million. In addition, our losses from operations may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our clinical trials and our expenditures on other research and development activities.

We anticipate that our expenses and capital requirements will increase substantially in connection with our ongoing activities, particularly as we advance the preclinical studies and clinical trials of our product candidates. In addition, we incur additional costs associated with operating as a public company. We expect that our expenses and capital requirements will increase substantially if and as we:

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations or other strategic transactions. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on favorable terms, or at all. If we fail to raise capital or enter into such agreements as, and when, needed, we may have to significantly delay, scale back or discontinue the development and commercialization of one or more of our product candidates.

We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain marketing approval for our product candidates. The lengthy process of securing marketing approvals for new drugs requires the expenditure of substantial resources. Any delay or failure to obtain regulatory approvals would materially adversely affect the development efforts of our product candidates and our business overall. Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate revenue from product sales, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and be forced to reduce or terminate our operations.

As of December 31, 2024, we had cash and cash equivalents and marketable securities of $151.1 million. We believe that our existing cash and cash equivalents and marketable securities will enable us to fund our operating expenses and capital expenditure requirements into the second half of 2026. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See "Liquidity and Capital Resources" below.

Components of Our Results of Operations

Revenue

Since inception, we have not generated any revenue and do not expect to generate any revenue from the sale of products in the foreseeable future. If our development efforts for one or more of our product candidates are successful and result in regulatory approval, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from collaboration or license agreements. We cannot predict if, and when, or to what extent, we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.

Operating Expenses

Research and Development Expenses

Research and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts and the development of our bel-sar program, and include:

We expense research and development costs as incurred. Costs for external development activities are recognized based on an evaluation of the progress to completion of specific tasks using information provided to us by our vendors. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our financial statements as prepaid or accrued research and development expenses. We allocate our direct external research and development costs across the entire bel-sar program. Preclinical expenses consist of external research and development costs associated with activities to support our current and future clinical programs, but are not allocated by specific indications due to the overlap of the potential benefit of those efforts across the entire bel-sar program.

Research and development activities are central to our business. We expect that our research and development expenses will increase for the foreseeable future as we continue clinical development for bel-sar and continue to discover and develop additional product candidates. If any of our product candidates enter into later stages of clinical development, they will generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials.

General and Administrative Expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive and finance functions. General and administrative expenses also include professional fees for legal, accounting, auditing, tax and consulting services; travel expenses; and facility-related expenses, which include allocated expenses for rent and maintenance of facilities and other operating costs not included in research and development.

We expect that our general and administrative expenses will increase in the near-term as we continue to build a team to support our administrative, accounting and finance, communications, legal and business development efforts. We expect to incur increased expenses associated with our growth, including costs of accounting, audit, legal, regulatory and tax compliance services; director and officer insurance costs; and investor and public relations costs.

Other Income (Expense)

Our other income (expense) consists of accretion, interest income and realized gains and losses on marketable securities, interest income on our invested cash balances, and gains and losses on disposals of equipment.

Income Tax Provision, Net

For the year ended December 31, 2024, we recorded a $0.1 million income tax provision related to current state income taxes. Since our inception, we have not recorded any U.S. federal or state tax benefits for our net operating loss carryforwards or research and development tax credits due to the realizability of future taxable income to utilize these tax attributes. As of December 31, 2024, we had accumulated federal, state, and foreign net operating loss carryforwards of approximately $209.8 million, $183.6 million, and $0.7 million, respectively, which may be available to offset future taxable income before applicable expiration periods. As of December 31, 2024, we had federal and state research and development credit carryforwards of $11.3 million and $2.9 million, respectively, which may be available to offset future income tax liabilities before applicable expiration periods. We have recorded a full valuation allowance against the tax benefits, as the determination of the realization of the deferred tax assets was not determined to be more likely than not.

Results of Operations

Comparison of the Years Ended December 31, 2024 and 2023

The following table summarizes our results of operations for the years ended December 31, 2024 and 2023:

		Year Ended December 31,
		2024				2023				Change
		(in thousands)
Operating expenses:
Research and development		$	73,302			$	65,232			$	8,070
General and administrative			22,814				19,759				3,055
Total operating expenses			96,116				84,991				11,125
Loss from operations			(96,116	)			(84,991	)			(11,125	)
Other income (expense):
Interest income, including amortization and accretion income			9,429				8,588				841
Gain on disposal of property and equipment			-				208				(208	)
Other expense			(120	)			(76	)			(44	)
Total other income			9,309				8,720				589
Loss before income taxes			(86,807	)			(76,271	)			(10,536	)
Income tax provision, net			(112	)			(137	)			25
Net loss		$	(86,919	)		$	(76,408	)		$	(10,511	)

Research and Development Expenses

The following table summarizes our research and development expenses for the years ended December 31, 2024 and 2023:

		Year Ended December 31,
		2024				2023				Change
		(in thousands)
Preclinical		$	1,651			$	805			$	846
Clinical trials			22,512				17,310				5,202
Manufacturing development			15,977				12,992				2,985
Personnel/overhead expenses			33,162				34,125				(963	)
Total research and development expenses		$	73,302			$	65,232			$	8,070

Research and development expenses increased to $73.3 million for the year ended December 31, 2024, from $65.2 million for the year ended December 31, 2023, primarily due to ongoing clinical and CRO costs associated with the progression of our Phase 3 global trial, and manufacturing and development costs for bel-sar.

General and Administrative Expenses

General and administrative expenses increased to $22.8 million for the year ended December 31, 2024, from $19.8 million for the year ended December 31, 2023, primarily driven by personnel expenses, as well as increases in general corporate expenses related to the global growth of our company.

Liquidity and Capital Resources

To date we have funded our operations primarily through the sale of convertible preferred stock, warrants and common stock. Through December 31, 2024, we have raised an aggregate of approximately $419.9 million of gross proceeds primarily from private placements of our equity and convertible preferred stock and warrants, as well as through the issuance of our common stock. On November 9, 2023, we issued and sold 11,000,000 shares of common stock at a price to the public of $9.00 per share for aggregate gross proceeds of $99.0 million in the 2023 Follow-On Offering. We received approximately $92.6 million in net proceeds from the 2023 Follow-On Offering after deducting underwriting discounts and commissions and offering expenses. On December 5, 2022, we issued and sold 7,705,000 shares of common stock, including the full exercise of the underwriters' option to purchase additional shares at a price to the public of $12.00 per share for aggregate gross proceeds of $92.5 million in the 2022 Follow-On Offering. We received approximately $86.7 million in net proceeds from the 2022 Follow-On Offering after deducting underwriting discounts, commissions and offering expenses. On November 1, 2022, we filed the 2022 Shelf with the SEC in relation to the registration of up to an aggregate offering price of $250.0 million of common stock, preferred stock, debt securities, warrants and units or any combination thereof. We also simultaneously entered into the Sales Agreement with the Sales Agent to provide for the offering, issuance and sale by us of up to an aggregate of $75.0 million of our common stock from time to time in the ATM under the 2022 Shelf and subject to the limitations thereof. In connection with the 2023 Follow-On Offering, on November 6, 2023, we delivered written notice to Jefferies that we were suspending and terminating the prospectus related to the shares issuable in the ATM pursuant to the terms of the Sales Agreement. During the year ended December 31, 2023, we issued a total of 261,807 shares of common stock at an average price of $12.49 for aggregate gross proceeds of $3.3 million under the ATM. On March 27, 2024, we filed a new shelf registration statement on Form S-3, or the 2024 Shelf, with the SEC in relation to the registration of up to an aggregate offering price of $350.0 million of common stock, preferred stock, debt securities, warrants and units or any combination thereof, which superseded the 2022 Shelf. The 2024 Shelf included a prospectus supplement to provide for offerings in the ATM under the Sales Agreement. We did not issue any shares of common stock during the year ended December 31, 2024 under the ATM.

The following table summarizes our cash flows for each of the periods presented:

		Year Ended December 31,
		2024				2023
		(in thousands)
Net cash used in operating activities		$	(79,805	)		$	(63,847	)
Net cash provided by (used in) investing activities			68,821				(113,963	)
Net cash provided by financing activities			1,595				97,290
Net decrease in cash, cash equivalents, and restricted cash		$	(9,389	)		$	(80,520	)

Operating Activities

During the year ended December 31, 2024, net cash used in operating activities was $79.8 million, primarily due to our net loss of $86.9 million and an increase in clinical and CRO prepaid expenses and other assets for bel-sar, partially offset by an increase in stock-based compensation expense.

During the year ended December 31, 2023, net cash used in operating activities was $63.8 million, primarily due to our net loss of $76.4 million, partially offset by an increase in accrued clinical and CRO expenses for bel-sar.

Investing Activities

Net cash provided by investing activities for the year ended December 31, 2024 was $68.8 million, primarily due to maturities of marketable securities, partially offset by purchases of marketable securities and property and equipment.

Net cash used in investing activities for the year ended December 31, 2023 was $114.0 million, primarily due to purchases of marketable securities and property and equipment, partially offset by proceeds from maturities of marketable securities.

Financing Activities

During the year ended December 31, 2024, net cash provided by financing activities was $1.6 million from proceeds from stock option exercises and ESPP purchases.

During the year ended December 31, 2023, net cash provided by financing activities was $97.3 million from the net proceeds from the 2023 Follow-On Offering, ATM draw-downs, and proceeds from stock option exercises and ESPP purchases.

Funding Requirements

Our plan of operation is to continue implementing our business strategy, continue research and development of bel-sar and any other product candidates we may acquire or develop and continue to expand our research pipeline and our internal research and development capabilities. We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the preclinical activities and clinical trials of our current and future product candidates. In addition, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or terminate our research and development programs or future commercialization efforts. Our future capital requirements will depend on many factors, including:

A change in the outcome of any of these variables with respect to the development of a product candidate could mean a significant change in the costs and timing associated with the development of that product candidate. As of December 31, 2024, we had cash, cash equivalents, and marketable securities of $151.1 million. Based on our research and development plans, we believe that our existing cash, cash equivalents, and marketable securities will be sufficient to fund our operations into the second half of 2026. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect.

Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations from the sale of additional equity or debt financings, or other capital which comes in the form of strategic collaborations, licensing, or other arrangements. In the event that additional financing is required, we may not be able to raise it on terms acceptable to us, or at all. If we raise additional funds through the issuance of equity or convertible preferred stock, it may result in dilution to our existing stockholders. Debt financing or preferred equity financing, if available, may result in increased fixed payment obligations, and the existence of securities with rights

that may be senior to those of our common stock. If we incur indebtedness, we could become subject to covenants that would restrict our operations.

If we raise funds through strategic collaboration, licensing or other arrangements, we may relinquish significant rights or grant licenses on terms that are not favorable to us. Our ability to raise additional funds may be adversely impacted by potential worsening global economic conditions and the recent disruptions to, and volatility in, the credit and financial markets in the United States and worldwide. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market products or product candidates that we would otherwise prefer to develop and market ourselves.

Material Cash Requirements

The following table summarizes our contractual obligations and commitments as of December 31, 2024.

								Payments Due by Period
			Total					Less than 1 Year					1 to 3 Years					3 to 5 Years					More than 5 Years
			(in thousands)
Operating lease commitments		$		27,653			$		3,306					6,913					7,327					10,107
Total		$		27,653			$		3,306			$		6,913			$		7,327			$		10,107

On May 16, 2022, we entered into an office and laboratory lease in Boston, MA with an initial 10-year term and one renewal option to extend the lease for an additional seven years. The lease commenced on August 1, 2022.

Except as disclosed in the table above, we have no long-term debt or finance leases and no material non-cancelable purchase commitments with service providers, as we have generally contracted on a cancelable, purchase-order basis. We enter into contracts in the normal course of business with equipment and reagent vendors, CROs, CDMOs and other third parties for clinical trials, preclinical research studies and testing and manufacturing services. These contracts are cancelable by us upon prior notice. Payments due upon cancellation consist only of payments for services provided or expenses incurred, including noncancelable obligations of our service providers, up to the date of cancellation. We have also acquired exclusive and non-exclusive rights to use, research, develop and offer for sale certain products and patents under license agreements. The license agreements obligate us to make payments to the licensors for license fees, milestones, license maintenance fees and royalties. These payments are not included in the preceding table as the amount and timing of such payments are not known.

Critical Accounting Policies and Significant Judgments and Estimates

Our management's discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles, or U.S. GAAP. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in greater detail in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Research and Development Costs

We expense all costs in performing research and development activities in the periods in which they are incurred. Research and development expenses include salaries and benefits, stock-based compensation expense, lab supplies and facility costs, as well as fees paid to nonemployees and entities that conduct certain research and development activities on our behalf and expenses incurred in connection with license agreements. Non-refundable advance payments for goods or services that will be used for rendered or future research and development activities are deferred and amortized over the period that the goods are delivered, or the related services are performed, subject to an assessment of recoverability.

As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses. We make estimates of our accrued expenses as of each balance sheet date in the consolidated financial statements based on facts and circumstances known to us at that time. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the expense. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, we adjust the accrual or the amount of prepaid expenses accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in reporting amounts that are too high or too low in any particular period. To date, there have not been any material adjustments to our prior estimates of accrued research and development expenses.

Stock-Based Compensation

We account for our stock-based compensation as expense in the consolidated statements of operations and comprehensive loss based on the awards' grant date fair values. We account for forfeitures as they occur by reversing any expense recognized for unvested awards.

For grants of restricted stock units, we base the fair value on the stock price as of the date of grant. We estimate the fair value of options granted using the Black-Scholes option pricing model. The Black-Scholes option pricing model requires inputs based on certain subjective assumptions, including (a) the expected stock price volatility, (b) the calculation of expected term of the award, (c) the risk-free interest rate and (d) expected dividends. Due to a lack of company-specific historical and implied volatility data, we have based our estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. The historical volatility is calculated based on a period of time commensurate with the expected term assumption. The computation of expected volatility is based on the historical volatility of a representative group of companies with similar characteristics to us, including stage of product development and life science industry focus. We use the simplified method as allowed by the SEC, Staff Accounting Bulletin, or SAB, No. 107,Share-Based Payment, to calculate the expected term for options granted to employees as we do not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. The expected dividend yield is assumed to be zero as we have never paid dividends and have no current plans to pay any dividends on our common stock. The fair value of stock-based payments is recognized as expense over the requisite service period which is generally the vesting period.

Recent Accounting Pronouncements

See Note 2 in our consolidated financial statements included elsewhere in this Annual Report on Form 10-K for a description of recent accounting pronouncements applicable to our consolidated financial statements. Other than as disclosed in our consolidated financial statements, we do not expect that any recently issued accounting standards will have a material impact on our consolidated financial statements or will otherwise apply to our operations.

Emerging Growth Company and Smaller Reporting Company Status

The JOBS Act permits that an "emerging growth company" may take advantage of the extended transition period to comply with new or revised accounting standards applicable to public companies until those standards would otherwise apply to private companies. We have elected to use the extended transition period under the JOBS Act. Accordingly, our consolidated financial statements may not be comparable to the financial statements of public companies that comply with such new or revised accounting standards. The JOBS Act also exempts us from having to provide an auditor attestation of internal control over financial reporting under Sarbanes-Oxley Act Section 404(b).

We will remain an "emerging growth company" until the earliest of: the last day of the fiscal year in which we have more than $1.235 billion in annual revenue; the date we qualify as a "large accelerated filer," with at least $700.0 million of equity securities held by non-affiliates; the issuance, in any three-year period, by us of more than $1.0 billion in non-convertible debt securities; or the last day of the fiscal year ending after the fifth anniversary of our IPO.

We are also a "smaller reporting company," meaning that the market value of our stock held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during the most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our stock held by non-affiliates is less than $250 million or (ii) our annual revenue is less than $100 million during the most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700 million.

If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company we will not be required to obtain a separate attestation of internal control over financial reporting, or ICFR, from an outside auditor.