Vaxcyte, Inc. 10-K

Item 8. Financial Statements and Supplementary Data. INDEX TO FINANCIAL STATEMENTS Report of Independent Registered Public Accounting Firm 2 Balance Sheets 2 Statements of Operations and Comprehensive Loss 2 Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit ) 2 Statements of Cash Flows 2 Notes to Financial Statements 2 117 Report of Independent Registered Public Accounting Firm To the stockholders and the Board of Directors of Vaxcyte, Inc. Opinion on the Financial Statements We have audited the accompanying balance sheets of Vaxcyte, Inc. (the "Company") as of December 31, 2020 and 2019, the related statements of operations and comprehensive loss, redeemable convertible preferred stock and stockholders' equity (deficit), and cash flows, for each of the three years in the period ended December 31, 2020, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2020 and 2019, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2020, in conformity with accounting principles generally accepted in the United States of America. Basis for Opinion These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion. /s/ Deloitte & Touche LLP San Francisco, California March 29, 2021 We have served as the Company’s auditor since 2017. 118 VAXCYTE, INC. Balance Sheets (in thousands, except share and per share data) December 31, 2020 2019 Assets Current assets: Cash and cash equivalents $ 386,200 $ 58,976 Prepaid expenses and other current assets 2,804 2,747 Total current assets 389,004 61,723 Property and equipment, net 3,272 3,391 Other assets 550 584 Total assets $ 392,826 $ 65,698 Liabilities, Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) Current liabilities: Accounts payable $ 29,785 $ 3,376 Accrued compensation 284 414 Accrued manufacturing expenses 13,012 5,777 Accrued expenses (including related party accrual of $ 677 and $ 15 as of December 31, 2020 and December 31, 2019, respectively) 3,766 1,305 Deferred rent — current portion 14 19 Lease liability — current portion — 161 Total current liabilities 46,861 11,052 Deferred rent — long-term portion 10 17 Redeemable convertible preferred stock warrant liability — 450 Other liabilities 112 242 Total liabilities 46,983 11,761 Commitments and contingencies (Note 5) Redeemable Convertible Preferred Stock Series A redeemable convertible preferred stock, $ 0.001 par value; no and 10,502,804 shares authorized at December 31, 2020 and December 31, 2019, respectively; no and 6,225,719 shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively; liquidation value of $ 0 and $ 26,887 at December 31, 2020 and December 31, 2019, respectively — 24,967 Series B redeemable convertible preferred stock, $ 0.001 par value; no and 11,449,515 shares authorized at December 31, 2020 and December 31, 2019, respectively; no and 6,786,896 shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively; liquidation value of $ 0 and $ 60,150 at December 31, 2020 and December 31, 2019, respectively — 55,151 Series C redeemable convertible preferred stock, $ 0.001 par value; no and 14,010,043 shares authorized at December 31, 2020 and December 31, 2019, respectively; no and 7,377,480 shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively; liquidation value of $ 0 and $ 85,000 at December 31, 2020 and December 31, 2019, respectively — 80,192 Stockholders' Equity (Deficit) Preferred stock, $ 0.001 par value — 10,000,000 and no shares authorized at December 31, 2020 and December 31, 2019, respectively; no shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively — — Common stock, $ 0.001 par value — 500,000,000 and 52,000,000 shares authorized at December 31, 2020 and December 31, 2019, respectively; 51,071,593 and 4,059,909 shares issued and outstanding at December 31, 2020 and December 31, 2019, respectively 54 7 Additional paid-in capital 544,353 2,967 Accumulated deficit ( 198,564 ) ( 109,347 ) Total stockholders' equity (deficit) 345,843 ( 106,373 ) Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit) $ 392,826 $ 65,698 The accompanying notes are an integral part of these financial statements. 119 VAXCYTE, INC. Statements of Operations and Comprehensive Loss (in thousands, except share and per share data) Year Ended December 31, 2020 2019 2018 Operating expenses: Research and development (including related party expenses of $ 1,331 , $ 1,137 and $ 1,878 in 2020, 2019 and 2018, respectively) $ 73,564 $ 45,607 $ 30,145 General and administrative 16,017 8,546 5,388 Total operating expenses 89,581 54,153 35,533 Loss from operations ( 89,581 ) ( 54,153 ) ( 35,533 ) Other income (expense), net: Interest expense ( 7 ) ( 40 ) ( 75 ) Interest income 244 632 903 Grant income 2,478 237 — Foreign currency transaction losses ( 2,351 ) ( 135 ) 42 Change in fair value of the redeemable convertible preferred stock tranche liability — 3,185 5,178 Total other income (expense), net 364 3,879 6,048 Net loss and comprehensive loss $ ( 89,217 ) $ ( 50,274 ) $ ( 29,485 ) Net loss per share, basic and diluted $ ( 3.02 ) $ ( 13.25 ) $ ( 8.12 ) Weighted-average shares outstanding, basic and diluted 29,545,810 3,795,090 3,629,896 The accompanying notes are an integral part of these financial statements. 120 VAXCYTE, INC. Statements of Redeemable Convertible Preferred Stock and Stockholders’ Equity (Deficit) (in thousands, except share data) Series A Series B Series C Series D Total Redeemable Convertible Redeemable Convertible Redeemable Convertible Redeemable Convertible Additional Stockholders’ Preferred Stock Preferred Stock Preferred Stock Preferred Stock Common Stock Paid-in Accumulated Equity Shares Amount Shares Amount Shares Amount Shares Amount Shares Amount Capital Deficit (Deficit) Balance — December 31, 2017 6,225,719 $ 24,967 4,524,600 $ 35,101 — $ — — $ — 3,671,235 $ 6 $ 452 $ ( 29,588 ) $ ( 29,130 ) Issuance of Series C redeemable convertible preferred stock, net of issuance costs of $ 206 and fair value of redeemable convertible preferred stock tranche liability of $ 4,602 — — — — 3,688,740 37,692 — — — — — — — Issuance of Series B redeemable convertible preferred stock, net of issuance costs of $ 229 — — 2,262,296 20,050 — — — — — — — — — Exercise of stock options 17,336 — 5 — 5 Issuance of common stock related to early exercised stock options — — — — — — — — 68,832 — — — — Vesting of early exercised stock options — — — — — — — — — — 133 — 133 Stock-based compensation expense — — — — — — — — — — 749 — 749 Net loss — — — — — — — — — — — ( 29,485 ) ( 29,485 ) Balance — December 31, 2018 6,225,719 24,967 6,786,896 55,151 3,688,740 37,692 — — 3,757,403 6 1,339 ( 59,073 ) ( 57,728 ) Issuance of Series C redeemable convertible preferred stock, net of issuance costs of $ 0 — — — — 3,688,740 42,500 — — — — — — — Exercise of stock options — — — — — — — — 243,230 1 321 — 322 Issuance of common stock related to early exercised stock options — — — — — — — — 59,276 — — — — Vesting of early exercised stock options — — — — — — — — — — 122 — 122 Stock-based compensation expense — — — — — — — — — — 1,185 — 1,185 Net loss — — — — — — — — — — — ( 50,274 ) ( 50,274 ) Balance — December 31, 2019 6,225,719 $ 24,967 6,786,896 $ 55,151 7,377,480 $ 80,192 — $ — 4,059,909 $ 7 $ 2,967 $ ( 109,347 ) $ ( 106,373 ) Issuance of Series D redeemable convertible preferred stock, net of issuance costs of $ 121 — — — — — — 8,220,242 $ 109,879 — — — — — Conversion of preferred stock ( 6,225,719 ) ( 24,967 ) ( 6,786,896 ) ( 55,151 ) ( 7,377,480 ) ( 80,192 ) ( 8,220,242 ) ( 109,879 ) 28,610,337 29 270,161 270,190 Conversion of common stock warrant — — — — — — — — 30,278 — — — — Conversion of preferred stock warrant — — — — — — — — 16,591 — — — — Warrant liability write-off — — — — — — — — — — 629 — 629 Issuance of common stock upon initial public offering, net of issuance costs of $ 3,368 — — — — — — — — 17,968,750 18 263,989 — 264,007 Exercise of stock options — — — — — — — — 343,444 — 635 — 635 Issuance of common stock related to early exercised stock options — — — — — — — — 14,819 — — — — Issuance of common stock under Employee Stock Purchase Plan — — — — — — — — 27,465 — 374 374 Vesting of early exercised stock options — — — — — — — — — — 164 — 164 Issuance of preferred stock — — — — — — — — — — — — Stock-based compensation expense — — — — — — — — — — 5,434 — 5,434 Net loss — — — — — — — — — — — ( 89,217 ) ( 89,217 ) Balance — December 31, 2020 — $ — — $ — — $ — — $ — 51,071,593 $ 54 $ 544,353 $ ( 198,564 ) $ 345,843 The accompanying notes are an integral part of these financial statements. 121 VAXCYTE, INC. Statements of Cash Flows (in thousands) (unaudited) Year Ended December 31, 2020 2019 2018 Cash flows from operating activities: Net loss $ ( 89,217 ) $ ( 50,274 ) $ ( 29,485 ) Adjustments to reconcile net loss to net cash used in operating activities: Depreciation and amortization 1,405 1,232 1,037 Stock-based compensation expense 5,434 1,185 749 Expense on issuance of redeemable convertible preferred stock warrant — — 465 Change in fair value of redeemable convertible preferred stock warrant 179 ( 12 ) ( 3 ) Change in fair value of redeemable convertible preferred stock tranche liabilities — ( 3,185 ) ( 5,178 ) Loss on disposal of assets 34 1 54 Asset impairment charges 267 — — Changes in operating assets and liabilities: Prepaid expenses and other current assets ( 58 ) ( 1,070 ) ( 378 ) Other assets ( 75 ) 120 ( 412 ) Accounts payable 26,102 868 1,266 Accrued compensation ( 130 ) ( 775 ) 541 Accrued manufacturing expenses 7,235 3,970 1,646 Accrued expenses 2,207 718 73 Accrued legal settlement — — ( 850 ) Deferred rent and other long-term liabilities ( 11 ) 77 9 Net cash used in operating activities ( 46,628 ) ( 47,145 ) ( 30,466 ) Cash flows from investing activities: Purchases of property and equipment ( 1,155 ) ( 1,195 ) ( 1,774 ) Proceeds from sale of property and equipment 50 — 1 Net cash used in investing activities ( 1,105 ) ( 1,195 ) ( 1,773 ) Cash flows from financing activities: Payments of capital lease obligations ( 61 ) ( 278 ) ( 283 ) Proceeds from initial public offering, net of underwriters' commissions and discounts 267,375 — — Payment of issuance costs for initial public offering ( 3,368 ) — — Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs 109,879 42,500 62,345 Proceeds from exercise of common stock options 635 322 5 Proceeds from issuance of common stock related to early exercised stock options 36 120 123 Proceeds from issuance of common stock under the Employee Stock Purchase Plan 374 — — Payments of deferred offering costs — ( 1,097 ) — Net cash provided by financing activities 374,870 41,567 62,190 Effect of exchange rate changes on cash and cash equivalents 87 ( 341 ) — Net increase (decrease) in cash and cash equivalents 327,224 ( 7,114 ) 29,951 Cash and cash equivalents, beginning of period 58,976 66,090 36,139 Cash and cash equivalents, end of period $ 386,200 $ 58,976 $ 66,090 Supplemental disclosure of cash flow information: Cash paid for interest $ 7 $ 40 $ 75 Supplemental disclosures of non-cash investing and financing activities: Purchases of property and equipment recorded in accounts payable and accrued expenses $ 494 $ 21 $ 3 Conversion of convertible preferred stock into common stock $ 270,190 $ — $ — Deferred offering costs included in accounts payable and accrued expenses $ 134 $ 33 $ — The accompanying notes are an integral part of these unaudited financial statements. 122 VAXCYTE, INC. Notes to Financial Statements 1. Company Organization and Nature of Business Vaxcyte, Inc. (“we”, “us”, “the Company”, or “Vaxcyte”), headquartered in Foster City, California, was incorporated in the state of Delaware on November 27, 2013 as SutroVax, Inc. and we changed our name to Vaxcyte, Inc. in May 2020. We are a next-generation vaccine company seeking to improve global health by developing superior and novel vaccines designed to prevent or treat some of the most common and deadly infectious diseases worldwide. Our cell-free protein synthesis platform enables us to design and produce protein carriers and antigens, the critical building blocks of vaccines, in ways that we believe conventional vaccine technologies currently cannot. Our pipeline includes pneumococcal conjugate vaccine (“PCV”) candidates that we believe are among the most broad-spectrum PCV candidates currently in development, targeting the $ 7 billion global pneumococcal vaccine market. Our lead vaccine candidate, VAX-24, is a 24-valent investigational PCV. We anticipate submitting our initial investigational new drug (“IND”) application to the U.S. Food and Drug Administration (“FDA”) for VAX-24 between January and June 2022 and initiating our Phase 1/2 clinical proof-of-concept study in adults thereafter. We expect to announce topline data from this study between late 2022 and early 2023. Our second PCV candidate, VAX-XP, leverages our scalable and modular platform and builds on the technical proof of concept established by VAX-24 and is designed to expand the breadth of coverage to at least 30 strains without compromising immunogenicity due to carrier suppression. In addition to our PCV franchise, our pipeline includes a novel conjugate vaccine candidate for Group A Strep, a novel protein vaccine candidate targeting the keystone pathogen responsible for periodontitis and other discovery-stage programs. Our primary activities since incorporation have been to perform research and development, undertake preclinical studies and enable manufacturing activities in support of our product development efforts, organize and staff the Company, plan for the business and establish our intellectual property portfolio, and raise capital to support and expand such activities. Reverse Stock Split On June 5, 2020, we filed a certificate of amendment to our amended and restated certificate of incorporation to effect a one-for-1.6870 reverse stock split of our issued and outstanding common stock, preferred stock, stock options and warrants effective on June 5, 2020. Accordingly, all share and per share amounts for all periods presented in the financial statements and notes thereto have been retroactively adjusted. Initial Public Offering In June 2020, we completed an initial public offering (“IPO”) in which we issued and sold 17,968,750 shares of common stock, including shares issued upon the exercise in full of the underwriters’ option to purchase 2,343,750 additional shares of common stock, at a public offering price of $ 16.00 per share. We received $ 264.0 million in net proceeds, after deducting underwriting discounts and commissions of $ 20.1 million and offering expenses of $ 3.4 million. Immediately prior to the completion of our IPO, all outstanding shares of redeemable convertible preferred stock were converted into 28,610,337 shares of common stock. Subsequent to the completion of the IPO, there were no shares of redeemable convertible preferred stock outstanding. 2. Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding annual reporting. Certain changes in presentation were made in these financial statements as of and for the years ended December 31, 2018 and 2019 to conform to the presentation as of and for the year ended December 31, 2020. 123 Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities at the date of the financial statements. On an ongoing basis, we evaluate our estimates and assumptions, including those related to stock-based compensation expense, accruals for certain research and development costs, the valuation of deferred tax assets and income taxes. Management bases our estimates on historical experience and on various other assumptions that are believed to be 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. Actual results may differ materially from those estimates. Concentration of Credit Risk and Other Risks and Uncertainties Financial instruments that potentially subject us to a concentration of credit risk consist primarily of cash and cash equivalents. We invested in money market funds as of December 31, 2020. We maintain bank deposits in federally insured financial institutions and these deposits may exceed federally insured limits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash and cash equivalents. We have not experienced any losses on our deposits of cash and cash equivalents. We are subject to supplier concentration risk from our suppliers. We source our critical raw materials from a sole source supplier, Sutro Biopharma, Inc. (“Sutro Biopharma”). We also use one contract manufacturing organization (“CMO”), Lonza Ltd. (“Lonza”), to handle most of our manufacturing activities. If we were to experience disruptions in raw materials supplied by Sutro Biopharma, or in manufacturing activities at Lonza, we may experience significant delays in our product development timelines and may incur substantial costs to secure alternative sources of raw materials or manufacturing. Our future results of operations involve a number of other risks and uncertainties. Factors that could affect our future operating results and cause actual results to vary materially from expectations include, but are not limited to: our early stages of clinical vaccine development; our ability to advance vaccine candidates into, and successfully complete, clinical trials on the timelines we project; our ability to adequately demonstrate sufficient safety and efficacy of our vaccine candidates; our ability to enroll subjects in our ongoing and future clinical trials; our ability to successfully manufacture and supply our vaccine candidates for clinical trials; our ability to obtain additional capital to finance our operations; our ability to obtain, maintain and protect our intellectual property rights; developments relating to our competitors and our industry, including competing vaccine candidates; general and market conditions; and other risks and uncertainties, including those more fully described in the “Risk Factors” section of this Annual Report on Form 10-K. Segment and Geographical Information We operate and manage our business as one reportable and operating segment. Our chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of our long-lived assets are based in the United States. Long-lived assets are comprised of property and equipment. Cash and Cash Equivalents We consider all highly liquid investments purchased with a maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2020 and 2019, cash and cash equivalents consisted of cash and investments in short-term money market funds. Interest income reflected in the statements of operations consists primarily of interest received on the money market funds. 124 Deferred Offering Costs Deferred offering costs consist of fees and expenses incurred in connection with the sale of our common stock in equity transactions, including legal, accounting, printing and other issuance-related costs. Prior to the completion of equity transactions, deferred offering costs were included in Other assets on the balance sheet. In connection with and as of the closing of equity transactions, these costs would be reclassified to Additional paid-in capital, representing a reduction to the gross proceeds. As of December 31, 2020, $ 3.4 million of IPO-related costs are included in the Additional paid-in capital line item on the balance sheet. As of December 31, 2020 and 2019, $ 0.1 million and $ 1.1 million of deferred offering costs, respectively, were included in Other assets on the balance sheet. Property and Equipment, Net Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are amortized over the shorter of the expected life or lease term. Repairs and maintenance expenditures, which are not considered improvements and do not extend the useful life of property and equipment, are expensed as incurred. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the balance sheet and the resulting gain or loss is reflected in the statements of operations and comprehensive loss in the period realized. Impairment of Long-Lived Assets We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows generated by the assets. There were $ 0.3 million of impairments of long-lived assets during the year ended December 31, 2020 and no impairments of long-lived assets in either the year ended December 31, 2019 or 2018. Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of our financial instruments, including cash and cash equivalents, prepaid and other current assets, accounts payable, accrued expenses, and other liabilities, approximate fair value due to their short-term maturities. Prior to their automatic conversion upon our IPO in June 2020, the redeemable convertible preferred stock tranche liability and redeemable convertible preferred stock warrant were carried at fair value (see Note 3). Research and Development Research and development costs are expensed as incurred. Research and development costs include salaries, stock-based compensation, and benefits for employees performing research and development activities, an allocation of facility and overhead expenses, expenses incurred under agreements with consultants, CMO, contract research organizations (“CROs”) and investigative sites that conduct preclinical studies, other supplies and costs associated with product development efforts, preclinical activities and regulatory operations. 125 Accrued Research and Development We have entered into various agreements with CROs and CMOs. Our research and development accruals are estimated based on the level of services performed, progress of the studies, including the phase or completion of events, and contracted costs. The estimated costs of research and development services provided, but not yet invoiced, are included in accrued expenses on the balance sheet. If the actual timing of the performance of services or the level of effort varies from the original estimates, we will adjust the accrual accordingly. Payments made to CROs or CMOs under these arrangements in advance of the performance of the related services are recorded as prepaid expenses and other current assets until the services are rendered. To date, there have been no material differences between our estimates of such expenses and the amounts actually incurred. Income Taxes We account for income taxes using the asset and liability method. We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. In evaluating the ability to recover our deferred income tax assets, we consider all available positive and negative evidence, including our operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event we determine that we would be able to realize our deferred income tax assets in the future in excess of their net recorded amount, we would make an adjustment to the valuation allowance that would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not to be realizable in the future, an adjustment to the valuation allowance would be charged to earnings in the period when such determination is made. As of December 31, 2020 and 2019, we have recorded a full valuation allowance on our deferred tax assets. Tax benefits related to uncertain tax positions are recognized when it is more likely than not that a tax position will be sustained during an audit. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax. Stock-Based Compensation Expense For options granted to employees, non-employees, and directors, stock-based compensation is measured at grant date based on the fair value of the award. We determine the grant-date fair value of the options using the Black-Scholes option-pricing model. The grant-date fair value of awards is amortized over the employees’ requisite service period or the non-employees’ vesting period as the goods are received or services rendered. Forfeitures are accounted for as they occur. Additionally, our 2020 Employee Stock Purchase Plan is deemed to be a compensatory plan and is therefore included in stock-based compensation expense. Comprehensive Loss Comprehensive loss includes all changes in equity (net assets) during a period from non-owner sources. There have been no items qualifying as other comprehensive income or loss, and as such, comprehensive loss was the same as net loss for the periods presented. Foreign Currency Transactions Transactions denominated in foreign currencies are initially measured in U.S. dollars using the exchange rate on the date of the transaction. Foreign currency denominated monetary assets and liabilities are subsequently re-measured at the end of each reporting period using the exchange rate at that date, with the corresponding foreign 126 currency transaction gain or loss recorded in the statements of operations and comprehensive loss and statements of cash flows. Nonmonetary assets and liabilities are not subsequently re-measured. Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, redeemable convertible preferred stock warrant, common stock subject to repurchase, and stock options are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities as the redeemable convertible preferred stock is considered a participating security. Our participating securities do not have a contractual obligation to share in our losses. As such, the net loss was attributed entirely to common stockholders. Because we have reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. Recently Adopted Accounting Pronouncements In June 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-07, Improvements to Nonemployee Share-Based Payment Accounting , which simplifies the accounting for share-based payments granted to non-employees for goods and services. This standard expands the scope of Topic 718, Compensation-Stock Compensation , to include share-based payments issued to non-employees for goods and services. Consequently, the accounting for share-based payments to non-employees and employees was substantially aligned. The ASU supersedes Subtopic 505-50, Equity — Equity-Based Payments to Non-Employees . This standard is effective for fiscal years beginning after December 15, 2019 and interim periods within fiscal years beginning after December 15, 2020. The standard should be adopted on a modified retrospective basis which recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. We adopted this ASU as of January 1, 2020 . The adoption of this ASU had no material impact on our financial statements or disclosures. Recently Issued Accounting Pronouncements—Not Yet Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) . ASU 2016-02 was subsequently amended by ASU 2018-01, ASU 2018-10, ASU 2018-11, ASU 2018-20, ASU 2019-01, ASU 2019-10 and ASU 2020-05, which the FASB issued in January 2018, July 2018, July 2018, December 2018, March 2019, November 2019 and June 2020, respectively (collectively, the “ASC 842”). ASC 842 requires lessees to recognize leases on the balance sheet and disclose key information about leasing arrangements. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to recognize a ROU asset and a lease liability on the balance sheet for all leases with a term longer than 12 months. Under ASC 842, leases will be classified as either finance leases or operating leases, with classification affecting the pattern and classification of expense recognition in the income statement. 127 The new standard is effective for us on January 1, 2022, with early adoption permitted. We early adopted the new standard effective January 1, 2021 using the modified retrospective transition approach. We have completed a substantial portion of our evaluation of the effect of adopting ASC 842 on our financial statements. Upon adoption on January 1, 2021, we expect to recognize right-of-use assets and lease liabilities totaling approximately $ 1.0 million and $ 1.0 million, respectively, to reflect the present value of remaining lease payments under existing lease arrangements. The difference between the leased assets and lease liabilities represents the existing deferred rent liabilities balance, resulting from historical straight-lining of operating leases, which will be effectively reclassified upon adoption to reduce the measurement of the leased assets. The balance of our deferred rent liabilities to be reclassified to reduce the ROU assets upon adoption is immaterial. While the recognition of the lease assets and liabilities will impact the balance sheet, we do not expect a material impact on our statement of operations and comprehensive loss or cash flows. We will apply the modified retrospective transition approach and will not recast prior periods. Although we are applying this approach, we do not expect to record a cumulative effect adjustment to the opening balance of retained earnings upon adoption. As permitted by the standard, we will elect the transition practical expedient package, which among other things, allows the carryforward of historical lease classifications. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740) . The amendments in ASU 2019-12 simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The amendments also improve consistent application of and simplify U.S. GAAP or other areas of Topic 740 by clarifying and amending existing guidance. The new standard is effective for us on January 1, 2021 and for interim periods within 2021. We do not expect adoption of ASU 2019-12 will have a material impact on our financial statements. 3. Fair Value Measurements and Fair Value of Financial Instruments Assets and liabilities recorded at fair value on a recurring basis in the balance sheets, as well as assets and liabilities measured at fair value on a non-recurring basis or disclosed at fair value, are categorized based upon the level of judgment associated with inputs used to measure their fair values. The accounting guidance for fair value provides a framework for measuring fair value and requires certain disclosures about how fair value is determined. Fair value is defined as the price that would be received upon the sale of an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance also establishes a three-level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows: Level 1— Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2— Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and Level 3 — Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs. Level 1 securities consist of highly liquid money market funds for which the carrying amounts approximate their fair values due to their short maturities. Level 3 liabilities that are measured at fair value on a 128 recurring basis include the redeemable convertible preferred stock warrant. The redeemable convertible preferred stock warrant was measured using an option pricing method by estimating the value using the Black-Scholes model. The inputs used in the Black-Scholes model included the value of the redeemable convertible preferred stock, the risk-free interest rate, the expected term of the instrument and the expected volatility. There was no outstanding redeemable convertible preferred stock warrant as of December 31 , 2020. Below are inputs used for the Level 3 liability as of December 31, 2019: December 31, 2019 Redeemable Convertible Preferred Stock Warrant Value of Series C Redeemable Preferred Stock Per Share $ 6.82 Risk-Free Rate 1.90 % Volatility 73.5 % Term in Years 8.42 During the periods presented, we have not changed the manner in which we value liabilities that are measured at estimated fair value using Level 3 inputs. There were no transfers within the hierarchy during the years ended December 31, 2020, 2019 or 2018. The following tables set forth our financial instruments measured at fair value on a recurring basis by level within the fair value hierarchy at December 31, 2020 and December 31, 2019: December 31, 2020 Total Level 1 Level 2 Level 3 (In thousands) Assets: Money market funds (1) $ 381,412 $ 381,412 $ — $ — December 31, 2019 Total Fair Value Level 1 Level 2 Level 3 (In thousands) Assets: Money market funds (1) $ 48,168 $ 48,168 $ — $ — Liabilities: Redeemable convertible preferred stock warrant liability $ 450 $ — $ — $ 450 (1) Included within cash and cash equivalents on the balance sheet. 129 The following table provides a summary of changes in the estimated fair value of our Level 3 financial instrument, which was written off upon our IPO in June 2020. No new warrant liabilities were issued in the year ended December 31, 2020: Warrant Liability (in thousands) Balance — December 31, 2019 $ 450 Change in fair value 179 Balance — March 31, 2020 629 Warrant liability write-off upon IPO ( 629 ) Balance — June 30, 2020 $ — 4. Balance Sheet Details Property and Equipment, Net Property and equipment, net as of December 31, 2020 and 2019 consisted of the following: December 31, 2020 2019 (in thousands) Furniture and equipment $ 397 $ 397 Computers and computer software 111 146 Lab equipment 4,739 3,260 Leasehold improvements 1,903 1,884 Capital leases — lab equipment — 686 Construction in Progress 219 — Total property and equipment 7,369 6,373 Less: accumulated depreciation and amortization ( 4,097 ) ( 2,982 ) Property and equipment, net $ 3,272 $ 3,391 Depreciation and amortization expense for years ended December 31, 2020, 2019 and 2018 was $ 1.4 million, $ 1.2 million and $ 1.0 million respectively, of which $ 0 , $ 0.2 million and $ 0.3 million related to capital lease amortization expense for the years ended December 31, 2020, 2019 and 2018, respectively. Accrued Expenses Accrued expenses as of December 31, 2020 and 2019 consisted of the following: December 31, 2020 2019 (in thousands) Preclinical studies $ 2,844 $ 844 Professional fees 490 397 Other accrued expenses 432 64 Total $ 3,766 $ 1,305 130 5. Commitments and Contingencies Equipment Leases We entered into several capital lease obligations for lab equipment during 2016 and 2017. The terms of the leases were 36 months with interest rates ranging from 6.9 % to 15.0 %. Interest expense for the years ended December 31, 2020, 2019 and 2018 was immaterial. The present value of the annual rental payments, including guaranteed residual value, was equal to 90 % of the fair market value of the assets at the lease inception dates. The underlying assets and related amortization were included in the appropriate fixed asset category and related depreciation account, respectively. In October 2019 and March 2020, we entered into lease buyout agreements for two pieces of lab equipment. The remaining balances of the capital lease assets for these two pieces of equipment were transferred from Capital leases — lab equipment to Lab equipment at the time of the lease buyouts (See Note 4, “Property and Equipment, Net”). The remaining capital leases had bargain purchase options and we purchased the equipment related to these leases in June 2019 and March 2020 when the leases ended. As of December 31, 2020, there was no remaining balance of lease liability on the balance sheet and there were no future minimum payments required under capital leases. Property and equipment, net at December 31, 2019 included the following amounts for leases that had been capitalized: Useful Life (Years) December 31, 2019 (in thousands) Capital lease equipment 3 - 5 $ 686 Less: accumulated amortization ( 471 ) $ 215 Facility Leases In July 2016, we entered into a five-year lease agreement for our headquarters facility located in Foster City, California (the “Headquarter Facility”). The original term of the lease was from September 1, 2016 to August 31, 2021, with two 30 -month renewal options. In July 2019, we leased another facility in Foster City, California (the “Other Foster City Facility”) as a result of growth in personnel. The original term of this lease began on July 1, 2019 and ends on October 31, 2021, with no renewal options. In November 2020, we extended the term of the lease for both the Headquarter Facility and the Other Foster City Facility for six month s to March 1, 2022 and April 30, 2022, respectively. Both of the Foster City lease agreements provide for escalations of rent payments each year. We record rent expense for these two leases on a straight-line basis over the terms of the leases and deferred rent based on the difference between rent expenses and cash rental payments. In addition to payment of base rent, we are also required to pay property taxes, insurance and common area expenses for both of the Foster City leases. We also lease an office in San Diego, California with a lease term ending on April 30, 2021. In addition to payment of base rent for the San Diego office lease, we are also required to pay common area expenses. Rent is payable monthly for all facility leases. Future minimum payments required under operating leases as of December 31, 2020 are as follows: (in thousands) Years ending December 31, 2021 $ 742 2022 190 Total future minimum payments $ 932 131 Rent expense recognized under the leases was $ 0.7 million, $ 0.6 million and $ 0.4 million for the years ended December 31, 2020, 2019 and 2018, respectively. In January 2021, we entered into a lease agreement for our new corporate headquarters facility to be located in San Carlos, California and a license agreement for temporary lab and office space in Palo Alto, California as we move forward with our development and clinical programs. The lease term commenced on January 22, 2021 (the “Lease Commencement Date”) and will expire 48 months from the first day of the first full month following the Rent Commencement Date (the “Base Term”). The “Rent Commencement Date” is the earlier to occur of (i) the date that is 12 months after the Lease Commencement Date, or (ii) the date that the tenant improvements are substantially completed. We have two 60 -month renewal options after the Base Term expires. The license agreement for temporary space in Palo Alto will terminate when the San Carlos office leasehold improvements are completed and we move into our new corporate headquarters. The total lease payments over the lease term of both our new corporate headquarters and temporary office space in Palo Alto are expected to amount to approximately $ 38.2 million, which includes the lease payments, fixed operating expenses and estimated repayments of tenant improvement allowance. Upon lease commencement, we expect to recognize right-of-use lease assets and corresponding lease liabilities in accordance with ASC 842. Legal Contingencies From time to time, we may become involved in legal proceedings arising from the ordinary course of business. We record a liability for such matters when it is probable that future losses will be incurred and that such losses can be reasonably estimated. Significant judgment by us is required to determine both probability and the estimated amount. We do not believe that there is any litigation or asserted or unasserted claim pending that could, individually or in the aggregate, have a material adverse effect on our results of operations or financial condition. Guarantees and Indemnifications In the normal course of business, we enter into agreements that contain a variety of representations and provide for general indemnification. Our exposure under these agreements is unknown because it involves claims that may be made against us in the future. To date, we have not paid any claims or been required to defend any action related to our indemnification obligations. As of December 31, 2020, we did not have any material indemnification claims that were probable or reasonably possible and consequently have not recorded related liabilities. Indemnification To the extent permitted under Delaware law, we have agreed to indemnify our directors and officers for certain events or occurrences while the director or officer is, or was, serving at our request in such capacity. The indemnification period covers all pertinent events and occurrences during the director’s or officer’s service. The maximum potential amount of future payments we could be required to make under these indemnification agreements is not specified in the agreements; however, we have director and officer insurance coverage that reduces our exposure and enables us to recover a portion of any future amounts paid. We have not incurred any material costs as a result of such indemnification and are not currently aware of any indemnification claims. Development and Manufacturing Services Agreement On October 21, 2016, we entered into a development and manufacturing services agreement with Lonza (the “Lonza DMSA”), pursuant to which Lonza would provide certain process development and manufacturing services and we would pay certain fees according to specified project plans to support our efforts to develop superior, novel conjugate vaccines. In January 2017, July 2017 and September 2017, we entered into amendments to the Lonza DMSA, which significantly expanded the scope of process development and manufacturing work to be provided by Lonza for our lead PCV program. We have the option to cancel signed orders at any time upon written notice, which may or may not be subject to payment of a cancellation fee. The level of cancellation fees is generally dependent on the timing of the written notice in relation to the commencement date of the work, with the maximum cancellation fee equal to the full price of the work order. 132 In the September 2017 amended agreement, we and Lonza agreed to defer the completion payments for any stage that commences after December 31, 2019 or has not been completed by December 31, 2019 until the earlier of the completion of all Investigational New Drug (“IND”)-enabling activities or December 31, 2020. In March 2020, Lonza orally agreed to defer the completion payments until April 30, 2021. In June 2018, we and Lonza agreed to certain terms for potential future equity payments as partial satisfaction of future obligations to Lonza. This agreement states that the initial pre-IND cash payments will be subject to a specified dollar cap (the “Initial Cash Cap”). After the Initial Cash Cap has been reached, we have the option to make any further pre-IND payments due to Lonza in cash, equity, or a combination of both, at our election, provided that Lonza may elect to receive up to 25 % of pre-IND payments in equity, up to a maximum of $ 2.5 million and provided that no more than $ 10 million of pre-IND payments shall be made equity. The Initial Cash Cap had not been reached as of December 31, 2020. As such, no amount has been recorded with respect to the potential future payments above the Initial Cash Cap at December 31, 2020 and December 31, 2019. 6. Redeemable Convertible Preferred Stock There were no shares of redeemable convertible preferred stock authorized or outstanding as of December 31, 2020. In connection with our IPO in June 2020, the outstanding shares of our Series A, Series B, Series C and Series D Redeemable Convertible Preferred Stock automatically converted into 28,610,337 shares of common stock. In March 2020, we sold an aggregate of 8,220,242 shares of our Series D redeemable convertible preferred stock at a purchase price of $ 13.3816 per share for an aggregate purchase price of $ 110.0 million. The authorized, issued and outstanding shares of redeemable convertible preferred stock and liquidation preferences as of December 31, 2019 were as follows: December 31, 2019 Shares Authorized Issued and Outstanding Original Issuance Price Carrying Value Liquidation Preference (In thousands) Series A Redeemable Convertible Preferred 10,502,804 6,225,719 $ 4.32 $ 24,967 $ 26,887 Series B Redeemable Convertible Preferred 11,449,515 6,786,896 8.86 55,151 60,150 Series C Redeemable Convertible Preferred 14,010,043 7,377,480 11.52 80,192 85,000 35,962,362 20,390,095 $ 160,310 $ 172,037 7. Common Stock At December 31, 2020 and December 31, 2019, our certificate of incorporation authorized us to issue up to 500,000,000 and 52,000,000 shares of common stock with $ 0.001 par value per share, respectively, of which 51,071,593 and 4,059,909 shares were issued and outstanding, respectively. The holders of our common stock are also entitled to receive dividends whenever funds are legally available, when and if declared by our board of directors. As of December 31, 2020 and 2019, no dividends have been declared. Each share of common stock is entitled to one vote . 133 Common stock reserved for future issuances under the 2020 Equity Incentive Plan (the “2020 Plan”) and the 2014 Equity Incentive Plan (the “2014 Plan”) is as follows, which excludes 66,982 shares issued outside of the 2014 Plan and 2020 Plan: December 31, December 31, 2020 2019 Options issued and outstanding 5,188,531 3,364,568 Shares available for future stock option grants 4,651,149 835,941 Conversion of redeemable convertible preferred stock — 20,390,095 Common stock warrant — 31,857 Redeemable convertible preferred stock warrant — 59,276 Total 9,839,680 24,681,737 8. Warrants In connection with our IPO in June 2020, the common stock warrant and Series C redeemable convertible preferred stock warrant were automatically net exercised for an aggregate 46,869 shares of common stock. Warrants issued and outstanding as of December 31, 2019 were as follows: Warrants to Purchase Stock Number of Warrants Issued and Outstanding Issue Date Expiration Date Exercise Price Common stock 31,857 July 10, 2015 July 10, 2025 $ 0.79 Series C redeemable convertible preferred stock 59,276 May 29, 2018 May 29, 2028 $ 11.52 Total 91,133 9. Equity Incentive Plans 2020 and 2014 Equity Incentive Plans In June 2020, our board of directors adopted, and our stockholders approved, the 2020 Plan, which became effective on June 11, 2020. Under the 2020 Plan, we may grant stock options, appreciation rights, restricted stock and restricted stock units to employees, consultants and directors. Stock options granted under the 2020 Plan may be either incentive stock options or nonqualified stock options. Incentive stock options may be granted only to our employees, including officers and directors who are also employees. Nonqualified stock options may be granted to our employees, officers, directors, consultants and advisors. The exercise price of stock options granted under the 2020 Plan must be at least equal to the fair market value of the common stock on the date of grant, except that an incentive stock option granted to an employee who owns more than 10 % of the shares of our common stock shall have an exercise price of no less than 110 % of the fair value per share on the grant date and expire five years from the date of grant. The maximum term of stock options granted under the 2020 Plan is 10 years, unless subject to the provisions regarding 10 % stockholders. Our stock options granted to new employees generally vest over four years at a rate of 25 % upon the first anniversary of the vesting commencement date and monthly thereafter. Our other stock options granted to employees generally vest on terms consistent with stock options granted to new employees or monthly over four years from the vesting commencement date. A total of 10,150,000 shares of common stock were approved to be initially reserved for issuance under the 2020 Plan. The number of shares that remained available for issuance under the 2014 Plan as of the effective date of the 2020 Plan and shares subject to outstanding awards under the 2014 Plan as of the effective date of the 2020 Plan that are subsequently canceled, forfeited or repurchased by us will be added to the shares reserved under the 2020 Plan. In addition, the number of shares of common stock available for issuance under the 2020 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2020 Plan, beginning with January 1, 2021 and ending with January 1, 2030, by an amount equal to 5 % of the outstanding number of shares of our common stock on December 31 of the 134 preceding calendar year or such lesser amount as determined by our board of directors. As of December 31, 2020 , an aggregate of 4,651,149 shares of common stock were available for issuance under the 2020 Plan. Effective January 1, 2021, the number of shares of common stock available under the 2020 Plan increased by 2,553,579 shares pursuant to the evergreen provision of the 2020 Plan. Our 2014 Plan permitted the granting of incentive stock options, non-statutory stock options, restricted stock and other stock-based awards. Subsequent to the adoption of the 2020 Plan, no additional equity awards can be made under the 2014 Plan. Shares reserved and remaining available for issuance under the 2014 Plan were added to the 2020 Plan reserve upon its effectiveness. As of December 31, 2020, 4,714,549 shares and 407,000 shares of common stock were subject to outstanding options under the 2014 Plan and 2020 Plan, respectively. The terms of the 2014 Plan permit the exercise of options granted prior to vesting, subject to required approvals. The unvested shares are subject to our lapsing repurchase right upon termination of employment at the original purchase price. Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be issued until those shares vest according to their respective vesting schedules. Cash received for early exercised stock options is recorded as other liabilities on the balance sheet and is reclassified to common stock and additional paid-in capital as such shares vest. At December 31, 2020 and December 31, 2019, 15,056 and 86,409 shares, respectively, remained subject to our right of repurchase as a result of the early exercised stock options. The remaining liabilities related to early exercised shares as of December 31, 2020 and December 31, 2019 were $ 0 and $ 0.2 million, respectively, and were recorded in other liabilities. Activity under our 2020 Plan and 2014 Plan, which excludes options to purchase 66,982 shares granted outside of the 2020 Plan and 2014 Plan, was as follows: Options Outstanding Stock Option Activity Options Available for Grant Number of Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Balances — December 31, 2017 496,729 2,056,087 $ 1.50 Additional shares authorized 1,969,386 — Options granted ( 1,617,228 ) 1,617,228 $ 2.01 Options exercised — ( 86,163 ) $ 1.48 Options forfeited 620,948 ( 620,948 ) $ 0.66 Balances — December 31, 2018 1,469,835 2,966,204 $ 1.79 Options granted ( 887,659 ) 887,659 $ 2.18 Options exercised — ( 302,512 ) $ 1.46 Options forfeited 253,765 ( 253,765 ) $ 1.81 Balances — December 31, 2019 835,941 3,297,586 $ 1.93 Additional shares authorized 5,997,435 — Options granted ( 2,255,690 ) 2,255,690 $ 8.93 Options exercised — ( 358,264 ) $ 1.88 Options forfeited 73,463 ( 73,463 ) $ 3.50 Balances — December 31, 2020 4,651,149 5,121,549 $ 4.99 8.05 $ 112,239 Vested and expected to vest — December 31, 2020 5,121,549 $ 3.83 8.05 $ 112,239 Exercisable at December 31, 2020 1,921,993 $ 1.88 6.57 $ 47,457 During the years ended December 31, 2020, 2019 and 2018, 358,264 , 302,512 and 86,163 shares of stock options, respectively, were exercised for cash at a weighted-average price per share of $ 1.88 , $ 1.46 and $ 1.48 135 respectively. The weighted-average grant date fair value of options granted for the years ended December 31 , 2020 , 2019 and 2018 was $ 9.62 , $ 1.52 and $ 1.38 , respectively. The intrinsic value of the stock options exercised was $ 7.8 million , $ 0.3 million , and $ 0 for the years ended December 31 , 2020 , 2019 and 2018 , respectively. 2020 Employee Stock Purchase Plan In June 2020, our board of directors adopted, and our stockholders approved, the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), which became effective on June 11, 2020. The 2020 ESPP permits participants to purchase common stock through payroll deductions of up to 15 % of their eligible compensation. Employees purchase shares of common stock at a price per share equal to 85 % of the lower of the fair market value at the start or end of the six-month purchase periods within the two-year offering period. A total of 650,000 shares of common stock were approved to be initially reserved for issuance under the 2020 ESPP. In addition, the number of shares of common stock available for issuance under the 2020 ESPP will be automatically increased on the first day of each calendar year during the ten-year term of the 2020 Plan, beginning with January 1, 2021 and ending with January 1, 2030, by an amount of 1 % of the outstanding number of shares of our common stock on December 31 st of the preceding calendar year or such lesser amount as determined by our board of directors. For the year ended December 31, 2020, employees acquired 27,465 shares of our common stock under the 2020 ESPP and 622,535 shares of common stock remained available for issuance under the 2020 ESPP. Effective January 1, 2021, the number of shares of common stock available under the 2020 ESPP increased by 510,715 shares pursuant to the evergreen provision of the 2020 ESPP. Stock-based Compensation We estimated the fair value of employee stock options using the Black-Scholes option-pricing model for the years ended December 31, 2020, 2019 and 2018 using the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Fair Value Assumptions Expected volatility 81.2% - 94.1% 78.4% - 80.4% 77.0% - 78.2% Expected dividend yield 0 % 0 % 0 % Expected term (in years) 5.6 - 6.1 5.9 - 6.1 5.8 - 6.1 Risk-free interest rate 0.3% - 1.4% 1.6% - 2.4% 2.6% - 2.9% We estimated the fair value of shares under the 2020 ESPP using the Black-Scholes option-pricing model for the years ended December 31, 2020, 2019 and 2018 using the following weighted-average assumptions: Year Ended December 31, 2020 2019 2018 Fair Value Assumptions Expected volatility 105.8% - 158.2% N/A N/A Expected dividend yield 0 % N/A N/A Expected term (in years) 0.4 - 2.0 N/A N/A Risk-free interest rate 0.1% - 0.2% N/A N/A 136 We recorded total stock-based compensation expense for the years ended December 31, 2020, 2019 and 2018 related to the 2014 Plan, the 2020 Plan and the 2020 ESPP in the statements of operations and allocated the amounts as follows: Year Ended December 31, 2020 2019 2018 (In thousands) Research and development $ 1,861 $ 368 $ 274 General and administrative 3,573 817 475 Total $ 5,434 $ 1,185 $ 749 Upon our IPO, 362,935 performance-based awards vested and, as a result, we recognized $ 0.3 million of stock-based compensation expense during the three months ended June 30, 2020, which amount is included in the above table for the year ended December 31, 2020. As of December 31, 2020, there was $ 19.5 million of unrecognized stock-based compensation expense related to the employee and non-employee awards, which is expected to be recognized over a weighted-average period of 2.7 years. 10. Funding Arrangement In July 2019, we received a cost-reimbursement research award from Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (“CARB-X”), a public-private partnership funded under a Cooperative Agreement from Assistant Secretary for Preparedness and Response/Biomedical Advanced Research and Development Authority (“BARDA”) and by awards from Wellcome Trust, Germany’s Federal Ministry of Education and Research, the United Kingdom Global Antimicrobial Resistance Innovation Fund and the Bill & Melinda Gates Foundation. In connection with this funding, we entered into a cost-reimbursement sub-award agreement with the Trustees of Boston University, the administrator of the program. The initial award provided the potential for funding up to four years to develop a universal vaccine to prevent infections caused by Group A Strep bacteria, which include pharyngitis, impetigo and necrotizing fasciitis, at an amount equal to 50 % of reimbursable expenses up to specified amounts. The initial award committed initial funding of up to $ 1.6 million and, subject to a CARB-X decision to extend the options, up to $ 15.1 million in total funding available upon achievement of development milestones over the next four years . Specified research expenditures are reimbursable expenses associated with agreed-upon activities needed to advance the research project supported by the grant. These expenditures can include labor, laboratory supplies, travel, consulting and third-party vendor research and development support costs. Income from grants is recognized in the period during which the related specified expenses are incurred, provided that the conditions under which the grants were provided have been met. We recognized $ 2.5 million and $ 0.2 million of grant income under this award and recorded the amounts in Other income (expense), net in the statement of operations and comprehensive loss during the years ended December 31, 2020 and 2019, respectively. There was no grant income recorded in the year ended December 31, 2018. A grant receivable of $ 0.3 million and $ 0.2 million representing unreimbursed, eligible costs incurred under the CARB-X agreement was recorded and included in prepaid expenses and other current assets in the balance sheet as of December 31, 2020 and December 31, 2019, respectively. In July 2020, the CARB-X agreement was amended to increase the funding percentage for reimbursable expenses during the initial funding period from 50 % to 90 %. As a result, the initial funding amount increased from $ 1.6 million to $ 2.7 million. We anticipate that the increase in the funding percentage for reimbursable expenses may apply to future funding periods and, if so, the total funding amount over the four-year period, if the options to extend are exercised by CARB-X, would increase from the $ 15.1 million in the original agreement. In December 2020, we reached the maximum CARB-X funding limit for the initial year on our VAX-A1 program. We are in the process of submitting our funding proposal to CARB-X for the next funding period under our agreement. 137 11. Net Loss Per Share The following table sets forth the computation of basic and diluted net loss per share and excludes shares which are legally outstanding, but subject to repurchase by us: Year Ended December 31, 2020 2019 2018 Net loss (in thousands) $ ( 89,217 ) $ ( 50,274 ) $ ( 29,485 ) Weighted-average shares outstanding used in computing net loss per share, basic and diluted 29,545,810 3,795,090 3,629,896 Net loss per share, basic and diluted $ ( 3.02 ) $ ( 13.25 ) $ ( 8.12 ) The following potentially dilutive securities were excluded from the computation of diluted net loss per share for the period presented because including them would have been antidilutive: Year Ended December 31, 2020 2019 2018 Stock options 5,188,531 3,364,568 3,033,186 Redeemable convertible preferred stock: Series A — 6,225,719 6,225,719 Series B — 6,786,896 6,786,896 Series C — 7,377,480 3,688,740 Common stock warrant — 31,857 31,857 Redeemable convertible preferred stock warrant — 59,276 59,276 Total 5,188,531 23,845,796 19,825,674 12. Income Taxes Our pre-tax book loss was derived from our business operations within the United States. A reconciliation of our effective tax rate to the statutory U.S. federal rate is as follows: Year Ended December 31, 2020 2019 2018 (1) Statutory Rate 21.0 % 21.0 % 21.0 % Change in Fair Value of Tranche Liability 0.0 % 1.3 % 3.8 % Credits 0.6 % ( 0.5 )% 0.6 % Stock-based Compensation 0.8 % ( 0.4 )% ( 0.5 )% Other ( 0.3 )% 0.4 % ( 0.7 )% Change in valuation allowance ( 22.1 )% ( 21.8 )% ( 24.2 )% Total 0.0 % 0.0 % 0.0 % (1) The 2018 effective tax rate reconciliation has been updated to conform to the 2020 and 2019 presentation. 138 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of the assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The following table presents significant components of our deferred tax assets as of December 31, 2020 and 2019: As of December 31, 2020 2019 (1) (in thousands) Net operating losses $ 52,330 $ 25,582 Fixed assets 528 379 Accruals & reserves 2,786 467 Credits 1,222 872 Section 59(e) Capitalized expenses 3,381 — Accrued manufacturing expenses 3,374 871 Total 63,621 28,171 Valuation allowance ( 63,621 ) ( 28,171 ) Net deferred tax assets $ — $ — _________________ (1) The 2019 deferred tax asset presentation has been updated to conform to the 2020 presentation. At December 31, 2020, we have net operating loss carryforwards of approximately $ 186.5 million and $ 148.8 million available to reduce future taxable income, if any, for federal and state income tax purposes, respectively. The federal and state net operating loss carryforwards, except the federal loss carryforward arising in tax years beginning after December 31, 2017, begin to expire in 2034 unless previously utilized. Federal net operating losses arising in tax years beginning after December 31, 2017 have an indefinite carryover period and do not expire. At December 31, 2020, we have research credit carryforwards of $ 0.8 million and $ 0.9 million available to offset future income tax liabilities, if any, for federal and California income tax purposes, respectively. The federal research and development tax credit carryforwards expire beginning in 2039 unless previously utilized. The California tax credits can be carried forward indefinitely. We have evaluated the positive and negative evidences bearing upon the realizability of our deferred tax assets. Based on our history of operating losses, we have concluded that it is more likely than not that the benefit of our deferred tax assets will not be realized. Accordingly, we have provided a full valuation allowance for deferred tax assets as of December 31, 2020 and 2019. Utilization of the net operating loss carryforward and research credit carryforward may be subject to an annual limitation due to the ownership percentage change limitations under Section 382 and Section 383, respectively, provided by the Internal Revenue Code of 1986, as amended (the “Code”), and similar state provisions. The annual limitation may result in the expiration of the net operating loss before utilization. We have experienced ownership changes in the past. As a result of the ownership changes, we have determined that approximately $ 1.3 million of our federal research credits will expire unutilized, and such amounts are excluded from our research credit carryforwards. The Company does not expect any ownership changes during the year ended December 31, 2020 to result in a limitation that would materially reduce the total amount of net operating loss carryforwards and credits that can be utilized. Subsequent ownership changes may affect the limitation in future years. We have uncertain tax benefits (“UTBs”) totaling $ 0.4 million and $ 0.3 million as of December 31, 2020 and 2019, respectively, which were netted against deferred tax assets subject to valuation allowance. The UTBs had no effect on the effective tax rate. We recognize interest and penalties related to UTBs, when they occur, as a component of income tax expense. To the extent accrued interest and penalties do not ultimately become payable, amounts accrued will be reduced and reflected as a reduction of the provision for income taxes in the period such determination is made. There were no interest or penalties recognized for the years ended December 31, 2020 and 2019. We do not expect our UTBs to change significantly over the next 12 months. 139 A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows: December 31, 2020 2019 2018 (in thousands) Balance at the beginning of the year $ 271 $ 408 $ 119 Additions based on tax positions related to current year 287 217 228 Adjustments based on tax positions related to prior years ( 165 ) ( 354 ) 61 Balance at end of year $ 393 $ 271 $ 408 We file U.S. federal and state tax returns. In general, the Company is no longer subject to tax examination by the Internal Revenue Service or state taxing authorities for years before 2016. Although the federal and state statutes are closed for purposes of assessing additional income tax in those prior years, the taxing authorities may still make adjustments to the net operating loss, or NOL, and credit carryforwards used in open years. Therefore, the tax statutes should be considered open as it relates to the NOL and credit carryforwards used in open years. We do not have any tax audits or other issues pending. On March 27, 2020, the President of the United States signed into law the Coronavirus Aid, Relief, and Economic Security Act (CARES Act). The CARES Act, among other things, includes certain income tax provisions for individuals and corporations; however, these benefits do not impact our current tax provision. On December 21, 2020, the President of the United States signed into law the “Consolidated Appropriations Act, 2021” which includes further COVID-19 economic relief and extension of certain expiring tax provisions. The relief package includes a tax provision clarifying that businesses with forgiven Paycheck Protection Program, or PPP, loans can deduct regular business expenses that are paid for with the loan proceeds. Additional pandemic relief tax measures include an expansion of the employee retention credit, enhanced charitable contribution deductions and a temporary full deduction for business expenses for food and beverages provided by a restaurant. These benefits do not have a material impact on the current tax provision. 13. Related Party Transactions We have an ongoing relationship with Sutro Biopharma. In 2013, Sutro Biopharma provided support to facilitate the establishment of our Company. As of December 31, 2020 and December 31, 2019, Sutro Biopharma owned approximately 1.6 million shares of our common stock. As of December 31, 2019, Sutro Biopharma also owned warrants to purchase 31,857 shares of our common stock (the “Common Stock Warrant”) at an exercise price of $ 0.79289 per share and 59,276 shares of our Series C redeemable convertible stock (the “Preferred Stock Warrant”) at an exercise price of $ 11.5215 per share. The Common Stock Warrant and the Preferred Stock Warrant were automatically net exercised pursuant to their terms for 30,278 shares and 16,591 shares, respectively, of our common stock in connection with the IPO. In the agreements and amendments identified herein, we licensed certain intellectual property and acquired certain supply rights from Sutro Biopharma, including the right to use the XpressCF platform to discover and develop vaccine candidates for the treatment or prophylaxis of infectious diseases. On October 12, 2015, we and Sutro Biopharma (“the Parties”) entered into the Sutro Biopharma License Agreement, which amended and restated an agreement dated August 1, 2014. The Sutro Biopharma License Agreement was subsequently amended on May 9, 2018 (“License Amendment A1”) and May 29, 2018 (“License Amendment A2”). In consideration for the License Amendment A2, we issued to Sutro Biopharma the Preferred Stock Warrant to purchase 59,276 shares of Series C redeemable convertible preferred stock at a purchase price of $ 11.5215 per share. We also entered into a separate supply agreement with Sutro Biopharma on May 29, 2018 (the “Sutro Biopharma Supply Agreement”). Under the Sutro Biopharma License Agreement, Sutro Biopharma granted us an exclusive, worldwide license to research, develop, manufacture and commercialize vaccine products addressing infectious disease, which are discovered or produced based on the use of Sutro Biopharma’s proprietary cell-free protein expression technology, known as XpressCF, which utilizes extracts derived from strains of E. coli . In connection with the Sutro Biopharma License Agreement, under the Sutro Biopharma Supply Agreement, Sutro Biopharma has agreed to manufacture and supply extracts and reagents for us on a cost-plus basis. In consideration for the rights licensed, we 140 are obligated to pay a 4 % royalty on worldwide aggregate annual net sales of our vaccine products for human health and a 2 % royalty on such net sales of vaccine products for animal health. In addition, for a certain period of time, if we grant a sublicense to a third party to further develop or sell a vaccine product discovered or generated by us, we are obligated to pay Sutro Biopharma a percentage, in the low single digits, of any net sublicense fees received. Our obligation to pay single-digit royalties to Sutro Biopharma expires on a country-by-country basis on the later of the expiration of the last to expire patent covering the manufacture, use, offer for sale or importation of the applicable vaccine product and ten years from first commercial sale of the applicable vaccine product. Our obligation to pay sublicense fees to Sutro Biopharma expired in July 2020. In License Amendment A1, the Parties amended the license agreement to remove a pre-IND regulatory meeting as a diligence milestone and to agree that certain other diligence milestones had been satisfied. In License Amendment A2, the Parties amended the license agreement to add certain terms confirming our obligation to purchase Sutro Biopharma’s proprietary extract from E. coli (“Extract”) from Sutro Biopharma. In addition, the Parties amended the license agreement to specify our rights to a transfer of certain know-how relating to the manufacture of Extract in the event of a declaration of bankruptcy by Sutro Biopharma. Finally, the Parties agreed to terms providing for injunctive relief in the event of a breach or threatened breach by the other party. In the Sutro Biopharma Supply Agreement, the Parties agreed to terms for the supply of manufactured Extract and custom reagents by Sutro Biopharma for us to use in manufacturing vaccine compositions in non-clinical research or in Phase 1 or Phase 2 clinical trials. The term of the Sutro Biopharma Supply Agreement is from execution until the later of July 31, 2021 and the date the parties enter into and commence activities under the supply agreement unless extended through a subsequent supply agreement for the supply of Extract and custom reagents for vaccine compositions for Phase 3 and commercial uses as contemplated in the Supply Agreement. In February 2021, we entered into an amendment to the Sutro Biopharma Supply Agreement and extended the term to July 31, 2022. We recognized expense related to the Supply Agreement of $ 1.2 million, $ 1.1 million and $ 1.4 million for the years ended December 31, 2020, 2019 and 2018, respectively. In addition, we recorded $ 0.2 million, $ 0 and $ 0.5 million in changes in the fair value of the Preferred Stock Warrant for the years ended December 31, 2020, 2019 and 2018, respectively. The expense related to the changes in the fair value of the warrant is included in research and development expenses in the statements of operations and comprehensive loss. Accrued expenses payable to Sutro Biopharma were $ 0.7 million and $ 0 as of December 31, 2020 and December 31, 2019, respectively. 141 14. Selected Quarterly Financial Data (Unaudited) The following tables provide the selected quarterly financial data for the years ended December 31, 2020 and 2019 (in thousands, except share and per share data): 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Statements of Operations Data: Operating expenses: Research and development $ 24,315 $ 18,178 $ 16,410 $ 14,661 General and administrative 3,281 3,046 4,898 4,792 Total operating expenses 27,596 21,224 21,308 19,453 Loss from operations ( 27,596 ) ( 21,224 ) ( 21,308 ) ( 19,453 ) Other income (expense), net 454 904 290 ( 1,284 ) Net loss and comprehensive loss $ ( 27,142 ) $ ( 20,320 ) $ ( 21,018 ) $ ( 20,737 ) Net loss per share, basic and diluted $ ( 6.70 ) $ ( 1.72 ) $ ( 0.41 ) $ ( 0.41 ) Weighted-average common shares outstanding, basic and diluted 4,049,848 11,803,778 50,895,358 50,964,294 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Statements of Operations Data: Operating expenses: Research and development $ 12,628 $ 9,968 $ 9,630 $ 13,381 General and administrative 1,316 2,264 2,510 2,456 Total operating expenses 13,944 12,232 12,140 15,837 Loss from operations ( 13,944 ) ( 12,232 ) ( 12,140 ) ( 15,837 ) Other income (expense), net 273 1,567 823 1,216 Net loss and comprehensive loss $ ( 13,671 ) $ ( 10,665 ) $ ( 11,317 ) $ ( 14,621 ) Net loss per share, basic and diluted $ ( 3.72 ) $ ( 2.90 ) $ ( 2.93 ) $ ( 3.69 ) Weighted-average common shares outstanding, basic and diluted 3,671,102 3,682,897 3,857,298 3,965,166 15. Subsequent Events In January 2021, we entered into a lease agreement for our new corporate headquarters facility to be located in San Carlos, California and a license agreement for temporary lab and office space in Palo Alto, California. See Note 5, “Commitments and Contingencies,” for more details. 142 Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure. None.