Document and Entity Information
Document and Entity Information - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Mar. 15, 2019 | Jun. 30, 2018 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2018 | ||
Document Fiscal Year Focus | 2018 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | PHAS | ||
Entity Registrant Name | PhaseBio Pharmaceuticals Inc | ||
Entity Central Index Key | 0001169245 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | No | ||
Entity Current Reporting Status | Yes | ||
Entity Voluntary Filers | No | ||
Entity Filer Category | Non-accelerated Filer | ||
Entity Small Business | true | ||
Entity Emerging Growth Company | true | ||
Entity Ex Transition Period | true | ||
Entity Shell Company | false | ||
Entity Common Stock Shares Outstanding | 24,498,425 | ||
Entity Public Float | $ 0 |
BALANCE SHEETS
BALANCE SHEETS - USD ($) | Dec. 31, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 61,031,000 | $ 13,406,000 |
Restricted cash | 20,000 | 20,000 |
Other receivable | 233,000 | |
Prepaid expenses and other assets | 1,344,000 | 340,000 |
Total current assets | 62,628,000 | 13,766,000 |
Property and equipment, net | 355,000 | 302,000 |
Other assets | 43,000 | 31,000 |
Total assets | 63,026,000 | 14,099,000 |
Current liabilities: | ||
Convertible promissory notes, net of discount | 12,095,000 | |
Derivative liability | 3,028,000 | |
Current portion of long-term debt | 761,000 | |
Accounts payable | 1,806,000 | 430,000 |
Accrued expenses | 2,771,000 | 1,281,000 |
Total current liabilities | 4,577,000 | 17,595,000 |
Preferred stock warrant liability | 1,656,000 | |
Deferred rent | 22,000 | 5,000 |
Long-term debt | 7,500,000 | 2,625,000 |
Total liabilities | 12,099,000 | 21,881,000 |
Commitments and contingencies (Note 7) | ||
Redeemable convertible preferred stock, $0.001 par value; zero and 13,321,350 shares authorized at December 31, 2018 and 2017, respectively; zero and 9,131,999 shares issued and outstanding at December 31, 2018 and 2017, respectively. | 89,633,543 | |
Stockholders’ equity (deficit): | ||
Preferred stock, $0.001 par value; 10,000,000 and zero shares authorized at December 31, 2018 and 2017, respectively; zero shares issued and outstanding at December 31, 2018 and 2017, respectively | ||
Common stock, $0.001 par value; 200,000,000 and 14,918,087 shares authorized at December 31, 2018 and 2017, respectively; 24,528,242 shares issued and 24,498,275 shares outstanding at December 31, 2018; 775,755 shares issued and 745,788 shares outstanding at December 31, 2017 | 25,000 | 1,000 |
Treasury stock, at cost, 29,967 shares as of December 31, 2018 and 2017 | (24,000) | (24,000) |
Additional paid-in capital | 173,837,000 | 1,672,000 |
Accumulated deficit | (122,911,000) | (99,065,000) |
Total stockholders’ equity (deficit) | 50,927,000 | (97,416,000) |
Total liabilities, redeemable convertible preferred stock, and stockholders' equity (deficit) | $ 63,026,000 | $ 14,099,000 |
BALANCE SHEETS (Parenthetical)
BALANCE SHEETS (Parenthetical) - $ / shares | Dec. 31, 2018 | Dec. 31, 2017 |
Statement Of Financial Position [Abstract] | ||
Redeemable convertible preferred stock, par value | $ 0.001 | $ 0.001 |
Redeemable convertible preferred stock, shares authorized | 0 | 13,321,350 |
Redeemable convertible preferred stock, shares issued | 0 | 9,131,999 |
Redeemable convertible preferred stock, shares outstanding | 0 | 9,131,999 |
Preferred Stock, Par Value | $ 0.001 | $ 0.001 |
Preferred Stock, Shares Authorized | 10,000,000 | 0 |
Preferred Stock, Shares Issued | 0 | 0 |
Preferred Stock, Shares Outstanding | 0 | 0 |
Common stock, par value | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 200,000,000 | 14,918,087 |
Common stock, shares issued | 24,528,242 | 775,755 |
Common stock, shares outstanding | 24,498,275 | 745,788 |
Treasury stock, shares | 29,967 | 29,967 |
STATEMENTS OF OPERATIONS
STATEMENTS OF OPERATIONS - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Income Statement [Abstract] | ||
Grant revenues | $ 668 | |
Type of Revenue [Extensible List] | us-gaap:GrantMember | us-gaap:GrantMember |
Operating expenses: | ||
Research and development | $ 15,455 | $ 6,210 |
General and administrative | 4,857 | 2,328 |
Total operating expenses | 20,312 | 8,538 |
Loss from operations | (19,644) | (8,538) |
Other income (expense): | ||
Interest income | 387 | 52 |
Interest expense | (3,924) | (2,723) |
Change in fair value of warrant liability | 11 | 1,019 |
Change in fair value of derivative liability | (676) | (57) |
Total other income (expense) | (4,202) | (1,709) |
Net loss | $ (23,846) | $ (10,247) |
Net loss per common share, basic and diluted | $ (4.49) | $ (13.78) |
Weighted average common shares outstanding, basic and diluted | 5,305,062 | 743,470 |
STATEMENTS OF REDEEMABLE CONVER
STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) | Total | Common Stock | Treasury Stock | Additional Paid-in Capital | Accumulated Deficit | Redeemable Convertible Preferred Stock |
Redeemable convertible preferred stock, beginning balance at Dec. 31, 2016 | $ 89,567,000 | |||||
Redeemable convertible preferred stock, beginning balance, shares at Dec. 31, 2016 | 9,131,999 | |||||
Temporary equity, Accretion of redeemable preferred stock to redemption value | $ 67,000 | |||||
Redeemable convertible preferred stock, ending balance at Dec. 31, 2017 | $ 89,633,543 | $ 89,634,000 | ||||
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2017 | 9,131,999 | 9,131,999 | ||||
Beginning balance at Dec. 31, 2016 | $ (87,182,000) | $ 1,000 | $ (24,000) | $ 1,659,000 | $ (88,818,000) | |
Beginning balance, shares at Dec. 31, 2016 | 773,208 | (29,967) | ||||
Exercises of stock options | 3,000 | 3,000 | ||||
Exercises of stock options, shares | 2,547 | |||||
Stock-based compensation | 77,000 | 77,000 | ||||
Accretion of redeemable preferred stock to redemption value | (67,000) | (67,000) | ||||
Net loss | (10,247,000) | (10,247,000) | ||||
Ending balance at Dec. 31, 2017 | $ (97,416,000) | $ 1,000 | $ (24,000) | 1,672,000 | (99,065,000) | |
Ending balance, shares at Dec. 31, 2017 | 745,788 | 775,755 | (29,967) | |||
Issuance of redeemable preferred stock | $ 14,890,000 | |||||
Issuance of redeemable preferred stock, shares | 1,842,959 | |||||
Issuance of redeemable preferred stock upon conversion of promissory notes | $ 19,778,000 | |||||
Issuance of redeemable preferred stock upon conversion of promissory notes, shares | 2,080,209 | |||||
Exercises of warrants | $ 1,212,000 | |||||
Exercises of warrants, shares | 144,948 | |||||
Temporary equity, Accretion of redeemable preferred stock to redemption value | $ 95,000 | |||||
Temporary equity, conversion of redeemable convertible preferred stock into common stock | $ (125,609,000) | |||||
Temporary equity, conversion of redeemable convertible preferred stock into common stock, shares | (13,200,115) | |||||
Redeemable convertible preferred stock, ending balance, shares at Dec. 31, 2018 | 0 | |||||
Conversion of redeemable convertible preferred stock warrants into common stock warrants | $ 3,346,000 | 3,346,000 | ||||
Conversion of redeemable convertible preferred stock into common stock | 125,609,000 | $ 13,000 | 125,596,000 | |||
Conversion of redeemable convertible preferred stock into common stock, shares | 13,225,048 | |||||
Issuance of common stock in initial public offering, net | 42,974,000 | $ 10,000 | 42,964,000 | |||
Issuance of common stock in initial public offering, net, shares | 9,864,666 | |||||
Exercises of warrants for common stock, net | (69,000) | $ 1,000 | (70,000) | |||
Exercises of warrants for common stock, net (in shares) | 619,086 | |||||
Exercises of stock options | 92,000 | 92,000 | ||||
Exercises of stock options, shares | 43,687 | |||||
Stock-based compensation | 332,000 | 332,000 | ||||
Accretion of redeemable preferred stock to redemption value | (95,000) | (95,000) | ||||
Net loss | (23,846,000) | (23,846,000) | ||||
Ending balance at Dec. 31, 2018 | $ 50,927,000 | $ 25,000 | $ (24,000) | $ 173,837,000 | $ (122,911,000) | |
Ending balance, shares at Dec. 31, 2018 | 24,498,275 | 24,528,242 | (29,967) |
STATEMENTS OF CASH FLOWS
STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Operating activities | ||
Net loss | $ (23,846) | $ (10,247) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation and amortization | 105 | 96 |
Stock-based compensation | 332 | 77 |
Non-cash interest expense | 3,664 | 2,711 |
Change in fair value warrant liability | (11) | (1,019) |
Change in fair value derivative liability | 676 | 57 |
Changes in operating assets and liabilities: | ||
Other receivable | (233) | |
Prepaid expenses and other assets | (1,017) | 40 |
Accounts payable | 1,337 | (213) |
Accrued expenses | 1,923 | 242 |
Deferred rent | 17 | (3) |
Net cash used in operating activities | (17,053) | (8,259) |
Investing activities | ||
Purchases of property and equipment | (119) | (216) |
Net cash used in investing activities | (119) | (216) |
Financing activities | ||
Proceeds from issuance of common stock in initial public offering, net | 42,974 | |
Proceeds from issuance of redeemable convertible preferred stock, net | 17,712 | |
Proceeds from term loan, net | 3,995 | 3,480 |
Proceeds from exercise of stock options | 92 | 3 |
Proceeds from exercise of warrants | 24 | |
Proceeds from convertible promissory notes, net | 14,683 | |
Net cash provided by financing activities | 64,797 | 18,166 |
Net increase in cash and cash equivalents | 47,625 | 9,691 |
Cash, cash equivalents and restricted cash at the beginning of the year | 13,426 | 3,735 |
Cash, cash equivalents and restricted cash at the end of the year | 61,051 | 13,426 |
Supplemental disclosure for cash flow | ||
Cash paid for interest | 260 | 12 |
Supplemental disclosure of cash flow information | ||
Conversion of redeemable convertible preferred stock into common stock | 125,609 | |
Conversion of convertible promissory notes into redeemable convertible preferred stock | 19,778 | |
Warrant liability converted to redeemable convertible preferred stock upon the exercise of warrants | 4,297 | |
Issuance of warrants in conjunction with debt | 2,822 | 1,795 |
Conversion of redeemable convertible preferred stock warrants into common stock warrants | 3,346 | |
Accretion of redeemable convertible preferred stock | 95 | 67 |
Purchases of property and equipment included in accounts payable | $ 39 | |
Issuance of derivative in conjunction with debt | $ 2,971 |
Organization and Description of
Organization and Description of Business | 12 Months Ended |
Dec. 31, 2018 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Organization and Description of Business | 1. Organization and Description of Business Description of Business PhaseBio Pharmaceuticals, Inc. (the “Company”) was incorporated as a Delaware corporation on January 10, 2002. The Company is a clinical-stage biopharmaceutical company focused on the development and commercialization of novel therapies to treat orphan diseases, with an initial focus on cardiopulmonary indications. The Company’s lead product candidate, PB2452, is a novel reversal agent for the antiplatelet drug ticagrelor, which the Company is developing for the treatment of patients on ticagrelor who are experiencing a major bleeding event or those who require urgent surgery. The Company recently completed a Phase 1 clinical trial of PB2452 in healthy subjects and intends to initiate a Phase 2a clinical trial in healthy older subjects in the first half of 2019. The Company’s second product candidate, PB1046, is a once-weekly fusion protein currently in a Phase 2b clinical trial for the treatment of pulmonary arterial hypertension. PB1046 utilizes the Company’s proprietary half-life extending elastin-like polypeptide (“ELP”), technology, which also serves as the engine for future product pipeline Initial Public Offering On October 22, 2018, the Company completed an initial public offering (“IPO”) of its common stock, which resulted in the issuance and sale of an aggregate of 9,864,666 shares of common stock at a public offering price of $5.00 per share, generating net proceeds of approximately $43.0 million after deducting underwriting discounts and commissions and other offering costs. In connection with the completion of the IPO, all then-outstanding shares of the Company’s redeemable convertible preferred stock were converted into an aggregate of 13,200,115 shares of common stock. Upon completion of the IPO, the Company’s certificate of incorporation was amended and restated. Under the amended and restated certificate of incorporation, the Company’s authorized capital stock consists of 200,000,000 shares of common stock with a par value of $0.001 per share and 10,000,000 shares of preferred stock with a par value of $0.001 per share. Reverse Stock Split In October 2018, the Company effected a 11.0634-for-1 reverse split of its outstanding common stock and redeemable convertible preferred stock. All share and per share amounts, including stock options, have been retroactively adjusted in these financial statements for all periods presented to reflect the reverse stock split. Further, exercise prices of stock options have been retroactively adjusted in these financial statements for all periods presented to reflect the reverse stock split. Liquidity The Company has experienced net losses and negative cash flows from operations since its inception and, as of December 31, 2018, had an accumulated deficit of $122.9 believes that its existing cash and cash equivalents are sufficient to fund its operating expenses and capital requirements into the second quarter of 2020. Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). Certain non-significant The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions. |
Significant Accounting Policies
Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Significant Accounting Policies | 2. Significant Accounting Policies Use of Estimates The preparation of the Company’s financial statements requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to the valuation of redeemable convertible preferred stock warrants prior to the IPO, the conversion option on the convertible notes and clinical trial accruals. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results could differ materially from those estimates and assumptions. Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains certain deposits in federally insured financial institutions in excess of federally insured limits. The Company could experience losses on the money market funds in the future. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market Restricted Cash The Company had restricted cash of $20,000 as of December 31, 2018 and 2017 , Fair Value of Financial Instruments The carrying amounts of accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses are reasonable estimates of their fair value because of the short maturity of these items. Based on the borrowing rates currently available to the Company for loans with similar terms, the Company believes the fair value of the term loan approximates its carrying value (see Note Property and Equipment Property and equipment are recorded at cost and depreciated over the estimated useful lives of the assets (three to five years) using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the lease term. Long-Lived Assets The Company regularly reviews the carrying value and estimated lives of all of its long-lived assets, including property and equipment to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. The determinants used for this evaluation include management’s estimate of the asset’s ability to generate net positive cash flow in future periods as well as the strategic significance of the assets to the Company’s business objective. Should an impairment exist, the impairment loss would be measured based on the extent that the estimated fair value is less than its carrying value. The Company has not recognized any impairment Preferred Stock Warrant Liability The Company previously issued freestanding warrants to purchase shares of its redeemable convertible preferred stock. Since the underlying redeemable convertible preferred stock was classified outside of permanent equity, those warrants were classified as liabilities in the accompanying balance sheet. Warrants classified as liabilities were recorded at their estimated fair value on the date of issuance and were revalued at each subsequent balance sheet date, with fair value changes recognized as increases or reductions to other income (expense) in the accompanying statements of operations. The Company estimated the fair value of these warrants using the Black-Scholes option pricing In connection with the Company’s IPO in October 2018, all warrants were either exercised or converted into warrants to purchase common stock, at which time the liability was reclassified to stockholders’ equity. Preclinical and Clinical Trial Accruals The Company accrues and expenses preclinical studies and clinical trial activities performed by third parties based upon estimates of the proportion of work completed over the life of the individual trial and subject enrollment rates in accordance with agreements with clinical research organizations and clinical trial sites. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including the Company’s clinical development Management makes estimates of the Company’s accrued expenses as of each balance sheet date in the Company’s financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are Research and Development Expense Research and development costs are expensed as incurred. Stock-Based Compensation The Company measures and recognizes compensation expense for all stock-based compensation based on the estimated fair value at the date of grant. Currently, the Company’s stock-based awards consist only of stock options; however, future grants under the Company’s equity compensation plan may also consist of shares of restricted stock, restricted stock units, stock appreciation rights, performance awards and performance units. The Company estimates the fair value of stock options using the Black-Scholes option-pricing model, which requires the use of estimates. The Company recognizes stock-based compensation cost for ratably vesting stock options on a straight-line basis over the requisite service period of the award. The Black-Scholes option-pricing model requires the input of subjective assumptions, including the risk-free interest rate, the fair value of the underlying common stock prior to the IPO, the expected dividend yield of the Company’s common stock, the expected volatility of the price of the Company’s common stock, and the expected term of the option. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, the Company’s stock-based compensation expense could be materially different in the future. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences 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. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50% likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits, if any, within income tax expense, and any accrued interest and penalties are included within the related tax liability line. Grant Revenues Grant revenues are derived from government grants that support the Company’s efforts on specific research projects. The Company has determined that the government agencies providing grants to the Company are not customers. The Company recognizes grant revenue when there is reasonable assurance of compliance with the conditions of the grant and reasonable assurance that the grant revenue will be received. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. As of December 31, 2018 2017 Common stock options 1,545,403 1,075,209 Warrants to purchase common stock 75,597 — Redeemable convertible preferred stock — 9,131,999 Warrants to purchase redeemable convertible preferred stock — 486,356 Total 1,621,000 10,693,564 Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases The Company will adopt ASU 2016-02 in 2019. Upon adoption, the Company expects to record a right of use asset and a corresponding lease liability of an amount between $1.5 million and $2.5 million. In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230) In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting classified share-based payment awards issued to nonemployees will be measured at the grant date, instead of the previous requirement to remeasure the awards through the performance completion date, (2) for performance conditions, compensation cost associated with the award will be recognized when the achievement of the performance condition is probable, rather than upon achievement of the performance condition and (3) the current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. The Company adopted this standard effective October 1, 2018, and the adoption did not have a material impact on the Company’s financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement - Disclosure Framework (Topic 820): Changes to the Disclosure Requirements for Fair Value Measurement |
Fair Value Measurement
Fair Value Measurement | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurement | 3. Fair Value Measurement Fair value is defined as an exit price, representing the amount 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 a The Company classifies fair value measurements in one of the following three categories for disclosure purposes: Level 1: Quoted prices in active markets for identical assets or Level 2: Inputs other than Level 1 prices for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and values determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The Company’s cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The Company estimated the fair value of redeemable convertible preferred stock warrants at the time of issuance and subsequent remeasurement using the Black-Scholes option pricing model at each reporting date, based on the following inputs: the risk-free interest rate; the expected dividend rate; the remaining contractual life of the warrants; the fair value of the underlying stock; and the expected volatility of the price of the underlying common stock. The estimates were based, in part, on subjective assumptions. The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements at Reporting Date Total Level 1 Level 2 Level 3 As of December 31, 2018: Assets Cash equivalents $ 59,357 $ 59,357 $ — $ — As of December 31, 2017: Assets Cash equivalents $ 12,472 $ 12,472 $ — $ — Liabilities Derivative liability $ 3,028 $ — $ — $ 3,028 Preferred stock warrant liability 1,656 — — 1,656 Total liabilities $ 4,684 $ — $ — $ 4,684 The following weighted-average assumptions were used in determining the fair value of the preferred stock warrant liability valued using the Black-Scholes option pricing model as of December 31, 2017: December 31, 2017 Expected volatility 68.0 % Risk-free interest rate 2.2 % Contractual term (in years) 5.9 Expected dividend yield — The following estimated fair values per share of the Company’s underlying redeemable convertible preferred stock were used to determine the estimated fair value of the preferred stock warrant liability: December 31, 2017 Series AA $ 5.75 Series B $ 3.76 Series C-1 $ 3.76 The following tables present activity for the preferred stock warrant liability and the derivative liability measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2017 and 2018 (in thousands): Preferred Stock Warrant Liability Balance at December 31, 2016 $ 880 Issuance of warrants 1,795 Changes in fair value reflected as change in fair value of warrant liability (1,019 ) Balance at December 31, 2017 1,656 Issuance of warrants 2,822 Exercise of warrants (1,197 ) Changes in fair value reflected as change in fair value of warrant liability (11 ) Conversion to common stock warrants upon IPO (3,270 ) Balance at December 31, 2018 $ — Derivative Liability Balance at December 31, 2016 $ — Issuance of derivative 2,971 Changes in fair value reflected as change in fair value of derivative liability 57 Balance at December 31, 2017 3,028 Changes in fair value reflected as change in fair value of derivative liability 676 Extinguishment of derivative upon conversion of convertible promissory notes (3,704 ) Balance at December 31, 2018 $ — |
Property and Equipment
Property and Equipment | 12 Months Ended |
Dec. 31, 2018 | |
Property Plant And Equipment [Abstract] | |
Property and Equipment | 4. Property and Equipment The following table presents the composition of property and equipment, net as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018 2017 Lab equipment $ 1,764 $ 1,681 Computer hardware, software and telephone 228 174 Furniture and fixtures 98 70 Leasehold improvements 50 22 2,140 1,947 Less accumulated depreciation (1,785 ) (1,645 ) Property and equipment, net $ 355 $ 302 |
Accrued Expenses
Accrued Expenses | 12 Months Ended |
Dec. 31, 2018 | |
Payables And Accruals [Abstract] | |
Accrued Expenses | 5. Accrued Expenses The following table presents the composition of accrued expenses as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018 2017 Accrued clinical and related costs $ 1,358 $ 197 Accrued compensation and related costs 914 346 Accrued interest 194 628 Accrued other 305 110 Accrued expenses $ 2,771 $ 1,281 |
Debt
Debt | 12 Months Ended |
Dec. 31, 2018 | |
Debt Disclosure [Abstract] | |
Debt | 6. Debt Convertible Promissory Notes In January 2017 and October 2017, the Company issued $14.7 million of convertible promissory notes (the “2017 Notes”) to holders of Series C-1 redeemable convertible preferred stock (“Series C-1”). The 2017 Notes bore interest at the rate of 8% per annum. Upon a subsequent equity financing of at least $10.0 million prior to the stated maturity date, the 2017 Notes plus accrued interest would automatically convert into shares of the stock issued by the Company in such financing at a price equal to 80% of the lowest issue price. The 2017 Notes could have converted into a variable number of shares of preferred stock, and accordingly, the Company determined the conversion provision to be a redemption feature. The redemption feature was evaluated as an embedded derivative and bifurcated from the convertible promissory notes due to the substantial premium paid upon redemption and accounted for as a derivative instrument. Upon bifurcating the redemption feature, the Company recorded a debt discount of $3.0 million that was recognized in interest expense over the term of the 2017 Notes. In connection with the 2017 Notes, the Company issued warrants to the noteholders to purchase 304,397 shares of Series C-1. The warrants were exercisable for $0.12 per share and would expire upon the earlier of (1) the date of the initial closing of a liquidation event, as defined, (2) the closing of a firm commitment underwritten initial public offering or (3) January 2024. All warrants were exercised in connection with the closing of the Company’s IPO. The Company recorded a debt discount of $1.7 million, which represents the estimated fair value of the warrants, upon issuance of the 2017 Notes, which was being amortized to interest expense over the term of the 2017 Notes using the effective-interest method. In August 2018, the Company sold 1,842,959 shares of Series D redeemable preferred stock (“Series D”) to new and existing investors at a price of $9.659 per share for net proceeds of $17.7 million and issued warrants to purchase 368,582 shares of Series C-1 at an exercise price of $0.12 per share (the “Series D Financing”). Concurrent with the Series D Financing, all of the Company’s previously outstanding 2017 Notes, including accrued interest thereon, were converted into 2,080,209 shares of Series D. Interest expense, including the debt discount related to the 2017 Notes, was $3.4 million and $2.7 million for the years ended December 31, 2018 Term Loan In October 2017, the Company entered into a Loan and Security Agreement (“SVB Loan”) with Silicon Valley Bank (“SVB”), pursuant to which the Company could borrow up to $7.5 million, issuable in three separate tranches (“Growth Capital Advances”) of $3.5 million (“Tranche A”), $2.0 million (“Tranche B”) and $2.0 million (“Tranche C”). Each of the Growth Capital Advances would become available upon the achievement of certain clinical and regulatory milestones. Under the original terms of the SVB Loan, the Company was to make interest-only payments through June 30, 2018 at a rate equal to the Prime Rate as defined per the SVB Loan. The interest-only period would be extended to December 31, 2018 if the Company borrowed the remaining tranches, followed by an amortization period of 24 months of equal monthly payments of principal plus interest amounts until paid in full. In connection with the SVB Loan, the Company issued to SVB a warrant to purchase 49,713 shares of Series C-1 at an exercise price of $9.659 per share. The warrant is immediately exercisable and expires on October 18, 2027. The Company was required to make a final payment equal to 7% of the original aggregate principal amount of the Growth Capital Advances at maturity. In November 2017, the Company drew $3.5 million from Tranche A. The Company had the option to prepay all, but not less than all, of the borrowed amounts, provided that the Company would have been obligated to pay a prepayment fee equal to (a) 3.0% of the outstanding principal balance of the applicable Growth Capital Advances if prepayment was made prior to the first anniversary of the effective date of the SVB Loan, (b) 2.0% of the outstanding principal balance of the applicable Growth Capital Advances if prepayment was made by the second anniversary of the effective date of the SVB Loan or (c) 1.0% of the outstanding principal balance of the applicable Growth Capital Advances if prepayment was made after the second anniversary of the effective date of the SVB Loan. In April 2018, the SVB Loan was amended to extend the draw period of Tranche B and Tranche C to April 30, 2018 and July 31, 2018, respectively, as well as to extend the interest-only period through July 31, 2018, which would be extended to December 31, 2018 if the Company borrowed Tranche B and Tranche C. Additionally, all Capital Growth Advances would mature on June 1, 2020; however, if the Company were to draw Tranche B and Tranche C, the maturity date would be December 31, 2020. On April 30, 2018, the Company borrowed $2.0 million under Tranche B. In July 2018, the SVB Loan was amended to further extend the draw period of Tranche C to August 31, 2018, as well as to extend the interest-only period of the SVB Loan through August 31, 2018, which would be extended to December 31, 2018 if the Company were to draw Tranche C. In August 2018, the Company borrowed $2.0 million under Tranche C. The Company’s obligations under the SVB Loan are secured by a first priority security interest in substantially all of its current and future assets, other than its owned intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on its ability to encumber intellectual property assets. The Company recorded a debt discount of $0.4 million for the estimated fair value of warrants and debt issuance costs upon the borrowing of Tranche A and Tranche B, which is being amortized to interest expense over the term of the SVB Loan using the effective-interest method. As of December 31, 2018 and 2017, the Company had $7.5 million and $3.5 million, respectively, of outstanding principal under the SVB Loan and $7.5 million and $3.4 million, respectively, is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the term debt, totaled $0.6 million and $0.1 million for the years ended December 31, 2018 and 2017, respectively. The Company was in compliance with all covenants under the SVB Loan as of December 31, 2018 . On March 25, 2019, the Company repaid the outstanding principal balance and accrued portion of the final payment for the SVB Loan in full The following table sets forth by year the Company’s required future principal payments for the refinanced SVB Loan (in thousands): Years Ending December 31, 2019 $ — 2020 2,142 2021 2,285 2022 2,438 2023 635 Thereafter — $ 7,500 |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 7. Commitments and Contingencies Operating Leases The Company leases office and research and development facilities and equipment under various non-cancellable operating lease agreements. In January 2010, the Company entered into a lease for office and laboratory space in Malvern, Pennsylvania (the “Malvern Lease”). The Malvern Lease commenced in March 2010 and was amended to extend its term to September 30, 2023. This lease contains escalating rent payments. In December 2018, the Company entered into a lease for office space in San Diego, California, which expires in October 2022. The Company’s future minimum commitments under its non-cancelable operating leases were as follows (in thousands): Year Ending December 31, 2019 $ 342 2020 368 2021 373 2022 360 2023 204 Thereafter — Total $ 1,647 The Company recognizes rent expense for the facility operating leases on a straight-line basis. The Company accounts for the difference between the minimum lease payments and the straight-line amount as deferred rent. Rent expense was $0.4 million December 31, 2018 Legal Proceedings The Company is not currently a party to any litigation, nor is management aware of any pending or threatened litigation against the Company, that it believes would materially affect the Company’s business, operating results, financial condition or cash flows. Supply Agreement The Company has entered into a Master Services Agreement (“Supply Agreement”) with BioVectra Inc., (“BioVectra”). BioVectra will manufacture and supply cGMP-grade quantities of the Company’s PB2452 proprietary drug product (“Product”) for the Company’s potential PB2452 Phase 3 clinical trial as well as any work required to support the marketing authorization filing. A Commercial Supply Agreement is being put in place for the Product, if it is approved by the FDA. BioVectra is responsible for the facility, including performing all work related to the procurement, design, project management, installation, assembly, commissioning and validation of the facility and all equipment, and for financing all costs associated with building out the facility. The Company will be responsible for the purchase of certain equipment and raw materials for the production process. |
Preferred Stock Warrants
Preferred Stock Warrants | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Preferred Stock Warrants | 8. Preferred Stock Warrants The Company accounted for its warrants to purchase shares of redeemable convertible preferred stock as liabilities as they were exercisable for a redeemable instrument. The Company continued to adjust the liability for changes in fair value of these warrants until they were exercised or converted to common stock warrants. The following table summarizes the outstanding redeemable convertible preferred stock warrants and the corresponding exercise price as of December 31, 2017: Number of Shares Outstanding as of December 31, 2017 Exercise Price Expiration Date Series AA warrants 1,506 $ 13.28 March 7, 2018 2009 Series B warrants 25,884 $ 9.659 December 22, 2019 2014 Series B warrants 104,856 $ 0.12 May 14, 2021 Convertible debt Series C-1 warrants 304,397 $ 0.12 January 17, 2024 Term loan Series C-1 warrants 49,713 $ 9.659 October 18, 2027 486,356 In August 2018, as part of the Series D Financing, the Company issued warrants to purchase 368,582 shares of Series C-1 redeemable convertible preferred stock (the “2018 Series C-1 warrants”) at an exercise price of $0.12 per share. In connection with the IPO in October 2018, all outstanding redeemable convertible preferred stock warrants were either exercised or converted to common stock warrants. During 2018, stockholders exercised the outstanding 2014 Series B warrants, convertible debt Series C-1 warrants and the 2018 Series C-1 warrants to purchase an aggregate of 764,034 shares of the Company’s redeemable convertible preferred stock and common stock, at a weighted-average exercise price of $0.12 per share. The outstanding 2009 Series B warrants and Term loan Series C-1 warrants were automatically converted into an aggregate of 75,597 common stock warrants, to which the liability was reclassified to stockholders’ equity. |
Redeemable Convertible Preferre
Redeemable Convertible Preferred Stock and Stockholders’ Deficit | 12 Months Ended |
Dec. 31, 2018 | |
Stockholders Equity Note [Abstract] | |
Redeemable Convertible Preferred Stock and Stockholders’ Deficit | 9. Redeemable Convertible Preferred Stock and Stockholders’ Deficit Preferred Stock The Company issued Series 1 redeemable convertible preferred stock (“Series 1”), Series 2 redeemable preferred stock (“Series 2”), Series AA redeemable convertible preferred stock (“Series AA”), Series B redeemable convertible preferred stock (“Series B”), Series C-1, Series C-2 redeemable convertible preferred stock (“Series C-2”), Series C-3 redeemable convertible preferred stock (“Series C-3”), and Series D (collectively, “Preferred As of December 31, 2017, the authorized, issued, and outstanding shares of Preferred Stock and their carrying amounts and liquidation values were as follows: Shares Issued Shares and Carrying Liquidation Authorized Outstanding Amount Value Series 1 132,255 132,255 $ 522,266 $ 526,778 Series 2 1 1 240,242 250,000 Series AA 575,470 573,961 7,615,583 7,619,998 Series B 6,382,259 6,251,502 60,366,480 60,379,282 Series C-1 4,524,375 2,174,280 20,888,972 20,999,997 Series C-2 916,095 — — — Series C-3 790,895 — — — Total 13,321,350 9,131,999 $ 89,633,543 $ 89,776,055 Conversion All shares of Preferred Stock were automatically converted into an aggregate of 13,200,115 shares of common stock upon the closing of the IPO on October 22, 2018. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Stock-Based Compensation | 10. Stock-Based Compensation Stock Plans In July 2018, the Company amended the Company’s Amended and Restated 2002 Stock Plan (the “2002 Plan”) to reserve an additional 800,000 shares of common stock for issuance under the 2002 Plan. In October 2018, the Company’s board of directors and stockholders adopted and approved the 2018 Equity Incentive Plan (the “2018 Plan”), which is a successor to and continuation of the 2002 Plan. The 2018 Plan became effective upon the execution of the underwriting agreement related to the IPO on October 17, 2018. No further grants will be made under the 2002 Plan. Initially, the maximum number of shares of the Company’s common stock that may be issued under the 2018 Plan is 3,231,626 shares. As of December 31, 2018, the Company had 1,670,921 shares available for grant under the 2018 Plan. The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year, starting on January 1, 2019 through January 1, 2028, in an amount equal to 3% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Company’s board of directors. Subject to this provision, the Company added 734,948 shares available for grant to the 2018 Plan effective January 1, 2019. The maximum number of shares of the Company’s common stock that may be issued on the exercise of incentive stock options under the 2018 Plan is . The following table summarizes stock option activity for the 2002 Plan and 2018 Plan for the year ended December 31, 2018: Weighted- Weighted- Average Average Exercise Remaining Aggregate Total Price Per Contractual Intrinsic Options Share Term (in years) Value Outstanding at Ended December 31, 2016 1,001,546 $ 1.62 8.1 $ 58,619 Granted 99,866 $ 1.44 Exercised (2,547 ) $ 1.20 Cancelled or expired (23,656 ) $ 1.76 Outstanding at December 31, 2017 1,075,209 $ 1.60 7.3 $ 711,328 Granted 563,268 $ 4.07 Exercised (43,687 ) $ 2.12 Cancelled or expired (49,387 ) $ 1.65 Outstanding at December 31, 2018 1,545,403 $ 2.48 7.6 $ 1,593,487 Vested and expected to vest at December 31, 2018 1,545,403 $ 2.48 7.6 $ 1,593,487 Vested and exercisable at December 31, 2018 801,294 $ 1.65 6.3 $ 1,175,200 The weighted-average grant date fair value per share of options granted was $2.75 and $1.00 for the years ended December 31, 2018 and 2017, respectively. The aggregate intrinsic value of options exercised was $0.2 million and $686 for the years ended December 31, 2018 and 2017, respectively. As of December 31, 2018, the total unrecognized compensation expense related to unvested employee and non-employee stock option awards was $1.6 million, which was expected to be recognized in expense over a weighted-average period of approximately 2.9 years. In October 2018, the Company’s board of directors and stockholders approved the 2018 Employee Stock Purchase Plan (the “ESPP”). The ESPP became effective on October 17, 2018. The purpose of the ESPP is to secure the services of new employees, to retain the services of existing employees and to provide incentives for such individuals to exert maximum efforts toward the Company’s success and that of the Company’s affiliates. The ESPP is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423 of the Code for U.S. employees. The ESPP authorizes the issuance of 196,000 shares of the Company’s common stock under purchase rights granted to the Company’s employees or to employees of any of the Company’s designated affiliates. The number of shares of common stock reserved for issuance will automatically increase on January 1 of each calendar year, beginning on January 1, 2019 through January 1, 2028, by the lesser of (1) 1% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 490,000 shares; provided that before the date of any such increase, the Company’s board of directors may determine that such increase will be less than the amount set forth in clauses (1) and (2). Subject to this provision, the Company added 244,983 shares available for grant to the ESPP effective January 1, 2019. As of December 31, 2018, no shares of common stock have been purchased under the ESPP. Determining Fair Value of Stock Options The fair value of each grant of stock options was determined by the Company using the methods and assumptions discussed below. Certain of these inputs are subjective and generally require judgment to determine. Expected Term —The expected term of stock options represents the weighted average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term. The simplified method calculates the expected term as the average time-to-vesting and the contractual life of the options. Expected Volatility —Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Risk-Free Interest Rate —The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected Dividend —The Company has not paid and does not intend to pay dividends. Common Stock Valuation —Due to the absence of a public market trading the Company’s common stock prior to the IPO, it was necessary to estimate the fair value of the common stock underlying the stock-based grants when performing fair value calculations using the Black-Scholes option pricing model. The fair value of the common stock underlying the stock-based grants was assessed for each grant date by the board of directors. All options to purchase shares of common stock have been granted with an exercise price per share no less than the fair value per share of the common stock underlying those options on the date of grant. In the absence of a public trading market for the Company’s common stock, the Company determined the estimated fair value of its common stock using methodologies, approaches, and assumptions consistent with the American Institute of Certified Public Accountants (“AICPA”) Audit and Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation (“AICPA Practice Aid”). The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below: Year Ended December 31, 2018 2017 Risk-free interest rate 2.88 % 2.88 % Expected term (in years) 7.0 7.1 Expected volatility 69 % 68 % Expected dividend yield — — Estimated fair value of common stock $ 4.07 $ 1.00 Stock-based compensation expense has been reported in the Company’s statements of operations for the years ended December 31, 2018 and 2017 as follows (in thousands): Year Ended December 31, 2018 2017 General and administrative $ 208 $ 40 Research and development 124 37 Total stock-based compensation $ 332 $ 77 |
License Agreements
License Agreements | 12 Months Ended |
Dec. 31, 2018 | |
License Agreements [Abstract] | |
License Agreement | 11. License Agreements MedImmune Limited In November 2017, the Company entered into a license agreement (“MedImmune License”) with MedImmune Limited (“MedImmune”). MedImmune is a wholly owned subsidiary of AstraZeneca plc. Pursuant to the terms of the MedImmune License, MedImmune granted the Company exclusive global rights for the purpose of developing and commercializing products under the MedImmune License (“MedImmune licensed product”). In consideration of the license and other rights granted by MedImmune, the Company made an upfront payment of $0.1 million, which was included as research and development expense for the year ended December 31, 2017. The Company is also obligated to make a series of contingent milestone payments totaling up to an aggregate of $18.0 million upon the achievement of clinical development and regulatory milestones. As of December 31, 2018, none of the clinical development or regulatory filing milestones had been met. In addition, the Company will pay MedImmune tiered royalties ranging from mid-single-digit to low-teen percentages of net sales of any MedImmune licensed products and additional payments of up to $50.0 million in aggregate commercial milestones. The Company also must pay quarterly fees relating to technical services provided by MedImmune. The MedImmune License requires the Company to cooperate with MedImmune on commercial messaging of PB2452 and provides MedImmune with the return of rights to PB2452 if certain commercial diligence requirements are not achieved by the Company. In addition, the MedImmune License offers an option for third-party product storage costs. As of December 31, 2017, the Company had incurred and reimbursed MedImmune $0.5 million for such third-party product storage costs. The Company incurred an insignificant amount of third-party product storage costs in the year ended December 31, 2018. Duke University In October 2006, the Company entered into a license agreement with Duke University (“Duke”) (as amended, the “Duke License”). Pursuant to the Duke License, Duke granted to the Company an exclusive, worldwide license under certain patent rights and a non-exclusive license to know-how owned or controlled by Duke to develop and commercialize any products or processes covered under the Duke License (the “Duke licensed products”). The Duke License was amended in February 2016 to allow Duke to use the Company’s technology in the area of small-molecule oncologics. The Duke License is a worldwide, sublicensable agreement and remains in full effect for the life of the last-to-expire patents included in the patent rights, which is approximately 20 years. The Company is required to apply for, prosecute and maintain all U.S. and foreign patent rights under the Duke License. The Company is obligated to pay up to $2.2 million upon the achievement of clinical development and regulatory milestones and up to $0.4 million upon the achievement of commercial milestones. The Duke License may be terminated by Duke if the Company fails to meet certain clinical development and regulatory milestones within specified timeframes. As of December 31, 2018, the Company was in compliance with its development obligations. The Company is required to use commercially reasonable efforts to develop one or more products or processes and introduce them into commercial markets. Duke will receive low single-digit royalty percentages on net sales by the Company or its sublicensee, with minimum aggregate royalties of $0.2 million payable following the Company’s achievement of certain commercial milestones. No sales of Duke licensed products or services have occurred since the effective date through December 31, 2018. Certain alliance fee payments up to the greater of $0.3 million or a low double-digit percentage of the fees the Company receives from a third party in consideration of forming a strategic alliance, may be required depending upon how the patent rights are commercialized. The Company will pay Duke the first $1.0 million of nonroyalty payments it receives from a sublicensee, and thereafter a specified percentage of any additional nonroyalty payments it receives. If Duke receives revenue as a result of a license or sublicense to a third party in the field of small-molecule oncologics, it will pay the Company a specified percentage of the amount of such revenue in excess of $1.0 million. Duke is also a stockholder of the Company. |
Grant Revenue
Grant Revenue | 12 Months Ended |
Dec. 31, 2018 | |
Revenue From Contract With Customer [Abstract] | |
Grant Revenue | 12. Grant Revenue In February 2018, the Company received Small Business Innovation Research (“SBIR”) grants from the National Institutes of Health in an aggregate amount of $2.8 million to support the clinical development of PB1046 for the treatment of pulmonary arterial hypertension for the period from February 17, 2018 to July 31, 2020. In connection with the SBIR grants, the U.S. government will receive a non-exclusive, royalty-free license to use any technology the Company develops under such grants. The Company recognized $0.7 million under the SBIR grants in the year ended December 31, 2018. The Company did not recognize any grant revenues for the year ended December 31, 2017. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 13. The Company’s loss before income taxes was $23.8 million and $10.2 million for the years ended December 31, 2018 and 2017, respectively and was generated entirely in the United States. The Company did not record current or deferred income tax expense or benefit during the years ended December 31, 2018 and 2017. A reconciliation of income tax expense (benefit) to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2018 and 2017, respectively, as follows (in thousands): Year Ended December 31, 2018 2017 Income tax benefit at statutory rate $ (5,008 ) $ (3,484 ) State income tax, net of federal benefit (1,593 ) (528 ) Permanent items 3 4 Fair value adjustments 15 (164 ) Non-deductible interest expense 706 905 Stock-based compensation 45 21 Orphan drug credit (475 ) (616 ) Research and development credits (274 ) (218 ) Uncertain tax positions 222 209 Tax Cuts and Jobs Act (15 ) 10,978 Change in valuation allowance 6,426 (7,110 ) Other (52 ) 3 $ — $ — Significant components of the Company’s deferred tax assets as of December 31, 2018 and 2017 are shown below: Year Ended December 31, 2018 2017 Net deferred tax asset: Net operating loss carryforwards $ 31,744 $ 26,138 Research and development credits 4,615 3,863 Accrued expenses 332 239 Intangibles 69 110 Property and equipment (18 ) (2 ) Other, net 54 22 Total net deferred tax asset 36,796 30,370 Valuation allowance for deferred tax asset (36,796 ) (30,370 ) Deferred tax assets, net of valuation allowance $ — $ — As of December 31, 2018 and 2017, management assessed the realizability of deferred tax assets and evaluated the need for a valuation allowance against the deferred tax assets. This evaluation utilizes the framework contained in ASC 740, Income Taxes Management followed the guidance in ASC 740, which states that “a cumulative loss in recent years is a significant piece of negative evidence that is difficult to overcome” and concluded that the Company’s deferred tax assets were not realizable as of December 31, 2018 and 2017 and recorded a valuation allowance of $36.8 million and $30.4 million, respectively, to offset the deferred tax assets. The change in valuation allowance for the years ended December 31, 2018 and 2017 was an increase of $6.4 million and a decrease of $7.1 million, respectively. At December 31, 2018, the Company had federal and Pennsylvania net operating loss (“NOL”) carryforwards of $111.9 million, and $105.9 million, respectively. The federal NOLs generated prior to 2018 may be used to offset up to 100% of future taxable income and will begin to expire in 2022, unless previously utilized. The federal NOL generated in 2018 of $20.4 million will be available to offset up to 80% of future taxable income and may be carried forward indefinitely. The Pennsylvania NOLs may be used to offset 40% of future taxable income and will begin to expire in 2029, unless previously utilized. At December 31, 2018, the Company also has federal and Pennsylvania research and development tax credit carryforwards totaling $3.2 million and $0.2 million, respectively. The federal and Pennsylvania research and development tax credit carryforwards will begin to expire in 2028 and 2029, respectively, unless previously utilized. At December 31, 2018, the Company also has federal orphan drug credit carryforwards of $2.8 million, which will begin to expire in 2036, unless previously utilized. For all years through December 31, 2018, the Company generated a combination of research and development credits and orphan drug credits. Certain of these credits were derived from studies to document the qualified activities and certain other credits were not derived from studies. For the credits that were calculated through a study, the IRS, on audit, may disagree with the amount of credits calculated. When studies are ultimately performed for the other credits, they may result in an adjustment to those specific credits. Under the Internal Revenue Code, the utilization of a corporation’s net operating loss and tax credit carryforwards may be limited following a greater than 50% change in ownership over a three-year period. Any unused annual limitation may be carried forward to future years for the balance of the net operating loss and tax credit carryforward period. Under these rules, prior ownership changes may have created a limitation in the Company’s ability to use certain tax carryforwards on a yearly basis. Additionally, certain state operating losses may also be limited, including Pennsylvania, which limits net operating loss carryforward utilization to 35% (40% in 2019 and thereafter) of apportioned taxable income. In December 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act makes broad and complex changes to the U.S. tax code, including, but not limited to: (i) reducing the U.S. federal corporate tax rate from 35 percent to 21 percent; (ii) eliminating the corporate alternative minimum tax (“AMT”) and changing how existing AMT credits can be realized; (iii) creating a new limitation on deductible interest expense; and (iv) changing rules related to uses and limitations of net operating carryforwards created in tax years beginning after December 31, 2017. The Company applied the guidance in SEC Staff Accounting Bulletin 118 when accounting for the enactment-date effects of the Act in 2017 and throughout 2018. At December 31, 2017, the Company had not completed its accounting for all of the enactment-date income tax effects of the Act under ASC 740, Income Taxes, related to the remeasurement of deferred tax assets and liabilities. At December 31, 2018, the Company has now completed its accounting for all of the enactment-date income tax effects of the Act, and no adjustments were made to the provisional amounts recorded at December 31, 2017. The most significant impact of the Tax Act on the Company's consolidated financial statements was the reduction of $11.0 million of the deferred tax assets related to the net operating losses and other deferred tax assets. The reduction was offset by a change in the Company's valuation allowance. Another significant impact of the Tax Act was to reduce the applicable percentage to be used for the Orphan Drug Credit for tax years beginning after December 31, 2017. The Company applies the two-step approach to recognizing and measuring uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount, which is more than 50% likely of being realized upon ultimate settlement. Income tax positions must meet a more likely than not recognition threshold at the effective date to be recognized upon the adoption of ASC 740 and in subsequent periods. This interpretation also provides guidance on measurement, derecognition, classification, interest and penalties, accounting in interim periods, disclosure and transition. The Company files income tax returns in the U.S. federal jurisdiction, and various state jurisdictions. Tax years 2015 and forward remain open for examination for federal tax purposes and tax years 2015 and forward remain open for examination for the Company’s more significant state tax jurisdictions. To the extent utilized in future years’ tax returns, net operating loss carryforwards at December 31, 2018 will remain subject to examination until the respective tax year is closed. The following table summarizes the activity related to the Company’s gross unrecognized tax benefits for the years ended December 31, 2018 and 2017 (in thousands): Year Ended December 31, 2018 2017 Gross unrecognized tax benefits at the beginning of the year $ 1,293 $ 1,067 Increases related to current year positions 362 226 Increases related to prior year positions 154 — Decreases related to prior year positions — — Expiration of unrecognized tax benefits — — Gross unrecognized tax benefits at the end of the year $ 1,809 $ 1,293 Due to the Company's valuation allowance, none of the unrecognized tax benefits, if recognized, would affect the Company's effective tax rate. As of December 31, 2018, and 2017, the Company had unrecognized tax benefits of $1.8 million and $1.3 million, respectively. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. During the years ended December 31, 2018 and 2017, the Company did not accrue any interest and penalties on uncertain tax positions. The Company does not expect its unrecognized tax benefits to change significantly within the next 12 months. |
Related Party Transactions
Related Party Transactions | 12 Months Ended |
Dec. 31, 2018 | |
Related Party Transactions [Abstract] | |
Related Party Transactions | 1 4 . Related Party Transactions As described above in Note 11, the Company is party to the MedImmune License. MedImmune is a related party of the Company. |
Subsequent Events
Subsequent Events | 12 Months Ended |
Dec. 31, 2018 | |
Subsequent Events [Abstract] | |
Subsequent Events | 1 5 . Subsequent Events On March 25, 2019, the Company entered into a term loan agreement (the “2019 Loan”) with SVB and WestRiver Innovation Lending Fund VIII, L.P. (“WestRiver”), pursuant to which the Company may borrow up to $15.0 million, issuable in three separate tranches (“Advances”), of $7.5 million, or Tranche A, which was issued upon execution of the SVB and WestRiver Loan Agreement, $2.5 million available to be issued until May 31, 2019, (“Tranche B”), and $5.0 million (“Tranche C”), which the Company will draw upon the achievement of certain regulatory milestones (the “Tranche C milestones”) The maturity date of the 2019 Loan is March 1, 2023. Under the terms of the 2019 Loan, the Company is to make interest-only payments through December 31, 2019 on Tranche A and Tranche B at a rate equal to the greater of the Prime Rate plus 1.00%, as defined in the 2019 Loan, or 6.5%, followed by an amortization period of 39 months of equal monthly payments of principal plus interest amounts until paid in full. The interest-only period will automatically be extended to June 30, 2020 if the Company achieves the Tranche C milestones, followed by an amortization period of 33 months of equal monthly payments of principal plus interest amounts until paid in full. In addition to and not in substitution for the Company’s regular monthly payments of principal plus accrued interest, the Company is required to make a final payment equal to 6% of the aggregate principal amount of the Advances on the maturity date. The Company has agreed to issue to SVB and WestRiver warrants to purchase shares of common stock on when we draw on each of Tranche A (an aggregate of 12,131 shares of common stock) and Tranche B (an aggregate of 24,262 shares of common stock), with an exercise price of the lower of the average closing price of the Company’s common stock for the previous ten days of trading or the closing price on the day prior to funding. The warrants are immediately exercisable upon issuance and expire ten years from the date of issuance. Upon execution of the 2019 Loan, the Company drew $7.5 million from Tranche A and repaid the outstanding principal balance and accrued portion of the final payment for the SVB Loan in full. The Company’s obligations under the 2019 Loan are secured by a first priority security interest in substantially all of the Company’s current and future assets, excluding intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on the Company’s ability to encumber its intellectual property assets. |
Significant Accounting Polici_2
Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Basis of Presentation | Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (“SEC”). Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) promulgated by the Financial Accounting Standards Board (“FASB”). Certain non-significant The Company manages its operations as a single reportable segment for the purposes of assessing performance and making operating decisions. |
Use of Estimates | Use of Estimates The preparation of the Company’s financial statements requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities in the Company’s financial statements and accompanying notes. The most significant estimates in the Company’s financial statements relate to the valuation of redeemable convertible preferred stock warrants prior to the IPO, the conversion option on the convertible notes and clinical trial accruals. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results could differ materially from those estimates and assumptions. |
Concentrations of Credit Risk | Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains certain deposits in federally insured financial institutions in excess of federally insured limits. The Company could experience losses on the money market funds in the future. |
Cash and Cash Equivalents | Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market |
Restricted Cash | Restricted Cash The Company had restricted cash of $20,000 as of December 31, 2018 and 2017 , |
Fair Value of Financial Instruments | Fair Value of Financial Instruments The carrying amounts of accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses are reasonable estimates of their fair value because of the short maturity of these items. Based on the borrowing rates currently available to the Company for loans with similar terms, the Company believes the fair value of the term loan approximates its carrying value (see Note |
Property and Equipment | Property and Equipment Property and equipment are recorded at cost and depreciated over the estimated useful lives of the assets (three to five years) using the straight-line method. Leasehold improvements are amortized over the shorter of their estimated useful lives or the lease term. |
Long-Lived Assets | Long-Lived Assets The Company regularly reviews the carrying value and estimated lives of all of its long-lived assets, including property and equipment to determine whether indicators of impairment may exist which warrant adjustments to carrying values or estimated useful lives. The determinants used for this evaluation include management’s estimate of the asset’s ability to generate net positive cash flow in future periods as well as the strategic significance of the assets to the Company’s business objective. Should an impairment exist, the impairment loss would be measured based on the extent that the estimated fair value is less than its carrying value. The Company has not recognized any impairment |
Preferred Stock Warrant Liability | Preferred Stock Warrant Liability The Company previously issued freestanding warrants to purchase shares of its redeemable convertible preferred stock. Since the underlying redeemable convertible preferred stock was classified outside of permanent equity, those warrants were classified as liabilities in the accompanying balance sheet. Warrants classified as liabilities were recorded at their estimated fair value on the date of issuance and were revalued at each subsequent balance sheet date, with fair value changes recognized as increases or reductions to other income (expense) in the accompanying statements of operations. The Company estimated the fair value of these warrants using the Black-Scholes option pricing In connection with the Company’s IPO in October 2018, all warrants were either exercised or converted into warrants to purchase common stock, at which time the liability was reclassified to stockholders’ equity. |
Preclinical And Clinical Trial Accruals | Preclinical and Clinical Trial Accruals The Company accrues and expenses preclinical studies and clinical trial activities performed by third parties based upon estimates of the proportion of work completed over the life of the individual trial and subject enrollment rates in accordance with agreements with clinical research organizations and clinical trial sites. The Company determines the estimates by reviewing contracts, vendor agreements and purchase orders, and through discussions with internal clinical personnel and external service providers as to the progress or stage of completion of trials or services and the agreed-upon fee to be paid for such services. However, actual costs and timing of clinical trials are highly uncertain, subject to risks and may change depending upon a number of factors, including the Company’s clinical development Management makes estimates of the Company’s accrued expenses as of each balance sheet date in the Company’s financial statements based on facts and circumstances known to the Company at that time. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Nonrefundable advance payments for goods and services, including fees for process development or manufacturing and distribution of clinical supplies that will be used in future research and development activities, are deferred and recognized as expense in the period that the related goods are consumed or services are |
Research and Development Expenses | Research and Development Expense Research and development costs are expensed as incurred. |
Stock-Based Compensation | Stock-Based Compensation The Company measures and recognizes compensation expense for all stock-based compensation based on the estimated fair value at the date of grant. Currently, the Company’s stock-based awards consist only of stock options; however, future grants under the Company’s equity compensation plan may also consist of shares of restricted stock, restricted stock units, stock appreciation rights, performance awards and performance units. The Company estimates the fair value of stock options using the Black-Scholes option-pricing model, which requires the use of estimates. The Company recognizes stock-based compensation cost for ratably vesting stock options on a straight-line basis over the requisite service period of the award. The Black-Scholes option-pricing model requires the input of subjective assumptions, including the risk-free interest rate, the fair value of the underlying common stock prior to the IPO, the expected dividend yield of the Company’s common stock, the expected volatility of the price of the Company’s common stock, and the expected term of the option. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, the Company’s stock-based compensation expense could be materially different in the future. |
Income Taxes | Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences 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. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes net deferred tax assets to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, management considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If management determines that the Company would be able to realize its deferred tax assets in the future in excess of their net recorded amount, management would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions on the basis of a two-step process whereby (1) management determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, management recognizes the largest amount of tax benefit that is more than 50% likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits, if any, within income tax expense, and any accrued interest and penalties are included within the related tax liability line. |
Grant Revenues | Grant Revenues Grant revenues are derived from government grants that support the Company’s efforts on specific research projects. The Company has determined that the government agencies providing grants to the Company are not customers. The Company recognizes grant revenue when there is reasonable assurance of compliance with the conditions of the grant and reasonable assurance that the grant revenue will be received. |
Net Loss Per Share | Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. As of December 31, 2018 2017 Common stock options 1,545,403 1,075,209 Warrants to purchase common stock 75,597 — Redeemable convertible preferred stock — 9,131,999 Warrants to purchase redeemable convertible preferred stock — 486,356 Total 1,621,000 10,693,564 |
Recent Accounting Pronouncements | Recent Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases The Company will adopt ASU 2016-02 in 2019. Upon adoption, the Company expects to record a right of use asset and a corresponding lease liability of an amount between $1.5 million and $2.5 million. In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments (Topic 230) In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting classified share-based payment awards issued to nonemployees will be measured at the grant date, instead of the previous requirement to remeasure the awards through the performance completion date, (2) for performance conditions, compensation cost associated with the award will be recognized when the achievement of the performance condition is probable, rather than upon achievement of the performance condition and (3) the current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. The Company adopted this standard effective October 1, 2018, and the adoption did not have a material impact on the Company’s financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement - Disclosure Framework (Topic 820): Changes to the Disclosure Requirements for Fair Value Measurement |
Significant Accounting Polici_3
Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Schedule Of Outstanding Potentially Dilutive Securities Excluded In Calculation Of Diluted Net Loss Per Share | The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because their inclusion would be anti-dilutive. As of December 31, 2018 2017 Common stock options 1,545,403 1,075,209 Warrants to purchase common stock 75,597 — Redeemable convertible preferred stock — 9,131,999 Warrants to purchase redeemable convertible preferred stock — 486,356 Total 1,621,000 10,693,564 |
Fair Value Measurement (Tables)
Fair Value Measurement (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Summary of Assets and Liabilities that Require Fair Value Measurements on a Recurring Basis | The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands): Fair Value Measurements at Reporting Date Total Level 1 Level 2 Level 3 As of December 31, 2018: Assets Cash equivalents $ 59,357 $ 59,357 $ — $ — As of December 31, 2017: Assets Cash equivalents $ 12,472 $ 12,472 $ — $ — Liabilities Derivative liability $ 3,028 $ — $ — $ 3,028 Preferred stock warrant liability 1,656 — — 1,656 Total liabilities $ 4,684 $ — $ — $ 4,684 |
Weighted-Average Assumptions Used In Determining Fair Value of Preferred Stock Warrant Liability Valued Using Black-Scholes Option Pricing Model | The following weighted-average assumptions were used in determining the fair value of the preferred stock warrant liability valued using the Black-Scholes option pricing model as of December 31, 2017: December 31, 2017 Expected volatility 68.0 % Risk-free interest rate 2.2 % Contractual term (in years) 5.9 Expected dividend yield — |
Estimated Fair Values Per Share of Underlying Redeemable Convertible Preferred Stock | The following estimated fair values per share of the Company’s underlying redeemable convertible preferred stock were used to determine the estimated fair value of the preferred stock warrant liability: December 31, 2017 Series AA $ 5.75 Series B $ 3.76 Series C-1 $ 3.76 |
Activity for Preferred Stock Warrant Liability and Derivative Liability Measured At Fair Value Using Significant Unobservable Level 3 Inputs | The following tables present activity for the preferred stock warrant liability and the derivative liability measured at fair value using significant unobservable Level 3 inputs during the year ended December 31, 2017 and 2018 (in thousands): Preferred Stock Warrant Liability Balance at December 31, 2016 $ 880 Issuance of warrants 1,795 Changes in fair value reflected as change in fair value of warrant liability (1,019 ) Balance at December 31, 2017 1,656 Issuance of warrants 2,822 Exercise of warrants (1,197 ) Changes in fair value reflected as change in fair value of warrant liability (11 ) Conversion to common stock warrants upon IPO (3,270 ) Balance at December 31, 2018 $ — Derivative Liability Balance at December 31, 2016 $ — Issuance of derivative 2,971 Changes in fair value reflected as change in fair value of derivative liability 57 Balance at December 31, 2017 3,028 Changes in fair value reflected as change in fair value of derivative liability 676 Extinguishment of derivative upon conversion of convertible promissory notes (3,704 ) Balance at December 31, 2018 $ — |
Property and Equipment (Tables)
Property and Equipment (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Property Plant And Equipment [Abstract] | |
Composition of Property and Equipment, Net | The following table presents the composition of property and equipment, net as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018 2017 Lab equipment $ 1,764 $ 1,681 Computer hardware, software and telephone 228 174 Furniture and fixtures 98 70 Leasehold improvements 50 22 2,140 1,947 Less accumulated depreciation (1,785 ) (1,645 ) Property and equipment, net $ 355 $ 302 |
Accrued Expenses (Tables)
Accrued Expenses (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Payables And Accruals [Abstract] | |
Schedule of Composition of Accrued Expenses | The following table presents the composition of accrued expenses as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018 2017 Accrued clinical and related costs $ 1,358 $ 197 Accrued compensation and related costs 914 346 Accrued interest 194 628 Accrued other 305 110 Accrued expenses $ 2,771 $ 1,281 |
Debt (Tables)
Debt (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Debt Disclosure [Abstract] | |
Summary of Future Principal Payments | On March 25, 2019, the Company repaid the outstanding principal balance and accrued portion of the final payment for the SVB Loan in full The following table sets forth by year the Company’s required future principal payments for the refinanced SVB Loan (in thousands): Years Ending December 31, 2019 $ — 2020 2,142 2021 2,285 2022 2,438 2023 635 Thereafter — $ 7,500 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Schedule of Future Minimum Commitments Under Non-cancelable Operating Leases | The Company’s future minimum commitments under its non-cancelable operating leases were as follows (in thousands): Year Ending December 31, 2019 $ 342 2020 368 2021 373 2022 360 2023 204 Thereafter — Total $ 1,647 |
Preferred Stock Warrants (Table
Preferred Stock Warrants (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Summary of Outstanding Redeemable Convertible Preferred Stock Warrants and Corresponding Exercise Price | The following table summarizes the outstanding redeemable convertible preferred stock warrants and the corresponding exercise price as of December 31, 2017: Number of Shares Outstanding as of December 31, 2017 Exercise Price Expiration Date Series AA warrants 1,506 $ 13.28 March 7, 2018 2009 Series B warrants 25,884 $ 9.659 December 22, 2019 2014 Series B warrants 104,856 $ 0.12 May 14, 2021 Convertible debt Series C-1 warrants 304,397 $ 0.12 January 17, 2024 Term loan Series C-1 warrants 49,713 $ 9.659 October 18, 2027 486,356 |
Redeemable Convertible Prefer_2
Redeemable Convertible Preferred Stock and Stockholders’ Deficit (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Stockholders Equity Note [Abstract] | |
Summary of Authorized, Issued, and Outstanding Shares of Preferred Stock and Carrying Amounts and Liquidation Values | As of December 31, 2017, the authorized, issued, and outstanding shares of Preferred Stock and their carrying amounts and liquidation values were as follows: Shares Issued Shares and Carrying Liquidation Authorized Outstanding Amount Value Series 1 132,255 132,255 $ 522,266 $ 526,778 Series 2 1 1 240,242 250,000 Series AA 575,470 573,961 7,615,583 7,619,998 Series B 6,382,259 6,251,502 60,366,480 60,379,282 Series C-1 4,524,375 2,174,280 20,888,972 20,999,997 Series C-2 916,095 — — — Series C-3 790,895 — — — Total 13,321,350 9,131,999 $ 89,633,543 $ 89,776,055 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Summary of Stock Option Activity | The following table summarizes stock option activity for the 2002 Plan and 2018 Plan for the year ended December 31, 2018: Weighted- Weighted- Average Average Exercise Remaining Aggregate Total Price Per Contractual Intrinsic Options Share Term (in years) Value Outstanding at Ended December 31, 2016 1,001,546 $ 1.62 8.1 $ 58,619 Granted 99,866 $ 1.44 Exercised (2,547 ) $ 1.20 Cancelled or expired (23,656 ) $ 1.76 Outstanding at December 31, 2017 1,075,209 $ 1.60 7.3 $ 711,328 Granted 563,268 $ 4.07 Exercised (43,687 ) $ 2.12 Cancelled or expired (49,387 ) $ 1.65 Outstanding at December 31, 2018 1,545,403 $ 2.48 7.6 $ 1,593,487 Vested and expected to vest at December 31, 2018 1,545,403 $ 2.48 7.6 $ 1,593,487 Vested and exercisable at December 31, 2018 801,294 $ 1.65 6.3 $ 1,175,200 |
Estimated Fair Value of Option on Grant Date using Weighted Average Assumptions | The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below: Year Ended December 31, 2018 2017 Risk-free interest rate 2.88 % 2.88 % Expected term (in years) 7.0 7.1 Expected volatility 69 % 68 % Expected dividend yield — — Estimated fair value of common stock $ 4.07 $ 1.00 |
Stock-based Compensation Expense | Stock-based compensation expense has been reported in the Company’s statements of operations for the years ended December 31, 2018 and 2017 as follows (in thousands): Year Ended December 31, 2018 2017 General and administrative $ 208 $ 40 Research and development 124 37 Total stock-based compensation $ 332 $ 77 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Summary of Reconciliation of Income Tax Expense (Benefit) | A reconciliation of income tax expense (benefit) to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2018 and 2017, respectively, as follows (in thousands): Year Ended December 31, 2018 2017 Income tax benefit at statutory rate $ (5,008 ) $ (3,484 ) State income tax, net of federal benefit (1,593 ) (528 ) Permanent items 3 4 Fair value adjustments 15 (164 ) Non-deductible interest expense 706 905 Stock-based compensation 45 21 Orphan drug credit (475 ) (616 ) Research and development credits (274 ) (218 ) Uncertain tax positions 222 209 Tax Cuts and Jobs Act (15 ) 10,978 Change in valuation allowance 6,426 (7,110 ) Other (52 ) 3 $ — $ — |
Significant Components of Deferred Tax Assets | Significant components of the Company’s deferred tax assets as of December 31, 2018 and 2017 are shown below: Year Ended December 31, 2018 2017 Net deferred tax asset: Net operating loss carryforwards $ 31,744 $ 26,138 Research and development credits 4,615 3,863 Accrued expenses 332 239 Intangibles 69 110 Property and equipment (18 ) (2 ) Other, net 54 22 Total net deferred tax asset 36,796 30,370 Valuation allowance for deferred tax asset (36,796 ) (30,370 ) Deferred tax assets, net of valuation allowance $ — $ — |
Summary of Activity Related to Gross Unrecognized Tax Benefits | The following table summarizes the activity related to the Company’s gross unrecognized tax benefits for the years ended December 31, 2018 and 2017 (in thousands): Year Ended December 31, 2018 2017 Gross unrecognized tax benefits at the beginning of the year $ 1,293 $ 1,067 Increases related to current year positions 362 226 Increases related to prior year positions 154 — Decreases related to prior year positions — — Expiration of unrecognized tax benefits — — Gross unrecognized tax benefits at the end of the year $ 1,809 $ 1,293 |
Organization and Description _2
Organization and Description of Business - Additional Information (Details) $ / shares in Units, $ in Thousands | Oct. 22, 2018USD ($)$ / sharesshares | Oct. 31, 2018 | Dec. 31, 2018USD ($)$ / sharesshares | Dec. 31, 2017USD ($)$ / sharesshares |
Organization and Description of Business [Line Item] | ||||
Proceeds from issuance of common stock in initial public offering, net | $ | $ 42,974 | |||
Common stock, shares authorized | 200,000,000 | 14,918,087 | ||
Common stock, par value | $ / shares | $ 0.001 | $ 0.001 | ||
Preferred Stock, Shares Authorized | 10,000,000 | 0 | ||
Preferred Stock, Par Value | $ / shares | $ 0.001 | $ 0.001 | ||
Reverse stock split description | The Company effected a 11.0634-for-1 reverse split of its outstanding common stock and redeemable convertible preferred stock. | |||
Accumulated deficit | $ | $ (122,911) | $ (99,065) | ||
Cash and cash equivalents | $ | 61,031 | $ 13,406 | ||
Working capital | $ | $ 58,100 | |||
Common Stock | ||||
Organization and Description of Business [Line Item] | ||||
Common stock, shares, issued and sold | 9,864,666 | |||
Conversion of redeemable convertible preferred stock into common stock, shares | 13,225,048 | |||
Reverse stock split conversion ratio | 11.0634 | |||
Initial Public Offering | ||||
Organization and Description of Business [Line Item] | ||||
Common stock, shares, issued and sold | 9,864,666 | |||
Common stock,public offering price | $ / shares | $ 5 | |||
Proceeds from issuance of common stock in initial public offering, net | $ | $ 43,000 | |||
Conversion of redeemable convertible preferred stock into common stock, shares | 13,200,115 | |||
Common stock, shares authorized | 200,000,000 | |||
Common stock, par value | $ / shares | $ 0.001 | |||
Preferred Stock, Shares Authorized | 10,000,000 | |||
Preferred Stock, Par Value | $ / shares | $ 0.001 | |||
Initial Public Offering | Common Stock | ||||
Organization and Description of Business [Line Item] | ||||
Conversion of redeemable convertible preferred stock into common stock, shares | 13,200,115 |
Significant Accounting Polici_4
Significant Accounting Policies - Additiona Information (Details) - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2019 | Dec. 31, 2017 | |
Significant Accounting Policies [Line Items] | |||
Restricted cash | $ 20,000 | $ 20,000 | |
Minimum | |||
Significant Accounting Policies [Line Items] | |||
Property plant and equipment estimated useful lives | three | ||
Minimum | ASU 2016-02 | Scenario, Plan | |||
Significant Accounting Policies [Line Items] | |||
Operating lease, liability | $ 1,500,000 | ||
Maximum | |||
Significant Accounting Policies [Line Items] | |||
Property plant and equipment estimated useful lives | five | ||
Maximum | ASU 2016-02 | Scenario, Plan | |||
Significant Accounting Policies [Line Items] | |||
Operating lease, liability | $ 2,500,000 |
Significant Accounting Polici_5
Significant Accounting Policies - Schedule Of Outstanding Potentially Dilutive Securities Excluded In Calculation Of Diluted Net Loss Per Share (Details) - shares | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Significant Accounting Policies [Line Items] | ||
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share | 1,621,000 | 10,693,564 |
Redeemable Convertible Preferred Stock | ||
Significant Accounting Policies [Line Items] | ||
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share | 9,131,999 | |
Common Stock Options | ||
Significant Accounting Policies [Line Items] | ||
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share | 1,545,403 | 1,075,209 |
Warrants to purchase common stock | ||
Significant Accounting Policies [Line Items] | ||
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share | 75,597 | |
Warrants to Purchase Redeemable Convertible Preferred Stock | ||
Significant Accounting Policies [Line Items] | ||
Outstanding potentially dilutive securities excluded in calculation of diluted net loss per share | 486,356 |
Fair Value Measurement - Summar
Fair Value Measurement - Summary of Assets and Liabilities that Require Fair Value Measurements on a Recurring Basis (Details) - Fair Value Measurements on Recurring Basis - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Assets | ||
Cash equivalents | $ 59,357 | $ 12,472 |
Liabilities | ||
Derivative liability | 3,028 | |
Preferred stock warrant liability | 1,656 | |
Total liabilities | 4,684 | |
Level 1 | ||
Assets | ||
Cash equivalents | $ 59,357 | 12,472 |
Level 3 | ||
Liabilities | ||
Derivative liability | 3,028 | |
Preferred stock warrant liability | 1,656 | |
Total liabilities | $ 4,684 |
Fair Value Measurement - Weight
Fair Value Measurement - Weighted-Average Assumptions Used In Determining Fair Value of Preferred Stock Warrant Liability Valued Using Black-Scholes Option Pricing Model (Details) - Weighted-Average Assumptions - Preferred Stock Warrant Liability | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Contractual term (in years) | 5 years 10 months 24 days |
Expected Volatility | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Debt instrument, Measurement input | 0.680 |
Risk-Free Interest Rate | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Debt instrument, Measurement input | 0.022 |
Fair Value Measurement - Estima
Fair Value Measurement - Estimated Fair Values Per Share of Underlying Redeemable Convertible Preferred Stock (Details) | Dec. 31, 2017$ / shares |
Series AA | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Estimated fair values preferred stock | $ 5.75 |
Series B | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Estimated fair values preferred stock | 3.76 |
Series C-1 | |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] | |
Estimated fair values preferred stock | $ 3.76 |
Fair Value Measurement - Activi
Fair Value Measurement - Activity for Preferred Stock Warrant Liability and Derivative Liability Measured At Fair Value Using Significant Unobservable Level 3 Inputs (Details) - Level 3 - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Derivative Liability | ||
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Beginning balance | $ 3,028 | |
Issuance of warrants or derivative | $ 2,971 | |
Changes in fair value reflected as change in fair value of liability | 676 | 57 |
Extinguishment of derivative upon conversion of convertible promissory notes | (3,704) | |
Ending balance | 3,028 | |
Preferred Stock Warrant Liability | ||
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | ||
Beginning balance | 1,656 | 880 |
Issuance of warrants or derivative | 2,822 | 1,795 |
Exercise of warrants | (1,197) | |
Changes in fair value reflected as change in fair value of liability | (11) | (1,019) |
Conversion to common stock warrants upon IPO | $ (3,270) | |
Ending balance | $ 1,656 |
Property and Equipment - Compos
Property and Equipment - Composition of Property and Equipment, Net (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | $ 2,140 | $ 1,947 |
Less accumulated depreciation | (1,785) | (1,645) |
Property and equipment, net | 355 | 302 |
Lab Equipment | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 1,764 | 1,681 |
Computer Hardware, Software and Telephone | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 228 | 174 |
Furniture and Fixtures | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | 98 | 70 |
Leasehold Improvements | ||
Property Plant And Equipment [Line Items] | ||
Property and equipment, gross | $ 50 | $ 22 |
Accrued Expenses - Schedule of
Accrued Expenses - Schedule of Composition of Accrued Expenses (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Payables And Accruals [Abstract] | ||
Accrued clinical and related costs | $ 1,358 | $ 197 |
Accrued compensation and related costs | 914 | 346 |
Accrued interest | 194 | 628 |
Accrued other | 305 | 110 |
Accrued expenses | $ 2,771 | $ 1,281 |
Debt - Additional Information (
Debt - Additional Information (Details) - USD ($) | 1 Months Ended | 12 Months Ended | ||||||
Aug. 31, 2018 | Jul. 31, 2018 | Apr. 30, 2018 | Nov. 30, 2017 | Oct. 31, 2017 | Jan. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | |
Debt Instrument [Line Items] | ||||||||
Sale of stock | 0 | 9,131,999 | ||||||
Net proceeds from sale of shares | $ 17,712,000 | |||||||
Term Loan | Silicon Valley Bank | ||||||||
Debt Instrument [Line Items] | ||||||||
Number of warrants issued | 49,713 | |||||||
Exercise price of warrant | $ 9.659 | |||||||
Warrants exercisable date | Oct. 18, 2027 | |||||||
Interest expense | 600,000 | $ 100,000 | ||||||
Line of credit facility, maximum borrowing capacity | $ 7,500,000 | |||||||
Interest only period extended | Dec. 31, 2018 | |||||||
Amortization period of payments of principal plus interest amounts | 24 months | |||||||
Percentage of aggregate principal amount | 7.00% | |||||||
Debt instrument, maturity date | Jun. 1, 2020 | |||||||
Long-term Debt, gross | 7,500,000 | 3,500,000 | ||||||
Long-term debt, net of discount | 7,500,000 | $ 3,400,000 | ||||||
Term Loan | Silicon Valley Bank | Tranche A | ||||||||
Debt Instrument [Line Items] | ||||||||
Line of credit facility, maximum borrowing capacity | $ 3,500,000 | |||||||
Proceeds from lines of credit | $ 3,500,000 | |||||||
Term Loan | Silicon Valley Bank | Tranche B | ||||||||
Debt Instrument [Line Items] | ||||||||
Line of credit facility, maximum borrowing capacity | $ 2,000,000 | 2,000,000 | ||||||
Line of credit facility, extended period | Apr. 30, 2018 | |||||||
Term Loan | Silicon Valley Bank | Tranche C | ||||||||
Debt Instrument [Line Items] | ||||||||
Line of credit facility, maximum borrowing capacity | $ 2,000,000 | $ 2,000,000 | ||||||
Interest only period extended | Aug. 31, 2018 | |||||||
Line of credit facility, extended period | Dec. 31, 2018 | Jul. 31, 2018 | ||||||
Term Loan | Silicon Valley Bank | Prepayment Made Prior To First Anniversary | Loan and Security Agreement | ||||||||
Debt Instrument [Line Items] | ||||||||
Prepayment fee percentage | 3.00% | |||||||
Term Loan | Silicon Valley Bank | Prepayment Made By Second Anniversary | Loan and Security Agreement | ||||||||
Debt Instrument [Line Items] | ||||||||
Prepayment fee percentage | 2.00% | |||||||
Term Loan | Silicon Valley Bank | Prepayment Made After Second Anniversary | Loan and Security Agreement | ||||||||
Debt Instrument [Line Items] | ||||||||
Prepayment fee percentage | 1.00% | |||||||
Term Loan | Silicon Valley Bank | Tranche B and C | ||||||||
Debt Instrument [Line Items] | ||||||||
Interest only period extended | Dec. 31, 2018 | |||||||
Debt instrument, maturity date | Dec. 31, 2020 | |||||||
Term Loan | Silicon Valley Bank | Tranche A and B | ||||||||
Debt Instrument [Line Items] | ||||||||
Debt discount | 400,000 | |||||||
Series D Redeemable Preferred Stock | ||||||||
Debt Instrument [Line Items] | ||||||||
Sale of stock | 1,842,959 | |||||||
Sale of stock price per share | $ 9.659 | |||||||
Net proceeds from sale of shares | $ 17,700,000 | |||||||
Debt converted into shares | 2,080,209 | |||||||
Series C-1 | ||||||||
Debt Instrument [Line Items] | ||||||||
Sale of stock | 2,174,280 | |||||||
Warrants | Series C-1 | ||||||||
Debt Instrument [Line Items] | ||||||||
Number of warrants issued | 368,582 | |||||||
Exercise price of warrant | $ 0.12 | |||||||
2017 Notes | ||||||||
Debt Instrument [Line Items] | ||||||||
Debt instrument principal amount | $ 14,700,000 | |||||||
Interest rate | 8.00% | |||||||
Proceeds from sale of equity | $ 10,000,000 | |||||||
Debt instrument, Redemption price, percentage | 80.00% | |||||||
Debt discount | 3,000,000 | |||||||
Interest expense | 3,400,000 | $ 2,700,000 | ||||||
2017 Notes | Warrants | ||||||||
Debt Instrument [Line Items] | ||||||||
Debt discount | $ 1,700,000 | |||||||
Number of warrants issued | 304,397 | |||||||
Exercise price of warrant | $ 0.12 | |||||||
Warrants exercisable date | Jan. 31, 2024 |
Debt - Summary of Future Princi
Debt - Summary of Future Principal Payments (Details) - Silicon Valley Bank $ in Thousands | Dec. 31, 2018USD ($) |
Debt Instrument [Line Items] | |
2020 | $ 2,142 |
2021 | 2,285 |
2022 | 2,438 |
2023 | 635 |
Total | $ 7,500 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended | |||
Dec. 31, 2018 | Feb. 28, 2018 | Jan. 31, 2010 | Dec. 31, 2018 | Dec. 31, 2017 | |
Commitments And Contingencies [Line Items] | |||||
Rent expense | $ 0.4 | $ 0.4 | |||
Malvern, Pennsylvania | |||||
Commitments And Contingencies [Line Items] | |||||
Lease commencement date | Mar. 31, 2010 | ||||
Lease extended expiration date | Sep. 30, 2023 | ||||
Lessee, operating lease, option to extend description | amended to extend its term to September 30, 2023 | ||||
Lessee, operating lease, existence of option to extend [true false] | true | ||||
San Diego, California | |||||
Commitments And Contingencies [Line Items] | |||||
Lease expiration date | Oct. 31, 2022 |
Commitment and Contingencies -
Commitment and Contingencies - Schedule of Future Minimum Commitments Under Non-cancelable Operating Leases (Details) $ in Thousands | Dec. 31, 2018USD ($) |
Commitments And Contingencies Disclosure [Abstract] | |
2019 | $ 342 |
2020 | 368 |
2021 | 373 |
2022 | 360 |
2023 | 204 |
Total | $ 1,647 |
Preferred Stock Warrants - Summ
Preferred Stock Warrants - Summary of Outstanding Redeemable Convertible Preferred Stock Warrants and Corresponding Exercise Price (Details) - Redeemable Convertible Preferred Stock | Dec. 31, 2017$ / sharesshares |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 486,356 |
Series AA Warrants | |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 1,506 |
Exercise Price | $ / shares | $ 13.28 |
Expiration Date | Mar. 7, 2018 |
2009 Series B Warrants | |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 25,884 |
Exercise Price | $ / shares | $ 9.659 |
Expiration Date | Dec. 22, 2019 |
2014 Series B Warrants | |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 104,856 |
Exercise Price | $ / shares | $ 0.12 |
Expiration Date | May 14, 2021 |
Convertible Debt Series C-1 Warrants | |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 304,397 |
Exercise Price | $ / shares | $ 0.12 |
Expiration Date | Jan. 17, 2024 |
Term Loan Series C-1 Warrants | |
Class Of Warrant Or Right [Line Items] | |
Number of Shares Outstanding | 49,713 |
Exercise Price | $ / shares | $ 9.659 |
Expiration Date | Oct. 18, 2027 |
Preferred Stock Warrants - Addi
Preferred Stock Warrants - Additional Information (Details) - $ / shares | Oct. 22, 2018 | Aug. 31, 2018 | Dec. 31, 2017 |
Redeemable Convertible Preferred Stock | |||
Class Of Warrant Or Right [Line Items] | |||
Common stock, warrants | 486,356 | ||
2018 Series C-1 Warrants | Redeemable Convertible Preferred Stock | |||
Class Of Warrant Or Right [Line Items] | |||
Warrants issued to purchase shares | 368,582 | ||
Exercise price of warrant | $ 0.12 | ||
2014 Series B, Convertible Debt Series C-1, and 2018 Series C-1 Warrants | Redeemable Convertible Preferred Stock and Common Stock | Initial Public Offering | |||
Class Of Warrant Or Right [Line Items] | |||
Warrants issued to purchase shares | 764,034 | ||
2014 Series B, Convertible Debt Series C-1, and 2018 Series C-1 Warrants | Redeemable Convertible Preferred Stock and Common Stock | Weighted-average | Initial Public Offering | |||
Class Of Warrant Or Right [Line Items] | |||
Exercise price of warrant | $ 0.12 | ||
Two Thousand Nine Series B And Term Loan Series C-1 Warrants | Initial Public Offering | Common Stock Warrants | |||
Class Of Warrant Or Right [Line Items] | |||
Common stock, warrants | 75,597 |
Redeemable Convertible Prefer_3
Redeemable Convertible Preferred Stock and Stockholders' Deficit - Additional Information (Details) | Oct. 22, 2018shares |
Initial Public Offering | |
Temporary Equity [Line Items] | |
Redeemable convertible preferred stock converted to aggregate of common stock | 13,200,115 |
Redeemable Convertible Prefer_4
Redeemable Convertible Preferred Stock and Stockholders' Deficit - Summary of Authorized, Issued, and Outstanding Shares of Preferred Stock and Carrying Amounts and Liquidation Values (Details) - USD ($) | Dec. 31, 2018 | Dec. 31, 2017 |
Temporary Equity [Line Items] | ||
Shares Authorized | 0 | 13,321,350 |
Shares Issued | 0 | 9,131,999 |
Shares Outstanding | 0 | 9,131,999 |
Carrying Amount | $ 89,633,543 | |
Liquidation Value | $ 89,776,055 | |
Series 1 | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 132,255 | |
Shares Issued | 132,255 | |
Shares Outstanding | 132,255 | |
Carrying Amount | $ 522,266 | |
Liquidation Value | $ 526,778 | |
Series 2 | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 1 | |
Shares Issued | 1 | |
Shares Outstanding | 1 | |
Carrying Amount | $ 240,242 | |
Liquidation Value | $ 250,000 | |
Series AA | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 575,470 | |
Shares Issued | 573,961 | |
Shares Outstanding | 573,961 | |
Carrying Amount | $ 7,615,583 | |
Liquidation Value | $ 7,619,998 | |
Series B | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 6,382,259 | |
Shares Issued | 6,251,502 | |
Shares Outstanding | 6,251,502 | |
Carrying Amount | $ 60,366,480 | |
Liquidation Value | $ 60,379,282 | |
Series C-1 | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 4,524,375 | |
Shares Issued | 2,174,280 | |
Shares Outstanding | 2,174,280 | |
Carrying Amount | $ 20,888,972 | |
Liquidation Value | $ 20,999,997 | |
Series C-2 | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 916,095 | |
Series C-3 | ||
Temporary Equity [Line Items] | ||
Shares Authorized | 790,895 |
Stock-Based Compensation - Addi
Stock-Based Compensation - Additional Information (Details) - USD ($) | Jan. 01, 2019 | Oct. 17, 2018 | Oct. 31, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2027 | Jul. 31, 2018 |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Weighted average fair value of options granted | $ 2.75 | $ 1 | |||||
Intrinsic value of share option awards exercised | $ 200,000 | $ 686 | |||||
2018 Employee Stock Purchase Plan | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Number of shares of common stock that may be issued | 196,000 | ||||||
Plan description | The number of shares of common stock reserved for issuance will automatically increase on January 1 of each calendar year, beginning on January 1, 2019 through January 1, 2028, by the lesser of (1) 1% of the total number of shares of the Company’s common stock outstanding on the last day of the calendar month before the date of the automatic increase, and (2) 490,000 shares; provided that before the date of any such increase, the Company’s board of directors may determine that such increase will be less than the amount set forth in clauses (1) and (2). | ||||||
Share-based payment award, percentage of outstanding stock Maximum | 1.00% | ||||||
Common stock purchased | 0 | ||||||
2018 Employee Stock Purchase Plan | Scenario, Forecast | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Number of shares of common stock that may be issued | 490,000 | ||||||
Additional shares available for grant to ESPP | 244,983 | ||||||
Employee Stock Option | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Unrecognized compensation expense | $ 1,600,000 | ||||||
Weighted-average period expected to be recognized | 2 years 10 months 24 days | ||||||
2002 Plan | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Additional Common stock reserved for future Issuance | 800,000 | ||||||
Number of share grants made under the plan | 0 | ||||||
2018 Plan | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Additional Common stock reserved for future Issuance | 1,670,921 | ||||||
Number of shares of common stock that may be issued | 3,231,626 | ||||||
Plan description | The number of shares of common stock reserved for issuance under the 2018 Plan will automatically increase on January 1 of each calendar year, starting on January 1, 2019 through January 1, 2028, in an amount equal to 3% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the Company’s board of directors. | ||||||
Number of options or stock awards available for grant under the Plan | 734,948 | ||||||
Share-based payment award, percentage of outstanding stock Maximum | 3.00% | ||||||
2018 Plan | Maximum | |||||||
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||||
Number of shares of common stock that may be issued | 9,694,878 |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Stock Option Activity (Details) - 2002 Plan and 2018 Plan - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||
Total Options, Outstanding at December 31, 2016 | 1,075,209 | 1,001,546 | |
Total Options, Granted | 563,268 | 99,866 | |
Total Options, Exercised | (43,687) | (2,547) | |
Total Options, Cancelled or expired | (49,387) | (23,656) | |
Total Options, Outstanding at December 31, 2018 | 1,545,403 | 1,075,209 | 1,001,546 |
Total Options, Vested and expected to vest at December 31, 2018 | 1,545,403 | ||
Total Options, Vested and exercisable at December 31, 2018 | 801,294 | ||
Weighted- Average Exercise Price Per Share, Outstanding at December 31, 2016 | $ 1.60 | $ 1.62 | |
Weighted- Average Exercise Price Per Share, Granted | 4.07 | 1.44 | |
Weighted- Average Exercise Price Per Share, Exercised | 2.12 | 1.20 | |
Weighted- Average Exercise Price Per Share, Cancelled or expired | 1.65 | 1.76 | |
Weighted- Average Exercise Price Per Share, Outstanding at December 31, 2018 | 2.48 | $ 1.60 | $ 1.62 |
Weighted- Average Exercise Price Per Share, Vested and expected to vest at December 31, 2018 | 2.48 | ||
Weighted- Average Exercise Price Per Share, Vested and exercisable at December 31, 2018 | $ 1.65 | ||
Weighted- Average Remaining Contractual Term (in years), Outstanding Balance | 7 years 7 months 6 days | 7 years 3 months 18 days | 8 years 1 month 6 days |
Weighted- Average Remaining Contractual Term (in years), Vested and expected to vest at December 31, 2018 | 7 years 7 months 6 days | ||
Weighted- Average Remaining Contractual Term (in years), Vested and exercisable at December 31, 2018 | 6 years 3 months 18 days | ||
Aggregate Intrinsic Value, Outstanding | $ 1,593,487 | $ 711,328 | $ 58,619 |
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2018 | 1,593,487 | ||
Aggregate Intrinsic Value, Vested and exercisable at December 31, 2018 | $ 1,175,200 |
Stock-Based Compensation - Esti
Stock-Based Compensation - Estimated Fair Value of Option on Grant Date using Weighted Average Assumptions (Details) - Employee Stock Option - $ / shares | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
Risk-free interest rate | 2.88% | 2.88% |
Expected term (in years) | 7 years | 7 years 1 month 6 days |
Expected volatility | 69.00% | 68.00% |
Estimated fair value of common stock | $ 4.07 | $ 1 |
Stock-Based Compensation - Stoc
Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
Total stock-based compensation | $ 332 | $ 77 |
General and Administrative | ||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
Total stock-based compensation | 208 | 40 |
Research and Development | ||
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | ||
Total stock-based compensation | $ 124 | $ 37 |
License Agreements - Additional
License Agreements - Additional Information (Details) | 1 Months Ended | 12 Months Ended | ||
Nov. 30, 2017USD ($) | Feb. 01, 2016 | Dec. 31, 2018USD ($)Milestone | Dec. 31, 2017USD ($) | |
Duke University | ||||
License Agreements [Line Items] | ||||
Sublicensable agreement term | 20 years | |||
Sale of licensed products or services | $ 0 | |||
Fees payment | 300,000 | |||
Nonroyalty payment received | $ 1,000,000 | |||
Nonroyalty agreement term | The Company will pay Duke the first $1.0 million of nonroyalty payments it receives from a sublicensee, and thereafter a specified percentage of any additional nonroyalty payments it receives. If Duke receives revenue as a result of a license or sublicense to a third party in the field of small-molecule oncologics, it will pay the Company a specified percentage of the amount of such revenue in excess of $1.0 million. | |||
Maximum | Achievement Of Clinical Development And Regulatory Milestones | Duke University | ||||
License Agreements [Line Items] | ||||
Potential milestones payment | $ 2,200,000 | |||
Maximum | Commercial Milestones | Duke University | ||||
License Agreements [Line Items] | ||||
Potential milestones payment | 400,000 | |||
Minimum | Duke University | ||||
License Agreements [Line Items] | ||||
Aggregate royalties payment | $ 200,000 | |||
MedImmune Limited | ||||
License Agreements [Line Items] | ||||
License agreement upfront payment | $ 100,000 | |||
Number of milestones met | Milestone | 0 | |||
Reimbursement of costs incurred to product storage costs | $ 500,000 | |||
MedImmune Limited | Maximum | Achievement Of Clinical Development And Regulatory Milestones | ||||
License Agreements [Line Items] | ||||
Potential milestones payment | 18,000,000 | |||
MedImmune Limited | Maximum | Commercial Milestones | ||||
License Agreements [Line Items] | ||||
Potential milestones payment | $ 50,000,000 |
Grant Revenue - Additional Info
Grant Revenue - Additional Information (Details) - USD ($) | 1 Months Ended | 12 Months Ended | |
Feb. 28, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | |
Disaggregation Of Revenue [Line Items] | |||
Revenue | $ 668,000 | ||
Type of Revenue [Extensible List] | us-gaap:GrantMember | us-gaap:GrantMember | |
SBIR Grants | |||
Disaggregation Of Revenue [Line Items] | |||
Revenue | $ 700,000 | $ 0 | |
Grants from the National Institutes of Health | $ 2,800,000 | ||
Type of Revenue [Extensible List] | us-gaap:GrantMember | us-gaap:GrantMember |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Details) - USD ($) | 12 Months Ended | |||
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Taxes [Line Items] | ||||
Loss before income taxes | $ 23,800,000 | $ 10,200,000 | ||
Income tax expense (benefit) | 0 | 0 | ||
Deferred tax assets, valuation allowance | 36,796,000 | 30,370,000 | ||
Deferred tax assets, increase (decrease) in valuation allowance | $ 6,400,000 | $ 7,100,000 | ||
Net operating losses and tax credit carryforwards limitations on change in ownership minimum percentage | 50.00% | |||
Net operating losses and tax credit carryforwards limitations on change in ownership period | 3 years | |||
U.S.federal corporate statutory tax rate | 21.00% | 35.00% | ||
Adjustments made to the provisional amounts | $ 0 | |||
Reduction of deferred tax assets | 11,000,000 | |||
Unrecognized tax benefits that would affect effective tax rate | 0 | |||
Unrecognized tax benefits | 1,809,000 | $ 1,293,000 | $ 1,067,000 | |
Income tax penalties and interest accrued on uncertain tax positions | $ 0 | $ 0 | ||
Federal | ||||
Income Taxes [Line Items] | ||||
Operating loss carryforwards, limitations on use, description | The federal NOLs generated prior to 2018 may be used to offset up to 100% of future taxable income and will begin to expire in 2022, unless previously utilized. The federal NOL generated in 2018 of $20.4 million will be available to offset up to 80% of future taxable income and may be carried forward indefinitely. | |||
Operating loss carryforwards available to offset future taxable income, amount | $ 20,400,000 | |||
Tax years which remaining open for examination | 2015 2016 2017 2018 | |||
Federal | 2018 Tax Year | ||||
Income Taxes [Line Items] | ||||
Net operating loss carryforwards | $ 111,900,000 | |||
Federal | 2018 Tax Year | Research and Development | ||||
Income Taxes [Line Items] | ||||
Tax credit carryforwards, amount | $ 3,200,000 | |||
Tax credit carryforwards, expiration year | 2028 | |||
Federal | 2018 Tax Year | Orphan Drug | ||||
Income Taxes [Line Items] | ||||
Tax credit carryforwards, amount | $ 2,800,000 | |||
Tax credit carryforwards, expiration year | 2036 | |||
Federal | Prior to 2018 | ||||
Income Taxes [Line Items] | ||||
Net operating loss carryforwards expiration beginning year | 2022 | |||
Federal | Maximum | 2018 Tax Year | ||||
Income Taxes [Line Items] | ||||
Percentage of utilization net operating loss carryforwards to taxable income | 80.00% | |||
Federal | Maximum | Prior to 2018 | ||||
Income Taxes [Line Items] | ||||
Percentage of utilization net operating loss carryforwards to taxable income | 100.00% | |||
Pennsylvania | ||||
Income Taxes [Line Items] | ||||
Operating loss carryforwards, limitations on use, description | The Pennsylvania NOLs may be used to offset 40% of future taxable income and will begin to expire in 2029, unless previously utilized. | |||
Percentage of utilization net operating loss carryforwards to taxable income | 35.00% | |||
Tax years which remaining open for examination | 2015 2016 2017 2018 | |||
Pennsylvania | Subsequent Event | ||||
Income Taxes [Line Items] | ||||
Percentage of utilization net operating loss carryforwards to taxable income | 40.00% | |||
Pennsylvania | 2018 Tax Year | ||||
Income Taxes [Line Items] | ||||
Net operating loss carryforwards | $ 105,900,000 | |||
Net operating loss carryforwards expiration beginning year | 2029 | |||
Percentage of utilization net operating loss carryforwards to taxable income | 40.00% | |||
Pennsylvania | 2018 Tax Year | Research and Development | ||||
Income Taxes [Line Items] | ||||
Tax credit carryforwards, amount | $ 200,000 | |||
Tax credit carryforwards, expiration year | 2029 |
Income Taxes - Summary of Recon
Income Taxes - Summary of Reconciliation of Income Tax Expense (Benefit) (Details) - USD ($) | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | ||
Income tax benefit at statutory rate | $ (5,008,000) | $ (3,484,000) |
State income tax, net of federal benefit | (1,593,000) | (528,000) |
Permanent items | 3,000 | 4,000 |
Fair value adjustments | 15,000 | (164,000) |
Non-deductible interest expense | 706,000 | 905,000 |
Stock-based compensation | 45,000 | 21,000 |
Orphan drug credit | (475,000) | (616,000) |
Research and development credits | (274,000) | (218,000) |
Uncertain tax positions | 222,000 | 209,000 |
Tax Cuts and Jobs Act | (15,000) | 10,978,000 |
Change in valuation allowance | 6,426,000 | (7,110,000) |
Other | (52,000) | 3,000 |
Income tax expense (benefit) | $ 0 | $ 0 |
Income Taxes - Significant Comp
Income Taxes - Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Net deferred tax asset: | ||
Net operating loss carryforwards | $ 31,744 | $ 26,138 |
Research and development credits | 4,615 | 3,863 |
Accrued expenses | 332 | 239 |
Intangibles | 69 | 110 |
Property and equipment | (18) | (2) |
Other, net | 54 | 22 |
Total net deferred tax asset | 36,796 | 30,370 |
Valuation allowance for deferred tax asset | (36,796) | (30,370) |
Deferred tax assets, net of valuation allowance | $ 0 | $ 0 |
Income Taxes - Summary of Activ
Income Taxes - Summary of Activity Related to Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | ||
Gross unrecognized tax benefits at the beginning of the year | $ 1,293 | $ 1,067 |
Increases related to current year positions | 362 | 226 |
Increases related to prior year positions | 154 | |
Gross unrecognized tax benefits at the end of the year | $ 1,809 | $ 1,293 |
Subsequent Events - Additional
Subsequent Events - Additional Information (Details) - Refinancing Agreement | Mar. 25, 2019USD ($)dshares | Dec. 31, 2019USD ($) | May 31, 2019USD ($) |
SVB and WestRiver | Tranche C | Scenario, Forecast | |||
Subsequent Event [Line Items] | |||
Line of credit facility, maximum borrowing capacity | $ 5,000,000 | ||
SVB and WestRiver | Tranche B | Scenario, Forecast | |||
Subsequent Event [Line Items] | |||
Line of credit facility, maximum borrowing capacity | $ 2,500,000 | ||
Subsequent Event | Silicon Valley Bank | |||
Subsequent Event [Line Items] | |||
Debt instrument, maturity date | Mar. 1, 2023 | ||
Interest rate, terms | the Company is to make interest-only payments through December 31, 2019 on Tranche A and Tranche B at a rate equal to the greater of the Prime Rate plus 1.00%, as defined in the 2019 Loan, or 6.5%, followed by an amortization period of 39 months of equal monthly payments of principal plus interest amounts until paid in full. The interest-only period will automatically be extended to June 30, 2020 if the Company achieves the Tranche C milestones, followed by an amortization period of 33 months of equal monthly payments of principal plus interest amounts until paid in full. | ||
Percentage of final payment on principal amount of refinanced advances | 6.00% | ||
Subsequent Event | Silicon Valley Bank | Tranche A and Tranche B | |||
Subsequent Event [Line Items] | |||
Interest rate | 6.50% | ||
Amortization period of payments of principal plus interest amounts | 39 months | ||
Subsequent Event | Silicon Valley Bank | Tranche A and Tranche B | Prime Rate | |||
Subsequent Event [Line Items] | |||
Interest rate, percentage point added to reference rate | 1.00% | ||
Subsequent Event | Silicon Valley Bank | Tranche C | |||
Subsequent Event [Line Items] | |||
Amortization period of payments of principal plus interest amounts | 33 months | ||
Subsequent Event | Silicon Valley Bank | Tranche A | |||
Subsequent Event [Line Items] | |||
Proceeds from lines of credit | $ 7,500,000 | ||
Subsequent Event | SVB and WestRiver | |||
Subsequent Event [Line Items] | |||
Threshold trading days | d | 10 | ||
Warrants expiration period | 10 years | ||
Line of credit facility, maximum borrowing capacity | $ 15,000,000 | ||
Subsequent Event | SVB and WestRiver | Tranche A | |||
Subsequent Event [Line Items] | |||
Number of warrants issued | shares | 12,131 | ||
Line of credit facility, maximum borrowing capacity | $ 7,500,000 | ||
Subsequent Event | SVB and WestRiver | Tranche B | |||
Subsequent Event [Line Items] | |||
Number of warrants issued | shares | 24,262 |