Document and Entity Information
Document and Entity Information - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2018 | Feb. 22, 2019 | Jun. 29, 2018 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2018 | ||
Document Fiscal Year Focus | 2,018 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | SRRA | ||
Entity Registrant Name | Sierra Oncology, Inc. | ||
Entity Central Index Key | 1,290,149 | ||
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 | Accelerated Filer | ||
Entity Emerging Growth Company | true | ||
Entity Small Business | true | ||
Entity Ex Transition Period | true | ||
Entity Shell Company | false | ||
Entity Common Stock, Shares Outstanding | 74,467,746 | ||
Entity Public Float | $ 193.5 |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
CURRENT ASSETS: | ||
Cash and cash equivalents | $ 106,046 | $ 100,348 |
Prepaid expenses and other current assets | 2,706 | 1,377 |
Total current assets | 108,752 | 101,725 |
Property and equipment, net | 168 | 154 |
Other assets | 549 | 319 |
TOTAL ASSETS | 109,469 | 102,198 |
CURRENT LIABILITIES: | ||
Accrued liabilities | 8,812 | 6,133 |
Accounts payable | 1,287 | 1,339 |
Total current liabilities | 10,099 | 7,472 |
Term loan | 4,891 | |
TOTAL LIABILITIES | 14,990 | 7,472 |
Commitments and Contingencies (Note 7) | ||
STOCKHOLDERS' EQUITY: | ||
Preferred stock, $0.001 par value; 10,000,000 shares authorized as of December 31, 2018 and December 31, 2017; nil shares issued and outstanding as of December 31, 2018 and December 31, 2017 | ||
Common stock, $0.001 par value; 500,000,000 shares authorized as of December 31, 2018 and 2017; 74,365,965 and 52,395,223 shares issued and outstanding as of December 31, 2018 and 2017 | 74 | 52 |
Additional paid-in capital | 771,817 | 718,751 |
Accumulated deficit | (677,412) | (624,077) |
TOTAL STOCKHOLDERS' EQUITY | 94,479 | 94,726 |
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY | $ 109,469 | $ 102,198 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2018 | Dec. 31, 2017 |
Statement of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | 10,000,000 | 10,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 500,000,000 | 500,000,000 |
Common stock, shares issued | 74,365,965 | 52,395,223 |
Common stock, shares outstanding | 74,365,965 | 52,395,223 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Operating expenses: | |||
Research and development | $ 41,078 | $ 30,157 | $ 33,895 |
General and administrative | 14,339 | 12,462 | 14,180 |
Total operating expenses | 55,417 | 42,619 | 48,075 |
Loss from operations | (55,417) | (42,619) | (48,075) |
Other income, net | 1,780 | 760 | 351 |
Loss before provision for (benefit from) income taxes, net | (53,637) | (41,859) | (47,724) |
Provision for (benefit from) income taxes, net | (302) | 156 | 143 |
Net loss and comprehensive loss | $ (53,335) | $ (42,015) | $ (47,867) |
Net loss per common share, basic and diluted | $ (0.75) | $ (0.84) | $ (1.58) |
Weighted-average shares used in computing net loss per common share, basic and diluted | 70,739,210 | 49,899,299 | 30,240,258 |
Consolidated Statements of Stoc
Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock [Member] | Additional Paid-In Capital [Member] | Accumulated Deficit [Member] |
Stockholders Equity, Beginning Balance at Dec. 31, 2015 | $ 145,371 | $ 30 | $ 679,528 | $ (534,187) |
Stockholders Equity, Beginning Balance, Shares at Dec. 31, 2015 | 30,058,105 | |||
Issuance of common stock for exercise of stock options | 211 | 211 | ||
Issuance of common stock for exercise of stock options, Shares | 312,841 | |||
Stock-based compensation | 5,510 | 5,510 | ||
Vesting of early exercised stock options | 23 | 23 | ||
Net loss | (47,867) | (47,867) | ||
Stockholders Equity, Ending Balance at Dec. 31, 2016 | 103,248 | $ 30 | 685,272 | (582,054) |
Stockholders Equity, Ending Balance, Shares at Dec. 31, 2016 | 30,370,946 | |||
Issuance of common stock for exercise of stock options | 166 | 166 | ||
Issuance of common stock for exercise of stock options, Shares | 176,641 | |||
Cumulative effect of adoption of new accounting standard | 8 | (8) | ||
Stock-based compensation | 5,905 | 5,905 | ||
Issuance of stock, value | 27,422 | $ 22 | 27,400 | |
Issuance of stock, shares | 21,847,636 | |||
Net loss | (42,015) | (42,015) | ||
Stockholders Equity, Ending Balance at Dec. 31, 2017 | 94,726 | $ 52 | 718,751 | (624,077) |
Stockholders Equity, Ending Balance, Shares at Dec. 31, 2017 | 52,395,223 | |||
Issuance of common stock for exercise of stock options | 180 | 180 | ||
Issuance of common stock for exercise of stock options, Shares | 120,742 | |||
Stock-based compensation | 6,796 | 6,796 | ||
Issuance of stock, value | 45,996 | $ 22 | 45,974 | |
Issuance of stock, shares | 21,850,000 | |||
Issuance of common stock warrant | 116 | 116 | ||
Net loss | (53,335) | (53,335) | ||
Stockholders Equity, Ending Balance at Dec. 31, 2018 | $ 94,479 | $ 74 | $ 771,817 | $ (677,412) |
Stockholders Equity, Ending Balance, Shares at Dec. 31, 2018 | 74,365,965 |
Consolidated Statements of St_2
Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Statement of Stockholders' Equity [Abstract] | ||
Issuance of common stock in connection with initial public offering, issuance costs | $ 3.2 | $ 2.1 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
CASH FLOWS FROM OPERATING ACTIVITIES: | |||
Net loss | $ (53,335) | $ (42,015) | $ (47,867) |
Adjustments to reconcile net loss to net cash used in operating activities: | |||
Stock-based compensation | 6,796 | 5,905 | 5,510 |
Depreciation | 111 | 258 | 197 |
Non-cash restructuring charges | 811 | ||
Other | (68) | 31 | 15 |
Changes in operating assets and liabilities: | |||
Prepaid expenses and other assets | (1,341) | (115) | (362) |
Accrued liabilities | 2,770 | 990 | (1,713) |
Accounts payable | (48) | (1,217) | 2,246 |
Net cash used in operating activities | (45,115) | (36,163) | (41,163) |
CASH FLOWS FROM INVESTING ACTIVITIES: | |||
Purchase of property and equipment | (118) | (92) | (214) |
Proceeds from sale of property and equipment | 43 | ||
Net cash used in investing activities | (118) | (92) | (171) |
CASH FLOWS FROM FINANCING ACTIVITIES: | |||
Proceeds from issuance of common stock upon follow-on offering, net of offering costs | 45,996 | 27,422 | |
Proceeds from issuance of term loan, net of issuance costs | 4,955 | ||
Proceeds from exercise of common stock options | 180 | 166 | 211 |
Payment of deferred offering costs | (15) | ||
Net cash provided by financing activities | 51,131 | 27,588 | 196 |
Effect of exchange rate changes on cash, cash equivalents and restricted cash | (88) | (4) | (60) |
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH | 5,810 | (8,671) | (41,198) |
CASH, CASH EQUIVALENTS AND RESTRICTED CASH-Beginning of period | 100,536 | 109,207 | 150,405 |
CASH, CASH EQUIVALENTS AND RESTRICTED CASH-End of period | 106,346 | 100,536 | 109,207 |
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION: | |||
Cash paid for income taxes, net | 15 | 260 | 107 |
Cash paid for interest | 87 | ||
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION: | |||
Property and equipment purchases included in accounts payable and accrued liabilities | 11 | $ 4 | $ 85 |
Issuance of common stock warrant | $ 116 |
The Company and Basis of Presen
The Company and Basis of Presentation | 12 Months Ended |
Dec. 31, 2018 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
The Company and Basis of Presentation | 1. The Company and Basis of Presentation Organization and Description of Business Sierra Oncology, Inc. (together with its subsidiaries, collectively referred to as the “Company”), a Delaware corporation, is a clinical stage drug development company advancing targeted therapeutics for the treatment of patients with unmet medical needs in hematology and oncology. Pursuant to an asset purchase agreement entered into in August 2018 (Note 7), the Company acquired its lead drug candidate, momelotinib, a potent, selective and orally-bioavailable JAK1, JAK2 and ACVR1 inhibitor that has been investigated in two completed Phase 3 clinical trials for the treatment of myelofibrosis and has demonstrated a potentially differentiated therapeutic profile encompassing anemia-related benefits, as well as achieving substantive splenic volume reduction and constitutional symptom control. The Company is also advancing SRA737 and SRA141. SRA737 is a potent, highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key regulator of cell cycle progression and the DNA Damage Response (DDR) replication stress response. SRA141 is a potent, selective and orally bioavailable small molecule inhibitor of cell division cycle 7 kinase (Cdc7), a key regulator of DNA replication and involved in the DDR network. The Company’s primary activities since inception have been conducting research and development activities, conducting preclinical and clinical testing, recruiting personnel, performing business and financial planning, identifying and evaluating additional drug candidates for potential in-licensing The Company has not generated any product revenue related to its primary business purpose to date, nor has it generated any income, and is subject to a number of risks and uncertainties, which include dependence on key individuals, the need to identify and successfully develop commercially viable products, the need to obtain regulatory approval for its products and commercialize them, and the need to obtain adequate additional financing to fund the development of its product candidates. As of December 31, 2018, the Company had $106.0 million of cash and cash equivalents. The Company believes that its balance of cash and cash equivalents as of the date of the issuance of these consolidated financial statements is sufficient to fund its current operational plan for at least the next twelve months though it may pursue raising additional capital through equity financings or other arrangements. Follow On Offerings On February 14, 2017, the Company completed an underwritten public offering of 19,500,000 shares of common stock. As part of the underwritten public offering, on February 21, 2017 the Company issued an additional 2,347,636 shares of common stock representing the underwriters’ exercise of a majority of their over-allotment option. All shares were offered by the Company at a price to the public of $1.35 per share. The aggregate net proceeds received by the Company from the offering were $27.4 million, net of underwriting discounts and commissions and offering expenses of $2.1 million. On March 6, 2018, the Company completed an underwritten public offering of an aggregate of 21,850,000 shares of common stock, including the underwriters’ exercise of their overallotment option, at a price to the public of $2.25 per share. The aggregate net proceeds received by the Company from the offering were $46.0 million, net of underwriting discounts and commissions and offering expenses of $3.2 million. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP). The accompanying consolidated financial statements include the accounts of Sierra Oncology, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of consolidated financial statements and the reported amounts of expense during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include, but are not limited to the fair value of stock options and the warrant issued, accruals such as research and development costs, and recoverability of the Company’s net deferred tax assets, and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates. Foreign Currency The functional currency of the Company’s foreign subsidiaries is the U.S. Dollar. Transactions denominated in currencies other than the functional currency are recorded at prevailing exchange rates during the period. At the end of each reporting period, monetary assets and liabilities are remeasured to the functional currency using exchange rates in effect at the balance sheet date. Non-monetary Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist primarily of funds invested in readily available checking and savings accounts and highly liquid investments in money market funds. Restricted Cash Restricted cash, which consists of funds invested in a money market fund, represents collateral for a corporate credit card facility and is included in other assets in the accompanying consolidated balance sheets. Restricted cash at December 31, 2017 also included security deposits required for a facility lease that expired in February 2018. Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist of cash, cash equivalents and restricted cash. All of the Company’s cash, cash equivalents and restricted cash are held at financial institutions in the United States and Canada that management believes to be of high credit quality. Deposits held in the United States and Canada with these financial institutions exceed federally insured limits. The primary focus of the Company’s investment strategy is to preserve capital and meet liquidity requirements. The Company’s investment policy addresses the level of credit exposure by limiting the concentration in any one corporate issuer and establishing a minimum allowable credit rating. Fair Value of Financial Instruments The Company’s cash and cash equivalents, restricted cash, other current assets, accounts payable, and accrued liabilities approximate their fair value at December 31, 2018 and 2017, due to their short duration. The term loan bears interest at prevailing market rates for instruments with similar characteristics, accordingly, the carrying value of this instrument approximates its fair value. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines the fair value of its financial instruments based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: Level 1 Level 2 Level 3 Property and Equipment, Net Property and equipment, net are stated at cost, less accumulated depreciation. Depreciation on property and equipment, excluding leasehold improvements, is computed using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful lives of the assets or the remaining lease term. Other Assets Other assets consist primarily of restricted cash pledged as collateral for a corporate credit card facility, long-term prepaid rent and deferred income tax assets in foreign jurisdictions. Research and Development Costs Research and development costs are expensed as incurred. The Company accounts for non-refundable Upfront payments made in connection with license and asset purchase agreements are expensed as research and developments costs, as the assets acquired do not have alternative future use. Contingent milestone payment obligations due to third parties under license and asset purchase agreements are expensed when the milestones are considered probable of occurring. Research and development costs include fees incurred in connection with license and asset purchase agreements, compensation and other related costs for employees engaged in research and development, costs associated with research and preclinical studies, clinical trials, regulatory activities, manufacturing activities to support clinical activities, fees paid to external service providers that conduct certain research and development, clinical, and manufacturing activities on behalf of the Company and an allocation of overhead expenses. Stock-Based Compensation The Company accounts for stock-based payments at fair value, which is measured using the Black-Scholes option-pricing model. For stock-based awards that vest subject to the satisfaction of a service requirement, the fair value measurement date for employee stock-based compensation awards is the date of grant and the expense is recognized on a straight-line basis over the vesting period. Stock-based compensation arrangements with non-employees Income Taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and the tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Management makes an assessment of the likelihood that the resulting deferred tax assets will be realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. Due to the Company’s historical operating performance and the recorded cumulative net losses in prior fiscal periods, the net U.S. deferred tax assets have been offset by a full valuation allowance. The Company recognizes uncertain income tax positions at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Changes in recognition or measurement are reflected in the period in which judgment occurs. The Company recognizes interest and penalties related to the underpayment of income taxes as a component of provision for (benefit from) income taxes, net. Segment Information Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and assessing performance. The Company’s chief operating decision maker is its Chief Executive Officer. The Company’s Chief Executive Officer views the Company’s operations and manages its business in one operating segment, which is the business of researching, developing and commercializing therapies for the treatment of patients with hematology and oncology. Accordingly, the Company has a single reporting segment. Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (FASB) issued FASB Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) right-of-use assets In June 2018, the FASB issued FASB ASU No. 2018-07, non-employees |
Net Loss Per Share
Net Loss Per Share | 12 Months Ended |
Dec. 31, 2018 | |
Earnings Per Share [Abstract] | |
Net Loss Per Share | 3. Net Loss Per Share Basic net loss per share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, stock options and the warrant for common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following shares of common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented because including them would have been antidilutive: As of December 31, 2018 2017 2016 Options to purchase common stock 10,504,412 7,470,601 6,543,654 Warrant for common stock 73,529 — — Total potential dilutive shares 10,577,941 7,470,601 6,543,654 |
Fair Value Measurements
Fair Value Measurements | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | 4. Fair Value Measurements The Company measures and reports its cash equivalents and restricted cash at fair value. The following table sets forth the fair value of the Company’s financial assets and liabilities measured on a recurring basis by level within the fair value hierarchy: December 31, 2018 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 105,224 $ — $ — $ 105,224 Restricted money market funds 300 — — 300 Total financial assets $ 105,524 $ — $ — $ 105,524 December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 99,792 $ — $ — $ 99,792 Restricted money market funds 188 — — 188 Total financial assets $ 99,980 $ — $ — $ 99,980 Money market funds and restricted money market funds are measured at fair value on a recurring basis using quoted prices and are classified as a Level 1 input. There were no transfers between Levels 1, 2 or 3 during the years ended December 31, 2018 and 2017. |
Balance Sheet Components
Balance Sheet Components | 12 Months Ended |
Dec. 31, 2018 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Balance Sheet Components | 5. Balance Sheet Components Cash and Cash Equivalents Cash and cash equivalents consist of the following: December 31, 2018 2017 (in thousands) Cash $ 822 $ 556 Cash equivalents: Money market accounts 105,224 99,792 Total cash and cash equivalents $ 106,046 $ 100,348 In November 2016, the FASB issued new guidance ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash beginning-of-period end-of-period The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheets to the amounts shown in the consolidated statements of cash flows. December 31, 2018 December 31, (in thousands) Cash and cash equivalents $ 106,046 $ 100,348 Restricted cash included in other assets 300 188 Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows $ 106,346 $ 100,536 Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist of the following: December 31, 2018 2017 (in thousands) Prepaid research and development project costs $ 762 $ 549 Other receivables 751 103 Prepaid insurance 555 478 Income taxes receivable 163 — Other 475 247 Total prepaid expenses and other current assets $ 2,706 $ 1,377 Property and Equipment, net Property and equipment, net consists of the following: December 31, 2018 2017 (in thousands) Software $ 325 $ 254 Leasehold improvements 112 79 Computer equipment 89 93 Furniture and fixtures 3 3 Property and equipment, gross 529 429 Less: accumulated depreciation (361 ) (275 ) Total property and equipment, net $ 168 $ 154 Depreciation related to the Company’s property and equipment for the years ended December 31, 2018, 2017 and 2016 was $0.1 million, $0.3 million and $0.2 million, respectively. Accrued Liabilities Accrued liabilities consist of the following: December 31, 2018 2017 (in thousands) Accrued research and development costs $ 4,485 $ 2,763 Accrued employee related costs 3,223 2,699 Accrued professional fees 357 317 Accrued restructuring costs (Note 11) 33 137 Other 714 217 Total accrued liabilities $ 8,812 $ 6,133 |
Term Loan
Term Loan | 12 Months Ended |
Dec. 31, 2018 | |
Debt Disclosure [Abstract] | |
Term Loan | 6. Term Loan On August 21, 2018, the Company entered into a Loan and Security Agreement (Loan Agreement) with Silicon Valley Bank (SVB), pursuant to which the Company may obtain a loan of aggregate principal amount of up to $15.0 million (Term Loans), which becomes available in three tranches, each of an aggregate principal amount of up to $5.0 million. Contemporaneously with executing the Loan Agreement, the Company drew down the first $5.0 million tranche. The second and third $5.0 million tranches may be drawn only upon the achievement of certain development milestones. Borrowings under the Loan Agreement bear interest at the greater of (i) 6.0% or (ii) a floating per annum rate 1.0% above the prime rate (for an interest rate of 6.50% at December 31, 2018), with interest only due and payable monthly, until March 1, 2020 (unless extended under the conditions set forth in the Loan Agreement), at which time interest and principal will be due and payable in equal monthly payments; and are subject to a final payment fee equal to 6.75% of the aggregate principal amount. The Company may prepay all, but not less than all, of the loaned amounts subject to a prepayment fee in the amount of 3.0% of the outstanding principal balance if such prepayment occurs prior to August 21, 2019; 2.0% of the outstanding principal balance if such prepayment occurs on or after August 21, 2019, but prior to August 21, 2020; or 1.0% of the outstanding principal balance if such prepayment occurs on August 21, 2020 or at any time thereafter prior to the maturity date of the Term Loans on August 1, 2022. The Loan Agreement is secured by substantially all of the Company’s personal property, except for its intellectual property and requires the Company to maintain the lesser of $10 million or 80% of its cash and cash equivalents with SVB. The Loan Agreement contains customary covenants that limit the Company’s ability to dispose of assets, enter into mergers or acquisitions, incur indebtedness, incur liens, pay dividends or make distributions on the Company’s capital stock, make investments or loans, and enter into certain affiliate transactions, among others. The Loan Agreement contains customary events of default that include, among others, non-payment defaults, In connection with the Loan Agreement, the Company issued a warrant to SVB to purchase 73,529 of the Company’s common stock at a price per share of $1.87. The warrant was immediately exercisable, will expire on August 21, 2028, contains a cashless exercise provision and is classified as equity. If the Company is to draw the second or third tranche available under the Loan Agreement, the Company will grant an additional amount of common stock issuable upon exercise of the warrant based upon the principal amount advanced. In no event will the number of common stock issuable pursuant to the exercise of the warrant exceed 220,588 in aggregate. The fair value of the warrant and the debt issuance costs were recorded as debt discounts and together with the final payment fee are being amortized using the effective interest rate method over the term of the loan. As of December 31, 2018, the effective interest rate on the initial tranche of the loan was 9.89% and the unamortized debt discount was $0.1 million. Amortization of the debt discount and the accrual of final payment was $0.1 million for the year ended December 31, 2018. Scheduled payments due under the Loan Agreement, excluding the final payment fee of $0.3 million and interest payments, are as follows: December 31, (in thousands) 2020 $ 1,667 2021 2,000 2022 1,333 Total $ 5,000 For the year ended December 31, 2018, the Company recognized $0.2 million of interest expense related to the Loan Agreement. |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2018 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 7. Commitments and Contingencies Asset Purchase Agreement In August 2018, the Company entered into an asset purchase agreement with Gilead Sciences, Inc. (Gilead) whereby the Company acquired worldwide rights to the pharmaceutical product momelotinib, an investigational inhibitor of Janus kinase, together with all related intellectual property rights and certain other related assets. The Company paid Gilead an upfront payment of $3.0 million in August 2018. The related expense was included in research and development for the year ended December 31, 2018 in the accompanying consolidated statement of operations. The Company will be required to pay Gilead milestone payments of up to an aggregate of $195.0 million upon the achievement of certain development, regulatory and commercial milestones events, including a milestone payment of $5.0 million upon the dosing of the first patient in a registrational clinical trial. These milestones will be accrued once they are considered probable of occurring. In addition, the Company is required to pay Gilead mid-teen License Agreements In September 2016, the Company entered into an exclusive license agreement with CRT Pioneer Fund LP (CPF) for worldwide rights, know-how one-time product-by-product country-by-country In May 2016, the Company entered into an exclusive license agreement (Carna License Agreement) with Carna Biosciences, Inc. (Carna) for worldwide rights to develop and commercialize SRA141, a small molecule kinase inhibitor targeting Cdc7. In exchange for this exclusive right, the Company paid Carna an upfront payment of $0.9 million in June 2016. The Company will be required to pay Carna milestone payments of up to an aggregate of $270.0 million upon achievement of certain developmental, regulatory and commercial milestone events, including a milestone payment of $4.0 million upon dosing of the first patient in the first Phase 1 clinical trial for SRA141. These milestones will be accrued once they are considered probable of occurring. As of December 31, 2018, the Company had not recorded any milestone payments to Carna. In addition, the Company is required to pay Carna tiered single-digit royalties on net sales of product candidates (as defined under the Carna License Agreement). Lease Agreements In February 2015, the Company entered into an operating lease agreement to sublease office space in Vancouver, Canada. In June 2017, the Company entered into a new operating lease agreement to continue leasing the office space in Vancouver, Canada commencing March 1, 2018. The new lease expires on February 28, 2023 and can be extended for an additional term of 5 years. In January 2016, the Company entered into an operating lease agreement to lease office space near San Francisco, California. The operating lease agreement expires on April 30, 2019. In September 2017, the Company entered into a sublease agreement to sublet the premises to a third party until April 30, 2019. The fair value of the remaining contractual obligation, net of sublease income was included in accrued liabilities in the accompanying consolidated balance sheets as of December 31, 2018 and 2017. In addition to base rent, these leases require payment of taxes and other operating costs. These operating costs are not included in the table below. As of December 31, 2018, the aggregate future non-cancelable Years Ending December 31: Operating (in thousands) 2019 $ 243 2020 208 2021 211 2022 169 Total $ 831 The total rent expense for each of the years ended December 31, 2018, 2017 and 2016 was $0.5 million. Legal On November 9, 2016, a purported securities class action lawsuit was filed in the United States District Court for the Southern District of New York against the Company and certain of its executive officers (the New York Lawsuit). The New York Lawsuit was brought by purported stockholders of the Company seeking to represent a class consisting of stockholders who purchased stock between July 15, 2015 and June 6, 2016. The New York Lawsuit asserts claims under Sections 10(b) and 20(a) of the Exchange Act and seeks unspecified damages and other relief. On March 13, 2018, the United States District Court for the Southern District of New York granted the defendants’ motion to dismiss and entered a final judgment dismissing the New York Lawsuit with prejudice. Plaintiffs thereafter filed an appeal. On December 3, 2018, the United States Court of Appeals for the Second Circuit affirmed the district court’s final judgment of dismissal. The Company believes that the claims in the New York Lawsuit are without merit and intends to defend the lawsuit vigorously. At this point in time, the Company does not expect the outcome of these claims will have a material impact on its consolidated financial statements. On November 18, 2016, a purported securities class action lawsuit was filed in the Superior Court of the State of California for the County of San Mateo against the Company, certain of its executive officers and directors, and the underwriters for the Company’s initial public offering of its common stock. On February 9, 2017, a substantially identical putative class action suit was filed in the Superior Court of the State of California for the County of San Mateo asserting the same claims on behalf of the same putative class (the two lawsuits together, the California Lawsuits). The California Lawsuits were brought by purported stockholders of the Company seeking to represent a class consisting of stockholders who purchased stock pursuant to and/or traceable to the Company’s Registration Statement on Form S-1. From time to time, the Company may become subject to other legal proceedings, claims and litigation arising in the ordinary course of business. In addition, the Company may receive letters alleging infringement of patent or other intellectual property rights. The Company is not currently a party to any other material legal proceedings, nor is it aware of any pending or threatened litigation that, in the Company’s opinion, would have a material adverse effect on the business, operating results, cash flows or financial condition should such litigation be resolved unfavorably. |
Common Stock Reserved for Issua
Common Stock Reserved for Issuance | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Common Stock Reserved for Issuance | 8. Common Stock Reserved for Issuance The Company is required to reserve and keep available out of its authorized but unissued shares of common stock a number of shares sufficient to effect the conversion of all outstanding options granted and available for grant under the incentive plans, shares reserved for issuance under the employee stock purchase plan and issued warrant. December 31, 2018 2017 Outstanding stock options under equity incentive plans 10,504,412 7,470,601 Shares reserved for future option grants under equity plans 1,945,025 1,503,770 Shares reserved under the 2015 employee stock purchase plan 700,000 700,000 Shares reserved under warrant upon contingent events 147,059 — Outstanding warrant 73,529 — Total common stock reserved for issuance 13,370,025 9,674,371 |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Stock-Based Compensation | 9. Stock-Based Compensation In the accompanying consolidated statement of operations, the Company recognized stock-based compensation expense for its employees and non-employees Year Ended December 31, 2018 2017 2016 (in thousands) Research and development $ 4,499 $ 3,966 $ 3,635 General and administrative 2,297 1,939 1,875 Total stock-based compensation $ 6,796 $ 5,905 $ 5,510 Determination of Fair Value The estimated grant-date fair value of all the Company’s stock-based awards was calculated using the Black-Scholes option pricing model, based on the following assumptions: Year Ended December 31, 2018 2017 2016 Expected term (in years) 5.3 – 7.0 5.3 – 7.0 5.1 – 9.9 Expected volatility 88 – 91 % 86 – 96 % 77 – 87 % Risk-free interest rate 2.6 – 3.1 % 1.8 – 2.3 % 1.1 – 2.4 % Expected dividend rate — % — % — % The fair value of each stock option grant was determined by the Company on the date of grant using the methods and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment and estimation by management. Expected Term— non-employees Expected Volatility— Risk-Free Interest Rate— zero-coupon Expected Dividend Rate— Forfeiture Rate— Fair Value of Common Stock— On January 1, 2017, the Company adopted FASB ASU No. 2016-09 2016-09), Compensation—Stock Compensation (Topic 718) , Equity Incentive Plans 2018 Equity Inducement Plan In September 2018, the Company’s Compensation Committee approved the 2018 Equity Inducement Plan (2018 Plan). The number of shares reserved for issuance under the 2018 Plan was set to 1,500,000. The exercise price of each stock-based award issued under the 2018 Plan is required to be no less than the fair value of the Company’s capital stock on the date of grant. The vesting and exercise provisions of options or restricted awards granted are determined individually with each grant. Stock options have a 10-year 2015 Plan The 2015 Equity Incentive Plan (2015 Plan) became effective on July 14, 2015. As of December 31, 2018, 8,637,065 shares were reserved for issuance under the 2015 Plan. The number of shares reserved for issuance under the 2015 Plan will increase automatically on January 1 of each calendar year from 2016 through 2025 by the number of shares equal to 4% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31. The Company’s Board of Directors or Compensation Committee may reduce the amount of the increase in any particular year. The exercise price of each stock-based award issued under the 2015 Plan is required to be no less than the fair value of the Company’s capital stock on the date of grant. The vesting and exercise provisions of options or restricted awards granted are determined individually with each grant. Stock options have a 10-year 2008 Plan The Company granted options under the 2008 Stock Plan (2008 Plan) until July 2015 when it was terminated as to future awards, although it continues to govern the terms of options that remain outstanding under the 2008 Plan. The 2008 Plan provided for the granting of Incentive Stock Options (ISO), nonqualified stock options and stock purchase rights. In connection with the Board of Directors approval of the 2015 Plan, all remaining shares available for future award under the 2008 Plan were transferred to the 2015 Plan, and the 2008 Plan was terminated. A summary of activity under the 2008 Plan, 2015 Plan and 2018 Plan and related information is as follows: Options Outstanding Shares Number Weighted- Weighted- Aggregate Outstanding—December 31, 2017 1,503,770 7,470,601 $3.09 8.12 $ 12,363 Awards authorized under the 2015 Plan 2,095,808 Awards authorized under the 2018 Plan 1,500,000 Options granted (3,566,150 ) 3,566,150 2.35 Options exercised — (120,742 ) 1.49 Options forfeited/cancelled 411,597 (411,597 ) 2.98 Outstanding—December 31, 2018 1,945,025 10,504,412 $2.86 7.80 $ 545 Exercisable—December 31, 2018 5,797,657 $3.10 7.00 $ 542 Vested and expected to vest—December 31, 2018 10,504,412 $2.86 7.80 $ 545 The weighted-average grant date fair values of options granted during the years ended December 31, 2018, 2017 and 2016 was $1.75, $1.09 and $2.19 per share. The aggregate intrinsic value of options exercised was $0.2 million, $0.2 million and $1.2 million for the years ended December 31, 2018, 2017 and 2016. The total grant date fair value of options vested for the years ended December 31, 2018, 2017 and 2016 was $5.9 million, $6.5 million and $6.1 million. As of December 31, 2018, total unrecognized stock-based compensation related to unvested stock options was $8.0 million, which the Company expects to recognize over a remaining weighted-average period of 2.1 years. 2015 Employee Stock Purchase Plan The Company adopted the 2015 Employee Stock Purchase Plan (ESPP) and initially reserved 700,000 shares of common stock as of its effective date of July 15, 2015. The number of shares initially reserved for issuance under the ESPP will increase automatically on January 1 for nine years from the first offering date by the number of shares equal to 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31. The aggregate number of shares issued over the term of the 2015 Employee Stock Purchase Plan will not exceed 3,400,000 shares of common stock. Under the ESPP, participants are offered the options to purchase shares of Company’s common stock at a 15% discount during a series of discrete offering periods, subject to any plan limitations. The ESPP will not become effective until such time as the Compensation Committee determines in the future, and as of December 31, 2018, the initial offering periods had not commenced. As of December 31, 2018, no shares of common stock have been issued to employees participating in the ESPP and 700,000 shares were available for issuance under the ESPP. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 10. Income Taxes On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (Tax Act). The Tax Act significantly revised U.S. tax law by, among other provisions, lowering the U.S. federal statutory income tax rate from 35% to 21%, changing rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017 and eliminating or reducing certain income tax deductions. The effects of changes in tax laws are required to be recognized in the period in which the legislation is enacted. However, due to the complexity and significance of the Tax Act’s provisions, the SEC staff issued Staff Accounting Bulletin No. 118 (SAB 118), which allowed companies to record the tax effects of the Tax Act on a provisional basis based on a reasonable estimate, and then, if necessary, subsequently adjust such amounts during a limited measurement period as more information becomes available. The measurement period ends when a company has obtained, prepared, and analyzed the information necessary to finalize its accounting, but cannot extend beyond one year from enactment. In connection with the Company’s initial analysis of the Tax Act, it recorded a decrease of its net deferred tax assets of $7.2 million for the period ended December 31, 2017, to account for the rate reduction. This did not have an impact on the Company’s financial statements since its U.S. deferred tax assets are fully offset by a valuation allowance. The Company finalized the analysis during the third quarter of 2018, with no material changes to the initial estimated decrease of its net deferred tax assets, and the accounting is now complete. The geographical breakdown of loss before provision for income taxes is as follows: Year Ended December 31, 2018 2017 2016 (in thousands) United States $ (54,395 ) $ (42,425 ) $ (48,244 ) International 758 566 520 Loss before provision for (benefit from) income taxes, net $ (53,637 ) $ (41,859 ) $ (47,724 ) The components of the provision for (benefit from) income taxes are as follows: Year Ended December 31, 2018 2017 2016 (in thousands) Current tax provision (benefit): Federal $ — $ — $ — State — — — Foreign (180 ) 183 170 Total current tax provision (benefit) (180 ) 183 170 Deferred tax provision (benefit): Foreign (122 ) (27 ) (27 ) Total deferred tax provision (benefit) $ (122 ) $ (27 ) $ (27 ) Total provision for (benefit from) income taxes $ (302 ) $ 156 $ 143 The reconciliation between income taxes computed at the federal statutory income tax rate and the provision for (benefit from) income taxes is as follows: Year Ended December 31, 2018 2017 2016 Federal statutory rate 21.0 % 34.0 % 34.0 % Effect of: Change in valuation allowance (22.2 ) 69.5 (33.5 ) Federal Tax Credit 2.4 (0.9 ) 1.6 State income tax benefit, net of federal benefit 0.3 0.1 0.1 Effect of ownership change on deferred tax assets — (84.8 ) — US tax reform deferred impact on tax rate change — (17.3 ) — Other permanent items (1.0 ) (1.0 ) (2.5 ) Total provision for (benefit from) income taxes 0.5 % (0.4 )% (0.3 )% The components of the deferred tax assets are as follows: December 31, 2018 2017 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 18,347 $ 9,183 Stock based compensation 3,642 2,444 License fee 2,008 1,346 59 (e) expenditures and amortization 1,435 1,435 Research and development credits 1,137 365 Other 972 698 Gross deferred tax assets 27,541 15,471 Valuation allowance (27,317 ) (15,395 ) Total deferred tax assets 224 76 Deferred tax liabilities: Other 39 13 Total deferred tax liabilities 39 13 Total net deferred tax assets $ 185 $ 63 Recognition of deferred tax assets is appropriate when realization of these assets is more likely than not. Based upon the weight of available evidence, which includes historical operating performance and the recorded cumulative net losses in prior fiscal periods, the Company recorded a full valuation allowance of $27.3 million and $15.4 million against the net U.S. deferred tax assets as of December 31, 2018 and 2017. The net valuation allowance increased by $11.9 million for the year ended December 31, 2018. The net valuation allowance decreased by $29.0 million for the year ended December 31, 2017, primarily due to the effects of an ownership change and the Tax Act rate change. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use the existing U.S. deferred tax assets. Based on the weight of all evidence, including a history of operating losses and the Company’s ability to generate future taxable income to realize the assets, management has determined that it is more likely than not that the U.S. deferred tax assets will not be realized. Utilization of the Company’s net operating loss and U.S. research and development credit carryforwards to offset taxable income are subject to an annual limitation, pursuant to Internal Revenue Code (IRC) Sections 382 and 383. As a result of ownership changes that have occurred, certain of the Company’s tax attributes existing as of the date of the ownership change are not be available for future use. The loss of these attributes does not have any impact on the financial statements since the net U.S. deferred tax assets are offset by a full valuation allowance. As of December 31, 2018, the Company has U.S. federal tax net operating loss carryforwards of $74.3 million, of which $31.4 million expire in 2037 and $42.9 million are eligible for indefinite carryforward, and state operating loss carryforwards of $56.3 million expiring in years ranging from 2022 to 2038. The Company also has U.S. net tax credit carryforwards of $1.1 million which begin to expire in 2032 and net tax credit carryforwards in a foreign jurisdiction of $0.2 million which begin to expire in 2037. Uncertain Tax Positions The activity related to the gross amount of unrecognized tax benefits is as follows: Year Ended December 31, 2018 2017 2016 (in thousands) Beginning balance $ 43 $ 311 $ 232 Increases based on tax positions related to prior years 109 — — Decreases based on tax positions related to prior years — (79 ) — Decreases due to ownership change — (232 ) — Increases based on tax positions in current year 112 43 79 Settlement — — — Lapse of statute of limitations — — — Ending balance $ 264 $ 43 $ 311 If recognized, gross unrecognized tax benefits would not have a material impact on the Company’s effective tax rate due to the Company’s full valuation allowance position on the U.S. deferred tax assets. From time to time, the Company is subject to review by tax authorities. It is not possible to estimate the impact of changes, if any, to previously recorded uncertain tax positions. However, the Company does not expect the changes, if any, to be materially different from what is recorded and will adjust its estimate and liability as necessary. The Company recognizes interest and penalties related to unrecognized tax benefits in the provision for income taxes in the accompanying consolidated statement of operations. Accrued interest and penalties, if applicable, are included in accrued liabilities in the consolidated balance sheet. For the years ended December 31, 2018 and 2017, the Company did not recognize any accrued interest and penalties. The Company is subject to taxation in the United States, various states, Canada and Australia. Tax years 2015 through 2017 remain open to examination by the United States, various state jurisdictions and Canada. The tax year ended December 31, 2017 remains open to examination in Australia. Other than routine reviews by tax authorities for tax credits claimed, the Company is not under examination in any tax jurisdiction for any year. |
Restructuring Costs
Restructuring Costs | 12 Months Ended |
Dec. 31, 2018 | |
Restructuring and Related Activities [Abstract] | |
Restructuring Costs | 11. Restructuring Costs In June 2016, the Company halted investment in PNT2258 and the DNAi platform and closed the related Phase 2 clinical trials to further enrollment. As a result, the Company closed its research facility in Plymouth, Michigan, renegotiated and terminated certain contracts, and implemented staff reductions in the United States and Canada. The following table summarizes restructuring activities for the years ended December 31, 2018, 2017 and 2016: Contract Employee Asset Total (in thousands) Accrual balance at December 31, 2015 $ — $ — $ — $ — Restructuring costs charged to research and development expense 2,249 — — 2,249 Restructuring costs charged to general and administration expense 5 332 130 467 Non-cash (681 ) — (130 ) (811 ) Cash payments (909 ) (233 ) — (1,142 ) Accrual balance at December 31, 2016 $ 664 $ 99 $ — $ 763 Adjustments to research and development expense (69 ) — — (69 ) Cash payments (458 ) (99 ) — (557 ) Accrual balance at December 31, 2017 $ 137 $ — $ — $ 137 Adjustments to research and development expense (99 ) — — (99 ) Cash payments (5 ) — — (5 ) Accrual balance at December 31, 2018 $ 33 $ — $ — $ 33 The accrual balance, which was included in accrued liabilities in the accompanying balance sheet, is currently expected to be substantially paid by 2019. |
Selected Quarterly Financial Da
Selected Quarterly Financial Data | 12 Months Ended |
Dec. 31, 2018 | |
Quarterly Financial Information Disclosure [Abstract] | |
Selected Quarterly Financial Data | 12. Selected Quarterly Financial Data (Unaudited) The following tables present certain selected unaudited consolidated quarterly financial information for each of the eight quarters ended December 31, 2018. This consolidated quarterly information has been prepared on the same basis as the consolidated financial statements and includes all adjustments necessary to state fairly the information for the periods presented. The selected consolidated quarterly financial results from operations for the years ended December 31, 2018 and 2017 are set forth therein. Fiscal 2018 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Operating expenses $ 11,754 $ 12,963 $ 16,051 $ 14,649 Net loss (1) $ (11,525 ) $ (11,960 ) $ (15,567 ) $ (14,283 ) Basic and diluted net loss per share $ (0.19 ) $ (0.16 ) $ (0.21 ) $ (0.19 ) Fiscal 2017 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Operating expenses $ 11,154 $ 10,477 $ 10,183 $ 10,805 Net loss (1) $ (11,092 ) $ (10,329 ) $ (9,995 ) $ (10,599 ) Basic and diluted net loss per share $ (0.26 ) $ (0.20 ) $ (0.19 ) $ (0.20 ) (1) Net loss from continuing operations and net loss attributable to common stockholders are the same as net loss for all periods presented. |
Summary of Significant Accoun_2
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2018 | |
Accounting Policies [Abstract] | |
Basis of Presentation | Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP). The accompanying consolidated financial statements include the accounts of Sierra Oncology, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. |
Use of Estimates | Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of consolidated financial statements and the reported amounts of expense during the reporting period. Significant estimates and assumptions made in the accompanying consolidated financial statements include, but are not limited to the fair value of stock options and the warrant issued, accruals such as research and development costs, and recoverability of the Company’s net deferred tax assets, and related valuation allowance. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors and adjusts those estimates and assumptions when facts and circumstances dictate. Actual results could materially differ from those estimates. |
Foreign Currency | Foreign Currency The functional currency of the Company’s foreign subsidiaries is the U.S. Dollar. Transactions denominated in currencies other than the functional currency are recorded at prevailing exchange rates during the period. At the end of each reporting period, monetary assets and liabilities are remeasured to the functional currency using exchange rates in effect at the balance sheet date. Non-monetary |
Cash and Cash Equivalents | Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist primarily of funds invested in readily available checking and savings accounts and highly liquid investments in money market funds. |
Restricted Cash | Restricted Cash Restricted cash, which consists of funds invested in a money market fund, represents collateral for a corporate credit card facility and is included in other assets in the accompanying consolidated balance sheets. Restricted cash at December 31, 2017 also included security deposits required for a facility lease that expired in February 2018. |
Concentrations of Credit Risk | Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist of cash, cash equivalents and restricted cash. All of the Company’s cash, cash equivalents and restricted cash are held at financial institutions in the United States and Canada that management believes to be of high credit quality. Deposits held in the United States and Canada with these financial institutions exceed federally insured limits. The primary focus of the Company’s investment strategy is to preserve capital and meet liquidity requirements. The Company’s investment policy addresses the level of credit exposure by limiting the concentration in any one corporate issuer and establishing a minimum allowable credit rating. |
Fair Value of Financial Instruments | Fair Value of Financial Instruments The Company’s cash and cash equivalents, restricted cash, other current assets, accounts payable, and accrued liabilities approximate their fair value at December 31, 2018 and 2017, due to their short duration. The term loan bears interest at prevailing market rates for instruments with similar characteristics, accordingly, the carrying value of this instrument approximates its fair value. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines the fair value of its financial instruments based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels: Level 1 Level 2 Level 3 |
Property and Equipment, Net | Property and Equipment, Net Property and equipment, net are stated at cost, less accumulated depreciation. Depreciation on property and equipment, excluding leasehold improvements, is computed using the straight-line method over the estimated useful lives of the respective assets, generally three to five years. Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations. Leasehold improvements are amortized on a straight-line basis over the shorter of the estimated useful lives of the assets or the remaining lease term. |
Other Assets | Other Assets Other assets consist primarily of restricted cash pledged as collateral for a corporate credit card facility, long-term prepaid rent and deferred income tax assets in foreign jurisdictions. |
Research and Development Costs | Research and Development Costs Research and development costs are expensed as incurred. The Company accounts for non-refundable Upfront payments made in connection with license and asset purchase agreements are expensed as research and developments costs, as the assets acquired do not have alternative future use. Contingent milestone payment obligations due to third parties under license and asset purchase agreements are expensed when the milestones are considered probable of occurring. Research and development costs include fees incurred in connection with license and asset purchase agreements, compensation and other related costs for employees engaged in research and development, costs associated with research and preclinical studies, clinical trials, regulatory activities, manufacturing activities to support clinical activities, fees paid to external service providers that conduct certain research and development, clinical, and manufacturing activities on behalf of the Company and an allocation of overhead expenses. |
Stock-Based Compensation | Stock-Based Compensation The Company accounts for stock-based payments at fair value, which is measured using the Black-Scholes option-pricing model. For stock-based awards that vest subject to the satisfaction of a service requirement, the fair value measurement date for employee stock-based compensation awards is the date of grant and the expense is recognized on a straight-line basis over the vesting period. Stock-based compensation arrangements with non-employees |
Income Taxes | Income Taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and the tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Management makes an assessment of the likelihood that the resulting deferred tax assets will be realized. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. Due to the Company’s historical operating performance and the recorded cumulative net losses in prior fiscal periods, the net U.S. deferred tax assets have been offset by a full valuation allowance. The Company recognizes uncertain income tax positions at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Changes in recognition or measurement are reflected in the period in which judgment occurs. The Company recognizes interest and penalties related to the underpayment of income taxes as a component of provision for (benefit from) income taxes, net. |
Segment Information | Segment Information Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and assessing performance. The Company’s chief operating decision maker is its Chief Executive Officer. The Company’s Chief Executive Officer views the Company’s operations and manages its business in one operating segment, which is the business of researching, developing and commercializing therapies for the treatment of patients with hematology and oncology. Accordingly, the Company has a single reporting segment. |
Recent Accounting Pronouncements | Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (FASB) issued FASB Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) right-of-use assets In June 2018, the FASB issued FASB ASU No. 2018-07, non-employees |
Net Loss Per Share (Tables)
Net Loss Per Share (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Earnings Per Share [Abstract] | |
Schedule of Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share | The following shares of common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented because including them would have been antidilutive: As of December 31, 2018 2017 2016 Options to purchase common stock 10,504,412 7,470,601 6,543,654 Warrant for common stock 73,529 — — Total potential dilutive shares 10,577,941 7,470,601 6,543,654 |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Fair Value Disclosures [Abstract] | |
Schedule of Fair Value of Financial Assets Measured on Recurring Basis | The following table sets forth the fair value of the Company’s financial assets and liabilities measured on a recurring basis by level within the fair value hierarchy: December 31, 2018 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 105,224 $ — $ — $ 105,224 Restricted money market funds 300 — — 300 Total financial assets $ 105,524 $ — $ — $ 105,524 December 31, 2017 Level 1 Level 2 Level 3 Total (in thousands) Financial Assets Money market funds $ 99,792 $ — $ — $ 99,792 Restricted money market funds 188 — — 188 Total financial assets $ 99,980 $ — $ — $ 99,980 |
Balance Sheet Components (Table
Balance Sheet Components (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Summary of Cash and Cash Equivalents | Cash and cash equivalents consist of the following: December 31, 2018 2017 (in thousands) Cash $ 822 $ 556 Cash equivalents: Money market accounts 105,224 99,792 Total cash and cash equivalents $ 106,046 $ 100,348 |
Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash | The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheets to the amounts shown in the consolidated statements of cash flows. December 31, 2018 December 31, (in thousands) Cash and cash equivalents $ 106,046 $ 100,348 Restricted cash included in other assets 300 188 Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows $ 106,346 $ 100,536 |
Summary of Prepaid Expenses and Other Current Assets | Prepaid expenses and other current assets consist of the following: December 31, 2018 2017 (in thousands) Prepaid research and development project costs $ 762 $ 549 Other receivables 751 103 Prepaid insurance 555 478 Income taxes receivable 163 — Other 475 247 Total prepaid expenses and other current assets $ 2,706 $ 1,377 |
Summary of Property and Equipment, Net | Property and equipment, net consists of the following: December 31, 2018 2017 (in thousands) Software $ 325 $ 254 Leasehold improvements 112 79 Computer equipment 89 93 Furniture and fixtures 3 3 Property and equipment, gross 529 429 Less: accumulated depreciation (361 ) (275 ) Total property and equipment, net $ 168 $ 154 |
Summary of Accrued Liabilities | Accrued liabilities consist of the following: December 31, 2018 2017 (in thousands) Accrued research and development costs $ 4,485 $ 2,763 Accrued employee related costs 3,223 2,699 Accrued professional fees 357 317 Accrued restructuring costs (Note 11) 33 137 Other 714 217 Total accrued liabilities $ 8,812 $ 6,133 |
Term Loan (Tables)
Term Loan (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Debt Disclosure [Abstract] | |
Schedule of Estimated Future Principal Payments Due Under Loan Agreement | Scheduled payments due under the Loan Agreement, excluding the final payment fee of $0.3 million and interest payments, are as follows: December 31, (in thousands) 2020 $ 1,667 2021 2,000 2022 1,333 Total $ 5,000 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Commitments and Contingencies Disclosure [Abstract] | |
Schedule of Aggregate Future Non-Cancelable Minimum Lease Payments | As of December 31, 2018, the aggregate future non-cancelable Years Ending December 31: Operating (in thousands) 2019 $ 243 2020 208 2021 211 2022 169 Total $ 831 |
Common Stock Reserved for Iss_2
Common Stock Reserved for Issuance (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Equity [Abstract] | |
Schedule of Common Stock Reserved for Issuance | The Company is required to reserve and keep available out of its authorized but unissued shares of common stock a number of shares sufficient to effect the conversion of all outstanding options granted and available for grant under the incentive plans, shares reserved for issuance under the employee stock purchase plan and issued warrant. December 31, 2018 2017 Outstanding stock options under equity incentive plans 10,504,412 7,470,601 Shares reserved for future option grants under equity plans 1,945,025 1,503,770 Shares reserved under the 2015 employee stock purchase plan 700,000 700,000 Shares reserved under warrant upon contingent events 147,059 — Outstanding warrant 73,529 — Total common stock reserved for issuance 13,370,025 9,674,371 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Schedule of Stock-based Compensation Expense for Employees and Non-employees | In the accompanying consolidated statement of operations, the Company recognized stock-based compensation expense for its employees and non-employees Year Ended December 31, 2018 2017 2016 (in thousands) Research and development $ 4,499 $ 3,966 $ 3,635 General and administrative 2,297 1,939 1,875 Total stock-based compensation $ 6,796 $ 5,905 $ 5,510 |
Schedule of Estimated Grant-date Fair Value of Stock-based Awards Using Black-Scholes Option Pricing Model Assumptions | The estimated grant-date fair value of all the Company’s stock-based awards was calculated using the Black-Scholes option pricing model, based on the following assumptions: Year Ended December 31, 2018 2017 2016 Expected term (in years) 5.3 – 7.0 5.3 – 7.0 5.1 – 9.9 Expected volatility 88 – 91 % 86 – 96 % 77 – 87 % Risk-free interest rate 2.6 – 3.1 % 1.8 – 2.3 % 1.1 – 2.4 % Expected dividend rate — % — % — % |
Summary of Stock-Based Compensation Activity | A summary of activity under the 2008 Plan, 2015 Plan and 2018 Plan and related information is as follows: Options Outstanding Shares Number Weighted- Weighted- Aggregate Outstanding—December 31, 2017 1,503,770 7,470,601 $3.09 8.12 $ 12,363 Awards authorized under the 2015 Plan 2,095,808 Awards authorized under the 2018 Plan 1,500,000 Options granted (3,566,150 ) 3,566,150 2.35 Options exercised — (120,742 ) 1.49 Options forfeited/cancelled 411,597 (411,597 ) 2.98 Outstanding—December 31, 2018 1,945,025 10,504,412 $2.86 7.80 $ 545 Exercisable—December 31, 2018 5,797,657 $3.10 7.00 $ 542 Vested and expected to vest—December 31, 2018 10,504,412 $2.86 7.80 $ 545 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Income Tax Disclosure [Abstract] | |
Schedule of Geographical Breakdown of Loss Before Provision for Income Taxes | The geographical breakdown of loss before provision for income taxes is as follows: Year Ended December 31, 2018 2017 2016 (in thousands) United States $ (54,395 ) $ (42,425 ) $ (48,244 ) International 758 566 520 Loss before provision for (benefit from) income taxes, net $ (53,637 ) $ (41,859 ) $ (47,724 ) |
Components of Provision (Benefit from) for Income Taxes | The components of the provision for (benefit from) income taxes are as follows: Year Ended December 31, 2018 2017 2016 (in thousands) Current tax provision (benefit): Federal $ — $ — $ — State — — — Foreign (180 ) 183 170 Total current tax provision (benefit) (180 ) 183 170 Deferred tax provision (benefit): Foreign (122 ) (27 ) (27 ) Total deferred tax provision (benefit) $ (122 ) $ (27 ) $ (27 ) Total provision for (benefit from) income taxes $ (302 ) $ 156 $ 143 |
Reconciliation Between Income Taxes Computed at the Federal Statutory Income Tax Rate and the Provision for Income Taxes | The reconciliation between income taxes computed at the federal statutory income tax rate and the provision for (benefit from) income taxes is as follows: Year Ended December 31, 2018 2017 2016 Federal statutory rate 21.0 % 34.0 % 34.0 % Effect of: Change in valuation allowance (22.2 ) 69.5 (33.5 ) Federal Tax Credit 2.4 (0.9 ) 1.6 State income tax benefit, net of federal benefit 0.3 0.1 0.1 Effect of ownership change on deferred tax assets — (84.8 ) — US tax reform deferred impact on tax rate change — (17.3 ) — Other permanent items (1.0 ) (1.0 ) (2.5 ) Total provision for (benefit from) income taxes 0.5 % (0.4 )% (0.3 )% |
Components of the Deferred Tax Assets | The components of the deferred tax assets are as follows: December 31, 2018 2017 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 18,347 $ 9,183 Stock based compensation 3,642 2,444 License fee 2,008 1,346 59 (e) expenditures and amortization 1,435 1,435 Research and development credits 1,137 365 Other 972 698 Gross deferred tax assets 27,541 15,471 Valuation allowance (27,317 ) (15,395 ) Total deferred tax assets 224 76 Deferred tax liabilities: Other 39 13 Total deferred tax liabilities 39 13 Total net deferred tax assets $ 185 $ 63 |
Unrecognized Tax Benefits | The activity related to the gross amount of unrecognized tax benefits is as follows: Year Ended December 31, 2018 2017 2016 (in thousands) Beginning balance $ 43 $ 311 $ 232 Increases based on tax positions related to prior years 109 — — Decreases based on tax positions related to prior years — (79 ) — Decreases due to ownership change — (232 ) — Increases based on tax positions in current year 112 43 79 Settlement — — — Lapse of statute of limitations — — — Ending balance $ 264 $ 43 $ 311 |
Restructuring Costs (Tables)
Restructuring Costs (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Restructuring and Related Activities [Abstract] | |
Summary of Restructuring Activities | The following table summarizes restructuring activities for the years ended December 31, 2018, 2017 and 2016: Contract Employee Asset Total (in thousands) Accrual balance at December 31, 2015 $ — $ — $ — $ — Restructuring costs charged to research and development expense 2,249 — — 2,249 Restructuring costs charged to general and administration expense 5 332 130 467 Non-cash (681 ) — (130 ) (811 ) Cash payments (909 ) (233 ) — (1,142 ) Accrual balance at December 31, 2016 $ 664 $ 99 $ — $ 763 Adjustments to research and development expense (69 ) — — (69 ) Cash payments (458 ) (99 ) — (557 ) Accrual balance at December 31, 2017 $ 137 $ — $ — $ 137 Adjustments to research and development expense (99 ) — — (99 ) Cash payments (5 ) — — (5 ) Accrual balance at December 31, 2018 $ 33 $ — $ — $ 33 |
Selected Quarterly Financial _2
Selected Quarterly Financial Data (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Quarterly Financial Information Disclosure [Abstract] | |
Summary of Selected Unaudited Consolidated Quarterly Financial Information | The selected consolidated quarterly financial results from operations for the years ended December 31, 2018 and 2017 are set forth therein. Fiscal 2018 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Operating expenses $ 11,754 $ 12,963 $ 16,051 $ 14,649 Net loss (1) $ (11,525 ) $ (11,960 ) $ (15,567 ) $ (14,283 ) Basic and diluted net loss per share $ (0.19 ) $ (0.16 ) $ (0.21 ) $ (0.19 ) Fiscal 2017 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except per share amounts) Operating expenses $ 11,154 $ 10,477 $ 10,183 $ 10,805 Net loss (1) $ (11,092 ) $ (10,329 ) $ (9,995 ) $ (10,599 ) Basic and diluted net loss per share $ (0.26 ) $ (0.20 ) $ (0.19 ) $ (0.20 ) (1) Net loss from continuing operations and net loss attributable to common stockholders are the same as net loss for all periods presented. |
The Company and Basis of Pres_2
The Company and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | Mar. 06, 2018 | Feb. 21, 2017 | Feb. 14, 2017 | Dec. 31, 2018 | Dec. 31, 2017 |
Class of Stock [Line Items] | |||||
Cash and cash equivalents | $ 106,046 | $ 100,348 | |||
Follow on Offering [Member] | |||||
Class of Stock [Line Items] | |||||
Stock issued, shares | 21,850,000 | 2,347,636 | 19,500,000 | ||
Shares issued, price per share | $ 2.25 | $ 1.35 | |||
Proceeds from issuance of common stock, net of deferred financing costs | $ 46,000 | $ 27,400 | |||
Underwriting discounts and commissions and offering expenses | $ 3,200 | $ 2,100 |
Summary of Significant Accoun_3
Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions | 12 Months Ended | ||
Dec. 31, 2018USD ($)Segment | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | |
Summary Of Significant Accounting Policy [Line Items] | |||
Net foreign exchange transaction loss | $ 0.1 | $ 0.1 | |
Number of operating segment | Segment | 1 | ||
Total lease liability | $ 1 | ||
Minimum [Member] | Property Plant and Equipment Other than Leasehold Improvement [Member] | |||
Summary Of Significant Accounting Policy [Line Items] | |||
Estimated useful lives of assets | 3 years | ||
Maximum [Member] | Property Plant and Equipment Other than Leasehold Improvement [Member] | |||
Summary Of Significant Accounting Policy [Line Items] | |||
Estimated useful lives of assets | 5 years |
Net Loss Per Share - Schedule o
Net Loss Per Share - Schedule of Outstanding Shares of Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Total potential dilutive shares | 10,577,941 | 7,470,601 | 6,543,654 |
Options to Purchase Common Stock [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Total potential dilutive shares | 10,504,412 | 7,470,601 | 6,543,654 |
Warrants for Common Stock [Member] | |||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | |||
Total potential dilutive shares | 73,529 |
Fair Value Measurements - Sched
Fair Value Measurements - Schedule of Fair Value of Financial Assets Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Financial Assets | ||
Total financial assets | $ 105,524 | $ 99,980 |
Money Market Funds [Member] | ||
Financial Assets | ||
Total financial assets | 105,224 | 99,792 |
Restricted Money Market Funds [Member] | ||
Financial Assets | ||
Total financial assets | 300 | 188 |
Level 1 [Member] | ||
Financial Assets | ||
Total financial assets | 105,524 | 99,980 |
Level 1 [Member] | Money Market Funds [Member] | ||
Financial Assets | ||
Total financial assets | 105,224 | 99,792 |
Level 1 [Member] | Restricted Money Market Funds [Member] | ||
Financial Assets | ||
Total financial assets | $ 300 | $ 188 |
Fair Value Measurements - Addit
Fair Value Measurements - Additional Information (Detail) - USD ($) | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | ||
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount | $ 0 | $ 0 |
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount | 0 | 0 |
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount | 0 | 0 |
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount | 0 | 0 |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 | 0 | 0 |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | 0 | 0 |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3 | 0 | 0 |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 | $ 0 | $ 0 |
Balance Sheet Components - Summ
Balance Sheet Components - Summary of Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Cash and Cash Equivalents [Abstract] | ||
Cash | $ 822 | $ 556 |
Cash equivalents: | ||
Money market accounts | 105,224 | 99,792 |
Total cash and cash equivalents | $ 106,046 | $ 100,348 |
Balance Sheet Components - Su_2
Balance Sheet Components - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Cash and Cash Equivalents [Abstract] | ||||
Cash and cash equivalents | $ 106,046 | $ 100,348 | ||
Restricted cash included in other assets | 300 | 188 | ||
Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows | $ 106,346 | $ 100,536 | $ 109,207 | $ 150,405 |
Balance Sheet Components - Su_3
Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] | ||
Prepaid research and development project costs | $ 762 | $ 549 |
Other receivables | 751 | 103 |
Prepaid insurance | 555 | 478 |
Income taxes receivable | 163 | |
Other | 475 | 247 |
Total prepaid expenses and other current assets | $ 2,706 | $ 1,377 |
Balance Sheet Components - Su_4
Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 529 | $ 429 |
Less: accumulated depreciation | (361) | (275) |
Total property and equipment, net | 168 | 154 |
Software [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 325 | 254 |
Computer Equipment [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 112 | 79 |
Leasehold Improvements [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 89 | 93 |
Furniture and Fixtures [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 3 | $ 3 |
Balance Sheet Components - Addi
Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Property, Plant and Equipment [Abstract] | |||
Depreciation related to property and equipment | $ 111 | $ 258 | $ 197 |
Balance Sheet Components - Su_5
Balance Sheet Components - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Payables and Accruals [Abstract] | ||
Accrued research and development costs | $ 4,485 | $ 2,763 |
Accrued employee related costs | 3,223 | 2,699 |
Accrued professional fees | 357 | 317 |
Accrued restructuring costs | 33 | 137 |
Other | 714 | 217 |
Accrued Liabilities, Current, Total | $ 8,812 | $ 6,133 |
Term Loan - Additional Informat
Term Loan - Additional Information (Detail) | Aug. 21, 2018USD ($)Tranches | Dec. 31, 2018USD ($)$ / sharesshares |
Debt Instrument [Line Items] | ||
Amount borrowed | $ 5,000,000 | |
Silicon Valley Bank [Member] | Maximum [Member] | ||
Debt Instrument [Line Items] | ||
Number of common stock issuable | shares | 220,588 | |
Silicon Valley Bank [Member] | Term Loans [Member] | ||
Debt Instrument [Line Items] | ||
Aggregate principal amount of loans | $ 15,000,000 | |
Number of tranches | Tranches | 3 | |
Loan agreement, description | Contemporaneously with executing the Loan Agreement, the Company drew down the first $5.0 million tranche. The second and third $5.0 million tranches may be drawn only upon the achievement of certain development milestones. | |
Loan agreement, frequency of payments | Monthly | |
Interest payment description | Borrowings under the Loan Agreement bear interest at the greater of (i) 6.0% or (ii) a floating per annum rate 1.0% above the prime rate (for an interest rate of 6.50% at December 31, 2018), with interest only due and payable monthly, until March 1, 2020 (unless extended under the conditions set forth in the Loan Agreement), at which time interest and principal will be due and payable in equal monthly payments; and are subject to a final payment fee equal to 6.75% of the aggregate principal amount. | |
Final payment fee as percent of aggregate principal amount of borrowing | 6.75% | |
Minimium requirement of cash and cash equivalents held with bank | $ 10,000,000 | |
Minimium percentage requirement of cash and cash equivalents held with bank | 80.00% | |
Applicable interest rate of loan | 5.00% | |
Loan payment fee | $ 300,000 | |
Interest expense | $ 200,000 | |
Silicon Valley Bank [Member] | Term Loans [Member] | Prepayment Prior To August 21,2019 [Member] | ||
Debt Instrument [Line Items] | ||
Principal prepayment fee percentage | 3.00% | |
Silicon Valley Bank [Member] | Term Loans [Member] | Prepayment After August 21,2019 But Prior To August 21,2020 [Member] | ||
Debt Instrument [Line Items] | ||
Principal prepayment fee percentage | 2.00% | |
Silicon Valley Bank [Member] | Term Loans [Member] | Prepayment on August 21,2020 Or Prior To Maturity Date on August 1, 2022 [Member] | ||
Debt Instrument [Line Items] | ||
Principal prepayment fee percentage | 1.00% | |
Silicon Valley Bank [Member] | Term Loans [Member] | Prime Rate [Member] | ||
Debt Instrument [Line Items] | ||
Loan agreement bear interest rate | 6.50% | |
Variable rate on borrowings above prime rate, percentage | 1.00% | |
Silicon Valley Bank [Member] | Term Loans [Member] | Minimum [Member] | ||
Debt Instrument [Line Items] | ||
Loan agreement bear interest rate | 6.00% | |
Silicon Valley Bank [Member] | Term Loans [Member] | Tranche One [Member] | ||
Debt Instrument [Line Items] | ||
Aggregate principal amount of loans | $ 5,000,000 | |
Amount borrowed | 5,000,000 | |
Effective interest rate of loan | 9.89% | |
Unamortized debt discount | $ 100,000 | |
Amortization of debt discount and accrual of final payment | $ 100,000 | |
Silicon Valley Bank [Member] | Term Loans [Member] | Tranche Two [Member] | ||
Debt Instrument [Line Items] | ||
Aggregate principal amount of loans | 5,000,000 | |
Silicon Valley Bank [Member] | Term Loans [Member] | Tranche Three [Member] | ||
Debt Instrument [Line Items] | ||
Aggregate principal amount of loans | $ 5,000,000 | |
Silicon Valley Bank [Member] | Warrants to Purchase Common Stock [Member] | ||
Debt Instrument [Line Items] | ||
Warrant expiration date | Aug. 21, 2028 | |
Silicon Valley Bank [Member] | Warrants to Purchase Common Stock [Member] | Term Loans [Member] | ||
Debt Instrument [Line Items] | ||
Warrants issued in connection with loan | shares | 73,529 | |
Price per share of issued warrants | $ / shares | $ 1.87 |
Term Loan - Schedule of Estimat
Term Loan - Schedule of Estimated Future Principal Payments Due Under Loan Agreement (Detail) $ in Thousands | Dec. 31, 2018USD ($) |
Debt Disclosure [Abstract] | |
2,020 | $ 1,667 |
2,021 | 2,000 |
2,022 | 1,333 |
Total | $ 5,000 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) $ in Millions | 1 Months Ended | 12 Months Ended | ||||||
Aug. 31, 2018USD ($) | Oct. 31, 2016USD ($) | Jun. 30, 2016USD ($) | Jan. 31, 2016 | Dec. 31, 2018USD ($)Payments | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Jan. 31, 2017USD ($) | |
Lease Agreements [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Total rent expense | $ 0.5 | $ 0.5 | $ 0.5 | |||||
Operating Lease Agreement To Lease Office Space [Member] | San Francisco [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Operating lease agreement expiration date | Apr. 30, 2019 | |||||||
Vancouver Lease [Member] | Vancouver [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Operating lease agreement expiration date | Feb. 28, 2023 | |||||||
Additional lease term to be extended | 5 years | |||||||
Carna License Agreement [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Aggregate milestone payment | $ 270 | |||||||
Upfront payment paid | $ 0.9 | |||||||
Number of milestone payments recorded | Payments | 0 | |||||||
Milestone payment | $ 4 | |||||||
CPF License Agreements [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Milestone payment | $ 2 | |||||||
Upfront payment paid | $ 7 | |||||||
Additional milestone payment payable | 319.5 | |||||||
Asset Purchase Agreement [Member] | ||||||||
Loss Contingencies [Line Items] | ||||||||
Upfront payment paid | $ 3 | |||||||
Aggregate milestone payment | 195 | |||||||
Milestone payment | $ 5 |
Commitments and Contingencies_2
Commitments and Contingencies - Schedule of Aggregate Future Non-Cancelable Minimum Lease Payments (Detail) $ in Thousands | Dec. 31, 2018USD ($) |
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] | |
2,019 | $ 243 |
2,020 | 208 |
2,021 | 211 |
2,022 | 169 |
Total | $ 831 |
Common Stock Reserved for Iss_3
Common Stock Reserved for Issuance - Schedule of Common Stock Reserved for Issuance (Detail) - shares | Dec. 31, 2018 | Dec. 31, 2017 | Jul. 15, 2015 |
Class of Stock [Line Items] | |||
Total common stock reserved for future issuance | 13,370,025 | 9,674,371 | |
Equity Incentive Plan [Member] | |||
Class of Stock [Line Items] | |||
Awards outstanding | 10,504,412 | 7,470,601 | |
Total common stock reserved for future issuance | 1,945,025 | 1,503,770 | |
2015 Employee Stock Purchase Plan [Member] | |||
Class of Stock [Line Items] | |||
Total common stock reserved for future issuance | 700,000 | 700,000 | 700,000 |
Warrants to Purchase Common Stock [Member] | |||
Class of Stock [Line Items] | |||
Total common stock reserved for future issuance | 147,059 | ||
Outstanding warrant | 73,529 |
Stock-Based Compensation - Sche
Stock-Based Compensation - Schedule of Stock-based Compensation Expense for Employees and Non-employees (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total stock-based compensation | $ 6,796 | $ 5,905 | $ 5,510 |
Research and development [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total stock-based compensation | 4,499 | 3,966 | 3,635 |
General and administrative [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total stock-based compensation | $ 2,297 | $ 1,939 | $ 1,875 |
Stock-Based Compensation - Sc_2
Stock-Based Compensation - Schedule of Estimated Grant-date Fair Values of Stock-based Awards Using Black-Scholes Option Pricing Model Assumptions (Detail) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected volatility, Minimum | 88.00% | 86.00% | 77.00% |
Expected volatility, Maximum | 91.00% | 96.00% | 87.00% |
Risk-free interest rate, Minimum | 2.60% | 1.80% | 1.10% |
Risk-free interest rate, Maximum | 3.10% | 2.30% | 2.40% |
Expected dividend rate | 0.00% | 0.00% | 0.00% |
Minimum [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (in years) | 5 years 3 months 18 days | 5 years 3 months 18 days | 5 years 1 month 6 days |
Maximum [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Expected term (in years) | 7 years | 7 years | 9 years 10 months 24 days |
Stock-Based Compensation - Addi
Stock-Based Compensation - Additional Information (Detail) - USD ($) | Jul. 15, 2015 | Jul. 14, 2015 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Expected dividend rate | 0.00% | 0.00% | 0.00% | ||
Number of common stock shares reserved for issuance | 13,370,025 | 9,674,371 | |||
Accounting Standards Update 2016-09 [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Retrospective adjustment to retained earnings | $ 8,000 | ||||
2015 Employee Stock Purchase Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Number of common stock shares reserved for issuance | 700,000 | 700,000 | 700,000 | ||
Stock option grants description | The number of shares initially reserved for issuance under the ESPP will increase automatically on January 1 for nine years from the first offering date by the number of shares equal to 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31. | ||||
Percentage threshold of outstanding shares increased annually under the plan | 1.00% | ||||
Common shares authorized to be issued during the period | 3,400,000 | ||||
Options to purchase shares of common stock, discount percentage | 15.00% | ||||
Number of common stock issued | 0 | ||||
2015 Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Number of common stock shares reserved for issuance | 8,637,065 | ||||
Stock option life in years | 10 years | ||||
Stock option grants description | The number of shares reserved for issuance under the 2015 Plan will increase automatically on January 1 of each calendar year from 2016 through 2025 by the number of shares equal to 4% of the total outstanding shares of the Company's common stock as of the immediately preceding December 31 | ||||
Percentage threshold of outstanding shares increased annually under the plan | 4.00% | ||||
Common shares authorized to be issued during the period | 2,095,808 | ||||
2008 Plan, 2015 Plan and 2018 Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Awards issued | 3,566,150 | ||||
Awards outstanding | 10,504,412 | 7,470,601 | |||
Weighted-average grant date fair values of options granted | $ 1.75 | $ 1.09 | $ 2.19 | ||
Aggregate intrinsic value of options exercised | $ 200,000 | $ 200,000 | $ 1,200,000 | ||
Total grant date fair value of options vested | 5,900,000 | $ 6,500,000 | $ 6,100,000 | ||
Total unrecognized stock-based compensation related to unvested stock options | $ 8,000,000 | ||||
Weighted-average period | 2 years 1 month 6 days | ||||
2018 Equity Inducement Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Number of common stock shares reserved for issuance | 1,500,000 | ||||
Stock option life in years | 10 years | ||||
Awards issued | 0 | ||||
Awards outstanding | 0 | ||||
Common shares authorized to be issued during the period | 1,500,000 |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Stock-Based Compensation Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | |
Dec. 31, 2018 | Dec. 31, 2017 | |
2008 Plan, 2015 Plan and 2018 Plan [Member] | ||
Options Outstanding, Shares Available for Grant | ||
Shares Available for Grant, Beginning balance | 1,503,770 | |
Shares Available for Grant, Granted | (3,566,150) | |
Shares Available for Grant, Exercised | 0 | |
Shares Available for Grant, forfeited/cancelled | 411,597 | |
Shares Available for Grant, Ending balance | 1,945,025 | 1,503,770 |
Options Outstanding, Number of Shares Outstanding | ||
Number of Shares Outstanding, Beginning balance | 7,470,601 | |
Number of Shares Outstanding, Options granted | 3,566,150 | |
Number of Shares Outstanding, Options exercised | (120,742) | |
Number of Shares Outstanding, Options forfeited/cancelled | (411,597) | |
Number of Shares Outstanding, Ending balance | 10,504,412 | 7,470,601 |
Number of Shares Outstanding, Exercisable | 5,797,657 | |
Number of Shares Outstanding, Vested and expected to vest | 10,504,412 | |
Options Outstanding, Weighted-Average Exercise Price Per Share | ||
Weighted-Average Exercise Price Per Share, Beginning balance | $ 3.09 | |
Weighted-Average Exercise Price Per Share, Options granted | 2.35 | |
Weighted-Average Exercise Price Per Share, Options exercised | 1.49 | |
Weighted-Average Exercise Price Per Share, Options forfeited/cancelled | 2.98 | |
Weighted-Average Exercise Price Per Share, Ending balance | 2.86 | $ 3.09 |
Weighted-Average Exercise Price Per Share, Exercisable | 3.10 | |
Weighted-Average Exercise Price Per Share, Vested and expected to vest | $ 2.86 | |
Options Outstanding, Weighted-Average Remaining Contractual Term (Years) | ||
Weighted-Average Remaining Contractual Term (Years) | 7 years 9 months 18 days | 8 years 1 month 13 days |
Weighted-Average Remaining Contractual Term (Year), Exercisable | 7 years | |
Weighted-Average Remaining Contractual Term (Year), Vested and expected to vest | 7 years 9 months 18 days | |
Options Outstanding, Aggregate Intrinsic Value of Outstanding Options | ||
Aggregate Intrinsic Value of Outstanding Options | $ 545 | $ 12,363 |
Aggregate Intrinsic Value of Outstanding Options, Exercisable | 542 | |
Aggregate Intrinsic Value of Outstanding Options, Vested and expected to vest | $ 545 | |
2015 Plan [Member] | ||
Options Outstanding, Shares Available for Grant | ||
Shares Available for Grant, Awards authorized | 2,095,808 | |
2018 Equity Inducement Plan [Member] | ||
Options Outstanding, Shares Available for Grant | ||
Shares Available for Grant, Awards authorized | 1,500,000 | |
Options Outstanding, Number of Shares Outstanding | ||
Number of Shares Outstanding, Options granted | 0 | |
Number of Shares Outstanding, Ending balance | 0 |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 22, 2017 | Dec. 31, 2016 | |
Income Tax Contingency [Line Items] | ||||
Federal statutory rate | 21.00% | 34.00% | 35.00% | 34.00% |
Decrease of net deferred tax assets | $ 0 | $ 7,200,000 | ||
Deferred tax assets, valuation allowance | 27,317,000 | 15,395,000 | ||
Deferred tax assets, valuation allowance, change in amount | 11,900,000 | (29,000,000) | ||
Operating loss carry forwards | 74,300,000 | |||
Tax credit carry forwards | $ 1,100,000 | |||
Tax credit carry forwards, year begin to expiration | 2,032 | |||
Unrecognized tax benefits, accrued interest and penalties | $ 0 | $ 0 | ||
Domestic Tax Authority [Member] | ||||
Income Tax Contingency [Line Items] | ||||
Operating loss carry forwards | $ 31,400,000 | |||
Tax credit carry forwards, year begin to expiration | 2,037 | |||
Operating loss carry forwards, indefinite life | $ 42,900,000 | |||
State and Local Jurisdiction [Member] | ||||
Income Tax Contingency [Line Items] | ||||
Operating loss carry forwards | $ 56,300,000 | |||
Operating loss carry forwards, expiry year start | 2,022 | |||
Operating loss carry forwards, expiry year end | 2,038 | |||
Foreign Tax Authority [Member] | ||||
Income Tax Contingency [Line Items] | ||||
Tax credit carry forwards | $ 200,000 | |||
Tax credit carry forwards, year begin to expiration | 2,037 | |||
Earliest Tax Year [Member] | ||||
Income Tax Contingency [Line Items] | ||||
Open tax year | 2,015 | |||
Latest Tax Year [Member] | ||||
Income Tax Contingency [Line Items] | ||||
Open tax year | 2,017 |
Income Taxes - Schedule of Geog
Income Taxes - Schedule of Geographical Breakdown of Loss Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Tax Disclosure [Abstract] | |||
United States | $ (54,395) | $ (42,425) | $ (48,244) |
International | 758 | 566 | 520 |
Loss before provision for (benefit from) income taxes, net | $ (53,637) | $ (41,859) | $ (47,724) |
Income Taxes - Components of Pr
Income Taxes - Components of Provision for (Benefit from) Income Taxes (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Current tax provision (benefit): | |||
Federal | $ 0 | $ 0 | $ 0 |
State | 0 | 0 | 0 |
Foreign | (180) | 183 | 170 |
Total current tax provision (benefit) | (180) | 183 | 170 |
Deferred tax provision (benefit): | |||
Foreign | (122) | (27) | (27) |
Total deferred tax provision (benefit) | (122) | (27) | (27) |
Total provision for (benefit from) income taxes | $ (302) | $ 156 | $ 143 |
Income Taxes - Reconciliation B
Income Taxes - Reconciliation Between Income Taxes Computed at the Federal Statutory Income Tax Rate and the Provision for Income Taxes (Detail) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 22, 2017 | Dec. 31, 2016 | |
Income Tax Disclosure [Abstract] | ||||
Federal statutory rate | 21.00% | 34.00% | 35.00% | 34.00% |
Change in valuation allowance | (22.20%) | 69.50% | (33.50%) | |
Federal Tax Credit | 2.40% | (0.90%) | 1.60% | |
State income tax benefit, net of federal benefit | 0.30% | 0.10% | 0.10% | |
Effect of ownership change on deferred tax assets | (84.80%) | |||
US tax reform deferred impact on tax rate change | (17.30%) | |||
Other permanent items | (1.00%) | (1.00%) | (2.50%) | |
Total provision for (benefit from) income taxes | 0.50% | (0.40%) | (0.30%) |
Income Taxes - Components of De
Income Taxes - Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Deferred tax assets: | ||
Net operating loss carryforwards | $ 18,347 | $ 9,183 |
Stock based compensation | 3,642 | 2,444 |
License fee | 2,008 | 1,346 |
59 (e) expenditures and amortization | 1,435 | 1,435 |
Research and development credits | 1,137 | 365 |
Other | 972 | 698 |
Gross deferred tax assets | 27,541 | 15,471 |
Valuation allowance | (27,317) | (15,395) |
Total deferred tax assets | 224 | 76 |
Deferred tax liabilities: | ||
Other | 39 | 13 |
Total deferred tax liabilities | 39 | 13 |
Total net deferred tax assets | $ 185 | $ 63 |
Income Taxes - Unrecognized Tax
Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Tax Disclosure [Abstract] | |||
Beginning balance | $ 43 | $ 311 | $ 232 |
Increases based on tax positions related to prior years | 109 | ||
Decreases based on tax positions related to prior years | (79) | ||
Decreases due to ownership change | (232) | ||
Increases based on tax positions in current year | 112 | 43 | 79 |
Settlement | 0 | 0 | 0 |
Lapse of statute of limitations | 0 | 0 | 0 |
Ending balance | $ 264 | $ 43 | $ 311 |
Restructuring Costs - Summary o
Restructuring Costs - Summary of Restructuring Activities (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Restructuring Cost and Reserve [Line Items] | |||
Beginning balance | $ 137 | ||
Non-cash charges | $ (811) | ||
Ending balance | 33 | $ 137 | |
PNT2258 [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Beginning balance | 137 | 763 | |
Adjustments to research and development expense | (99) | (69) | |
Non-cash charges | (811) | ||
Cash payments | (5) | (557) | (1,142) |
Ending balance | 33 | 137 | 763 |
PNT2258 [Member] | Contract Termination [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Beginning balance | 137 | 664 | |
Adjustments to research and development expense | (99) | (69) | |
Non-cash charges | (681) | ||
Cash payments | (5) | (458) | (909) |
Ending balance | $ 33 | 137 | 664 |
PNT2258 [Member] | Employee Termination [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Beginning balance | 99 | ||
Cash payments | $ (99) | (233) | |
Ending balance | 99 | ||
PNT2258 [Member] | Asset Impairment [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Non-cash charges | (130) | ||
Research and development [Member] | PNT2258 [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | 2,249 | ||
Research and development [Member] | PNT2258 [Member] | Contract Termination [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | 2,249 | ||
General and administrative [Member] | PNT2258 [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | 467 | ||
General and administrative [Member] | PNT2258 [Member] | Contract Termination [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | 5 | ||
General and administrative [Member] | PNT2258 [Member] | Employee Termination [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | 332 | ||
General and administrative [Member] | PNT2258 [Member] | Asset Impairment [Member] | |||
Restructuring Cost and Reserve [Line Items] | |||
Restructuring cost | $ 130 |
Selected Quarterly Financial _3
Selected Quarterly Financial Data - Summary of Selected Unaudited Consolidated Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Quarterly Financial Information Disclosure [Abstract] | |||||||||||
Operating expenses | $ 14,649 | $ 16,051 | $ 12,963 | $ 11,754 | $ 10,805 | $ 10,183 | $ 10,477 | $ 11,154 | $ 55,417 | $ 42,619 | $ 48,075 |
Net loss | $ (14,283) | $ (15,567) | $ (11,960) | $ (11,525) | $ (10,599) | $ (9,995) | $ (10,329) | $ (11,092) | $ (53,335) | $ (42,015) | $ (47,867) |
Basic and diluted net loss per share | $ (0.19) | $ (0.21) | $ (0.16) | $ (0.19) | $ (0.20) | $ (0.19) | $ (0.20) | $ (0.26) | $ (0.75) | $ (0.84) | $ (1.58) |