Document and Entity Information
Document and Entity Information - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Feb. 15, 2018 | Jun. 30, 2017 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2017 | ||
Document Fiscal Year Focus | 2,017 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | SAGE | ||
Entity Registrant Name | Sage Therapeutics, Inc. | ||
Entity Central Index Key | 1,597,553 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Current Reporting Status | Yes | ||
Entity Voluntary Filers | No | ||
Entity Filer Category | Large Accelerated Filer | ||
Entity Common Stock, Shares Outstanding | 45,777,940 | ||
Entity Public Float | $ 2,730,487,424 |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) | Dec. 31, 2017 | Dec. 31, 2016 |
Current assets: | ||
Cash and cash equivalents | $ 306,235,000 | $ 168,517,000 |
Marketable securities | 212,613,000 | 228,962,000 |
Prepaid expenses and other current assets | 6,227,000 | 5,100,000 |
Total current assets | 525,075,000 | 402,579,000 |
Property and equipment, net | 4,013,000 | 1,388,000 |
Restricted cash | 849,000 | 564,000 |
Total assets | 529,937,000 | 404,531,000 |
Current liabilities: | ||
Accounts payable | 9,350,000 | 12,817,000 |
Accrued expenses | 42,601,000 | 22,352,000 |
Total current liabilities | 51,951,000 | 35,169,000 |
Other liabilities | 2,511,000 | 845,000 |
Total liabilities | 54,462,000 | 36,014,000 |
Commitments and contingencies (Note 5) | ||
Stockholders’ equity: | ||
Preferred stock, $0.0001 par value per share; 5,000,000 shares authorized at December 31, 2017 and 2016; no shares issued or outstanding at December 31, 2017 and 2016 | ||
Common stock, $0.0001 par value per share; 120,000,000 shares authorized at December 31, 2017 and 2016; 42,003,894 and 37,222,518 shares issued at December 31, 2017 and 2016, respectively; 42,002,934 and 37,222,172 shares outstanding at December 31, 2017 and 2016, respectively | 5,000 | 4,000 |
Treasury stock, at cost, 960 and 346 shares at December 31, 2017 and 2016, respectively | (113,000) | (17,000) |
Additional paid-in capital | 1,066,059,000 | 688,959,000 |
Accumulated deficit | (590,447,000) | (320,327,000) |
Accumulated other comprehensive loss | (29,000) | (102,000) |
Total stockholders’ equity | 475,475,000 | 368,517,000 |
Total liabilities and stockholders’ equity | $ 529,937,000 | $ 404,531,000 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2017 | Dec. 31, 2016 |
Statement Of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.0001 | $ 0.0001 |
Preferred stock, shares authorized | 5,000,000 | 5,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value | $ 0.0001 | $ 0.0001 |
Common stock, shares authorized | 120,000,000 | 120,000,000 |
Common stock, shares issued | 42,003,894 | 37,222,518 |
Common stock, shares outstanding | 42,002,934 | 37,222,172 |
Treasury stock, shares | 960 | 346 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Operating expenses: | |||
Research and development | $ 210,277 | $ 120,756 | $ 69,357 |
General and administrative | 62,878 | 39,407 | 25,293 |
Total operating expenses | 273,155 | 160,163 | 94,650 |
Loss from operations | (273,155) | (160,163) | (94,650) |
Interest income, net | 3,099 | 1,211 | 178 |
Other expense, net | (64) | (35) | (23) |
Net loss | $ (270,120) | $ (158,987) | $ (94,495) |
Net loss per share—basic and diluted | $ (7.09) | $ (4.75) | $ (3.40) |
Weighted average number of common shares outstanding—basic and diluted | 38,113,678 | 33,492,795 | 27,778,288 |
Comprehensive loss: | |||
Net loss | $ (270,120) | $ (158,987) | $ (94,495) |
Other comprehensive items: | |||
Unrealized gain (loss) on marketable securities | 73 | (102) | |
Total other comprehensive gain (loss) | 73 | (102) | |
Total comprehensive loss | $ (270,047) | $ (159,089) | $ (94,495) |
Consolidated Statements of Chan
Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock [Member] | Treasury Stock [Member] | Additional Paid-in Capital [Member] | Accumulated other comprehensive income (loss) [Member] | Accumulated Deficit [Member] |
Balances at Dec. 31, 2014 | $ 121,885 | $ 3 | $ 188,727 | $ (66,845) | ||
Balances, Shares at Dec. 31, 2014 | 25,621,791 | |||||
Issuance of common stock from exercise of stock options, Amount | 603 | 603 | ||||
Issuance of common stock from exercise of stock options, Shares | 417,475 | |||||
Vesting of restricted stock, Amount | 17 | 17 | ||||
Vesting of restricted stock, Shares | 128,051 | |||||
Issuance of common stock under employee stock purchase plan | 127 | 127 | ||||
Issuance of common stock under employee stock purchase plan, Shares | 3,852 | |||||
Issuance of common stock in payment of consultant fees, Amount | 1,211 | 1,211 | ||||
Issuance of common stock in payment of consultant fees, Shares | 23,809 | |||||
Stock-based compensation expense | 15,176 | 15,176 | ||||
Public offering of common stock, net of offering costs, Amount | 129,171 | 129,171 | ||||
Public offering of common stock, net of offering costs, Shares | 2,628,571 | |||||
Net loss | (94,495) | (94,495) | ||||
Balances at Dec. 31, 2015 | 173,695 | $ 3 | 335,032 | (161,340) | ||
Balances, Shares at Dec. 31, 2015 | 28,823,549 | |||||
Issuance of common stock from exercise of stock options, Amount | 1,011 | 1,011 | ||||
Issuance of common stock from exercise of stock options, Shares | 124,557 | |||||
Vesting of restricted stock, Amount | 11 | 11 | ||||
Vesting of restricted stock, Shares | 42,781 | |||||
Issuance of common stock under employee stock purchase plan | 510 | 510 | ||||
Issuance of common stock under employee stock purchase plan, Shares | 10,499 | |||||
Purchase of treasury stock, Amount | $ (17) | $ (17) | ||||
Purchase of treasury stock, Shares | 346 | 346 | ||||
Stock-based compensation expense | $ 22,855 | 22,855 | ||||
Public offering of common stock, net of offering costs, Amount | 329,541 | $ 1 | 329,540 | |||
Public offering of common stock, net of offering costs, Shares | 8,220,786 | |||||
Unrealized gain (loss) on available-for-sale securities | (102) | $ (102) | ||||
Net loss | (158,987) | (158,987) | ||||
Balances at Dec. 31, 2016 | 368,517 | $ 4 | $ (17) | 688,959 | (102) | (320,327) |
Balances, Shares at Dec. 31, 2016 | 37,222,172 | 346 | ||||
Issuance of common stock from exercise of stock options, Amount | 15,437 | $ 1 | 15,436 | |||
Issuance of common stock from exercise of stock options, Shares | 706,222 | |||||
Issuance of common stock under employee stock purchase plan | 771 | 771 | ||||
Issuance of common stock under employee stock purchase plan, Shares | 15,718 | |||||
Purchase of treasury stock, Amount | $ (96) | $ (96) | ||||
Purchase of treasury stock, Shares | 614 | 614 | ||||
Stock-based compensation expense | $ 35,142 | 35,142 | ||||
Public offering of common stock, net of offering costs, Amount | 325,751 | 325,751 | ||||
Public offering of common stock, net of offering costs, Shares | 4,058,822 | |||||
Unrealized gain (loss) on available-for-sale securities | 73 | 73 | ||||
Net loss | (270,120) | (270,120) | ||||
Balances at Dec. 31, 2017 | $ 475,475 | $ 5 | $ (113) | $ 1,066,059 | $ (29) | $ (590,447) |
Balances, Shares at Dec. 31, 2017 | 42,002,934 | 960 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Cash flows from operating activities | |||
Net loss | $ (270,120) | $ (158,987) | $ (94,495) |
Adjustments to reconcile net loss to net cash used in operating activities: | |||
Stock-based compensation expense | 35,534 | 23,020 | 15,240 |
Non-cash licensing and consulting fees | 1,211 | ||
Premium on marketable securities | (105) | (756) | |
Amortization of premium (discount) on marketable securities | (293) | 286 | |
Depreciation | 531 | 281 | 115 |
Changes in operating assets and liabilities: | |||
Prepaid expenses and other current assets | (1,127) | (3,362) | (681) |
Accounts payable | (3,693) | 7,796 | 2,590 |
Accrued expenses and other liabilities | 19,996 | 13,044 | 5,339 |
Net cash used in operating activities | (219,277) | (118,678) | (70,681) |
Cash flows from investing activities | |||
Proceeds from sales and maturities of marketable securities | 261,225 | 30,499 | |
Purchases of marketable securities | (244,403) | (259,093) | |
Purchases of property and equipment | (1,360) | (1,421) | (198) |
Increase in restricted cash | (285) | (525) | |
Net cash provided by (used in) investing activities | 15,177 | (230,540) | (198) |
Cash flows from financing activities | |||
Proceeds from stock option exercises and employee stock purchase plan issuances | 15,972 | 1,406 | 730 |
Payments of offering costs | (179) | (599) | (584) |
Proceeds from public offerings of common stock, net of commissions and underwriting discounts | 326,025 | 330,175 | 129,720 |
Net cash provided by financing activities | 341,818 | 330,982 | 129,866 |
Net increase (decrease) in cash and cash equivalents | 137,718 | (18,236) | 58,987 |
Cash and cash equivalents at beginning of period | 168,517 | 186,753 | 127,766 |
Cash and cash equivalents at end of period | 306,235 | 168,517 | 186,753 |
Supplemental disclosure of non-cash financing activities | |||
Purchases of property and equipment financed with landlord tenant incentive | 1,665 | ||
Purchases of property and equipment included in accounts payable | 138 | $ 8 | |
Public offering costs included in accounts payable or accrued expenses | $ 95 | $ 165 |
Nature of the Business
Nature of the Business | 12 Months Ended |
Dec. 31, 2017 | |
Organization Consolidation And Presentation Of Financial Statements [Abstract] | |
Nature of the Business | 1. Nature of the Business Sage Therapeutics, Inc. (“Sage” or the “Company”) is a clinical-stage biopharmaceutical company committed to developing and commercializing novel medicines to treat life-altering central nervous system, or CNS, disorders, where there are no approved therapies or existing therapies are inadequate. The Company has a portfolio of product candidates with a current focus on modulating two critical CNS receptor systems, GABA and NMDA. The GABA receptor family, which is recognized as the major inhibitory neurotransmitter in the CNS, mediates downstream neurologic and bodily function via activation of GABA A The Company was incorporated under the laws of the State of Delaware on April 16, 2010, and commenced operations on January 19, 2011 as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc. The Company is subject to risks and uncertainties common to companies in the biotech industry, including, but not limited to, the risks associated with developing product candidates at each stage of non-clinical and clinical development; the challenges associated with gaining regulatory approval of such product candidates; the risks associated with commercializing pharmaceutical products, if approved for marketing and sale; the potential for development by third parties of new technological innovations that may compete with the Company’s products; the dependence on key personnel; the challenges of protecting proprietary technology; the need to comply with government regulations; the high costs of drug development; and the uncertainty of being able to secure additional capital when needed to fund operations. Under Accounting Standards Update, or ASU, 2014-15, Presentation of Financial Statements—Going Concern The Company has incurred losses and negative cash flows from operations since its inception. As of December 31, 2017, the Company had an accumulated deficit of $590.4 million. From its inception through December 31, 2017, the Company received net proceeds of $969.0 million from the sales of redeemable convertible preferred stock, the issuance of convertible notes, and the sales of common stock in its initial public offering (“IPO”) in July 2014 and follow-on public offerings in April 2015, January 2016, September 2016 and November 2017. In February 2018, the Company received net proceeds of $631.1 million from the sale of common stock (see Note 13). Until such time, if ever, as the Company can generate substantial product revenue and achieve profitability, the Company expects to finance its cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements and other sources of funding. If the Company is unable to raise additional funds through equity or debt financings when needed, the Company may be required to delay, limit, reduce or terminate product development or future commercialization efforts or grant rights to develop and market products or product candidates that the Company would otherwise prefer to develop and market itself. The Company expects that, based on its current operating plans, the Company’s existing cash, cash equivalents and marketable securities will be sufficient to fund its current planned operations for at least the next twelve months from the issuance of these consolidated financial statements. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies The following is a summary of significant accounting policies followed in the preparation of these financial statements. Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2017, cash equivalents were comprised of money market funds and overnight reverse repurchase agreements. As of December 31, 2016, cash equivalents were comprised of money market funds. Marketable securities Marketable securities consist of investments with original maturities greater than 90 days. The Company considers its investment portfolio of investments to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as a component of accumulated other comprehensive items in stockholders’ equity. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other expense, net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers several factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. No declines in value were deemed to be other than temporary during the year ended December 31, 2017. Restricted Cash A deposit of $39,000 was restricted from withdrawal as of December 31, 2017 and 2016. The restriction is related to securing the lease for the initial facility of the Company and the restriction expires in 2024, in accordance with the most recent amendment to the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. For this same facility, a deposit of $0.3 million was restricted from withdrawal as of December 31, 2017. The restriction is related to securing an amendment to the lease of the initial facility of the Company and the restriction expires in 2024, in accordance with the most recent amendment to the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. A deposit of $0.5 million was restricted from withdrawal as of December 31, 2017 and 2016. The restriction is related to securing the separate facility lease in May 2016 that will expire on February 28, 2022, under which, beginning on September 1, 2016, the Company rents 19,805 square feet of additional office space in a separate multi-tenant building. The restriction expires in 2022, in accordance with the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to income. Repairs and maintenance costs are expensed as incurred. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Research and Development Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the United States. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Patent Costs The Company expenses patent costs as incurred and classifies such costs as general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss. Stock-Based Compensation The Company recognizes compensation expense for stock-based awards, including grants of stock options and restricted stock, made to employees and nonemployee directors based on the estimated fair value on the date of grant, over the requisite service period. The Company recognizes compensation expense for stock-based awards granted to non-employee consultants based on the fair value of the award on each date on which the awards vest. Compensation expense is recognized over the vesting period, provided that services are rendered by such non-employee consultants during that time. At the end of each financial reporting period, the fair value of unvested options is re-measured using the then-current fair value of our common stock and updated assumptions in the Black-Scholes option-pricing model; and the fair value of restricted stock awards is re-measured using the then-current fair value of our common stock. For awards that vest upon achievement of a performance condition, the Company recognizes compensation expense when achievement of the performance condition is met or during the period from which meeting the condition is deemed probable until the expected date of meeting the performance condition. The fair value of each option grant is estimated using the Black-Scholes option-pricing model. Through December 31, 2015, the Company lacked sufficient Company-specific historical and implied volatility information, and as a result, the Company used the volatility of a group of publicly-traded peer companies in the Black-Scholes calculations. Beginning in 2016, the Company estimated its expected volatility using a weighted average of the historical volatility of publicly-traded peer companies and the volatility of its common stock, and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its traded stock price for the duration of the expected term. The expected term of the Company’s options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options, while the expected term of its options granted to consultants and nonemployees has been determined based on the contractual term of the options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The Company also applies a forfeiture rate in order to calculate stock-based compensation expense. Expected forfeitures are based on the historical experience of the Company and management’s expectations of future forfeitures. To the extent actual forfeitures differ from the estimates, the difference is recorded as a cumulative adjustment in the period in which the estimates are revised. The Company recognizes stock-based compensation expense for only the portion of awards that are expected to vest. Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares received from an employee as consideration for exercises of stock options. Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the diluted net loss by the weighted average number of common shares outstanding for the period, including potentially-dilutive common shares, by assuming the dilutive effect of outstanding stock options and unvested restricted stock, as determined using the treasury stock method. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2017, 2016 and 2015. Risks and Uncertainties The product candidates developed by the Company require approvals from the U.S. Food and Drug Administration or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed, it may have a material adverse impact on the Company’s business and its financial statements. Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. The Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs. Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2017 and 2016 were carried at fair value, determined according to the fair value hierarchy; see Footnote 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2017 and 2016, respectively. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is on advancing medicines to treat central nervous system disorders, where there are inadequate or no approved existing therapies. All tangible assets are held within the United States. Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2017 and 2016, the difference between net loss and comprehensive loss was the unrealized gain (loss) on marketable securities. For the year ended December 31, 2015, there was no difference between net loss and comprehensive loss. Public Offerings On July 23, 2014, the Company completed the sale of 5,750,000 shares of its common stock in its IPO at a price to the public of $18.00 per share, resulting in net proceeds to the Company of $94.0 million after deducting underwriting discounts and commissions and offering costs paid by the Company. The shares began trading on the Nasdaq Global Market on July 18, 2014. On April 20, 2015, the Company completed the sale of 2,628,571 shares of its common stock at a price to the public of $52.50 per share, resulting in net proceeds to the Company of $129.1 million after deducting underwriting discounts and commissions and offering costs paid by the Company. On January 12, 2016, the Company completed the sale of 3,157,894 shares of its common stock at a price to the public of $47.50 per share, resulting in net proceeds to the Company of $140.4 million after deducting underwriting discounts and commissions and offering costs paid by the Company. On September 14, 2016, the Company completed the sale of 5,062,892 shares of its common stock at a price to the public of $39.75 per share, resulting in net proceeds to the Company of $189.2 million after deducting underwriting discounts and commissions paid by the Company. On November 17, 2017, the Company completed the sale of 4,058,822 shares of its common stock at a price to the public of $85.00 per share, resulting in net proceeds to the Company of $325.8 million after deducting underwriting discounts and commissions and offering costs paid by the Company. Also see Note 13, “Subsequent Event”. Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers The FASB has continued to issue accounting standards updates to clarify and provide implementation guidance related to Revenue from Contracts with Customers, including ASU 2016-08 , Revenue from Contract with Customers: Principal versus Agent Considerations , ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing , and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. These amendments In February 2016, the FASB issued ASU No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . The standard The standard will be effective . In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash For the years ended December 31, 2017 and 2016, our restricted cash and restricted cash equivalents were not significant. The Company currently does not expect this guidance to have a significant impact on its consolidated financial statements and related disclosures In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718) — Scope of Modification Accounting currently does not expect this guidance to have a significant impact on its consolidated financial statements and related disclosures Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. |
Fair Value Measurements
Fair Value Measurements | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Fair Value Measurements | 3. Fair Value Measurements The Company’s cash equivalents are classified within Level 1 of the fair value hierarchy. The Company’s investments in marketable securities are classified within Level 2 of the fair value hierarchy. The fair values of the Company’s marketable securities are based on prices obtained from independent pricing sources. Consistent with the fair value hierarchy described above, securities with validated quotes from pricing services are reflected within Level 2, as they are primarily based on observable pricing for similar assets or other market observable inputs. Typical inputs used by these pricing services include, but are not limited to, reported trades, benchmark yields, issuer spreads, bids, offers or estimates of cash flow, prepayment spreads and default rates. The following tables summarize the Company’s money market funds and marketable securities as of December 31, 2017 and 2016: December 31, 2017 Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Cash equivalents: Cash equivalents $ 306,235 $ 306,235 $ — $ — Total cash equivalents 306,235 306,235 — — Marketable securities: U.S. government securities 49,606 — 49,606 — U.S. corporate bonds 48,959 — 48,959 — U.S. commercial paper 65,583 — 65,583 — International commercial paper 48,465 — 48,465 — Total marketable securities 212,613 — 212,613 — Total cash equivalents and marketable securities $ 518,848 $ 306,235 $ 212,613 $ — December 31, 2016 Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Cash equivalents: Cash equivalents $ 168,517 $ 168,517 $ — $ — Total cash equivalents 168,517 168,517 — — Marketable securities: U.S. government securities 100,031 — 100,031 — U.S. corporate bonds 58,452 — 58,452 — International corporate bonds 24,190 — 24,190 — U.S. commercial paper 30,351 — 30,351 — International commercial paper 15,938 — 15,938 — Total marketable securities 228,962 — 228,962 — Total cash equivalents and marketable securities $ 397,479 $ 168,517 $ 228,962 $ — During the years ended December 31, 2017 and 2016, there were no transfers among the Level 1, Level 2 and Level 3 categories. Marketable Securities The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2017 and 2016: December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Assets: U.S. government securities $ 49,612 $ — $ (6 ) $ 49,606 U.S. corporate bonds 48,982 2 (25 ) 48,959 U.S. commercial paper 65,583 — — 65,583 International commercial paper 48,465 — — 48,465 $ 212,642 $ 2 $ (31 ) $ 212,613 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Assets: U.S. government securities $ 100,055 $ 2 $ (26 ) $ 100,031 U.S. corporate bonds 58,508 — (56 ) 58,452 International corporate bonds 24,212 — (22 ) 24,190 U.S. commercial paper 30,351 — — 30,351 International commercial paper 15,938 — — 15,938 $ 229,064 $ 2 $ (104 ) $ 228,962 As of December 31, 2017, all marketable securities held by the Company had remaining contractual maturities of one year or less. As of December 31, 2017 and 2016, the Company held 11 and 27 marketable securities, respectively, that were in a loss position for less than one year due to fluctuations in interest rates. There have been no impairments of the Company’s assets measured and carried at fair value during the years ended December 31, 2017 and 2016. |
Balance Sheet Components
Balance Sheet Components | 12 Months Ended |
Dec. 31, 2017 | |
Balance Sheet Related Disclosures [Abstract] | |
Balance Sheet Components | 4. Balance Sheet Components Property and Equipment, net Property and equipment, net consists of the following: December 31, 2017 2016 (in thousands) Computer hardware and software $ 1,090 $ 708 Furniture and equipment 1,029 695 Leasehold improvements 2,967 527 5,086 1,930 Less: Accumulated depreciation (1,073 ) (542 ) $ 4,013 $ 1,388 Depreciation expense for the years ended December 31, 2017, 2016 and 2015 was $0.5 million, $0.3 million and $0.1 million, respectively. The useful life for computer hardware and software is 3 years, furniture and equipment is 5 years and leasehold improvements is the lesser of the useful life or the term of the respective lease. Accrued Expenses Accrued expenses consist of the following: December 31, 2017 2016 (in thousands) Development costs $ 23,473 $ 14,541 Employee-related expenses 15,838 5,948 Professional services 3,166 1,751 Other accrued expenses 124 112 $ 42,601 $ 22,352 |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2017 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 5. Commitments and Contingencies Operating Leases In May 2017, the Company entered into the Sixth Amendment to the Lease (“the Sixth Amendment”) to increase the amount of square feet of office space that the Company leases in a multi-tenant building. Prior to entering the Sixth Amendment, the Company rented 22,067 square feet of office space in this multi-tenant building under an operating lease that was scheduled to expire on February 28, 2022. The Sixth Amendment increased the amount of leased space at this location by 32,876 square feet, with the additional space consisting of (i) 8,200 square feet beginning on August 15, 2017, and (ii) 24,676 square feet beginning on January 1, 2018. The lease for this additional space will expire no later than August 15, 2024. Additionally, the term of the existing lease has been extended from March 1, 2022 until the expiration date of the Sixth Amendment on August 15, 2024. In May 2016, the Company entered into a separate lease that will expire on February 28, 2022, under which, beginning on September 1, 2016, the Company rents 19,805 square feet of additional office space in a separate multi-tenant building. Rent expense, net of sublease income, for the years ended December 31, 2017, 2016 and 2015, was $3.7 million, $2.0 million, and $0.4 million, respectively. Future minimum lease payments under non-cancelable operating leases are as follows at December 31, 2017: Years Ending December 31, (in thousands) 2018 $ 4,444 2019 4,537 2020 4,632 2021 4,728 2022 3,485 Thereafter 5,450 $ 27,276 License Agreements CyDex License Agreement In September 2015, the Company and CyDex Pharmaceuticals, Inc. (“CyDex”) amended and restated their existing commercial license agreement. Under the terms of the commercial license agreement as amended and restated, CyDex has granted to the Company an exclusive license to CyDex’s Captisol drug formulation technology and related intellectual property for the manufacture of pharmaceutical products incorporating the Company’s compounds known as brexanolone and SAGE-689, and the development and commercialization of the resulting products in the treatment, prevention or diagnosis of any disease or symptom in humans or animals other than (i) the ocular treatment of any disease or condition with a formulation, including a hormone; (ii) topical ocular treatment of inflammatory conditions; (iii) treatment and prophylaxis of fungal infections in humans; and (iv) any ocular treatment for retinal degeneration. As consideration for the inclusion of SAGE-689 in the license granted by CyDex, the Company paid to CyDex $0.1 million, which was recorded as research and development expense for the year ended December 31, 2015 in connection with the execution of the amended and restated license agreement. The Company is obligated to make milestone payments under the amended and restated license agreement with CyDex based on the achievement of clinical development and regulatory milestones in the amount of up to $0.8 million in clinical milestones and up to $3.8 million in regulatory milestones for each of the first two fields with respect to brexanolone; up to $1.3 million in clinical milestones and up to $8.5 million in regulatory milestones for each of the third and fourth fields with respect to brexanolone; and up to $0.8 million in clinical milestones and up to $1.8 million in regulatory milestones for one field with respect to SAGE-689. For the year ended December 31, 2015, additional clinical development milestones were met for the brexanolone program under the license agreement with CyDex, and accordingly, the Company recorded research and development expense and made cash payments totaling $0.8 million. For the year ended December 31, 2016, additional clinical development milestones were met for the brexanolone program under the license agreement with CyDex, and accordingly, the Company recorded research and development expense and made cash payments totaling $0.8 million. For the year ended December 31, 2017, the Company did not record any expense or make any milestone payments related to clinical development milestones for the brexanolone program under the license agreement with CyDex. University of California License Agreements In October 2013, the Company entered into a non-exclusive license agreement with The Regents of the University of California under which the Company was granted a non-exclusive license to certain clinical data and clinical material for use in the development and commercialization of biopharmaceutical products in the licensed field, including status epilepticus and postpartum depression. In May 2014, the license agreement was amended to add the treatment of essential tremor to the licensed field of use, materials and milestone fee provisions of the agreement. As of December 31, 2015, the Company paid to The Regents of the University of California clinical development milestones of $0.1 million and will be required to pay royalties of less than 1% on net sales for a period of fifteen years following the sale of the first product developed using the data and materials. The license will terminate on the earlier to occur of (i) 27 years after the effective date or (ii) 15 years after the last-derived product is first commercially sold. For the years ended December 31, 2013 and 2014, the Company did not record any expense or make any milestone or royalty payments under the license agreement with the University of California. In June 2015, the Company entered into an exclusive license agreement with The Regents of the University of California whereby the Company was granted an exclusive license to certain patent rights related to the use of allopregnanolone to treat various diseases. In exchange for such license, the Company paid an upfront payment of $50,000 and will make payments of $15,000 for annual maintenance fees until the calendar year following the first sale, if any, of a licensed product. The Company is obligated to make milestone payments following the achievement of specified regulatory and sales milestones of up to $0.7 million and $2.0 million in the aggregate, respectively, of which none have been paid to date. Following the first sale, if any, of a licensed product, the Company is obligated to pay royalties at a low single digit percentage of net sales, if any, of licensed products, subject to specified minimum annual royalty amounts. Unless terminated by operation of law or by acts of the parties under the terms of the agreement, the license agreement will terminate when the last-to-expire patents or last-to-be abandoned patent applications expire, whichever is later. For the year ended December 31, 2015, three clinical development milestones were met, and accordingly, the Company recorded research and development expenses and made cash payments totaling $0.1 million. For the years ended December 31, 2017 and 2016, the Company did not record any expense or make any milestone or royalty payments under either license agreement with The Regents of the University of California. Washington University License Agreement In November 2013, the Company entered into a license agreement with Washington University whereby the Company was granted exclusive, worldwide rights to develop and commercialize a novel set of neuroactive steroids developed by Washington University. In exchange for development and commercialization rights, the Company paid an upfront, non-refundable payment of $50,000 and is required to pay an annual license maintenance fee of $15,000 on each subsequent anniversary date, until the first Phase 2 clinical trial for a licensed product is initiated. The Company is obligated to make milestone payments to Washington University based on achievement of clinical development and regulatory milestones of up to $0.7 million and $0.5 million, respectively. Additionally, the Company fulfilled its obligation to issue to Washington University 47,619 shares of common stock on December 13, 2013. The fair value of these shares of $0.1 million was recorded as research and development expense in 2013. The Company is obligated to pay royalties to Washington University at rates in the low single digits on net sales of licensed products covered under patent rights and royalties at rates in the low single digits on net sales of licensed products not covered under patent rights. Additionally, the Company has the right to sublicense and is required to make payments at varying percentages of sublicensing revenue received, initially in the mid-teens and descending to the mid-single digits over time. For the year ended December 31, 2015, a regulatory milestone was met for one of the programs under the license agreement with Washington University, and accordingly, the Company recorded research and development expenses and made a cash payment of $50,000. For the years ended December 31, 2017 and 2016, the Company did not record any expense or make any milestone payments under the license agreement with Washington University. Consulting Agreement In January 2014, the Company entered into a consulting agreement with a non-employee advisor whereby the Company is obligated to make cash payments of up to $2.0 million and to issue up to 126,984 shares of common stock upon attainment of certain clinical development and regulatory milestones. During the year ended December 31, 2014, the first clinical development milestones for each of two programs included in the consulting agreement were met. Accordingly, the Company recorded research and development expense for the year ended December 31, 2014 of $0.2 million, comprised of $50,000 in cash and $0.1 million related to the issuance of 15,872 shares of the Company’s common stock, related to the achievement of these milestones. During the year ended December 31, 2015, the second and third clinical development milestones for one of the programs included in the consulting agreement were met. Accordingly, the Company recorded research and development expense for the year ended December 31, 2015 of $1.7 million, comprised of $0.5 million in cash and $1.2 million related to the issuance of 23,809 shares of the Company’s common stock, related to the achievement of these milestones. For the years ended December 31, 2017 and 2016, the Company did not record any expense or make any milestone payments under the consulting agreement with the non-employee advisor. |
Preferred Stock
Preferred Stock | 12 Months Ended |
Dec. 31, 2017 | |
Equity [Abstract] | |
Preferred Stock | 6. Preferred Stock The Board of Directors of the Company is authorized, without action by the stockholders, to designate and issue up to an aggregate of 5,000,000 shares of preferred stock in one or more series. The Board of Directors of the Company can designate the rights, preferences and privileges of the shares of each series and any of its qualifications, limitations or restrictions. The Board of Directors of the Company may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of common stock. As of December 31, 2017 and 2016, the Company had no shares of preferred stock issued or outstanding. The preferred stock was classified under stockholders’ equity as of December 31, 2017 and 2016. |
Common Stock
Common Stock | 12 Months Ended |
Dec. 31, 2017 | |
Text Block [Abstract] | |
Common Stock | 7. Common Stock As of December 31, 2017 and 2016, the Company authorized 120,000,000 shares of common stock with a par value of $0.0001 per share. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive dividends, as may be declared by the Board of Directors, if any. As of December 31, 2017 and 2016, no dividends have been declared. During the year ended December 31, 2017, the Company received 614 shares of the Company’s common stock from an employee as proceeds for an exercise of stock options. The total cost of shares held in treasury at December 31, 2017 was $113,000. During the year ended December 31, 2016, the Company received 346 shares of the Company’s common stock from an employee as proceeds for an exercise of stock options. The total cost of shares held in treasury at December 31, 2016 was $17,000. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Stock-Based Compensation | 8. Stock-Based Compensation Restricted Stock Units During the year ended December 31, 2017, the Company granted 32,500 restricted stock units to employees of the Company. The Company did not grant restricted stock units prior to January 1, 2017. During the year ended December 31, 2017, the Company recorded $0.6 million of stock-based compensation expense related to its restricted stock units. These restricted stock units vest ratably over two years, with cliff vesting of 50% at both the one-year and two-year anniversary of the grant, which will be in February 2018 and February 2019, respectively. The table below summarizes activity relating to restricted stock: Shares Outstanding as of December 31, 2016 — Granted 32,500 Vested — Forfeited (3,400 ) Outstanding as of December 31, 2017 29,100 Stock Option Plans On July 2, 2014, the stockholders of the Company approved the 2014 Stock Option and Incentive Plan (the “2014 Stock Option Plan”), which became effective upon the completion of the IPO. The 2014 Stock Option Plan provides for the grant of restricted stock awards, restricted stock units, incentive stock options and non-statutory stock options. The 2014 Stock Option Plan replaced the Company’s 2011 Stock Option and Grant Plan (the “2011 Stock Option Plan”). The Company will no longer grant stock options or other awards under the 2011 Stock Option Plan. Any options or awards outstanding under the 2011 Stock Option Plan remained outstanding and effective. As of December 31, 2017, the total number of shares reserved under all equity plans is 7,866,789, and the Company had 2,251,096 shares available for future issuance under such plans. On December 15, 2016, the Board of Directors of the Company approved the 2016 Inducement Equity Plan (the “2016 Stock Option Plan”), for which the initial grants were during the year ended December 31, 2017. The 2016 Stock Option Plan provides for the grant of equity awards to individuals who have not previously been an employee or a non-employee director of the Company to induce them to accept employment and to provide them with a proprietary interest in the Company. The 2014 Stock Option Plan provides for an annual increase, to be added on the first day of each fiscal year, by up to 4% of the Company’s outstanding shares of common stock as of the last day of the prior year. On January 1, 2018, 1,680,117 shares of common stock, representing 4% of the Company’s outstanding shares of common stock as of December 31, 2017, were added to the 2014 Stock Option Plan. Terms of restricted stock awards, restricted stock units, and stock options, including vesting requirements, are determined by the Board of Directors or the Compensation Committee of the Board of Directors, subject to the provisions of the applicable stock option plan. Options granted by the Company, that are not performance-based, generally vest based on the continued service of the grantee with the Company during a specified period following grant. These awards, when granted to employees, generally vest ratably over four years, with a 25% cliff vesting at the one year anniversary. All option awards expire in 10 years. During the years ended December 31, 2017, 2016 and 2015, the Company granted 449,208, 74,039 and 497,100 options, respectively, to employees to purchase shares of common stock that contain performance-based vesting criteria, primarily related to the achievement of certain clinical and regulatory development milestones related to product candidates. Recognition of stock-based compensation expense associated with these performance-based stock options commences when the performance condition is considered probable of achievement, using management’s best estimates, which consider the inherent risk and uncertainty regarding the future outcomes of the milestones. During the year ended December 31, 2015, one milestone was achieved. This milestone represents 35% of the performance-based option grants that were made during the year ended December 31, 2015. During the year ended December 31, 2015, the Company recognized stock-based compensation expense related to this milestone of $4.8 million. During the year ended December 31, 2016, one milestone was achieved. This milestone represents 50% and 30% of the performance-based option grants that were made during the years ended December 31, 2016 and 2015, respectively. During the year ended December 31, 2016, the Company recognized stock-based compensation expense related to this milestone of $5.0 million. During the year ended December 31, 2017, the achievement of the remaining milestones that are the criteria for vesting of performance-based stock options was considered not probable, nor met, and therefore no expense has been recognized related to these awards for the year ended December 31, 2017. Stock-based compensation expense for stock options, restricted stock units and the employee stock purchase plan recognized during the years ended December 31, 2017, 2016 and 2015 was as follows: Year Ended December 31, 2017 2016 2015 (in thousands) Research and development $ 19,893 $ 11,197 $ 5,924 General and administrative 15,641 11,823 9,316 $ 35,534 $ 23,020 $ 15,240 Stock-based compensation expense by award type recognized during the years ended December 31, 2017, 2016 and 2015 was as follows: Year Ended December 31, 2017 2016 2015 (in thousands) Stock options $ 34,525 $ 22,820 $ 14,796 Restricted stock units 617 — — Employee stock purchase plan 392 166 117 Restricted stock awards — 34 327 $ 35,534 $ 23,020 $ 15,240 For stock option awards, the fair value is estimated at the grant date using the Black-Scholes option-pricing model, taking into account the terms and conditions upon which options are granted. The fair value of the options is amortized on a straight-line basis for awards to employees and on a graded basis for awards to non-employees over the requisite service period of the awards. The weighted average grant date fair value per share relating to outstanding stock options granted under the Company’s stock option plans during the years ended December 31, 2017, 2016 and 2015 was $41.94, $24.97 and $34.08, respectively. The fair value of each option granted to employees and nonemployee directors during the years ended December 31, 2017, 2016 and 2015 under the Company’s stock option plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2017 2016 2015 Expected dividend yield 0 % 0 % 0 % Expected volatility 79.89 % 80.15 % 90.54 % Risk-free interest rate 2.03 % 1.47 % 1.59 % Expected life of option 6.03 years 6.05 years 6.03 years Expected dividend yield: the Company has not paid, and does not anticipate paying, any dividends in the foreseeable future. Risk-free interest rate: the Company determined the risk-free interest rate by using a weighted average equivalent to the expected term based on the U.S. Treasury yield curve in effect as of the date of grant. Expected volatility: the Company does not have sufficient history to support a calculation of volatility using only its historical data. Starting in 2016, the Company uses a weighted-average volatility considering the Company’s own volatility since the IPO in July 2014 and the volatilities of a peer group of comparable companies for time periods prior to the IPO. Prior to 2016, the Company used volatilities based on an analysis of reported data for a peer group of comparable companies. Expected term (in years): the expected term represents the period that the Company’s stock option grants are expected to be outstanding. The Company has been publicly-traded since July 2014, and there is not sufficient historical term data to calculate the expected term of the options. Therefore, the Company elected to utilize the “simplified” method to estimate the expected term of options granted to employees. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the option. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. The Company estimates forfeitures based on historical termination behavior. For the years ended December 31, 2017, 2016 and 2015, forfeiture rates of 13.3%, 9.6% and 10.0%, respectively, were applied. For options granted to non-employees, the expected term is 10 years, which is the contractual term of each option. All other assumptions used to calculate the grant date fair value are generally consistent with the assumptions used for options granted to employees. The table below summarizes activity related to stock options: Shares Weighted Average Exercise Price Weighted Average Remaining Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2016 4,231,807 $ 29.99 8.24 $ 92,843 Granted 2,360,933 60.59 Exercised (765,950 ) 20.94 Forfeited (240,197 ) 43.61 Outstanding as of December 31, 2017 5,586,593 $ 43.58 8.09 $ 676,717 Vested and expected to vest as of December 31, 2017 4,504,257 $ 42.22 7.98 $ 551,729 Exercisable as of December 31, 2017 2,045,229 $ 27.95 6.99 $ 279,699 At December 31, 2017, the Company had unrecognized stock-based compensation expense related to its unvested service-based stock option awards of $94.4 million, which is expected to be recognized over the remaining weighted average vesting period of 2.58 years. The total fair value of options vested for the years ended December 31, 2017, 2016 and 2015 was $24.2 million, $24.1 million, and $9.2 million, respectively. At December 31, 2017, 670,637 performance-based stock options were both outstanding and unvested, and the total unrecognized stock-based compensation expense related to those awards was $16.4 million. The intrinsic value of stock options exercised during the years ended December 31, 2017, 2016 and 2015 was $77.7 million, $4.6 million and $28.4 million, respectively. 2014 Employee Stock Purchase Plan On July 2, 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan, which had been previously approved by the Board of Directors. A total of 282,000 shares of common stock were initially authorized for issuance under this plan. The 2014 Employee Stock Purchase Plan became effective upon the completion of the IPO. As of December 31, 2017, 30,069 shares have been issued under this plan. At December 31, 2017, accrued expenses includes $0.3 million of stock-based compensation expense related to an enrollment period for which the related shares had not been issued as of December 31, 2017. |
Net Loss Per Share
Net Loss Per Share | 12 Months Ended |
Dec. 31, 2017 | |
Earnings Per Share [Abstract] | |
Net Loss Per Share | 9. Net Loss Per Share Basic and diluted net loss per share was calculated as follows for the years ended December 31, 2017, 2016 and 2015: Year Ended December 31, 2017 2016 2015 Basic net loss per share: Numerator: Net loss (in thousands) $ (270,120 ) $ (158,987 ) $ (94,495 ) Denominator: Weighted average common stock outstanding—basic 38,113,678 33,492,795 27,778,288 Dilutive effect of shares of common stock equivalents resulting from common stock options and restricted stock units — — — Weighted average common stock outstanding—diluted 38,113,678 33,492,795 27,778,288 Net loss per share—basic and diluted $ (7.09 ) $ (4.75 ) $ (3.40 ) The following common stock equivalents outstanding as of December 31, 2017 and 2016 were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Year Ended December 31, 2017 2016 Stock options 4,915,956 3,985,935 Restricted stock units 29,100 — Employee stock purchase plan 11,683 6,784 4,956,739 3,992,719 Stock options that are outstanding and contain performance-based vesting criteria for which the performance conditions have not been met are excluded from the common stock equivalents outstanding because meeting the performance conditions is not considered probable. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 10. Income Taxes There is no provision for income taxes because the Company has historically incurred operating losses and maintains a full valuation allowance against its net deferred tax assets. The reported amount of income tax expense for the years differs from the amount that would result from applying domestic federal statutory tax rates to pretax losses primarily because of changes in valuation allowance A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2017 2016 2015 Tax due at statutory rate 34.0 % 34.0 % 34.0 % State taxes, net of federal 5.1 4.2 4.0 Stock-based compensation 6.4 (1.0 ) (0.9 ) Foreign rate differential (3.2 ) (3.1 ) (3.1 ) Federal and state credits 7.2 10.3 13.2 Change in valuation allowance (22.5 ) (41.5 ) (43.1 ) Other — — 0.1 Federal and state rate change (24.6 ) — — Research and orphan drug credit addback (2.4 ) (2.9 ) (4.2 ) 0.0 % 0.0 % 0.0 % Significant components of the Company’s net deferred tax asset at December 31, 2017 and 2016 are as follows: December 31, 2017 2016 (in thousands) Net operating losses $ 131,151 $ 84,374 Capitalized start-up costs 1,362 2,155 Accounting method change — (673 ) Tax credit carryforwards 54,523 33,477 Accrued expenses 3,057 2,287 Depreciation and amortization 685 999 Stock options 13,573 12,103 Others 1,090 350 Total net deferred tax asset before valuation allowance 205,441 135,072 Valuation allowance (205,441 ) (135,072 ) Net deferred tax asset $ — $ — As of December 31, 2017, the Company had federal and state net operating loss carryforwards of $482.9 million and $479.9 million, respectively, which begin to expire in 2031. As of December 31, 2017, the Company had federal and state research and development tax credits carryforwards of $12.7 million and $2.3 million, respectively, which begin to expire in 2031 and 2027, respectively. As of December 31, 2017, the Company had federal orphan drug tax credit carry forwards of $40.0 million, which begin to expire in 2034. On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act (“The TCJA). This legislation reduced the U.S. corporate tax rate from the existing rate of 34% to 21% for tax years beginning after December 31, 2017. As a result of the enacted law, the Company was required to revalue deferred tax assets and liabilities existing as of December 31, 2017 from the 34% federal rate in effect through the end of 2017, to the new 21% rate. This revaluation resulted in a reduction to the Company’s deferred tax asset of $66.4 million. This amount was offset by a corresponding reduction to the Company’s valuation allowance. The other provisions of the TCJA did not have a material impact on the December 31, 2017 consolidated financial statements. Estimates used to prepare our income tax expense are based on the Company’s initial analysis of the TCJA. Given the complexity of the TCJA, anticipated guidance from the U. S. Treasury regarding implementation of the TCJA, and the potential for additional guidance from the Securities and Exchange Commission and the FASB related to the TCJA, these estimates may be adjusted during fiscal 2018 to reflect any such guidance provided. The Company adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, for the quarter ended March 31, 2017. As a result of adoption, the deferred tax assets as of December 31, 2016 As of December 31, 2017, net deferred tax assets increased approximately $70.4 million, primarily due to the operating loss and tax credits incurred during the year. This increase in net deferred tax assets was offset by a corresponding increase in the valuation allowance. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and tax credit carryforwards. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. Accordingly, a full valuation allowance of $205.4 million and $135.1 million has been established at December 31, 2017 and 2016, respectively. Pursuant to Section 382 of the Internal Revenue Code, and similar state tax law, certain substantial changes in the Company’s ownership may result in a limitation on the amount of net operating loss carryforwards and tax carryforwards that may be used in future years. Utilization of the net operating loss (“NOL”) and tax credit carryforwards may be subject to a substantial annual limitation under Section 382 of the Internal Revenue Code of 1986 due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes may limit the amount of NOL and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. The Company completed a detailed Section 382 study during 2017 on its Net Operating Losses and Credits incurred from the year it began operations in 2011 through December 31, 2016. Based on the study, the Company underwent two ownership changes for Section 382 purposes which occurred on March 11, 2014 and December 31, 2015. As a result of the ownership changes, all of the Company’s NOL and Tax Credit carryforwards as of the ownership change dates are subject to limitation under Section 382. Any NOLs or Tax Credits generated after the December 2015 change are not subject to this annual limitation. However, subsequent ownership changes, as defined by Section 382, may potentially further limit the amount of net operating loss carryforwards that could be utilized to offset future taxable income. The Company applies the authoritative guidance on accounting for and disclosure of uncertainty in tax positions, which requires the Company to determine whether a tax position of the Company is more likely than not to be sustained upon examination, including resolution of any related appeals of litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than fifty percent likelihood of being realized upon the ultimate settlement with the relevant taxing authority. The following is a rollforward of the Company’s unrecognized tax benefits: Year Ended December 31, 2017 2016 2015 (in thousands) Unrecognized tax benefits—as of the beginning of the year $ — $ — $ — Gross increases—current period tax positions — — — Gross decreases—tax positions of prior periods — — — Unrecognized tax benefits—as of the end of the year $ — $ — $ — The Company will recognize interest and penalties related to uncertain tax positions in income tax expense when in a taxable income position. As of December 31, 2017 and 2016, the Company had no accrued interest or penalties related to uncertain tax positions and no amounts have been recognized in the Company’s statement of operations. The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by federal and state jurisdictions, where applicable. There are currently no pending tax examinations, and the Company’s tax returns are open under statute from 2014 to the present. The tax attributes prior to 2014 may still be adjusted upon examination. The Company’s policy is to record interest and penalties related to income taxes as part of the tax provision. During November 2015, the FASB issued ASU 2015-17, Balance Sheet Classification of Deferred Taxes, which simplifies the presentation of deferred income taxes. ASU 2015-17 can be early adopted for any period that has not been issued on a prospective or retrospective basis. The Company elected to early adopt this guidance effective December 31, 2015 on a prospective basis. Adoption of this ASU resulted in a reclassification of the current deferred tax liability to a non-current deferred tax liability, in the amount of $0.6 million, which is netted with the long-term deferred tax asset in its consolidated balance sheet as of December 31, 2015. No prior periods were retrospectively adjusted. |
Employee Benefit Plan
Employee Benefit Plan | 12 Months Ended |
Dec. 31, 2017 | |
Postemployment Benefits [Abstract] | |
Employee Benefit Plan | 11. Employee Benefit Plan The Company maintains a 401(k) profit sharing plan (the “Plan”) for its employees. Each employee may elect to contribute a portion of his or her annual compensation to the Plan, subject to annual limits established by the Internal Revenue Service. For the years ended December 31, 2017, 2016 and 2015, the Company matched 50% of eligible contributions up to 6% of employee contributions. For the years ended December 31, 2017, 2016 and 2015 the Company contributed $0.9 million, $0.4 million and $0.2 million, respectively. |
Selected Quarterly Financial Da
Selected Quarterly Financial Data (Unaudited) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Selected Quarterly Financial Data (Unaudited) | 12. Selected Quarterly Financial Data (Unaudited) The following table contains quarterly financial information for 2017 and 2016. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total (in thousands, except per share amounts) Total operating expenses $ 57,480 $ 70,854 $ 74,373 $ 70,448 $ 273,155 Loss from operations (57,480 ) (70,854 ) (74,373 ) (70,448 ) (273,155 ) Net loss (56,778 ) (70,202 ) (73,719 ) $ (69,421 ) (270,120 ) Net loss per share—basic and diluted $ (1.52 ) $ (1.88 ) $ (1.97 ) $ (1.75 ) $ (7.09 ) 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Total (in thousands, except per share amounts) Total operating expenses $ 30,714 $ 35,006 $ 38,064 $ 56,379 $ 160,163 Loss from operations (30,714 ) (35,006 ) (38,064 ) (56,379 ) (160,163 ) Net loss (30,543 ) (34,747 ) (37,796 ) (55,901 ) (158,987 ) Net loss per share—basic and diluted $ (0.97 ) $ (1.08 ) $ (1.15 ) $ (1.50 ) $ (4.75 ) |
Subsequent Event
Subsequent Event | 12 Months Ended |
Dec. 31, 2017 | |
Subsequent Events [Abstract] | |
Subsequent Event | 13. Subsequent Event On February 13, 2018, the Company completed the sale of 4,032,012 shares of its common stock at a price to the public of $164.00 per share, resulting in net proceeds to the Company of $631.1 million, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. |
Summary of Significant Accoun20
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Basis of Presentation | Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiaries after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). |
Use of Estimates | Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. |
Cash and Cash Equivalents | Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. As of December 31, 2017, cash equivalents were comprised of money market funds and overnight reverse repurchase agreements. As of December 31, 2016, cash equivalents were comprised of money market funds. |
Marketable Securities | Marketable securities Marketable securities consist of investments with original maturities greater than 90 days. The Company considers its investment portfolio of investments to be available-for-sale. Accordingly, these investments are recorded at fair value, which is based on quoted market prices. Unrealized gains and losses are reported as a component of accumulated other comprehensive items in stockholders’ equity. Realized gains and losses and declines in value judged to be other than temporary are included as a component of other expense, net, based on the specific identification method. When determining whether a decline in value is other than temporary, the Company considers several factors, including whether the Company has the intent to sell the security, and whether it is more likely than not that the Company will be required to sell the security prior to recovery of its amortized cost basis. No declines in value were deemed to be other than temporary during the year ended December 31, 2017. |
Restricted Cash | Restricted Cash A deposit of $39,000 was restricted from withdrawal as of December 31, 2017 and 2016. The restriction is related to securing the lease for the initial facility of the Company and the restriction expires in 2024, in accordance with the most recent amendment to the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. For this same facility, a deposit of $0.3 million was restricted from withdrawal as of December 31, 2017. The restriction is related to securing an amendment to the lease of the initial facility of the Company and the restriction expires in 2024, in accordance with the most recent amendment to the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. A deposit of $0.5 million was restricted from withdrawal as of December 31, 2017 and 2016. The restriction is related to securing the separate facility lease in May 2016 that will expire on February 28, 2022, under which, beginning on September 1, 2016, the Company rents 19,805 square feet of additional office space in a separate multi-tenant building. The restriction expires in 2022, in accordance with the operating lease agreement. This balance is included in restricted cash on the accompanying consolidated balance sheets. |
Property and Equipment | Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight-line method. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is credited or charged to income. Repairs and maintenance costs are expensed as incurred. |
Impairment of Long-Lived Assets | Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. |
Research and Development | Research and Development Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, overhead costs, depreciation, contract services and other related costs. Research and development costs are expensed to operations as the related obligation is incurred. The Company has entered into various research and development contracts with research institutions and other companies both inside and outside of the United States. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research and development costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. |
Patent Costs | Patent Costs The Company expenses patent costs as incurred and classifies such costs as general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss. |
Stock-Based Compensation | Stock-Based Compensation The Company recognizes compensation expense for stock-based awards, including grants of stock options and restricted stock, made to employees and nonemployee directors based on the estimated fair value on the date of grant, over the requisite service period. The Company recognizes compensation expense for stock-based awards granted to non-employee consultants based on the fair value of the award on each date on which the awards vest. Compensation expense is recognized over the vesting period, provided that services are rendered by such non-employee consultants during that time. At the end of each financial reporting period, the fair value of unvested options is re-measured using the then-current fair value of our common stock and updated assumptions in the Black-Scholes option-pricing model; and the fair value of restricted stock awards is re-measured using the then-current fair value of our common stock. For awards that vest upon achievement of a performance condition, the Company recognizes compensation expense when achievement of the performance condition is met or during the period from which meeting the condition is deemed probable until the expected date of meeting the performance condition. The fair value of each option grant is estimated using the Black-Scholes option-pricing model. Through December 31, 2015, the Company lacked sufficient Company-specific historical and implied volatility information, and as a result, the Company used the volatility of a group of publicly-traded peer companies in the Black-Scholes calculations. Beginning in 2016, the Company estimated its expected volatility using a weighted average of the historical volatility of publicly-traded peer companies and the volatility of its common stock, and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its traded stock price for the duration of the expected term. The expected term of the Company’s options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options, while the expected term of its options granted to consultants and nonemployees has been determined based on the contractual term of the options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The Company also applies a forfeiture rate in order to calculate stock-based compensation expense. Expected forfeitures are based on the historical experience of the Company and management’s expectations of future forfeitures. To the extent actual forfeitures differ from the estimates, the difference is recorded as a cumulative adjustment in the period in which the estimates are revised. The Company recognizes stock-based compensation expense for only the portion of awards that are expected to vest. |
Treasury Stock | Treasury Stock The Company records treasury stock at cost. Treasury stock consists of shares received from an employee as consideration for exercises of stock options. |
Basic and Diluted Net Loss Per Share | Basic and Diluted Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the diluted net loss by the weighted average number of common shares outstanding for the period, including potentially-dilutive common shares, by assuming the dilutive effect of outstanding stock options and unvested restricted stock, as determined using the treasury stock method. For periods in which the Company has reported net losses, diluted net loss per share is the same as basic net loss per share, because dilutive common shares are not assumed to have been issued if their effect is antidilutive. The Company reported a net loss for the years ended December 31, 2017, 2016 and 2015. |
Risks and Uncertainties | Risks and Uncertainties The product candidates developed by the Company require approvals from the U.S. Food and Drug Administration or foreign regulatory agencies prior to commercial sales. There can be no assurance that the current and future product candidates of the Company will receive the necessary approvals. If the Company fails to successfully complete clinical development and generate results sufficient to file for regulatory approval or is denied approval or approval is delayed, it may have a material adverse impact on the Company’s business and its financial statements. |
Concentration of Credit Risk and of Significant Suppliers | Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains accounts for all cash and cash equivalents at accredited financial institutions, in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company is dependent on third-party manufacturers to supply products for research and development activities in its programs. The Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs. |
Income Taxes | Income Taxes The Company accounts for income taxes under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which these temporary differences are expected to be recovered or settled. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. |
Fair Value Measurements | Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three categories: Level 1 — Quoted market prices in active markets for identical assets or liabilities. Level 2 — Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s cash equivalents and marketable securities at December 31, 2017 and 2016 were carried at fair value, determined according to the fair value hierarchy; see Footnote 3, Fair Value Measurements. The carrying amounts reflected in the consolidated balance sheets for accounts payable and accrued expenses approximate their fair values due to their short-term maturities at December 31, 2017 and 2016, respectively. |
Segment Data | Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The singular focus of the Company is on advancing medicines to treat central nervous system disorders, where there are inadequate or no approved existing therapies. All tangible assets are held within the United States. |
Comprehensive Loss | Comprehensive Loss Comprehensive loss includes net loss as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. For the years ended December 31, 2017 and 2016, the difference between net loss and comprehensive loss was the unrealized gain (loss) on marketable securities. For the year ended December 31, 2015, there was no difference between net loss and comprehensive loss. |
Public Offerings | Public Offerings On July 23, 2014, the Company completed the sale of 5,750,000 shares of its common stock in its IPO at a price to the public of $18.00 per share, resulting in net proceeds to the Company of $94.0 million after deducting underwriting discounts and commissions and offering costs paid by the Company. The shares began trading on the Nasdaq Global Market on July 18, 2014. On April 20, 2015, the Company completed the sale of 2,628,571 shares of its common stock at a price to the public of $52.50 per share, resulting in net proceeds to the Company of $129.1 million after deducting underwriting discounts and commissions and offering costs paid by the Company. On January 12, 2016, the Company completed the sale of 3,157,894 shares of its common stock at a price to the public of $47.50 per share, resulting in net proceeds to the Company of $140.4 million after deducting underwriting discounts and commissions and offering costs paid by the Company. On September 14, 2016, the Company completed the sale of 5,062,892 shares of its common stock at a price to the public of $39.75 per share, resulting in net proceeds to the Company of $189.2 million after deducting underwriting discounts and commissions paid by the Company. On November 17, 2017, the Company completed the sale of 4,058,822 shares of its common stock at a price to the public of $85.00 per share, resulting in net proceeds to the Company of $325.8 million after deducting underwriting discounts and commissions and offering costs paid by the Company. Also see Note 13, “Subsequent Event”. |
Recently Issued Accounting Pronouncements | Recently Issued Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers The FASB has continued to issue accounting standards updates to clarify and provide implementation guidance related to Revenue from Contracts with Customers, including ASU 2016-08 , Revenue from Contract with Customers: Principal versus Agent Considerations , ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing , and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. These amendments In February 2016, the FASB issued ASU No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . The standard The standard will be effective . In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash For the years ended December 31, 2017 and 2016, our restricted cash and restricted cash equivalents were not significant. The Company currently does not expect this guidance to have a significant impact on its consolidated financial statements and related disclosures In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718) — Scope of Modification Accounting currently does not expect this guidance to have a significant impact on its consolidated financial statements and related disclosures Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. |
Fair Value Measurements (Tables
Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Summary of Company's Money Market Funds and Marketable Securities | The following tables summarize the Company’s money market funds and marketable securities as of December 31, 2017 and 2016: December 31, 2017 Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Cash equivalents: Cash equivalents $ 306,235 $ 306,235 $ — $ — Total cash equivalents 306,235 306,235 — — Marketable securities: U.S. government securities 49,606 — 49,606 — U.S. corporate bonds 48,959 — 48,959 — U.S. commercial paper 65,583 — 65,583 — International commercial paper 48,465 — 48,465 — Total marketable securities 212,613 — 212,613 — Total cash equivalents and marketable securities $ 518,848 $ 306,235 $ 212,613 $ — December 31, 2016 Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Cash equivalents: Cash equivalents $ 168,517 $ 168,517 $ — $ — Total cash equivalents 168,517 168,517 — — Marketable securities: U.S. government securities 100,031 — 100,031 — U.S. corporate bonds 58,452 — 58,452 — International corporate bonds 24,190 — 24,190 — U.S. commercial paper 30,351 — 30,351 — International commercial paper 15,938 — 15,938 — Total marketable securities 228,962 — 228,962 — Total cash equivalents and marketable securities $ 397,479 $ 168,517 $ 228,962 $ — |
Summary of Gross Unrealized Gains and Losses of Marketable Securities | The following tables summarize the gross unrealized gains and losses of the Company’s marketable securities as of December 31, 2017 and 2016: December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Assets: U.S. government securities $ 49,612 $ — $ (6 ) $ 49,606 U.S. corporate bonds 48,982 2 (25 ) 48,959 U.S. commercial paper 65,583 — — 65,583 International commercial paper 48,465 — — 48,465 $ 212,642 $ 2 $ (31 ) $ 212,613 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Assets: U.S. government securities $ 100,055 $ 2 $ (26 ) $ 100,031 U.S. corporate bonds 58,508 — (56 ) 58,452 International corporate bonds 24,212 — (22 ) 24,190 U.S. commercial paper 30,351 — — 30,351 International commercial paper 15,938 — — 15,938 $ 229,064 $ 2 $ (104 ) $ 228,962 |
Balance Sheet Components (Table
Balance Sheet Components (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Balance Sheet Related Disclosures [Abstract] | |
Summary of Property and Equipment, Net | Property and equipment, net consists of the following: December 31, 2017 2016 (in thousands) Computer hardware and software $ 1,090 $ 708 Furniture and equipment 1,029 695 Leasehold improvements 2,967 527 5,086 1,930 Less: Accumulated depreciation (1,073 ) (542 ) $ 4,013 $ 1,388 |
Summary of Accrued Expenses | Accrued expenses consist of the following: December 31, 2017 2016 (in thousands) Development costs $ 23,473 $ 14,541 Employee-related expenses 15,838 5,948 Professional services 3,166 1,751 Other accrued expenses 124 112 $ 42,601 $ 22,352 |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Commitments And Contingencies Disclosure [Abstract] | |
Schedule of Future Minimum Lease Payments, Under Non-Cancelable Operating Leases | Future minimum lease payments under non-cancelable operating leases are as follows at December 31, 2017: Years Ending December 31, (in thousands) 2018 $ 4,444 2019 4,537 2020 4,632 2021 4,728 2022 3,485 Thereafter 5,450 $ 27,276 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Summary of Activity Relating to Restricted Stock | The table below summarizes activity relating to restricted stock: Shares Outstanding as of December 31, 2016 — Granted 32,500 Vested — Forfeited (3,400 ) Outstanding as of December 31, 2017 29,100 |
Summary of Stock-Based Compensation Expense for Stock Options, Restricted Stock Units and Employee Stock Purchase Plan Recognized | Stock-based compensation expense for stock options, restricted stock units and the employee stock purchase plan recognized during the years ended December 31, 2017, 2016 and 2015 was as follows: Year Ended December 31, 2017 2016 2015 (in thousands) Research and development $ 19,893 $ 11,197 $ 5,924 General and administrative 15,641 11,823 9,316 $ 35,534 $ 23,020 $ 15,240 |
Summary of Stock-Based Compensation Expense by Award Type Recognized | Stock-based compensation expense by award type recognized during the years ended December 31, 2017, 2016 and 2015 was as follows: Year Ended December 31, 2017 2016 2015 (in thousands) Stock options $ 34,525 $ 22,820 $ 14,796 Restricted stock units 617 — — Employee stock purchase plan 392 166 117 Restricted stock awards — 34 327 $ 35,534 $ 23,020 $ 15,240 |
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted | The fair value of each option granted to employees and nonemployee directors during the years ended December 31, 2017, 2016 and 2015 under the Company’s stock option plans has been calculated on the date of grant using the following weighted average assumptions: Year Ended December 31, 2017 2016 2015 Expected dividend yield 0 % 0 % 0 % Expected volatility 79.89 % 80.15 % 90.54 % Risk-free interest rate 2.03 % 1.47 % 1.59 % Expected life of option 6.03 years 6.05 years 6.03 years |
Summary of Activity Relating to Stock Options | The table below summarizes activity related to stock options: Shares Weighted Average Exercise Price Weighted Average Remaining Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding as of December 31, 2016 4,231,807 $ 29.99 8.24 $ 92,843 Granted 2,360,933 60.59 Exercised (765,950 ) 20.94 Forfeited (240,197 ) 43.61 Outstanding as of December 31, 2017 5,586,593 $ 43.58 8.09 $ 676,717 Vested and expected to vest as of December 31, 2017 4,504,257 $ 42.22 7.98 $ 551,729 Exercisable as of December 31, 2017 2,045,229 $ 27.95 6.99 $ 279,699 |
Net Loss Per Share (Tables)
Net Loss Per Share (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Earnings Per Share [Abstract] | |
Summary of Basic and Diluted Net Loss Per Share | Basic and diluted net loss per share was calculated as follows for the years ended December 31, 2017, 2016 and 2015: Year Ended December 31, 2017 2016 2015 Basic net loss per share: Numerator: Net loss (in thousands) $ (270,120 ) $ (158,987 ) $ (94,495 ) Denominator: Weighted average common stock outstanding—basic 38,113,678 33,492,795 27,778,288 Dilutive effect of shares of common stock equivalents resulting from common stock options and restricted stock units — — — Weighted average common stock outstanding—diluted 38,113,678 33,492,795 27,778,288 Net loss per share—basic and diluted $ (7.09 ) $ (4.75 ) $ (3.40 ) |
Summary of Anti-Dilutive Common Stock Equivalents Outstanding | The following common stock equivalents outstanding as of December 31, 2017 and 2016 were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Year Ended December 31, 2017 2016 Stock options 4,915,956 3,985,935 Restricted stock units 29,100 — Employee stock purchase plan 11,683 6,784 4,956,739 3,992,719 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate | A reconciliation of the U.S. statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2017 2016 2015 Tax due at statutory rate 34.0 % 34.0 % 34.0 % State taxes, net of federal 5.1 4.2 4.0 Stock-based compensation 6.4 (1.0 ) (0.9 ) Foreign rate differential (3.2 ) (3.1 ) (3.1 ) Federal and state credits 7.2 10.3 13.2 Change in valuation allowance (22.5 ) (41.5 ) (43.1 ) Other — — 0.1 Federal and state rate change (24.6 ) — — Research and orphan drug credit addback (2.4 ) (2.9 ) (4.2 ) 0.0 % 0.0 % 0.0 % |
Summary of Significant Components of Company's Net Deferred Tax Asset | Significant components of the Company’s net deferred tax asset at December 31, 2017 and 2016 are as follows: December 31, 2017 2016 (in thousands) Net operating losses $ 131,151 $ 84,374 Capitalized start-up costs 1,362 2,155 Accounting method change — (673 ) Tax credit carryforwards 54,523 33,477 Accrued expenses 3,057 2,287 Depreciation and amortization 685 999 Stock options 13,573 12,103 Others 1,090 350 Total net deferred tax asset before valuation allowance 205,441 135,072 Valuation allowance (205,441 ) (135,072 ) Net deferred tax asset $ — $ — |
Summary of Rollforward of Company's Unrecognized Tax Benefits | The following is a rollforward of the Company’s unrecognized tax benefits: Year Ended December 31, 2017 2016 2015 (in thousands) Unrecognized tax benefits—as of the beginning of the year $ — $ — $ — Gross increases—current period tax positions — — — Gross decreases—tax positions of prior periods — — — Unrecognized tax benefits—as of the end of the year $ — $ — $ — |
Selected Quarterly Financial 27
Selected Quarterly Financial Data (Unaudited) (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Summary of Quarterly Financial Information | The following table contains quarterly financial information for 2017 and 2016. The Company believes that the following information reflects all normal recurring adjustments necessary for a fair statement of the information for the periods presented. The operating results for any quarter are not necessarily indicative of results for any future period. 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Total (in thousands, except per share amounts) Total operating expenses $ 57,480 $ 70,854 $ 74,373 $ 70,448 $ 273,155 Loss from operations (57,480 ) (70,854 ) (74,373 ) (70,448 ) (273,155 ) Net loss (56,778 ) (70,202 ) (73,719 ) $ (69,421 ) (270,120 ) Net loss per share—basic and diluted $ (1.52 ) $ (1.88 ) $ (1.97 ) $ (1.75 ) $ (7.09 ) 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Total (in thousands, except per share amounts) Total operating expenses $ 30,714 $ 35,006 $ 38,064 $ 56,379 $ 160,163 Loss from operations (30,714 ) (35,006 ) (38,064 ) (56,379 ) (160,163 ) Net loss (30,543 ) (34,747 ) (37,796 ) (55,901 ) (158,987 ) Net loss per share—basic and diluted $ (0.97 ) $ (1.08 ) $ (1.15 ) $ (1.50 ) $ (4.75 ) |
Nature of the Business - Additi
Nature of the Business - Additional Information (Detail) - USD ($) $ in Thousands | Feb. 13, 2018 | Nov. 17, 2017 | Sep. 14, 2016 | Jan. 12, 2016 | Apr. 20, 2015 | Dec. 31, 2017 | Dec. 31, 2016 |
Nature Of Business [Line Items] | |||||||
Accumulated deficit | $ (590,447) | $ (320,327) | |||||
Net proceeds from sale of common stock | $ 325,800 | $ 189,200 | $ 140,400 | $ 129,100 | |||
Subsequent Event [Member] | |||||||
Nature Of Business [Line Items] | |||||||
Net proceeds from sale of common stock | $ 631,100 | ||||||
Redeemable Convertible Preferred Stock [Member] | Convertible Notes [Member] | Initial Public Offering [Member] | |||||||
Nature Of Business [Line Items] | |||||||
Net proceeds from sale of equity and notes | $ 969,000 |
Summary of Significant Accoun29
Summary of Significant Accounting Policies - Additional Information (Detail) | Nov. 17, 2017USD ($)$ / sharesshares | Sep. 14, 2016USD ($)$ / sharesshares | Jan. 12, 2016USD ($)$ / sharesshares | Apr. 20, 2015USD ($)$ / sharesshares | Jul. 23, 2014USD ($)$ / sharesshares | May 31, 2017ft² | May 31, 2016ft² | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) |
Summary Of Significant Accounting Policies [Line Items] | |||||||||
Restricted cash deposit | $ 849,000 | $ 564,000 | |||||||
Issuance of common stock, shares | shares | 4,058,822 | 5,062,892 | 3,157,894 | 2,628,571 | |||||
Common stock price per share | $ / shares | $ 85 | $ 39.75 | $ 47.50 | $ 52.50 | |||||
Proceeds from public offering of common stock, net of commissions and underwriting discounts and estimated offering costs | $ 325,800,000 | $ 189,200,000 | $ 140,400,000 | $ 129,100,000 | |||||
Initial Public Offering [Member] | |||||||||
Summary Of Significant Accounting Policies [Line Items] | |||||||||
Issuance of common stock, shares | shares | 5,750,000 | ||||||||
Common stock price per share | $ / shares | $ 18 | ||||||||
Proceeds from initial public offering of common stock, net of commissions and underwriting discounts | $ 94,000,000 | ||||||||
Operating Lease Two [Member] | |||||||||
Summary Of Significant Accounting Policies [Line Items] | |||||||||
Restricted cash deposit | 39,000 | 39,000 | |||||||
Operating Lease Three [Member] | |||||||||
Summary Of Significant Accounting Policies [Line Items] | |||||||||
Restricted cash deposit | 300,000 | ||||||||
Operating Lease One [Member] | |||||||||
Summary Of Significant Accounting Policies [Line Items] | |||||||||
Restricted cash deposit | $ 500,000 | $ 500,000 | |||||||
Additional Office space rented under operating lease | ft² | 22,067 | 19,805 | |||||||
Lease expire date | Feb. 28, 2022 | Feb. 28, 2022 |
Fair Value Measurements - Summa
Fair Value Measurements - Summary of Company's Money Market Funds and Marketable Securities (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total cash equivalents | $ 306,235 | $ 168,517 |
Total marketable securities | 212,613 | 228,962 |
Total cash equivalents and marketable securities | 518,848 | 397,479 |
Cash Equivalents [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total cash equivalents | 306,235 | 168,517 |
Fair Value, Inputs, Level 1 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total cash equivalents | 306,235 | 168,517 |
Total cash equivalents and marketable securities | 306,235 | 168,517 |
Fair Value, Inputs, Level 1 [Member] | Cash Equivalents [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total cash equivalents | 306,235 | 168,517 |
Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 212,613 | 228,962 |
Total cash equivalents and marketable securities | 212,613 | 228,962 |
U.S. Government Securities [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 49,606 | 100,031 |
U.S. Government Securities [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 49,606 | 100,031 |
U.S. Corporate Bonds [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 48,959 | 58,452 |
U.S. Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 48,959 | 58,452 |
International Corporate Bonds [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 24,190 | |
International Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 24,190 | |
U.S. Commercial Paper [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 65,583 | 30,351 |
U.S. Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 65,583 | 30,351 |
International Commercial Paper [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | 48,465 | 15,938 |
International Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member] | ||
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
Total marketable securities | $ 48,465 | $ 15,938 |
Fair Value Measurements - Addit
Fair Value Measurements - Additional Information (Detail) | 12 Months Ended | |
Dec. 31, 2017USD ($)MarketableSecurity | Dec. 31, 2016USD ($)MarketableSecurity | |
Debt Instrument Fair Value Carrying Value [Line Items] | ||
Transfers among the Level 1, Level 2 and Level 3 categories | $ 0 | $ 0 |
Number of marketable securities loss position due to fluctuations in interest rates | MarketableSecurity | 11 | 27 |
Impairment of assets | $ 0 | $ 0 |
Maximum [Member] | ||
Debt Instrument Fair Value Carrying Value [Line Items] | ||
Marketable securities, remaining contractual maturities | 1 year |
Fair Value Measurements - Sum32
Fair Value Measurements - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | $ 212,642 | $ 229,064 |
Gross Unrealized Gains | 2 | 2 |
Gross Unrealized Losses | (31) | (104) |
Fair Value | 212,613 | 228,962 |
U.S. Government Securities [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 49,612 | 100,055 |
Gross Unrealized Gains | 2 | |
Gross Unrealized Losses | (6) | (26) |
Fair Value | 49,606 | 100,031 |
U.S. Corporate Bonds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 48,982 | 58,508 |
Gross Unrealized Gains | 2 | |
Gross Unrealized Losses | (25) | (56) |
Fair Value | 48,959 | 58,452 |
International Corporate Bonds [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 24,212 | |
Gross Unrealized Losses | (22) | |
Fair Value | 24,190 | |
U.S. Commercial Paper [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 65,583 | 30,351 |
Fair Value | 65,583 | 30,351 |
International Commercial Paper [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Amortized Cost | 48,465 | 15,938 |
Fair Value | $ 48,465 | $ 15,938 |
Balance Sheet Components - Summ
Balance Sheet Components - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 5,086 | $ 1,930 |
Less: Accumulated depreciation | (1,073) | (542) |
Property and equipment, net | 4,013 | 1,388 |
Computer Hardware and Software [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 1,090 | 708 |
Furniture and Equipment [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | 1,029 | 695 |
Leasehold Improvements [Member] | ||
Property, Plant and Equipment [Line Items] | ||
Property and equipment, gross | $ 2,967 | $ 527 |
Balance Sheet Components - Addi
Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Property, Plant and Equipment [Line Items] | |||
Depreciation and amortization | $ 0.5 | $ 0.3 | $ 0.1 |
Computer Hardware and Software [Member] | |||
Property, Plant and Equipment [Line Items] | |||
Property and equipment, useful life | 3 years | ||
Furniture and Equipment [Member] | |||
Property, Plant and Equipment [Line Items] | |||
Property and equipment, useful life | 5 years |
Balance Sheet Components - Su35
Balance Sheet Components - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Payables And Accruals [Abstract] | ||
Development costs | $ 23,473 | $ 14,541 |
Employee-related expenses | 15,838 | 5,948 |
Professional services | 3,166 | 1,751 |
Other accrued expenses | 124 | 112 |
Total accrued expenses | $ 42,601 | $ 22,352 |
Commitments and Contingencies -
Commitments and Contingencies - Operating Leases - Additional Information (Detail) $ in Millions | Jan. 01, 2018ft² | Aug. 15, 2017ft² | May 31, 2017ft² | May 31, 2017ft² | May 31, 2016ft² | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) |
Commitments And Contingencies [Line Items] | ||||||||
Rent expense, net of sublease income | $ | $ 3.7 | $ 2 | $ 0.4 | |||||
Operating Lease One [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Office space rent under operating lease | 22,067 | 19,805 | ||||||
Lease expire date | Feb. 28, 2022 | Feb. 28, 2022 | ||||||
Lease existence of option to extend | true | |||||||
Commencement date of lease | Sep. 1, 2016 | |||||||
Sixth Amendment to Lease [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Lease expire date | Aug. 15, 2024 | |||||||
Increased office space rent | 8,200 | 32,876 | ||||||
Sixth Amendment to Lease [Member] | Subsequent Event [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Increased office space rent | 24,676 |
Commitments and Contingencies37
Commitments and Contingencies - Schedule of Future Minimum Lease Payments, Under Non-Cancelable Operating Leases (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Commitments And Contingencies Disclosure [Abstract] | |
2,018 | $ 4,444 |
2,019 | 4,537 |
2,020 | 4,632 |
2,021 | 4,728 |
2,022 | 3,485 |
Thereafter | 5,450 |
Total Operating leases, future minimum payments | $ 27,276 |
Commitments and Contingencies38
Commitments and Contingencies - CyDex License Agreement - Additional Information (Detail) - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Commitments And Contingencies [Line Items] | |||
Research and development expense | $ 210,277,000 | $ 120,756,000 | $ 69,357,000 |
CyDex License Agreement [Member] | |||
Commitments And Contingencies [Line Items] | |||
Research and development expense | 100,000 | ||
CyDex License Agreement [Member] | First and Second Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | 800,000 | ||
CyDex License Agreement [Member] | First and Second Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | 3,800,000 | ||
CyDex License Agreement [Member] | Third and Fourth Clinical Development Milestones [Member] | Brexanolone [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | 1,300,000 | ||
CyDex License Agreement [Member] | Third and Fourth Regulatory Milestones [Member] | Brexanolone [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | 8,500,000 | ||
CyDex License Agreement [Member] | Clinical Development [Member] | |||
Commitments And Contingencies [Line Items] | |||
Research and development expense related to milestone expense | 0 | 800,000 | 800,000 |
Milestone payments | 0 | $ 800,000 | $ 800,000 |
CyDex License Agreement [Member] | Clinical Development [Member] | SAGE-689 [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | 800,000 | ||
CyDex License Agreement [Member] | Regulatory Milestones [Member] | SAGE-689 [Member] | Maximum [Member] | |||
Commitments And Contingencies [Line Items] | |||
Expected milestone payments | $ 1,800,000 |
Commitments and Contingencies39
Commitments and Contingencies - University of California License Agreements - Additional Information (Detail) - University of California License Agreements [Member] | Dec. 31, 2015USD ($) | Jun. 30, 2015USD ($) | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($)Milestone | Dec. 31, 2014USD ($) | Dec. 31, 2013USD ($) | Dec. 31, 2017USD ($) |
Commitments And Contingencies [Line Items] | ||||||||
Research and development expense related to milestone expense | $ 0 | $ 0 | $ 0 | $ 0 | ||||
Milestone payments | $ 0 | $ 0 | $ 0 | $ 0 | ||||
Upfront payment | $ 50,000 | |||||||
Annual license maintenance fee | $ 15,000 | |||||||
After The Effective Date [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Licenses Expiration period, maximum | 27 years | |||||||
After The First Sale [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Licenses Expiration period, maximum | 15 years | |||||||
Clinical Development [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Milestone payments | $ 100,000 | |||||||
Research and development expense related to milestone expense | 100,000 | |||||||
Milestone payments | $ 100,000 | |||||||
Milestones achieved | Milestone | 3 | |||||||
Clinical Development [Member] | Maximum [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Percentage of net sales paid as royalties | 1.00% | |||||||
Regulatory Milestones [Member] | Maximum [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Expected milestone payments | 700,000 | |||||||
Additional milestone payments | $ 0 | |||||||
Sales Milestones [Member] | Maximum [Member] | ||||||||
Commitments And Contingencies [Line Items] | ||||||||
Expected milestone payments | $ 2,000,000 | |||||||
Additional milestone payments | $ 0 |
Commitments and Contingencies40
Commitments and Contingencies - Washington University License Agreement - Additional Information (Detail) - Washington University License Agreement [Member] - USD ($) | 1 Months Ended | 12 Months Ended | |||
Nov. 30, 2013 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2013 | |
Commitments And Contingencies [Line Items] | |||||
Upfront non-refundable payment | $ 50,000 | ||||
Annual license maintenance fee | $ 15,000 | ||||
Issuance of common stock, shares | 47,619 | ||||
Research and development expense related to issue of common stock obligation | $ 100,000 | ||||
Research and development expense related to milestone expense | $ 0 | $ 0 | |||
Milestone payments | $ 0 | $ 0 | |||
Regulatory Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Research and development expense related to milestone expense | $ 50,000 | ||||
Milestone payments | $ 50,000 | ||||
Maximum [Member] | Clinical Development [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Expected milestone payments | 700,000 | ||||
Maximum [Member] | Regulatory Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Expected milestone payments | $ 500,000 |
Commitments and Contingencies41
Commitments and Contingencies - Consulting Agreement - Additional Information (Detail) - Consulting Agreement [Member] | 1 Months Ended | 12 Months Ended | |||
Jan. 31, 2014USD ($)shares | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($)Milestoneshares | Dec. 31, 2014USD ($)Milestoneshares | |
Commitments And Contingencies [Line Items] | |||||
Research and development expense related to milestone expense | $ 0 | $ 0 | |||
Milestone payments | $ 0 | $ 0 | |||
Clinical Development and Regulatory Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Shares of common stock for attaining milestones | shares | 126,984 | ||||
Clinical Development and Regulatory Milestones [Member] | Maximum [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Expected milestone payments | $ 2,000,000 | ||||
First Clinical Development Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Milestones achieved | Milestone | 2 | ||||
Research and development expense related to milestone expense | $ 200,000 | ||||
Milestone payments | 50,000 | ||||
Payments for stock issued upon reaching a milestone | $ 100,000 | ||||
Milestone based share compensation, shares issued | shares | 15,872 | ||||
Second Clinical Development Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Milestones achieved | Milestone | 1 | ||||
Research and development expense related to milestone expense | $ 1,700,000 | ||||
Milestone payments | 500,000 | ||||
Payments for stock issued upon reaching a milestone | $ 1,200,000 | ||||
Milestone based share compensation, shares issued | shares | 23,809 | ||||
Third Clinical Development Milestones [Member] | |||||
Commitments And Contingencies [Line Items] | |||||
Milestones achieved | Milestone | 1 | ||||
Research and development expense related to milestone expense | $ 1,700,000 | ||||
Milestone payments | 500,000 | ||||
Payments for stock issued upon reaching a milestone | $ 1,200,000 | ||||
Milestone based share compensation, shares issued | shares | 23,809 |
Preferred Stock - Additional In
Preferred Stock - Additional Information (Detail) - shares | Dec. 31, 2017 | Dec. 31, 2016 |
Temporary Equity Disclosure [Abstract] | ||
Preferred stock, shares authorized | 5,000,000 | 5,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common Stock - Additional Infor
Common Stock - Additional Information (Detail) - USD ($) | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Equity [Abstract] | ||
Common stock, shares authorized | 120,000,000 | 120,000,000 |
Common stock, par value | $ 0.0001 | $ 0.0001 |
Dividends declared | $ 0 | $ 0 |
Voting rights | Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. | |
Purchase of treasury stock, Shares | 614 | 346 |
Total cost of shares held in treasury | $ 113,000 | $ 17,000 |
Stock-Based Compensation - Addi
Stock-Based Compensation - Additional Information (Detail) | Jan. 01, 2018shares | Dec. 31, 2017USD ($)$ / sharesshares | Dec. 31, 2016USD ($)Milestone$ / sharesshares | Dec. 31, 2015USD ($)Milestone$ / sharesshares | Jul. 02, 2014shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Stock-based compensation expense | $ | $ 35,534,000 | $ 23,020,000 | $ 15,240,000 | ||
Share based compensation granted under plan vest period | 4 years | ||||
Total number of options outstanding | 7,866,789 | ||||
Share based compensation, vest period | 1 year | ||||
Share based compensation, term of plan | 10 years | ||||
Weighted average grant date fair value per share | $ / shares | $ 41.94 | $ 24.97 | $ 34.08 | ||
Share option, forfeiture rates | 13.30% | 9.60% | 10.00% | ||
Non-employees [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Share based compensation, term of plan | 10 years | ||||
2011 Stock Option Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Options granted | 0 | ||||
2014 Stock Option Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Common stock available for issuance under stock option plan | 2,251,096 | ||||
Milestones achieved | Milestone | 1 | 1 | |||
2014 Stock Option Plan [Member] | Milestone One [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Percentage of performance based grants that were achieved | 35.00% | ||||
2014 Stock Option Plan [Member] | Milestone Two [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Percentage of performance based grants that were achieved | 50.00% | 30.00% | |||
2014 Stock Option Plan [Member] | Maximum [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Percentage of increase on outstanding shares of Common stock | 4.00% | ||||
2014 Stock Option Plan [Member] | Subsequent Event [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Common stock shares annual increase added to plan | 1,680,117 | ||||
2014 Employee Stock Purchase Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Shares of common stock initially authorized for issuance under this plan | 282,000 | ||||
Number of shares issued under the plan | 30,069 | ||||
Accrued expenses | $ | $ 300,000 | ||||
Restricted Stock Units Vest One Year Anniversary [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Restricted stock units cliff vesting percentage | 25.00% | ||||
Restricted Stock Units [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Restricted stock units granted | 32,500 | ||||
Stock-based compensation expense | $ | $ 617,000 | ||||
Share based compensation granted under plan vest period | 2 years | ||||
Restricted Stock Units [Member] | Restricted Stock Units Vest One Year Anniversary [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Restricted stock units cliff vesting percentage | 50.00% | ||||
Restricted stock units vesting period month and year | 2018-02 | ||||
Restricted Stock Units [Member] | Restricted Stock Units Vest Two Year Anniversary [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Restricted stock units cliff vesting percentage | 50.00% | ||||
Restricted stock units vesting period month and year | 2019-02 | ||||
Performance Shares [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Options granted | 449,208 | 74,039 | 497,100 | ||
Total unrecognized stock-based compensation expense | $ | $ 16,400,000 | ||||
Number of shares outstanding and unvested stock options | 670,637 | ||||
Performance Milestone [Member] | 2014 Stock Option Plan [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Stock-based compensation expense | $ | $ 5,000,000 | $ 4,800,000 | |||
Performance-Based Stock Options [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Stock-based compensation expense | $ | $ 0 | ||||
Stock Options [Member] | |||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||
Stock-based compensation expense | $ | $ 34,525,000 | $ 22,820,000 | 14,796,000 | ||
Options granted | 2,360,933 | ||||
Total number of options outstanding | 5,586,593 | 4,231,807 | |||
Total unrecognized stock-based compensation expense | $ | $ 94,400,000 | ||||
Weighted average period of unrecognized compensation costs | 2 years 6 months 29 days | ||||
Total fair value of options vested | $ | $ 24,200,000 | $ 24,100,000 | 9,200,000 | ||
Intrinsic value of options exercised | $ | $ 77,700,000 | $ 4,600,000 | $ 28,400,000 |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Activity Relating to Restricted Stock (Detail) - Restricted Stock Units [Member] | 12 Months Ended |
Dec. 31, 2017shares | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
Granted, Shares- Restricted stock | 32,500 |
Forfeited, Shares-Restricted stock | (3,400) |
Outstanding, Shares at ending balance-Restricted stock | 29,100 |
Stock-Based Compensation - Su46
Stock-Based Compensation - Summary of Stock-Based Compensation Expense for Stock Options, Restricted Stock Units and Employee Stock Purchase Plan Recognized (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | $ 35,534 | $ 23,020 | $ 15,240 |
Research and Development [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | 19,893 | 11,197 | 5,924 |
General and Administrative [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | $ 15,641 | $ 11,823 | $ 9,316 |
Stock-Based Compensation - Su47
Stock-Based Compensation - Summary of Stock-Based Compensation Expense by Award Type Recognized (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | $ 35,534 | $ 23,020 | $ 15,240 |
Stock Options [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | 34,525 | 22,820 | 14,796 |
Restricted Stock Units [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | 617 | ||
Employee Stock Purchase Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | $ 392 | 166 | 117 |
Restricted Stock Awards [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Total Stock-based compensation expense | $ 34 | $ 327 |
Stock-Based Compensation - Su48
Stock-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |||
Expected dividend yield | 0.00% | 0.00% | 0.00% |
Expected volatility | 79.89% | 80.15% | 90.54% |
Risk-free interest rate | 2.03% | 1.47% | 1.59% |
Expected life of option | 6 years 10 days | 6 years 18 days | 6 years 10 days |
Stock-Based Compensation - Su49
Stock-Based Compensation - Summary of Activity Relating to Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Ending balance, Outstanding Shares | 7,866,789 | |
Stock Options [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Beginning balance, Outstanding Shares | 4,231,807 | |
Granted, Shares | 2,360,933 | |
Exercised, Shares | (765,950) | |
Forfeited, Shares | (240,197) | |
Ending balance, Outstanding Shares | 5,586,593 | 4,231,807 |
Vested and expected to vest, Shares | 4,504,257 | |
Exercisable, Shares | 2,045,229 | |
Beginning balance, Outstanding Weighted Average Exercise Price | $ 29.99 | |
Granted, Weighted Average Exercise Price | 60.59 | |
Exercised, Weighted Average Exercise Price | 20.94 | |
Forfeited, Weighted Average Exercise Price | 43.61 | |
Ending balance, Outstanding Weighted Average Exercise Price | 43.58 | $ 29.99 |
Vested and expected to vest, Weighted Average Exercise Price | 42.22 | |
Exercisable, Weighted Average Exercise Price | $ 27.95 | |
Outstanding, Weighted Average Remaining Life | 8 years 1 month 2 days | 8 years 2 months 26 days |
Vested and expected to vest, Weighted Average Remaining Life | 7 years 11 months 23 days | |
Exercisable, Weighted Average Remaining Life | 6 years 11 months 26 days | |
Outstanding, Aggregate Intrinsic Value | $ 676,717 | $ 92,843 |
Vested and expected to vest, Aggregate Intrinsic Value | 551,729 | |
Exercisable, Aggregate Intrinsic Value | $ 279,699 |
Net Loss Per Share - Summary of
Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Numerator: | |||||||||||
Net loss | $ (69,421) | $ (73,719) | $ (70,202) | $ (56,778) | $ (55,901) | $ (37,796) | $ (34,747) | $ (30,543) | $ (270,120) | $ (158,987) | $ (94,495) |
Denominator: | |||||||||||
Weighted average common stock outstanding—basic | 38,113,678 | 33,492,795 | 27,778,288 | ||||||||
Dilutive effect of shares of common stock equivalents resulting from common stock options and restricted stock units | 0 | 0 | 0 | ||||||||
Weighted average common stock outstanding—diluted | 38,113,678 | 33,492,795 | 27,778,288 | ||||||||
Net loss per share—basic and diluted | $ (1.75) | $ (1.97) | $ (1.88) | $ (1.52) | $ (1.50) | $ (1.15) | $ (1.08) | $ (0.97) | $ (7.09) | $ (4.75) | $ (3.40) |
Net Loss Per Share - Summary 51
Net Loss Per Share - Summary of Anti-Dilutive Common Stock Equivalents Outstanding (Detail) - shares | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Anti-dilutive common stock equivalents | 4,956,739 | 3,992,719 |
Stock Options [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Anti-dilutive common stock equivalents | 4,915,956 | 3,985,935 |
Restricted Stock Units [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Anti-dilutive common stock equivalents | 29,100 | |
Employee Stock Purchase Plan [Member] | ||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||
Anti-dilutive common stock equivalents | 11,683 | 6,784 |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Line Items] | ||||
Provision for income taxes | $ 0 | |||
Federal operating loss carryforwards | 482,900,000 | |||
State operating loss carryforwards | $ 479,900,000 | |||
Federal and state net operating loss carryforwards expiration year | 2,031 | |||
Federal orphan drug tax credit carry forwards | $ 40,000,000 | |||
Tax credit carry forwards expiration period | 2,034 | |||
U.S. corporate tax rate | 34.00% | 34.00% | 34.00% | |
Reduction to deferred tax asset | $ 66,400,000 | |||
Change in amount of deferred tax assets | 70,400,000 | |||
Valuation allowance | 205,441,000 | $ 135,072,000 | ||
Accrued interest or penalties related to uncertain tax positions | 0 | 0 | ||
Uncertain tax positions | 0 | |||
ASU 2016-09 [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Increase in deferred tax assets associated with net operating losses | 8,000,000 | |||
Increase in deferred tax assets associated with federal and state research credits | $ 1,400,000 | |||
ASU 2015-17 [Member] | ASU Early Adoption [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Decrease in deferred tax liability current | $ (600,000) | |||
Increase in deferred tax liability non-current | $ 600,000 | |||
Scenario Forecast [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
U.S. corporate tax rate | 21.00% | |||
Domestic Tax Authority [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Research and development tax credits carryforwards | $ 12,700,000 | |||
Research and development tax credits carryforwards expiration year | 2,031 | |||
State and Local Jurisdiction [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Research and development tax credits carryforwards | $ 2,300,000 | |||
Research and development tax credits carryforwards expiration year | 2,027 |
Income Taxes - Summary of Recon
Income Taxes - Summary of Reconciliation of U.S. Statutory Rate to Company's Effective Tax Rate (Detail) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Tax due at statutory rate | 34.00% | 34.00% | 34.00% |
State taxes, net of federal | 5.10% | 4.20% | 4.00% |
Stock-based compensation | 6.40% | (1.00%) | (0.90%) |
Foreign rate differential | (3.20%) | (3.10%) | (3.10%) |
Federal and state credits | 7.20% | 10.30% | 13.20% |
Change in valuation allowance | (22.50%) | (41.50%) | (43.10%) |
Other | 0.10% | ||
Federal and state rate change | (24.60%) | ||
Research and orphan drug credit addback | (2.40%) | (2.90%) | (4.20%) |
Total effective tax rate | 0.00% | 0.00% | 0.00% |
Income Taxes - Summary of Signi
Income Taxes - Summary of Significant Components of Company's Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Income Tax Disclosure [Abstract] | ||
Net operating losses | $ 131,151 | $ 84,374 |
Capitalized start-up costs | 1,362 | 2,155 |
Accounting method change | (673) | |
Tax credit carryforwards | 54,523 | 33,477 |
Accrued expenses | 3,057 | 2,287 |
Depreciation and amortization | 685 | 999 |
Stock options | 13,573 | 12,103 |
Others | 1,090 | 350 |
Total net deferred tax asset before valuation allowance | 205,441 | 135,072 |
Valuation allowance | $ (205,441) | $ (135,072) |
Employee Benefit Plan - Additio
Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Postemployment Benefits [Abstract] | |||
Employer matching contribution, percent of match | 50.00% | 50.00% | 50.00% |
Maximum annual contributions per employee, percent | 6.00% | 6.00% | 6.00% |
Employer contribution | $ 0.9 | $ 0.4 | $ 0.2 |
Selected Quarterly Financial 56
Selected Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Quarterly Financial Information Disclosure [Abstract] | |||||||||||
Total operating expenses | $ 70,448 | $ 74,373 | $ 70,854 | $ 57,480 | $ 56,379 | $ 38,064 | $ 35,006 | $ 30,714 | $ 273,155 | $ 160,163 | $ 94,650 |
Loss from operations | (70,448) | (74,373) | (70,854) | (57,480) | (56,379) | (38,064) | (35,006) | (30,714) | (273,155) | (160,163) | (94,650) |
Net loss | $ (69,421) | $ (73,719) | $ (70,202) | $ (56,778) | $ (55,901) | $ (37,796) | $ (34,747) | $ (30,543) | $ (270,120) | $ (158,987) | $ (94,495) |
Net loss per share—basic and diluted | $ (1.75) | $ (1.97) | $ (1.88) | $ (1.52) | $ (1.50) | $ (1.15) | $ (1.08) | $ (0.97) | $ (7.09) | $ (4.75) | $ (3.40) |
Subsequent Event - Additional I
Subsequent Event - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions | Feb. 13, 2018 | Nov. 17, 2017 | Sep. 14, 2016 | Jan. 12, 2016 | Apr. 20, 2015 |
Subsequent Event [Line Items] | |||||
Issuance of common stock, shares | 4,058,822 | 5,062,892 | 3,157,894 | 2,628,571 | |
Common stock price per share | $ 85 | $ 39.75 | $ 47.50 | $ 52.50 | |
Proceeds from public offering of common stock, net of commissions and underwriting discounts and estimated offering expenses payable | $ 325.8 | $ 189.2 | $ 140.4 | $ 129.1 | |
Subsequent Event [Member] | |||||
Subsequent Event [Line Items] | |||||
Issuance of common stock, shares | 4,032,012 | ||||
Common stock price per share | $ 164 | ||||
Proceeds from public offering of common stock, net of commissions and underwriting discounts and estimated offering expenses payable | $ 631.1 |