Document and Entity Information
Document and Entity Information - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Jan. 31, 2018 | Jun. 30, 2017 | |
Document and Entity Information | |||
Entity Registrant Name | ACCELERON PHARMA INC | ||
Entity Central Index Key | 1,280,600 | ||
Document Type | 10-K | ||
Document Period End Date | Dec. 31, 2017 | ||
Amendment Flag | false | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Voluntary Filers | No | ||
Entity Current Reporting Status | Yes | ||
Entity Filer Category | Large Accelerated Filer | ||
Entity Public Float | $ 999 | ||
Entity Common Stock, Shares Outstanding | 45,419,061 | ||
Document Fiscal Year Focus | 2,017 | ||
Document Fiscal Period Focus | FY |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Current assets: | ||
Cash and cash equivalents | $ 100,150 | $ 20,950 |
Short-term investments | 177,077 | 118,740 |
Collaboration receivables (all amounts are with a related party) | 3,570 | 3,234 |
Prepaid expenses and other current assets | 4,446 | 3,862 |
Total current assets | 285,243 | 146,786 |
Property and equipment, net | 6,966 | 5,201 |
Long-term investments | 95,723 | 94,692 |
Restricted cash | 1,132 | 946 |
Other assets | 113 | 22 |
Total assets | 389,177 | 247,647 |
Current liabilities: | ||
Accounts payable | 1,086 | 1,590 |
Accrued expenses | 14,936 | 13,249 |
Deferred revenue | 541 | 541 |
Deferred rent | 182 | 769 |
Total current liabilities | 16,745 | 16,149 |
Deferred revenue, net of current portion | 3,161 | 3,704 |
Deferred rent, net of current portion | 1,818 | 953 |
Warrants to purchase common stock | 2,236 | 1,244 |
Total liabilities | 23,960 | 22,050 |
Commitments and contingencies (Note 8) | 0 | 0 |
Stockholders' equity: | ||
Undesignated preferred stock, $0.001 par value: 25,000,000 shares authorized and no shares issued or outstanding | 0 | 0 |
Common stock, $0.001 par value: 175,000,000 shares authorized; 45,261,175 and 38,251,826, shares issued and outstanding at December 31, 2017 and 2016, respectively | 46 | 39 |
Additional paid-in capital | 839,090 | 590,474 |
Accumulated deficit | (473,024) | (364,491) |
Accumulated other comprehensive loss | (895) | (425) |
Total stockholders' equity | 365,217 | 225,597 |
Total liabilities and stockholders' equity | $ 389,177 | $ 247,647 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2017 | Dec. 31, 2016 |
Statement of Financial Position [Abstract] | ||
Preferred stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
Undesignated preferred stock shares authorized (in shares) | 25,000,000 | 25,000,000 |
Preferred stock, shares issued (in shares) | 0 | 0 |
Preferred stock, shares outstanding (in shares) | 0 | 0 |
Common stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
Common stock, shares authorized (in shares) | 175,000,000 | 175,000,000 |
Common stock, shares issued (in shares) | 45,261,175 | 38,251,826 |
Common stock, shares outstanding (in shares) | 45,261,175 | 38,251,826 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Collaboration revenue: | |||
License and milestone | $ 541 | $ 15,550 | $ 1,184 |
Cost-sharing, net | 12,940 | 12,221 | 16,913 |
Total revenue (all amounts are with a related party) | 13,481 | 27,771 | 18,097 |
Costs and expenses: | |||
Research and development | 89,726 | 68,580 | 58,404 |
General and administrative | 33,738 | 25,297 | 20,572 |
Total costs and expenses | 123,464 | 93,877 | 78,976 |
Loss from operations | (109,983) | (66,106) | (60,879) |
Other (expense) income, net | (992) | 7,262 | (3,527) |
Interest income | 2,553 | 1,854 | 512 |
Total other income (expense), net | 1,561 | 9,116 | (3,015) |
Loss before income taxes | (108,422) | (56,990) | (63,894) |
Income tax provision | (32) | (24) | 0 |
Net loss | (108,454) | (57,014) | (63,894) |
Other comprehensive loss: | |||
Net unrealized holding losses on short-term and long-term investments during the period | (470) | (205) | (220) |
Comprehensive loss | $ (108,924) | $ (57,219) | $ (64,114) |
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share) | $ (2.68) | $ (1.52) | $ (1.92) |
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders-basic and diluted (in shares) | 40,420 | 37,430 | 33,303 |
Consolidated Statements of Stoc
Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock | Additional Paid-In Capital | Accumulated Deficit | Comprehensive Loss |
Stockholders' equity beginning balance at Dec. 31, 2014 | $ 156,285 | $ 33 | $ 399,835 | $ (243,583) | $ 0 |
Stockholders' equity beginning balance (in shares) at Dec. 31, 2014 | 32,432,025 | ||||
AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||||
Stock-based compensation | 12,075 | 12,075 | |||
Exercise of stock options | 3,963 | $ 1 | 3,962 | ||
Exercise of stock options (in shares) | 837,361 | ||||
Issuance of common stock related to ESPP | 589 | 589 | |||
Issuance of common stock related to ESPP (in shares) | 23,787 | ||||
Net exercise of warrants to purchase common stock | 465 | 465 | |||
Net exercise of warrants to purchase common stock (in shares) | 20,182 | ||||
Net exercise of warrants to purchase common stock | (220) | (220) | |||
Net loss | (63,894) | (63,894) | |||
Stockholders' equity ending balance at Dec. 31, 2015 | 109,263 | $ 34 | 416,926 | (307,477) | (220) |
Stockholders' equity ending balance (in shares) at Dec. 31, 2015 | 33,313,355 | ||||
AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||||
Stock-based compensation | 18,557 | 18,557 | |||
Issuance of common stock | 140,344 | $ 4 | 140,340 | ||
Issuance of common stock (in shares) | 3,750,000 | ||||
Exercise of stock options | 5,312 | $ 1 | 5,311 | ||
Exercise of stock options (in shares) | 885,075 | ||||
Issuance of common stock related to ESPP | 658 | 658 | |||
Issuance of common stock related to ESPP (in shares) | 30,671 | ||||
Net exercise of warrants to purchase common stock | 8,682 | 8,682 | |||
Net exercise of warrants to purchase common stock (in shares) | 272,725 | ||||
Net exercise of warrants to purchase common stock | (205) | (205) | |||
Net loss | (57,014) | (57,014) | |||
Stockholders' equity ending balance at Dec. 31, 2016 | 225,597 | $ 39 | 590,474 | (364,491) | (425) |
Stockholders' equity ending balance (in shares) at Dec. 31, 2016 | 38,251,826 | ||||
AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||||
Effect of adoption of ASU 2016-09 | 79 | (79) | |||
Stock-based compensation | 28,248 | 28,248 | |||
Issuance of common stock | 215,802 | $ 6 | 215,796 | ||
Issuance of common stock (in shares) | 6,216,216 | ||||
Exercise of stock options | $ 3,893 | $ 1 | 3,892 | ||
Exercise of stock options (in shares) | 474,000 | 474,056 | |||
Vesting of restricted stock units | $ (226) | (226) | |||
Vesting of restricted stock units (in shares) | 282,158 | ||||
Issuance of common stock related to ESPP | 827 | 827 | |||
Issuance of common stock related to ESPP (in shares) | 33,698 | ||||
Net exercise of warrants to purchase common stock | 0 | ||||
Net exercise of warrants to purchase common stock (in shares) | 3,221 | ||||
Net exercise of warrants to purchase common stock | (470) | (470) | |||
Net loss | (108,454) | (108,454) | |||
Stockholders' equity ending balance at Dec. 31, 2017 | $ 365,217 | $ 46 | $ 839,090 | $ (473,024) | $ (895) |
Stockholders' equity ending balance (in shares) at Dec. 31, 2017 | 45,261,175 |
Consolidated Statements of Sto6
Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Statement of Stockholders' Equity [Abstract] | ||
Issuance costs | $ 397 | $ 665 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Operating Activities | |||
Net loss | $ (108,454) | $ (57,014) | $ (63,894) |
Adjustments to reconcile net loss to net cash used in operating activities: | |||
Depreciation and amortization | 2,825 | 1,676 | 1,176 |
Stock-based compensation | 28,248 | 18,557 | 12,075 |
Change in fair value of warrants | 992 | (7,262) | 3,528 |
Other non-cash items | 176 | (8) | (372) |
Changes in assets and liabilities: | |||
Prepaid expenses and other current assets | (675) | (1,411) | 7 |
Collaboration receivables (all amounts are with a related party) | (336) | 394 | (261) |
Accounts payable | (504) | 644 | 151 |
Accrued expenses | 1,493 | 524 | 4,976 |
Deferred revenue | (543) | (549) | (1,184) |
Deferred rent | 234 | (96) | (519) |
Restricted cash | (186) | (150) | 106 |
Net cash used in operating activities | (76,730) | (44,695) | (44,211) |
Investing Activities | |||
Purchase of investments | (179,935) | (218,314) | (134,697) |
Proceeds from sales and maturities of investments | 119,965 | 112,889 | 26,685 |
Purchases of property and equipment | (4,396) | (3,380) | (959) |
Net cash used in investing activities | (64,366) | (108,805) | (108,971) |
Financing Activities | |||
Proceeds from issuance of common stock from public offering, net of issuance costs | 215,802 | 140,697 | (47) |
Payments for withholding taxes on restricted stock units | (226) | 0 | 0 |
Proceeds from issuances of common stock related to employee stock purchase plan | 827 | 658 | 589 |
Proceeds from exercise of stock options and warrants to purchase common stock | 3,893 | 5,312 | 3,963 |
Net cash provided by financing activities | 220,296 | 146,667 | 4,505 |
Net increase (decrease) in cash and cash equivalents | 79,200 | (6,833) | (148,677) |
Cash and cash equivalents at beginning of year | 20,950 | 27,783 | 176,460 |
Cash and cash equivalents at end of year | 100,150 | 20,950 | 27,783 |
Supplemental Disclosure of Non-Cash Investing and Financing Activities: | |||
Reclassification of warrant liability to additional paid-in capital | 0 | 8,682 | 465 |
Capitalized follow-on public offering costs included in accrued expenses | 0 | 0 | 306 |
Purchase of property and equipment included in accounts payable and accrued expenses | $ 194 | $ 397 | $ 270 |
Nature of Business
Nature of Business | 12 Months Ended |
Dec. 31, 2017 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Nature of Business | Nature of Business Acceleron Pharma Inc. (Acceleron or the Company) is a Cambridge, Massachusetts-based clinical stage biopharmaceutical company dedicated to the discovery, development and commercialization of therapeutics to treat serious and rare diseases. The Company's leadership in the understanding of TGF-beta biology and protein engineering generates innovative compounds that engage the body's ability to regulate cellular growth and repair. The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, the risk that the Company never achieves profitability, the need for substantial additional financing, risk of relying on third parties, risks of clinical trial failures, dependence on key personnel, protection of proprietary technology and compliance with government regulations. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | Summary of Significant Accounting Policies The accompanying consolidated financial statements reflect the application of certain significant accounting policies as described below and elsewhere in these notes to the consolidated financial statements. The Company believes that a significant accounting policy is one that is both important to the portrayal of the Company's financial condition and results, and requires management's most difficult, subjective, or complex judgments, often as the result of the need to make estimates about the effect of matters that are inherently uncertain. Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its wholly-owned subsidiary, Acceleron Securities Corp. All significant intercompany balances and transactions have been eliminated in consolidation. Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts expensed during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the consolidated financial statements if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. In preparing these consolidated financial statements, management used significant estimates in the following areas, among others: revenue recognition, stock-based compensation expense, the determination of the fair value of stock-based awards, the fair value of liability-classified warrants, accrued expenses, and the recoverability of the Company's net deferred tax assets and related valuation allowance. Collaboration Receivable Credit is extended to customers based upon an evaluation of the customer's financial condition. Collaboration receivables are recorded at net realizable value. The Company does not charge interest on past due balances. Collaboration receivables are determined to be past due when the payment due date is exceeded. The Company utilizes a specific identification accounts receivable reserve methodology based on a review of outstanding balances and previous activities to determine the allowance for doubtful accounts. The Company charges off uncollectible receivables at the time the Company determines the receivable is no longer collectible. The Company did not have an allowance for doubtful accounts at December 31, 2017 or 2016 . Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision making group, in making decisions on how to allocate resources and assess performance. The Company's chief operating decision maker is the chief executive officer. The Company and the chief executive officer view the Company's operations and manage its business as one operating segment, which is the discovery, development and commercialization of highly innovative therapeutics to treat serious and rare diseases. All material long-lived assets of the Company reside in the United States. The Company does use contract research organizations (CROs) and research institutions located outside the United States. Some of these expenses are subject to collaboration reimbursement which is presented as a component of cost-sharing, net in the consolidated statements of operations and comprehensive loss. Cash, Cash Equivalents and Short-term and Long-term Investments The Company considers all highly liquid investments purchased with original maturities of 90 days or less at the date of acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in interest-bearing money market accounts. Cash equivalents are carried at cost, which approximates their fair market value. The Company determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified all of its marketable securities at December 31, 2017 and 2016 as “available-for-sale” pursuant to ASC 320, Investments – Debt and Equity Securities. The Company records available-for-sale securities at fair value, with the unrealized gains and losses included in accumulated other comprehensive income (loss) in stockholders’ equity. There were no realized gains or losses on marketable securities for the years ended December 31, 2017 , 2016 and 2015 . Investments not classified as cash equivalents are presented as either short-term or long-term investments based on both their maturities as well as the time period the Company intends to hold such securities. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income in the accompanying consolidated statements of operations and comprehensive loss. The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the consolidated statements of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period. The aggregate fair value of securities held by the Company in an unrealized loss position for less than twelve months as of December 31, 2017 and December 31, 2016 was $193.6 million and $172.2 million , respectively. The aggregate fair value of securities held by the Company in an unrealized loss position for more than twelve months as of December 31, 2017 and December 31, 2016 was $67.0 million and $5.5 million , respectively. The aggregate unrealized loss for those securities in an unrealized loss position for more than twelve months was $0.3 million and $2,000 , respectively. The Company evaluated its securities for other-than-temporary impairment and considered the decline in market value for the securities to be primarily attributable to current economic and market conditions. It is not more likely than not that the Company will be required to sell the securities, and the Company does not intend to do so prior to the recovery of the amortized cost basis. Based on this analysis, these marketable securities were not considered to be other-than-temporarily impaired as of December 31, 2017 and December 31, 2016 . Concentrations of Credit Risk and Off-Balance Sheet Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash, cash equivalents, restricted cash, short-term and long-term investments and collaboration receivables. The Company maintains its cash and cash equivalent balances and short-term and long-term investments with financial institutions that management believes are creditworthy. Short-term and long-term investments consist of investment grade corporate obligations, treasury notes, asset backed securities, and certificates of deposit. The Company's investment policy includes guidelines on the quality of the institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentrations of credit risk. The Company routinely assesses the creditworthiness of its customers and collaboration partners. The Company has not experienced any material losses related to receivables from individual customers and collaboration partners, or groups of customers. The Company does not require collateral. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's collaboration receivables. Disclosure of Fair Value of Financial Instruments The Company's financial instruments include cash, cash equivalents, short-term and long-term investments, collaboration receivables, common stock warrants, accounts payable, and accrued expenses. See discussion below on the determination of the fair value of the Company's common stock warrants and short-term and long-term investments. The carrying value of the remainder of the Company's financial instruments approximated their fair values at December 31, 2017 and 2016 due to the short-term nature of these instruments. The Company has evaluated the estimated fair value of financial instruments using available market information and management's estimates. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. Fair Value Measurements ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company's own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company's assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: • Level 1—Quoted market prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates, and yield curves. • Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Items measured at fair value on a recurring basis include short-term and long-term investments (Note 5), and warrants to purchase common stock (Note 7). During the periods presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. The following tables set forth the Company's financial instruments carried at fair value using the lowest level of input applicable to each financial instrument as of December 31, 2017 and 2016 (in thousands): December 31, 2017 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 90,702 $ — $ — $ 90,702 Corporate obligations — 158,849 — 158,849 U.S. Treasury securities — 37,813 — 37,813 Certificates of deposit — 12,244 — 12,244 Mortgage and other asset backed securities — 67,888 — 67,888 Restricted cash 1,132 — — 1,132 Total assets $ 91,834 $ 276,794 $ — $ 368,628 Liabilities: Warrants to purchase common stock $ — $ — $ 2,236 $ 2,236 Total liabilities $ — $ — $ 2,236 $ 2,236 December 31, 2016 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 19,818 $ — $ — $ 19,818 Corporate obligations — 88,492 — 88,492 U.S. Treasury securities — 33,968 — 33,968 Certificates of deposit — 23,373 — 23,373 Mortgage and other asset backed securities — 67,599 — 67,599 Restricted cash 946 — — 946 Total assets $ 20,764 $ 213,432 $ — $ 234,196 Liabilities: Warrants to purchase common stock $ — $ — $ 1,244 $ 1,244 Total liabilities $ — $ — $ 1,244 $ 1,244 The money market funds noted above are included in cash and cash equivalents in the accompanying consolidated balance sheets. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the years ended December 31, 2017 and 2016 . The following table sets forth a summary of changes in the fair value of the Company's common stock warrant liabilities, which represent a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Year Ended December 31, 2017 2016 Beginning balance $ 1,244 $ 17,187 Change in fair value 992 (7,262 ) Exercises — (8,681 ) Ending balance $ 2,236 $ 1,244 The fair value of the warrants to purchase common stock on the date of issuance and on each re-measurement date for those warrants classified as liabilities was estimated using either the Monte Carlo simulation framework, which incorporates future financing events over the remaining life of the warrants to purchase common stock, or for certain re-measurement dates, due to the warrants being deeply in the money, the Black-Scholes option pricing model. The Black-Scholes method of valuation involves using inputs such as the fair value of the Company's stock, stock price volatility, the contractual term of the warrants, risk-free interest rates, and dividend yields. At each reporting period the Company evaluates the best valuation methodology. At December 31, 2017 , the Black-Scholes option pricing model was used, at December 31, 2016 the Monte Carlo simulation framework was used, and at December 31, 2015 , the Black-Scholes option pricing model was used. Due to the nature of these inputs, the valuation of the warrants is considered a Level 3 measurement. See Note 7 for further discussions of the accounting for the warrants, as well as for a summary of the significant inputs and assumptions used to determine the fair value of the warrants. The Company measures eligible assets and liabilities at fair value, with changes in value recognized in earnings. Fair value treatment may be elected either upon initial recognition of an eligible asset or liability or, for an existing asset or liability, if an event triggers a new basis of accounting. The Company did not elect to remeasure any of its existing financial assets or liabilities, and did not elect the fair value option for any financial assets and liabilities transacted in the years ended December 31, 2017 or 2016 . Property and Equipment Property and equipment is stated at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which are as follows: Asset Estimated Useful Life Computer equipment and software 3 years Office and laboratory equipment 3 years Leasehold improvements Shorter of the useful life or remaining lease term The Company reviews long-lived assets when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparison of the book values of the assets to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets. No impairment losses have been recorded during the years ended December 31, 2017 , 2016 and 2015 . Revenue Recognition The company has primarily generated revenue through collaboration, license and research arrangements with collaboration partners for the development and commercialization of therapeutic candidates. The Company recognizes revenue in accordance with FASB ASC Topic 605, Revenue Recognition . Accordingly, revenue is recognized for each unit of accounting when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company's consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, current portion. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Multiple Element Revenue Arrangements The Company enters into collaboration agreements from time to time, which are more fully described in Note 10. The arrangements generally contain multiple elements or deliverables, which may include (1) licenses, or options to obtain licenses, to the Company's technology, (2) research and development activities performed for the collaboration partner, (3) participation on Joint Development Committees, and (4) the manufacturing of clinical or preclinical material. Payments pursuant to these arrangements typically include non-refundable, upfront payments, milestone payments upon achieving significant development events, research and development reimbursements, sales milestones, and royalties on future product sales. Effective January 1, 2011, the Company adopted ASU No. 2009-13, Multiple-Deliverable Revenue Arrangements (ASU 2009-13), which amends ASC Topic 605-25, Revenue Recognition—Multiple Element Arrangements (ASC 605-25). The Company applies this guidance to new arrangements as well as existing agreements that are significantly modified after January 1, 2011. For agreements that are significantly modified, the Company determines the estimated selling price for the remaining undelivered elements as of the date of the material modification and allocates arrangement consideration based upon the estimated selling price to the undelivered elements. The application of the multiple element guidance requires subjective determinations, and requires management to make judgments about the individual deliverables, and whether such deliverables are separable from the other aspects of the contractual relationship. Deliverables are considered separate units of accounting provided that: (1) the delivered item(s) has value to the customer on a stand-alone basis and (2) if the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. In determining the units of accounting, management evaluates certain criteria, including whether the deliverables have stand-alone value, based on the consideration of the relevant facts and circumstances for each arrangement, such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can use the other deliverable(s) for their intended purpose without the receipt of the remaining element(s), whether the value of the deliverable is dependent on the undelivered item(s) and whether there are other vendors that can provide the undelivered element(s). Arrangement consideration that is fixed or determinable is allocated among the separate units of accounting using the relative selling price method, and the applicable revenue recognition criteria, as described above, are applied to each of the separate units of accounting in determining the appropriate period or pattern of recognition. The Company determines the estimated selling price for deliverables within each agreement using vendor-specific objective evidence (VSOE) of selling price, if available, third-party evidence (TPE) of selling price if VSOE is not available, or management's best estimate of selling price (BESP) if neither VSOE nor TPE is available. Subsequent to the adoption of ASU 2009-13, the Company typically uses BESP to estimate the selling price of the deliverables. Determining the BESP for a unit of accounting requires significant judgment. In developing the BESP for a unit of accounting, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company validates the BESP for units of accounting by evaluating whether changes in the key assumptions used to determine the BESP will have a significant effect on the allocation of arrangement consideration between multiple units of accounting. The Company typically receives upfront, non-refundable payments when licensing its intellectual property in conjunction with a collaboration agreement. When management believes the license to its intellectual property does not have stand-alone value from the other deliverables to be provided in the arrangement, the Company generally recognizes revenue attributed to the license on a straight-line basis over the contractual or estimated performance period, which is typically the term of the Company's research and development or manufacturing obligations. The Company continually evaluates these periods, and will adjust the period of revenue recognition if circumstances change. When management believes the license to its intellectual property has stand-alone value, the Company generally recognizes revenue attributed to the license upon delivery. Research and development funding is recognized as revenue in the period that the related services are performed. When the Company acts as the principal under its collaboration agreements, it records payments received for the reimbursement of research and development costs as cost-sharing revenue in the consolidated statements of operations and comprehensive loss. To the extent that the Company reimburses the collaborator for costs incurred, the Company records these costs as a reduction of cost-sharing revenue. The Company's agreements may contain options which provide the collaboration partner the right to obtain additional licenses. Options are considered substantive if, at the inception of the arrangement, the Company is at risk as to whether the collaboration partner will choose to exercise the option. Factors considered in evaluating whether an option is substantive include the overall objective of the arrangement, the benefit the collaborator might obtain from the arrangement without exercising the option, the cost to exercise the option and the likelihood that the option will be exercised. For arrangements under which an option is considered substantive, the Company does not consider the item underlying the option to be a deliverable at the inception of the arrangement and the associated option fees are not included in allocable arrangement consideration, assuming the option is not priced at a significant and incremental discount. Conversely, for arrangements under which an option is not considered substantive or if an option is priced at a significant and incremental discount, the Company would consider the item underlying the option to be a deliverable at the inception of the arrangement and a corresponding amount would be included in allocable arrangement consideration. Effective January 1, 2011, the Company adopted ASU No. 2010-17, Revenue Recognition—Milestone Method (ASU 2010-17). At the inception of each arrangement that includes milestone payments, the Company evaluates, with respect to each milestone, whether the milestone is substantive and at-risk. This evaluation includes an assessment of whether (a) the consideration is commensurate with either (1) the entity's performance to achieve the milestone, or (2) the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting at least in part from the entity's performance to achieve the milestone, (b) the consideration relates solely to past performance, and (c) the consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. The Company evaluates factors such as the scientific, regulatory, commercial, and other risks that must be overcome to achieve the respective milestone, the level of effort and investment required to achieve the respective milestone, and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement in making this assessment. On the milestone achievement date, assuming all other revenue recognition criteria are met and the milestone is deemed substantive and at-risk, the Company recognizes the payment as license and milestone revenue. For milestones that are not deemed substantive and at-risk, where payment is reasonably assured, the Company recognizes the milestone payment over the remaining service period. Sales and commercial milestones and royalties will be recognized when and if earned, provided collectability is reasonably assured. Research and Development Expenses Research and development costs are charged to expense as costs are incurred in performing research and development activities. Research and development costs include all direct costs, including salaries, stock compensation and benefits for research and development personnel, outside consultants, costs of clinical trials, sponsored research, clinical trials insurance, other outside costs, depreciation and facility costs related to the development of drug candidates. The Company records upfront, non-refundable payments made to outside vendors, or other payments made in advance of services performed or goods being delivered, as prepaid expenses, which are expensed as services are performed or the goods are delivered. Certain research and development projects are, or have been, partially funded by collaboration agreements, and the expenses related to these activities are included in research and development costs. The Company records the related reimbursement of research and development costs under these agreements as revenue, as more fully described above and in Note 10. Stock-Based Compensation At December 31, 2017 , the Company had two stock-based compensation plans, which are more fully described in Note 11. The Company accounts for stock-based compensation in accordance with the provisions of ASC Topic 718, Compensation—Stock Compensation (ASC 718), which requires the recognition of expense related to the fair value of stock-based compensation awards in the consolidated statements of operations and comprehensive loss. For stock-based awards issued to employees and members of the Company's board of directors (the Board) for their services on the Board and for participation in the employee stock purchase plan, the Company estimates the grant date fair value of each option award using the Black-Scholes option pricing model. The use of the Black-Scholes option pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk-free interest rates and expected dividend yields of the common stock. For awards subject to service-based vesting conditions, the Company recognizes stock-based compensation expense, equal to the grant date fair value of stock options on a straight-line basis over the requisite service period, which is generally the vesting term. For awards subject to both performance and service-based vesting conditions, the Company recognizes stock-based compensation expense using an accelerated recognition method when it is probable that the performance condition will be achieved. If achievement of the performance condition is not probable, but the award will vest based on the service condition, expense is recognized over the requisite service period. Share-based payments issued to non-employees are recorded at their fair values, and are periodically revalued as the equity instruments vest and are recognized as expense over the related service period in accordance with the provisions of ASC 718 and ASC Topic 505 (ASC 505), Equity . For stock-based awards granted to non-employees, the Company recognizes stock-based compensation expense using an accelerated recognition method. Effective January 1, 2017, the Company adopted ASU 2016-09, Compensation - Stock Compensation, Improvements to Employee Share-Based Payment Accounting . In connection with the adoption of this standard, the Company records actual forfeitures as they occur, rather than estimating forfeitures by applying a forfeiture rate. See Note 11 for a discussion of the assumptions used by the Company in determining the grant date fair value of options granted under the Black-Scholes option pricing model, as well as a summary of the stock option activity under the Company's stock-based compensation plans for the year ended December 31, 2017 . Income Taxes Income taxes are recorded in accordance with ASC Topic 740, Income Taxes (ASC 740), which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided, if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for u |
Property and Equipment, Net
Property and Equipment, Net | 12 Months Ended |
Dec. 31, 2017 | |
Property, Plant and Equipment [Abstract] | |
Property and Equipment, Net | Property and Equipment, Net Property and equipment, net, consists of the following (in thousands): December 31, 2017 2016 Computer equipment and software $ 1,501 $ 1,260 Office equipment 522 519 Laboratory equipment 17,268 13,204 Leasehold improvements 11,501 11,126 Construction in progress 584 849 Total property and equipment 31,376 26,958 Accumulated depreciation and amortization (24,410 ) (21,757 ) Property and equipment, net $ 6,966 $ 5,201 Depreciation and amortization expense was $2.8 million , $1.7 million and $1.2 million for the years ending December 31, 2017 , 2016 and 2015 respectively. |
Restricted Cash
Restricted Cash | 12 Months Ended |
Dec. 31, 2017 | |
Cash and Cash Equivalents [Abstract] | |
Restricted Cash | Restricted Cash As of December 31, 2017 , and 2016 , the Company maintained letters of credit totaling $1.1 million and $0.9 million respectively, held in the form of certificates of deposit as collateral for the Company's facility lease obligations and its credit cards. |
Cash, Cash Equivalents and Shor
Cash, Cash Equivalents and Short-term and Long-term Investments | 12 Months Ended |
Dec. 31, 2017 | |
Cash and Cash Equivalents [Abstract] | |
Cash, Cash Equivalents and Short-term and Long-term Investments | Cash, Cash Equivalents and Short-term and Long-term Investments The following is a summary of cash, cash equivalents and available-for-sale securities as of December 31, 2017 and December 31, 2016 (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 100,150 $ — $ — $ 100,150 Available-for-sale securities: Corporate obligations due in one year or less 99,792 — (219 ) 99,573 Corporate obligations due in more than one year 57,537 — (261 ) 57,276 U.S. Treasury securities due in one year or less 27,987 — (93 ) 27,894 U.S. Treasury securities due in more than one year 9,968 — (48 ) 9,920 Certificates of deposit due in one year or less 10,529 — — 10,529 Certificates of deposit due in more than one year 1,715 — — 1,715 Mortgage and other asset backed securities due in one year or less 39,236 — (155 ) 39,081 Mortgage and other asset backed securities due in more than one year 26,931 — (119 ) 26,812 Total available-for-sale securities $ 273,695 $ — $ (895 ) $ 272,800 Total cash, cash equivalents and available-for-sale securities $ 373,845 $ — $ (895 ) $ 372,950 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 20,950 $ — $ — $ 20,950 Available-for-sale securities: Corporate obligations due in one year or less 45,839 1 (58 ) 45,782 Corporate obligations due in more than one year 42,895 — (185 ) 42,710 U.S. Treasury securities due in one year or less 22,490 — (10 ) 22,480 U.S. Treasury securities due in more than one year 11,541 — (53 ) 11,488 Certificates of deposit due in one year or less 13,562 — — 13,562 Certificates of deposit due in more than one year 9,811 — — 9,811 Mortgage and other asset backed securities due in one year or less 36,948 — (32 ) 36,916 Mortgage and other asset backed securities due in more than one year 30,771 — (88 ) 30,683 Total available-for-sale securities $ 213,857 $ 1 $ (426 ) $ 213,432 Total cash, cash equivalents and available-for-sale securities $ 234,807 $ 1 $ (426 ) $ 234,382 |
Accrued Expenses
Accrued Expenses | 12 Months Ended |
Dec. 31, 2017 | |
Payables and Accruals [Abstract] | |
Accrued Expenses | Accrued Expenses Accrued expenses consist of the following (in thousands): December 31, 2017 2016 Research and development related $ 4,014 $ 5,238 Employee compensation 6,809 4,840 Professional services 1,183 739 Other 2,930 2,432 Total accrued expenses $ 14,936 $ 13,249 |
Warrants
Warrants | 12 Months Ended |
Dec. 31, 2017 | |
Warrants and Rights Note Disclosure [Abstract] | |
Warrants | Warrants Below is a summary of the number of shares issuable upon exercise of outstanding warrants and the terms and accounting treatment for the outstanding warrants (in thousands, except per share data): Warrants as of Weighted- Average Exercise Balance Sheet Classification December 31, 2017 December 31, 2016 Price Per Share Expiration December 31, 2017 December 31, 2016 Warrants to purchase common stock 61 61 $ 5.88 June 10, 2020 - July 9, 2020 Liability Liability Warrants to purchase common stock — 4 4.00 - 7.40 March 28, 2017 - December 31, 2017 Equity(1) (2) (3) Equity(1) (2) (3) All warrants 61 65 $ 5.88 ______________________________________________________________________ (1) In March 2017, the warrant holders exercised warrants to purchase 1,187 shares of Common Stock on a net basis, resulting in the issuance of 1,014 shares of Common Stock. (2) In December 2017, the warrant holders exercised warrants to purchase 2,702 shares of Common Stock on a net basis, resulting in the issuance of 2,207 shares of Common Stock. (3) Warrants to purchase common stock were issued in connection with various debt financing transactions that were consummated prior to our initial public offering. In connection with the Series E redeemable convertible preferred stock (Series E Preferred Stock) financing transactions that took place in June 2010 and July 2010, the Company issued warrants to purchase up to 871,580 shares of common stock. Each warrant was immediately exercisable and expires ten years from the original date of issuance. The warrants to purchase shares of the Company's common stock have an exercise price equal to the estimated fair value of the underlying instrument as of the initial date such warrants were issued. Each warrant is exercisable on either a physical settlement or net share settlement basis from the date of issuance. The warrant agreement contains a provision requiring an adjustment to the number of shares in the event the Company issues common stock, or securities convertible into or exercisable for common stock, at a price per share lower than the warrant exercise price. The Company concluded the anti-dilution feature required the warrants to be classified as liabilities under ASC Topic 815, Derivatives and Hedging—Contracts in Entity's Own Equity (ASC 815). The warrants are measured at fair value, with changes in fair value recognized as a gain or loss to other income (expense) in the consolidated statements of operations and comprehensive loss for each reporting period thereafter. The fair value of the common stock warrants was recorded as a discount to the preferred stock issued, and the preferred stock was accreted to the redemption value. At the end of each reporting period, the Company remeasured the fair value of the outstanding warrants, using current assumptions, resulting in an increase (decrease) in fair value of $1.0 million , $(7.3) million and $3.5 million , respectively, which was recorded in other income (expense), net in the accompanying consolidated statements of operations and comprehensive loss for the years ended December 31, 2017 , 2016 and 2015 . The Company will continue to re-measure the fair value of the liability associated with the warrants to purchase common stock at the end of each reporting period until the earlier of the exercise or the expiration of the applicable warrants. All outstanding warrants were fully vested and exercisable as of December 31, 2017 . |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2017 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | Commitments and Contingencies Operating Leases The Company leases its facilities under non-cancelable operating leases that expire at various dates through September 2023. All of the Company's leases contain escalating rent clauses, which require higher rent payments in future years. The Company expenses rent on a straight-line basis over the term of the lease, including any rent-free periods. In addition, the Company received certain lease incentives, and recorded these incentives as deferred rent, which is amortized as a reduction of rent expense over the life of the lease. Rent expense of approximately $4.8 million , $3.8 million and $3.4 million were incurred during the years ended December 31, 2017 , 2016 and 2015 , respectively. Future annual minimum lease payments as of December 31, 2017, are as follows (in thousands): 2018 $ 5,551 2019 6,320 2020 6,506 2021 6,191 2022 6,207 2023 4,761 Total $ 35,536 In July 2017, the Company entered into a sublease agreement for one if its facility leases. The tenant will pay rent on the lease from August, 1 2017 until July 31, 2018. On January 8, 2018, the sublessee exercised its right to extend the sublease by an additional five months through December 31, 2018. Sublease income of approximately $0.3 million , zero , and zero was recorded during the years ended December 31, 2017 , 2016 and 2015 , respectively. In connection with this sublease the Company recognized a loss of $0.1 million during the year ended December 31, 2017 , which represents the difference between the Company's lease obligation to the landlord and the sublessee's lease obligation to the Company and other expenses associated with the sublease. Future annual minimum sublease proceeds expected as of December 31, 2017 are as follows (in thousands): 2018 $ 704 Total $ 704 Legal Proceedings The Company, from time to time, may be party to litigation arising in the ordinary course of its business. Except as discussed below, the Company was not subject to any material legal proceedings during the years ended December 31, 2017, 2016 and 2015, and, to the best of its knowledge, no material legal proceedings are currently pending or threatened. Other The Company is also party to various agreements, principally relating to licensed technology, that require future payments relating to milestones not met at December 31, 2017 and 2016 , or royalties on future sales of specified products. No milestone or royalty payments under these agreements are expected to be payable in the immediate future. See Note 10 for discussion of these arrangements. The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to the agreements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally the Company's business partners or customers, in connection with any U.S. patent or any copyright or other intellectual property infringement claim by any third party with respect to the Company's products. The term of these indemnification agreements is generally perpetual any time after execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited. The Company has never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. |
Stockholders' Equity
Stockholders' Equity | 12 Months Ended |
Dec. 31, 2017 | |
Stockholders' Equity Note [Abstract] | |
Stockholders' Equity | Stockholders' Equity On January 11, 2016, the Company completed the sale of 3,750,000 shares of common stock at a public offering price of $40.00 per share, resulting in net proceeds to the Company of approximately $140.3 million . On September 25, 2017, the Company completed the sale of 5,405,406 shares of common stock at a public offering price of $37.00 per share. On October 4, 2017, in connection with the September 2017 public offering, the underwriters fully exercised their option to purchase an additional 810,810 shares of common stock. The total net proceeds to the Company from the September 2017 public offering and the underwriters' exercise of their option to purchase additional shares of common stock was $215.8 million . Preferred Stock The Company’s certificate of incorporation authorizes the Board to issue up to 25,000,000 shares of preferred stock from time to time in one or more series. The rights, preferences, restrictions, qualifications and limitations of such stock are determined by the Board. As of December 31, 2017 no shares are issued or outstanding. Common Stock The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings. The holders of shares of common stock are entitled to receive dividends, if and when declared by the Board. No dividends have been declared or paid by the Company through December 31, 2017 . Common Stock Reserved for Future Issuance At December 31, 2017 , the Company has reserved for future issuance the following number of shares of common stock (in thousands): December 31, 2017 Outstanding stock options to purchase common stock 3,452 Outstanding restricted stock units 604 Shares available for future issuance under equity incentive plan 2,763 Warrants to purchase common stock 61 Shares available for future issuance under the employee stock purchase plan 187 Additional shares reserved for unissued, but designated, Preferred Stock 25,000 Total shares of authorized common stock reserved for future issuance 32,067 |
Significant Agreements
Significant Agreements | 12 Months Ended |
Dec. 31, 2017 | |
Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
Significant Agreements | Significant Agreements Celgene Overview On February 20, 2008 the Company entered into an agreement with Celgene relating to sotatercept (the Original Sotatercept Agreement), which was amended on August 2, 2011 (as amended, the Amended Sotatercept Agreement). The Company further amended and restated the Original Sotatercept Agreement in its entirety on September 18, 2017, (the Restated Sotatercept Agreement). On August 2, 2011 the Company entered into a second agreement with Celgene for luspatercept, (the Luspatercept Agreement). Restated Sotatercept Agreement The Restated Sotatercept Agreement provides Celgene with an exclusive license to sotatercept outside of the field of pulmonary hypertension, referred to as the PH field, and provides the Company with the worldwide rights to develop and commercialize sotatercept in the PH field. In connection with the Restated Sotatercept Agreement, Celgene agreed not to develop or commercialize in PH field any compound developed under the Restated Sotatercept Agreement or the Luspatercept Agreement, and the Company agreed not to develop or commercialize any compound developed under the Restated Sotatercept Agreement or the Luspatercept Agreement in any field outside the PH field. The Company has the right to license, transfer or sell its rights to develop and commercialize sotatercept in the PH field, subject to Celgene’s right of first negotiation. The Company is responsible for 100% of the costs related to its development and commercialization of sotatercept in the PH field. If sotatercept is commercialized to treat pulmonary hypertension and the Company recognizes such revenue, then Celgene will be eligible to receive a royalty in the low 20% range on global net sales. In certain circumstances Celgene may recognize revenue related to the commercialization of sotatercept in the PH field, and in this scenario, the Company will be eligible to receive a royalty from Celgene such that the economic position of the parties is equivalent to the scenario in which the Company recognizes such revenue. With respect to the development and commercialization of sotatercept outside of the PH field or the development and commercialization of any other compound under the Restated Sotatercept Agreement, the terms of the Amended Sotatercept Agreement, described below, remained unchanged. Pursuant to the Restated Sotatercept Agreement, Celgene will provide the Company with certain quantities of Celgene’s existing clinical supply of sotatercept for development in the PH field at no cost. For clinical or commercial supply of sotatercept in excess of that which is agreed to under the Restated Sotatercept Agreement, Celgene can elect to provide the Company with such clinical and commercial supply of sotatercept at a negotiated price or provide a tech transfer to enable the Company to manufacture on its own behalf. The conduct of the collaboration is managed by a Joint Development Committee and Joint Commercialization Committee. In the event of a deadlock of a committee, the Company shall determine the resolution of issues specifically related to the PH field, (other than pricing which shall be determined by consensus), and Celgene shall determine the resolution of all other issues. The Joint Commercialization Committee will oversee commercialization of sotatercept, and sotatercept pricing will be determined by mutual agreement of the Company and Celgene in the Joint Commercialization Committee. The Restated Sotatercept Agreement will expire on a country-by-country basis on the occurrence of the latest to occur of the following: (1) the expiration of the royalty term with respect to all license products outside the PH field in such country, (2) the expiration of the royalty term with respect to all sotatercept licensed products in the PH field in such country, and (3) the exercise or forfeiture by Celgene of its option with regard to each option compound. In the PH field, the royalty term for each licensed product in each country is the period commencing with first commercial sale of the applicable licensed product in the applicable country and ending on the latest of expiration of specified patent coverage or a specified period of years. Outside the PH field, the royalty term for each licensed product in each country outside North America is the period commencing with first commercial sale of the applicable licensed product in the applicable country and ending on the latest of expiration of specified patent coverage or a specified period of years, and the royalty term for each licensed product in North America is the period commencing with the first commercial sale in North America and ending, on a licensed product and country-by-country basis on the date which commercialization of such licensed product has ceased. The term for each option compound runs for a specified period of years unless Celgene exercises its option, in which case the compound becomes a licensed product, or forfeits its option by failing to make certain payments following the achievement of certain milestones in early clinical development of the option compound. The Restated Sotatercept Agreement is terminable by either party upon a breach that is uncured and continuing or by Celgene for convenience on a country-by-country or product-by-product basis, or in its entirety. Celgene may also terminate the Restated Sotatercept Agreement, in its entirety or on a product-by-product basis, for failure of a product to meet a development or clinical trial endpoint. Termination for cause by the Company or termination by Celgene for convenience or failure to meet an endpoint will have the effect of terminating the applicable license to Celgene and the rights granted to the Company with respect to the development of sotatercept in the PH field shall become irrevocable. Termination for cause by either party shall result in reducing the remaining royalties due to the breaching party by a certain percentage. Upon termination by Celgene for convenience or for failure to meet an endpoint, the Company and Celgene will enter into a termination agreement pursuant to which, among other things, Celgene will continue to be eligible to receive a royalty in the low 20% range on global net sales of sotatercept in the PH field. The Company was not required to make any upfront payments to Celgene upon execution of the Restated Sotatercept Agreement, and is not be required to make any milestone payments to Celgene in connection with its development and commercialization of sotatercept in the PH field. As a result of the changes to the economic terms under the Restated Sotatercept Agreement, the Company concluded the modification did not represent a material modification under ASU 2009-13. Further, the Company concluded there are no new deliverables which rise from the agreement. There have been no material changes to the accounting under the Amended Sotatercept Agreement pursuant to the Restated Sotatercept Agreement or the Luspatercept Agreement. Original and Amended Sotatercept Agreement Under the Original Sotatercept Agreement, as preserved by the Amended Sotatercept Agreement, the Company granted Celgene an exclusive license to sotatercept in all indications and an option to license discovery stage compounds against three specified targets. Celgene paid $45.0 million of nonrefundable, upfront license and option payments to the Company and bought $5.0 million of equity upon closing in February 2008. Per the Original Sotatercept Agreement, concurrent with the Company's 2013 IPO, Celgene purchased an additional $10.0 million of the Company's common stock. The Company retained responsibility for research and development of sotatercept through the end of Phase 2a clinical trials, as well as manufacturing the clinical supplies for these trials. These activities were substantially completed in 2011. Celgene will be responsible for any sotatercept Phase 3 clinical trials, as well as any additional Phase 2 clinical trials and is responsible for manufacturing or overseeing the manufacture of Phase 3 and commercial supplies. Commensurate with the execution of the Luspatercept Agreement described below, in August 2011 the Company and Celgene agreed to modify the terms of the collaboration. Outside of the PH field, the significant financial terms of the Amended Sotatercept Agreement, which were preserved in the Restated Sotatercept Agreement, are: • Since January 1, 2013, Celgene has been responsible for paying 100% of worldwide development costs for the sotatercept program; • Celgene will be responsible for all commercialization costs worldwide; • The Company will be eligible to receive tiered royalty payments in the low-to-mid 20% percent range on net sales of sotatercept subject to certain reductions, including for entry of a generic product onto the market; and • The Company is obligated to co-promote sotatercept and future products in all fields, in each case if approved, in North America, and Celgene will pay all costs related thereto; The Amended Sotatercept Agreement, as preserved in the Restated Sotatercept Agreement, contains a two-category contingent development milestone structure outside of the PH field (oncology and non-oncology) for sotatercept, including future clinical milestones of up to $27.0 million , regulatory milestones of up to $190.0 million and commercial milestones of up to $150.0 million . Additionally, the Company is eligible to receive option fees of up to $30.0 million for each of the three discovery-stage targets, and for all three discovery-stage targets in the aggregate, clinical milestones of up to $25.5 million , regulatory milestones of up to $142.5 million and commercial milestones of up to $150.0 million . None of the three discovery stage programs has advanced to the stage to achieve payment of a milestone, nor does the Company expect any such milestone payments in the near future. As of December 31, 2017, the Company has received $44.2 million in research and development funding and milestone payments for the sotatercept program. The next likely clinical milestone payment would be $10.0 million and result from Celgene's start of a Phase 3 study with sotatercept outside of the PH field. Luspatercept Agreement Under the terms of the Luspatercept Agreement, the Company and Celgene collaborate worldwide for the joint development and commercialization of luspatercept. The Company also granted Celgene an option for future products for which Acceleron files an Investigational New Drug application for the treatment of anemia. Celgene paid $25.0 million on the closing of the Luspatercept Agreement in August 2011. The Company retained responsibility for research and development through the end of Phase 1 and the Company's initial luspatercept beta-thalassemia and luspatercept MDS Phase 2 clinical trials, as well as manufacturing the clinical supplies for these studies. Celgene will conduct subsequent Phase 2 and Phase 3 clinical studies and will be responsible for overseeing the manufacture of Phase 3 and commercial supplies by third party contract manufacturing organizations. The significant financial terms of the Luspatercept Agreement are: • Since January 1, 2013, Celgene has been responsible for paying 100% of worldwide development costs for the luspatercept program • Celgene will be responsible for all commercialization costs worldwide; • The Company will be eligible to receive tiered royalty payments in the low-to-mid 20% percent range on net sales of luspatercept subject to certain reductions, including for entry of a generic product onto the market; and • The Company is obligated to co-promote luspatercept and future products in all fields, in each case if approved, in North America, and Celgene will pay all costs related thereto; The Company is eligible to receive clinical milestones of up to $32.5 million , regulatory milestones of up to $105.0 million and commercial milestones of up to $80.0 million for luspatercept. The Company will receive additional, lower development, regulatory, and commercial milestones for any additional products for the treatment of anemia on which Celgene exercises an option. The Luspatercept Agreement will expire on a country-by-country basis on the occurrence of both of the following: (1) the expiration of the royalty term with respect to all license products in such country, and (2) the end of the option term. The royalty term for each licensed product in each country outside North America is the period commencing with first commercial sale of the applicable licensed product in the applicable country and ending on the latest of expiration of specified patent coverage or a specified period of years. The royalty term for each licensed product in North America is the period commencing with the first commercial sale in North America and ending, on a licensed product and country-by-country basis on the date which commercialization of such licensed product has ceased. The option term runs until the later of (1) the date on which no development or commercialization activities are ongoing or are expected to commence for any licensed products under the Luspatercept Agreement; (2) the date on which no development or commercialization activities are ongoing or are expected to commence for any licensed products under the Restated Sotatercept Agreement and all option rights under the Restated Sotatercept Agreement have been forfeited with respect to each option compound where Celgene has made a payment with respect to such compound; and (3) the royalty term for all licensed products under the Luspatercept Agreement and the Restated Sotatercept Agreement has ended; provided that if at the time the option term would otherwise end any option compounds under the Luspatercept Agreement are in clinical development the option term shall continue until Celgene's rights to such compound are either exercised or forfeited. Celgene has the right to terminate the Luspatercept Agreement with respect to one or more licensed targets or in its entirety, upon 180 days' notice (or 45 days' notice if the licensed product has failed to meet certain end point criteria with respect to clinical trials or other development activities). The agreement may also be terminated in its entirety by either Celgene or the Company in the event of a material breach by the other party or in the event of a bankruptcy filing of the other party. There are no cancellation, termination or refund provisions in this arrangement that contain material financial consequences to the Company. Through December 31, 2017 , the Company has received $99.4 million in research and development funding and milestone payments for luspatercept. The next likely clinical milestone payment would be $25.0 million and result from the U.S. Food and Drug Administration or European Medical Association acceptance of a Biologics Licensing Application or equivalent for luspatercept in either myelodysplastic syndromes or beta-thalassemia. The Company has not yet identified additional compounds for the treatment of anemia so there is no assurance that the Company will generate future value from additional products. Accounting Analysis Prior to 2011, the Company accounted for the Original Sotatercept Agreement, as a multiple element arrangement under ASC 605-25 (prior to the amendments of ASU 2009-13). The Company identified the following deliverables under the arrangement; (1) the license to the ActRIIA compound, (2) the right to license option program compounds, (3) participation in the joint development committee, (4) participation in the joint commercialization committee and (5) research and development activities. Under the provisions of ASC 605-25, applicable to the arrangement, since the Company could not establish VSOE for the undelivered elements, the Company was required to recognize the initial consideration, consisting of the $45.0 million of nonrefundable upfront license and option payments, over the period the undelivered elements were to be delivered, which was initially estimated to be 15 years . As of the date of the modification of the agreement, there was approximately $34.7 million of deferred revenue under the arrangement. As a result of the Amended Sotatercept Agreement in August 2011, the Company concluded the modifications to the cost-sharing obligations, milestone payments structure and royalty payment structure represented a significant modification under ASU 2009-13, which required the Company to apply the updated provisions of ASU 2009-13 subsequent to the modification. Because the Luspatercept Agreement and the Amended Sotatercept Agreement were negotiated in contemplation of each other, and the Company had not yet completed all of its obligations pursuant to the Original Sotatercept Agreement, the agreements were considered one arrangement for accounting purposes. The deliverables under the combined arrangement include: (1) licenses to develop and commercialize sotatercept and luspatercept, (2) performance of research and development services, (3) participation on the joint development committees, and (4) the performance of manufacturing services to provide clinical material to Celgene. The Company has determined the option to future products related to the treatment of anemia represents a substantive option. The Company is under no obligation to discover, develop or deliver any new compounds that modulate anemia and Celgene is not contractually obligated to exercise the option. As a result, the Company is at risk as to whether Celgene will exercise the option. All of these deliverables identified in the arrangement were deemed to have stand-alone value and to meet the criteria to be accounted for as separate units of accounting under ASC 605-25. Factors considered in making this determination included, among other things, the subject of the licenses, the nature of the research and development services, and the capabilities of Celgene. The total arrangement consideration of $77.7 million under the Luspatercept Agreement and Amended Sotatercept Agreement consisted of (1) the $25.0 million upfront payment for the license of luspatercept, (2) the remaining deferred revenue from the Original Sotatercept Agreement of $34.7 million , and (3) estimated payments for development activities and manufacturing services of $18.0 million . The Company used its BESP for each of the undelivered elements as the Company did not have VSOE or TPE of selling price for each deliverable. The Company's BESP considered its development plan for the compounds, expected manufacturing services, and reimbursement from Celgene (reimbursement of more than half of development expenses through December 31, 2012 and 100% thereafter). The Company determined its BESP for each of the undelivered elements under the arrangements as of the arrangement execution date as follows: • $18.8 million for research and development services • $2.9 million for the sotatercept joint development committee • $3.7 million for the ACE 536 joint development committee • $2.8 million for the manufacturing services After determining the BESP of the undelivered elements, the remaining consideration of $49.5 million was recognized upon execution of the Luspatercept Agreement and Amended Sotatercept Agreement. The difference between the estimated payments of $18.0 million and the estimated selling prices which totaled $28.2 million , using BESP, for undelivered elements was $10.2 million . This amount was deferred at inception and will be recognized as the undelivered elements are delivered, using the proportional performance method, or ratably in the case of performance on the Joint Development Committee. As noted above, the total arrangement consideration includes estimated payments for development activities and manufacturing services identified at the outset of the Luspatercept Agreement and Amended Sotatercept Agreement. At the end of each reporting period, the Company reassesses the estimated payments to be received related to these services and the BESP of the undelivered elements based upon the Company's current estimates. The Company accounts for such changes as a change in accounting estimate and the cumulative impact of any change is reflected in the period of change. During 2011, the Company achieved a $7.5 million clinical milestone under its Luspatercept Agreement, related to the dosing of the first patient in a multiple-dose clinical trial. The Company evaluated the milestone and determined that it was not substantive, as there was no significant uncertainty to achieving the milestone upon execution of the Luspatercept Agreement. As such, the Company allocated the $7.5 million payment based on the allocation of arrangement consideration determined at the execution date of the Luspatercept Agreement and Amended Sotatercept Agreement. Based on this allocation, the Company recognized $4.8 million of the payment upon achievement, with the remaining $2.7 million recognized as revenue as the undelivered elements are delivered, consistent with the treatment of the upfront payment. During February 2016, the Company achieved a $15.0 million clinical milestone under its Luspatercept Agreement, related to the initiation of a Phase 3 clinical trial with Luspatercept. The Company evaluated the milestone and determined that it was substantive and consistent with the definition of a milestone included in ASU 2010-17 and, accordingly, recognized the $15.0 million payment in revenue during the year ended December 31, 2016. The remaining development milestones under the Luspatercept and the Amended Sotatercept Agreements were deemed to be substantive and consistent with the definition of a milestone included in ASU 2010-17 and, accordingly, the Company will recognize payments related to the achievement of such milestones, if any, when such milestone is achieved. Factors considered in this determination included scientific and regulatory risks that must be overcome to achieve the milestones, the level of effort and investment required to achieve each milestone, and the monetary value attributed to each milestone. During the years ended December 31, 2017 , 2016 and 2015 , the Company recognized $0.5 million , $0.5 million and $1.2 million , respectively, of the total deferred revenue as license and milestone revenue in the accompanying consolidated statements of operations and comprehensive loss. In November, 2013, the Company agreed to conduct additional activities for the benefit of the luspatercept program including certain clinical and non-clinical services such as toxicology studies, clinical extension studies, and market development work. These activities will be reimbursed under the same terms and rates of the existing agreements. The Company evaluated the additional services and determined that as the Company is under no obligation to conduct these additional activities, these services do not represent a deliverable or modification to the Luspatercept Agreement, but rather, represent a separate services arrangement which should be accounted for as the services are delivered. Payments from Celgene with respect to research and development costs incurred by the Company are recorded as cost-sharing revenue. During the years ended December 31, 2017 , 2016 and 2015 , the Company recorded net cost-sharing revenue of $12.9 million , $12.2 million and $16.9 million , respectively. Other Agreements Other In 2004, the Company entered into a license agreement with a non-profit institution for an exclusive, sublicensable, worldwide, royalty-bearing license to certain patents developed by the institution (Primary Licensed Products). In addition, the Company was granted a non-exclusive, non-sub-licensable license for Secondary Licensed Products. As compensation for the licenses, the Company issued 62,500 shares of its common stock to the institution, the fair value of which was $25,000 , and was expensed during 2004, to research and development expense. The Company also agreed to pay specified development milestone payments totaling up to $2.0 million for sotatercept and $0.7 million for luspatercept. In addition, the Company is obligated to pay milestone fees based on the Company's research and development progress, and U.S. sublicensing revenue ranging from 10% - 25% , as well as a royalty ranging from 1.0% - 3.5% of net sales on any products developed under the licenses. During the years ended December 31, 2017 , 2016 and 2015 , the Company paid and expensed milestones and fees defined under the agreement totaling $0.1 million , $0.1 million and $0.1 million , respectively, which is recorded as research and development expense. In May 2014, the Company executed a collaboration agreement with a research technology company. The Company paid an upfront and research fee of $0.3 million upon execution of the agreement and the Company is obligated to pay additional research fees of approximately $0.6 million over approximately the next year, depending on the success of the research program. The Company also received an option to obtain a commercial license to the molecules developed during the collaboration. During the years ended December 31, 2017 , 2016 , and 2015 , the Company expensed milestones and fees totaling $1.6 million , $1.0 million , and $1.4 million , which is recorded as research and development expense. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Stock-Based Compensation | Stock-Based Compensation At December 31, 2017 , the Company had two stock-based compensations plans, which are more fully described below. The Company's 2003 Stock Option and Restricted Stock Plan (the 2003 Plan) provided for the issuance of stock options and restricted stock to employees, officers, directors, consultants and key personnel of the Company as determined by the Board. In conjunction with the effectiveness of the 2013 Equity Incentive Plan (the 2013 Plan) described below, the Company determined that no further stock options or other equity-based awards may be granted under the 2003 Plan. On September 4, 2013, the Board and stockholders approved the adoption of the 2013 Equity Incentive Plan (the 2013 Plan), which provides for the issuance of stock options, restricted stock units, and other equity-based awards. The Company has reserved for issuance an aggregate of 1,500,000 shares of common stock under the 2013 Plan which is comprised of (i) the remaining 155,884 shares reserved for issuance under the 2003 Plan and (ii) an additional 1,344,116 shares. The 2013 Plan provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning in 2014, by the lesser of (i) 3,150,000 shares, or (ii) 4% of the outstanding number of shares of the Company's common stock on the immediately preceding December 31st. This number is subject to adjustment in the event of a stock split, stock dividend or other change in the Company's capitalization. The number of shares underlying equity awards available for future grant was 2,762,770 at December 31, 2017 . The Company has not granted unrestricted stock awards under the 2003 Plan or the 2013 Plan since its inception. Stock options carry an exercise price equal to the estimated fair value of the Company's common stock on the date of grant. Options generally expire 10 years following the date of grant. Stock options typically vest over 4 years , and restricted stock units typically vest over 3 years , but vesting provisions can vary based on the discretion of the Board. Shares of the Company's common stock underlying any awards that are forfeited, canceled, withheld upon exercise of an option, or settlement of an award to cover the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of shares of the Company's common stock, or otherwise terminated other than by exercise will be added back to the shares of common stock available for issuance under the 2013 Plan. Shares available for issuance under the 2013 Plan may be authorized but unissued shares of the Company's common stock or shares of the Company's common stock that have been reacquired by the Company. Additionally, on September 4, 2013, the Board and stockholders approved the adoption of the 2013 Employee Stock Purchase Plan (the 2013 ESPP). Under the 2013 ESPP, 275,000 shares of the Company's common stock will be available for issuance to eligible employees. The per-share purchase price at the end of each offering period is equal to 85% of the closing price of one share of the Company’s common stock at the beginning or end of the offering period, whichever is lower, subject to Internal Revenue Service limits. The 2013 ESPP will terminate on September 4, 2023, the tenth anniversary of the initial adoption of the plan. The Board determined the initial offering period commenced on September 16, 2014 and the initial purchase occurred on the 6 month anniversary with subsequent 6 month purchase periods commencing on the day following the purchase from the prior period. The Company recorded $0.3 million , $0.3 million , and $0.3 million of stock-based compensation expense during the years ended December 31, 2017 , 2016 , and 2015 , respectively related to the 2013 ESPP. The number of shares available for future issuance was 186,844 at December 31, 2017 . In December 2016, the Company entered into a consulting agreement with its former Chief Executive Officer. In accordance with the 2003 Plan and 2013 Plan, any vested shares remain exercisable and any outstanding and unvested options and restricted stock units will continue to vest in accordance with their terms so long as he continues to provides services as a non-employee consultant. During the years ended December 31, 2017 , 2016 and 2015 , the Company recognized $4.9 million , $0.5 million , and zero , respectively, of stock-based compensation expense related to the agreement. In April 2017, the Company amended the employment agreement with its former Chief Operating Officer as a result of his diagnosis of amyotrophic lateral sclerosis (ALS). The amended agreement modified the vesting conditions of his stock options and restricted stock units in the event of his termination of employment as a result of death or disability and extended the post termination exercise period of the options. These modifications resulted in $3.6 million of stock-based compensation, recognized within general and administrative expense, during the year ended December 31, 2017 . The Company recognized stock-based compensation expense under the various Plans in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year Ended December 31, 2017 2016 2015 Research and development $ 14,227 $ 8,171 $ 4,852 General and administrative 14,021 10,386 7,223 $ 28,248 $ 18,557 $ 12,075 On January 1, 2017, the Company adopted ASU 2016-09, which identifies areas for simplification involving several aspects of accounting for share-based payments, including income tax consequences, classification of awards as either equity or liabilities, an option to make a policy election to recognize gross share based compensation expense with actual forfeitures recognized as they occur as well as certain classification changes on the statement of cash flows. In connection with the adoption of this standard, the Company changed its accounting policy to record actual forfeitures as they occur, rather than estimating forfeitures by applying a forfeiture rate. The provisions of the standard related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements and forfeitures were adopted using a modified retrospective transition method. Accordingly, a cumulative adjustment of $0.1 million was booked to retained earnings for the impact of the forfeitures. The Company also recorded an increase in its net operating loss carryforward deferred tax asset of $21.5 million related to previously unrecognized excess tax benefits, which was offset by a $21.5 million increase to the valuation allowance. The provisions of the standard related to the recognition of the excess tax benefits in the income statement and classification in the statement of cash flows were adopted prospectively and prior periods were not retrospectively adjusted. The fair value of each option issued to employees was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Year Ended December 31, 2017 2016 2015 Expected volatility 65.7 % 65.1 % 67.0 % Expected term (in years) 6.0 6.0 6.0 Risk-free interest rate 2.13 % 1.69 % 1.67 % Expected dividend yield — % — % — % The expected volatility of the options granted has been determined using a weighted-average of the historical volatility measures of a peer group of companies as well as the historical volatility of the Company's own common stock. The expected life of options has been determined utilizing the “simplified method”. The simplified method is based on the average of the vesting tranches and the contractual life of each grant. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected life of the stock options. The Company has not paid, and does not anticipate paying, cash dividends on its common stock; therefore, the expected dividend yield is assumed to be zero . In addition, prior to the adoption of ASU 2016-09 on January 1, 2017, the company used historical actual forfeitures to estimate a forfeiture rate. The Company applied an estimated forfeiture rate of approximately zero , 3% , and 4% for the years ended December 31, 2017 , 2016 , and 2015 , respectively, in determining the expense recorded in the accompanying consolidated statements of operations and comprehensive loss. Stock Option Activity The following table summarizes the stock option activity under the Company's stock option plans during the year ended December 31, 2017 (in thousands, except per share amounts and years): Number Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2016 3,316 $ 25.96 Granted 701 $ 30.78 Exercised (474 ) $ 8.21 Canceled or forfeited (91 ) $ 34.85 Outstanding at December 31, 2017 3,452 $ 29.14 6.72 $ 46,115 Exercisable at December 31, 2017 2,110 $ 26.78 5.52 $ 33,208 ______________________________________________________ (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at December 31, 2017 and 2016 . During the years ended December 31, 2017 , 2016 and 2015 , the Company granted stock options to purchase an aggregate of 701,384 , 1,045,795 , and 870,526 shares of its common stock, respectively, with weighted-average grant date fair values of options granted of $18.58 , $18.55 , and $24.29 , respectively. During the years ended December 31, 2017 , 2016 and 2015 , current and former employees of the Company exercised a total of 474,056 , 885,075 , and 837,361 options, respectively, resulting in total proceeds of $3.9 million , $5.3 million , and $4.0 million , respectively. The aggregate intrinsic value of options exercised during the years ended December 31, 2017 , 2016 , and 2015 , under the Company's stock option plans, was $10.2 million , $23.8 million , and $25.2 million , respectively, calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options on the respective date of exercise. As of December 31, 2017 , there was $22.8 million of unrecognized compensation expense that is expected to be recognized over a weighted-average period of 2.39 years. Restricted Stock Units The following table summarizes the restricted stock unit (RSU) activity under the 2013 Plan during the year ended December 31, 2017 : Number of Weighted- Unvested balance at December 31, 2016 182 $ 31.50 Granted 156 $ 32.89 Vested (57 ) $ 30.52 Forfeited (14 ) $ 33.21 Unvested balance at December 31, 2017 267 $ 32.44 At December 31, 2017 , there was approximately $5.7 million of related unrecognized compensation cost which the Company expects to recognize over a remaining weighted-average period of 1.68 years. Performance-Based Restricted Stock Units The Company has granted performance-based restricted stock units (PSU) whereby vesting accelerates upon the occurrence of certain milestone events. In September 2019, any of these PSUs that remain unvested will vest. As a result, when achievement of a milestone becomes probable, compensation cost is recognized from the grant date through the estimated date of achievement. If achievement is not considered probable the expense is recognized from the grant date through September 2019. The following table summarizes PSU activity under the 2013 Plan during the year ended December 31, 2017 : Number of Weighted- Unvested balance at December 31, 2016 551 $ 31.57 Granted 28 $ 27.24 Vested (232 ) $ 31.12 Forfeited (10 ) $ 31.09 Unvested balance at December 31, 2017 337 $ 31.53 As of December 31, 2017 , there was approximately $4.8 million of related unrecognized compensation cost which the Company expects to recognize over a remaining weighted-average period of 1.43 years. |
401(k) Savings Plan
401(k) Savings Plan | 12 Months Ended |
Dec. 31, 2017 | |
Retirement Benefits [Abstract] | |
401(k) Savings Plan | 401(k) Savings Plan In 2004, the Company established a defined-contribution savings plan under Section 401(k) of the Internal Revenue Code (the 401(k) Plan). The 401(k) Plan covers all employees who meet defined minimum age and service requirements, and allows participants to defer a portion of their annual compensation on a pretax basis. For the years 2017 , 2016 , and 2015 , the Board approved matching contributions of up to $7,000 , $7,000 , and $5,000 , respectively, per eligible participant pursuant to the 401(k) Savings Plan’s matching formula. All matching contributions and participant contributions vest immediately. Matching contributions totaled $0.7 million , $0.6 million , and $0.3 million for the years ended December 31, 2017 , 2016 , and 2015 , respectively, and have been recorded in the consolidated statement of operations and comprehensive loss. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | Income Taxes The Company provides for income taxes under ASC 740. Under ASC 740, the liability method is used in accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. U.S. Tax Reform On December 22, 2017, the Tax Cuts and Jobs Act (the Tax Act) was signed into law. The Tax Act, among other changes, permanently lowers the corporate federal tax rate to 21% from the existing maximum rate of 35%, effective for tax years beginning January 1, 2018. As a result of the reduction of the corporate federal income tax rate to 21%, US GAAP requires companies to revalue their deferred tax assets and deferred tax liabilities as of the date of enactment, with the resulting tax effects accounted for in the reporting period of the enactment. This revaluation resulted in a provision of $59.3 million to income tax expense in continuing operations and a corresponding reduction in the valuation allowance. As a result, there was no impact on the Company's consolidated statements of operations from the reduction in the tax rate. The other provisions of the Tax Act did not have a material impact on the consolidated financial statements. The Company is still in the process of analyzing the impact to the Company of the Tax Act. Where the Company has been able to make reasonable estimates of the effects for which its analysis is not yet complete, the Company has recorded provisional amounts. Where the Company has not yet been able to make reasonable estimates of the impact of certain elements, the Company has not recorded any amounts related to those elements and has continued accounting for them in accordance with ASC 740 on the basis of the tax laws in effect immediately prior to the enactment of the Tax Act. Deferred tax assets and valuation allowance For the years ended December 31, 2017 , 2016 and 2015 , the Company recorded current income tax expense of $32,000 , $24,000 , and zero , respectively, related to state income taxes on its interest income. The Company's loss before income taxes was $108.4 million , $57.0 million and $63.9 million for the years ended December 31, 2017 , 2016 and 2015 , respectively, and was generated entirely in the United States. Deferred taxes are recognized for temporary differences between the basis of assets and liabilities for financial statement and income tax purposes. The significant components of the Company's deferred tax assets are comprised of the following (in thousands): Year Ended December 31, 2017 2016 Deferred tax assets: U.S. and state net operating loss carryforwards $ 116,812 $ 109,429 Research and development credits 12,548 9,717 Deferred revenue 1,010 1,666 Accruals and other temporary differences 15,287 15,725 Total deferred tax assets 145,657 136,537 Less valuation allowance (145,657 ) (136,537 ) Net deferred tax assets $ — $ — The Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets. Based on the Company's history of operating losses, the Company has concluded that it is more likely than not that the benefit of its deferred tax assets will not be realized. Accordingly, the Company has provided a full valuation allowance for deferred tax assets as of December 31, 2017 and 2016 . The valuation allowance increased by $9.1 million , $26.7 million , and $20.0 million during the years ended December 31, 2017 , 2016 , and 2015 , respectively, due primarily to the generation of net operating losses during the period. A reconciliation of income tax expense computed at the statutory federal income tax rate to income taxes as reflected in the consolidated financial statements is as follows: Year Ended December 31, 2017 2016 2015 Federal income tax expense at statutory rate 34.0 % 34.0 % 34.0 % State income tax, net of federal benefit 5.6 % 5.9 % 4.6 % Permanent differences 1.9 % 4.0 % (8.3 )% Research and development credit 1.9 % 3.1 % 1.2 % Tax reform rate change (54.7 )% — % — % Other (0.3 )% (0.1 )% — % Change in valuation allowance 11.6 % (46.9 )% (31.5 )% Effective income tax rate — % — % — % As of December 31, 2017 and 2016 , the Company had U.S. federal net operating loss carryforwards of $438.0 million and $339.3 million , respectively, which may be available to offset future income tax liabilities and expire at various dates through 2037 . As of December 31, 2017 and 2016 , the Company also had U.S. state net operating loss carryforwards of $393.6 million and $293.7 million , respectively, which may be available to offset future income tax liabilities and expire at various dates through 2037 . As of December 31, 2017 and 2016 , the Company had federal research and development tax credit carryforwards of $8.1 million and $6.7 million , respectively, available to reduce future tax liabilities which expire at various dates through 2037 . As of December 31, 2017 and 2016 , the Company had state research and development tax credit carryforwards of approximately $5.6 million and $4.5 million , respectively, available to reduce future tax liabilities which expire at various dates through 2032 . Under the provisions of the Internal Revenue Code, the net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three‑year period in excess of 50 percent, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has completed several financings since its inception which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future. The Company has completed an assessment through December 31, 2017 to determine whether there may have been a Section 382 ownership change and determined that it is more-likely-than-not that the Company’s net operating and tax credit amounts as disclosed are not subject to any material Section 382 limitations. The Company will recognize interest and penalties related to uncertain tax positions in income tax expense. 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 consolidated statements of operations and comprehensive loss. For all years through December 31, 2017 , the Company generated research credits but has not conducted a study to document the qualified activities. This study may result in an adjustment to the Company’s research and development credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position for the years ended December 31, 2017 and 2016 . A full valuation allowance has been provided against the Company’s research and development credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the deferred tax asset established for the research and development credit carryforwards and the valuation allowance. The Company files income tax returns in the United States, and various state jurisdictions. The federal and state income tax returns are generally subject to tax examinations for the tax years ended December 31, 2014 through December 31, 2017 . To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the Internal Revenue Service or state taxing authorities to the extent utilized in a future period. |
Related Party Transactions
Related Party Transactions | 12 Months Ended |
Dec. 31, 2017 | |
Related Party Transactions [Abstract] | |
Related Party Transactions | Related Party Transactions Celgene Corporation (Celgene) In connection with the Company's September 2017 and January 2016 public offerings, Celgene purchased 745,592 and 800,000 shares of common stock, respectively. In connection with these and prior transactions, Celgene owned 12.5% and 12.8% of the Company's fully diluted equity as of December 31, 2017 and 2016 , respectively. During the years ended December 31, 2017 , 2016 and 2015 , all revenue recognized by the Company was recognized under the Celgene collaboration agreement and as of December 31, 2017 and 2016 , the Company had $3.7 million and $4.2 million , respectively, of deferred revenue related to the Celgene collaboration arrangement. Refer to Note 10 for additional information regarding these collaboration agreements. |
Quarterly Financial Data (unaud
Quarterly Financial Data (unaudited) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Quarterly Financial Data (unaudited) | Quarterly Financial Data (unaudited) The following table presents certain unaudited quarterly financial information for the eight quarters in the period ended December 31, 2017 . This information has been prepared on the same basis as the audited financial statements and includes all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the unaudited quarterly results of operations set forth herein. For the Three Months Ended(1) March 31 June 30 September 30 December 31 (in thousands except per share data) 2017 Total revenue $ 3,705 $ 3,057 $ 3,014 $ 3,705 Total costs and expenses 29,563 32,968 28,592 32,341 Loss from operations (25,858 ) (29,911 ) (25,578 ) (28,636 ) Net loss (25,407 ) (29,669 ) (25,451 ) (27,926 ) Basic net loss per share $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) Diluted net loss per share $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) 2016 Total revenue $ 18,201 $ 3,195 $ 3,005 $ 3,369 Total costs and expenses 22,157 22,850 23,513 25,355 Loss from operations (3,956 ) (19,655 ) (20,508 ) (21,986 ) Net income (loss) 5,061 (22,016 ) (20,770 ) (19,288 ) Basic net income (loss) per share $ 0.14 $ (0.59 ) $ (0.55 ) $ (0.51 ) Diluted net income (loss) per share $ 0.13 $ (0.59 ) $ (0.55 ) $ (0.51 ) ______________________________________________________ (1) The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Summary of Significant Accoun23
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Principles of Consolidation | Principles of Consolidation The accompanying consolidated financial statements include those of the Company and its wholly-owned subsidiary, Acceleron Securities Corp. All significant intercompany balances and transactions have been eliminated in consolidation. |
Basis of Presentation | Basis of Presentation The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). |
Use of Estimates | Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts expensed during the reporting period. Management considers many factors in selecting appropriate financial accounting policies and controls, and in developing the estimates and assumptions that are used in the preparation of these consolidated financial statements. Management must apply significant judgment in this process. In addition, other factors may affect estimates, including: expected business and operational changes, sensitivity and volatility associated with the assumptions used in developing estimates, and whether historical trends are expected to be representative of future trends. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes and management must select an amount that falls within that range of reasonable estimates. This process may result in actual results differing materially from those estimated amounts used in the preparation of the consolidated financial statements if these results differ from historical experience, or other assumptions do not turn out to be substantially accurate, even if such assumptions are reasonable when made. In preparing these consolidated financial statements, management used significant estimates in the following areas, among others: revenue recognition, stock-based compensation expense, the determination of the fair value of stock-based awards, the fair value of liability-classified warrants, accrued expenses, and the recoverability of the Company's net deferred tax assets and related valuation allowance. |
Collaboration Receivable | Collaboration Receivable Credit is extended to customers based upon an evaluation of the customer's financial condition. Collaboration receivables are recorded at net realizable value. The Company does not charge interest on past due balances. Collaboration receivables are determined to be past due when the payment due date is exceeded. The Company utilizes a specific identification accounts receivable reserve methodology based on a review of outstanding balances and previous activities to determine the allowance for doubtful accounts. The Company charges off uncollectible receivables at the time the Company determines the receivable is no longer collectible. |
Segment Information | Segment Information Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision making group, in making decisions on how to allocate resources and assess performance. The Company's chief operating decision maker is the chief executive officer. The Company and the chief executive officer view the Company's operations and manage its business as one operating segment, which is the discovery, development and commercialization of highly innovative therapeutics to treat serious and rare diseases. All material long-lived assets of the Company reside in the United States. The Company does use contract research organizations (CROs) and research institutions located outside the United States. Some of these expenses are subject to collaboration reimbursement which is presented as a component of cost-sharing, net in the consolidated statements of operations and comprehensive loss. |
Cash, Cash Equivalents and Short-term and Long-term Investments | Cash, Cash Equivalents and Short-term and Long-term Investments The Company considers all highly liquid investments purchased with original maturities of 90 days or less at the date of acquisition to be cash equivalents. Cash and cash equivalents include cash held in banks and amounts held in interest-bearing money market accounts. Cash equivalents are carried at cost, which approximates their fair market value. The Company determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. The Company has classified all of its marketable securities at December 31, 2017 and 2016 as “available-for-sale” pursuant to ASC 320, Investments – Debt and Equity Securities. The Company records available-for-sale securities at fair value, with the unrealized gains and losses included in accumulated other comprehensive income (loss) in stockholders’ equity. There were no realized gains or losses on marketable securities for the years ended December 31, 2017 , 2016 and 2015 . Investments not classified as cash equivalents are presented as either short-term or long-term investments based on both their maturities as well as the time period the Company intends to hold such securities. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion in interest income. The cost of securities sold is based on the specific identification method. The Company includes interest and dividends on securities classified as available-for-sale in interest income in the accompanying consolidated statements of operations and comprehensive loss. The Company reviews marketable securities for other-than-temporary impairment whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable within a reasonable period of time. Other-than-temporary impairments of investments are recognized in the consolidated statements of operations if the Company has experienced a credit loss, has the intent to sell the marketable security, or if it is more likely than not that the Company will be required to sell the marketable security before recovery of the amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company’s investment policy, the severity and the duration of the impairment and changes in value subsequent to the end of the period. |
Concentrations of Credit Risk and Off-Balance Sheet Risk | Concentrations of Credit Risk and Off-Balance Sheet Risk The Company has no off-balance sheet risk, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash, cash equivalents, restricted cash, short-term and long-term investments and collaboration receivables. The Company maintains its cash and cash equivalent balances and short-term and long-term investments with financial institutions that management believes are creditworthy. Short-term and long-term investments consist of investment grade corporate obligations, treasury notes, asset backed securities, and certificates of deposit. The Company's investment policy includes guidelines on the quality of the institutions and financial instruments and defines allowable investments that the Company believes minimizes the exposure to concentrations of credit risk. The Company routinely assesses the creditworthiness of its customers and collaboration partners. The Company has not experienced any material losses related to receivables from individual customers and collaboration partners, or groups of customers. The Company does not require collateral. Due to these factors, no additional credit risk beyond amounts provided for collection losses is believed by management to be probable in the Company's collaboration receivables. |
Disclosure of Fair Value of Financial Instruments | Disclosure of Fair Value of Financial Instruments The Company's financial instruments include cash, cash equivalents, short-term and long-term investments, collaboration receivables, common stock warrants, accounts payable, and accrued expenses. See discussion below on the determination of the fair value of the Company's common stock warrants and short-term and long-term investments. The carrying value of the remainder of the Company's financial instruments approximated their fair values at December 31, 2017 and 2016 due to the short-term nature of these instruments. The Company has evaluated the estimated fair value of financial instruments using available market information and management's estimates. The use of different market assumptions and/or estimation methodologies could have a significant effect on the estimated fair value amounts. |
Fair Value Measurements | Fair Value Measurements ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company's own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company's assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier fair value hierarchy that distinguishes between the following: • Level 1—Quoted market prices in active markets for identical assets or liabilities. • Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates, and yield curves. • Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Items measured at fair value on a recurring basis include short-term and long-term investments (Note 5), and warrants to purchase common stock (Note 7). During the periods presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value using Level 3 inputs. The following tables set forth the Company's financial instruments carried at fair value using the lowest level of input applicable to each financial instrument as of December 31, 2017 and 2016 (in thousands): December 31, 2017 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 90,702 $ — $ — $ 90,702 Corporate obligations — 158,849 — 158,849 U.S. Treasury securities — 37,813 — 37,813 Certificates of deposit — 12,244 — 12,244 Mortgage and other asset backed securities — 67,888 — 67,888 Restricted cash 1,132 — — 1,132 Total assets $ 91,834 $ 276,794 $ — $ 368,628 Liabilities: Warrants to purchase common stock $ — $ — $ 2,236 $ 2,236 Total liabilities $ — $ — $ 2,236 $ 2,236 December 31, 2016 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 19,818 $ — $ — $ 19,818 Corporate obligations — 88,492 — 88,492 U.S. Treasury securities — 33,968 — 33,968 Certificates of deposit — 23,373 — 23,373 Mortgage and other asset backed securities — 67,599 — 67,599 Restricted cash 946 — — 946 Total assets $ 20,764 $ 213,432 $ — $ 234,196 Liabilities: Warrants to purchase common stock $ — $ — $ 1,244 $ 1,244 Total liabilities $ — $ — $ 1,244 $ 1,244 The money market funds noted above are included in cash and cash equivalents in the accompanying consolidated balance sheets. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the years ended December 31, 2017 and 2016 . The following table sets forth a summary of changes in the fair value of the Company's common stock warrant liabilities, which represent a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Year Ended December 31, 2017 2016 Beginning balance $ 1,244 $ 17,187 Change in fair value 992 (7,262 ) Exercises — (8,681 ) Ending balance $ 2,236 $ 1,244 The fair value of the warrants to purchase common stock on the date of issuance and on each re-measurement date for those warrants classified as liabilities was estimated using either the Monte Carlo simulation framework, which incorporates future financing events over the remaining life of the warrants to purchase common stock, or for certain re-measurement dates, due to the warrants being deeply in the money, the Black-Scholes option pricing model. The Black-Scholes method of valuation involves using inputs such as the fair value of the Company's stock, stock price volatility, the contractual term of the warrants, risk-free interest rates, and dividend yields. At each reporting period the Company evaluates the best valuation methodology. At December 31, 2017 , the Black-Scholes option pricing model was used, at December 31, 2016 the Monte Carlo simulation framework was used, and at December 31, 2015 , the Black-Scholes option pricing model was used. Due to the nature of these inputs, the valuation of the warrants is considered a Level 3 measurement. See Note 7 for further discussions of the accounting for the warrants, as well as for a summary of the significant inputs and assumptions used to determine the fair value of the warrants. The Company measures eligible assets and liabilities at fair value, with changes in value recognized in earnings. Fair value treatment may be elected either upon initial recognition of an eligible asset or liability or, for an existing asset or liability, if an event triggers a new basis of accounting. The Company did not elect to remeasure any of its existing financial assets or liabilities, and did not elect the fair value option for any financial assets and liabilities transacted in the years ended December 31, 2017 or 2016 . |
Property and Equipment | Property and Equipment Property and equipment is stated at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed to operations as incurred. Upon disposal, retirement or sale the related cost and accumulated depreciation is removed from the accounts and any resulting gain or loss is included in the results of operations. Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which are as follows: Asset Estimated Useful Life Computer equipment and software 3 years Office and laboratory equipment 3 years Leasehold improvements Shorter of the useful life or remaining lease term The Company reviews long-lived assets when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparison of the book values of the assets to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets. |
Revenue Recognition | Revenue Recognition The company has primarily generated revenue through collaboration, license and research arrangements with collaboration partners for the development and commercialization of therapeutic candidates. The Company recognizes revenue in accordance with FASB ASC Topic 605, Revenue Recognition . Accordingly, revenue is recognized for each unit of accounting when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the fee is fixed or determinable; and (4) collectability is reasonably assured. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company's consolidated balance sheets. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, current portion. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Multiple Element Revenue Arrangements The Company enters into collaboration agreements from time to time, which are more fully described in Note 10. The arrangements generally contain multiple elements or deliverables, which may include (1) licenses, or options to obtain licenses, to the Company's technology, (2) research and development activities performed for the collaboration partner, (3) participation on Joint Development Committees, and (4) the manufacturing of clinical or preclinical material. Payments pursuant to these arrangements typically include non-refundable, upfront payments, milestone payments upon achieving significant development events, research and development reimbursements, sales milestones, and royalties on future product sales. Effective January 1, 2011, the Company adopted ASU No. 2009-13, Multiple-Deliverable Revenue Arrangements (ASU 2009-13), which amends ASC Topic 605-25, Revenue Recognition—Multiple Element Arrangements (ASC 605-25). The Company applies this guidance to new arrangements as well as existing agreements that are significantly modified after January 1, 2011. For agreements that are significantly modified, the Company determines the estimated selling price for the remaining undelivered elements as of the date of the material modification and allocates arrangement consideration based upon the estimated selling price to the undelivered elements. The application of the multiple element guidance requires subjective determinations, and requires management to make judgments about the individual deliverables, and whether such deliverables are separable from the other aspects of the contractual relationship. Deliverables are considered separate units of accounting provided that: (1) the delivered item(s) has value to the customer on a stand-alone basis and (2) if the arrangement includes a general right of return relative to the delivered item(s), delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. In determining the units of accounting, management evaluates certain criteria, including whether the deliverables have stand-alone value, based on the consideration of the relevant facts and circumstances for each arrangement, such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the collaboration partner can use the other deliverable(s) for their intended purpose without the receipt of the remaining element(s), whether the value of the deliverable is dependent on the undelivered item(s) and whether there are other vendors that can provide the undelivered element(s). Arrangement consideration that is fixed or determinable is allocated among the separate units of accounting using the relative selling price method, and the applicable revenue recognition criteria, as described above, are applied to each of the separate units of accounting in determining the appropriate period or pattern of recognition. The Company determines the estimated selling price for deliverables within each agreement using vendor-specific objective evidence (VSOE) of selling price, if available, third-party evidence (TPE) of selling price if VSOE is not available, or management's best estimate of selling price (BESP) if neither VSOE nor TPE is available. Subsequent to the adoption of ASU 2009-13, the Company typically uses BESP to estimate the selling price of the deliverables. Determining the BESP for a unit of accounting requires significant judgment. In developing the BESP for a unit of accounting, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs. The Company validates the BESP for units of accounting by evaluating whether changes in the key assumptions used to determine the BESP will have a significant effect on the allocation of arrangement consideration between multiple units of accounting. The Company typically receives upfront, non-refundable payments when licensing its intellectual property in conjunction with a collaboration agreement. When management believes the license to its intellectual property does not have stand-alone value from the other deliverables to be provided in the arrangement, the Company generally recognizes revenue attributed to the license on a straight-line basis over the contractual or estimated performance period, which is typically the term of the Company's research and development or manufacturing obligations. The Company continually evaluates these periods, and will adjust the period of revenue recognition if circumstances change. When management believes the license to its intellectual property has stand-alone value, the Company generally recognizes revenue attributed to the license upon delivery. Research and development funding is recognized as revenue in the period that the related services are performed. When the Company acts as the principal under its collaboration agreements, it records payments received for the reimbursement of research and development costs as cost-sharing revenue in the consolidated statements of operations and comprehensive loss. To the extent that the Company reimburses the collaborator for costs incurred, the Company records these costs as a reduction of cost-sharing revenue. The Company's agreements may contain options which provide the collaboration partner the right to obtain additional licenses. Options are considered substantive if, at the inception of the arrangement, the Company is at risk as to whether the collaboration partner will choose to exercise the option. Factors considered in evaluating whether an option is substantive include the overall objective of the arrangement, the benefit the collaborator might obtain from the arrangement without exercising the option, the cost to exercise the option and the likelihood that the option will be exercised. For arrangements under which an option is considered substantive, the Company does not consider the item underlying the option to be a deliverable at the inception of the arrangement and the associated option fees are not included in allocable arrangement consideration, assuming the option is not priced at a significant and incremental discount. Conversely, for arrangements under which an option is not considered substantive or if an option is priced at a significant and incremental discount, the Company would consider the item underlying the option to be a deliverable at the inception of the arrangement and a corresponding amount would be included in allocable arrangement consideration. Effective January 1, 2011, the Company adopted ASU No. 2010-17, Revenue Recognition—Milestone Method (ASU 2010-17). At the inception of each arrangement that includes milestone payments, the Company evaluates, with respect to each milestone, whether the milestone is substantive and at-risk. This evaluation includes an assessment of whether (a) the consideration is commensurate with either (1) the entity's performance to achieve the milestone, or (2) the enhancement of the value of the delivered item(s) as a result of a specific outcome resulting at least in part from the entity's performance to achieve the milestone, (b) the consideration relates solely to past performance, and (c) the consideration is reasonable relative to all of the deliverables and payment terms within the arrangement. The Company evaluates factors such as the scientific, regulatory, commercial, and other risks that must be overcome to achieve the respective milestone, the level of effort and investment required to achieve the respective milestone, and whether the milestone consideration is reasonable relative to all deliverables and payment terms in the arrangement in making this assessment. On the milestone achievement date, assuming all other revenue recognition criteria are met and the milestone is deemed substantive and at-risk, the Company recognizes the payment as license and milestone revenue. For milestones that are not deemed substantive and at-risk, where payment is reasonably assured, the Company recognizes the milestone payment over the remaining service period. Sales and commercial milestones and royalties will be recognized when and if earned, provided collectability is reasonably assured. |
Research and Development Expenses | Research and Development Expenses Research and development costs are charged to expense as costs are incurred in performing research and development activities. Research and development costs include all direct costs, including salaries, stock compensation and benefits for research and development personnel, outside consultants, costs of clinical trials, sponsored research, clinical trials insurance, other outside costs, depreciation and facility costs related to the development of drug candidates. The Company records upfront, non-refundable payments made to outside vendors, or other payments made in advance of services performed or goods being delivered, as prepaid expenses, which are expensed as services are performed or the goods are delivered. Certain research and development projects are, or have been, partially funded by collaboration agreements, and the expenses related to these activities are included in research and development costs. The Company records the related reimbursement of research and development costs under these agreements as revenue, as more fully described above and in Note 10. |
Stock-Based Compensation | Stock-Based Compensation At December 31, 2017 , the Company had two stock-based compensation plans, which are more fully described in Note 11. The Company accounts for stock-based compensation in accordance with the provisions of ASC Topic 718, Compensation—Stock Compensation (ASC 718), which requires the recognition of expense related to the fair value of stock-based compensation awards in the consolidated statements of operations and comprehensive loss. For stock-based awards issued to employees and members of the Company's board of directors (the Board) for their services on the Board and for participation in the employee stock purchase plan, the Company estimates the grant date fair value of each option award using the Black-Scholes option pricing model. The use of the Black-Scholes option pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk-free interest rates and expected dividend yields of the common stock. For awards subject to service-based vesting conditions, the Company recognizes stock-based compensation expense, equal to the grant date fair value of stock options on a straight-line basis over the requisite service period, which is generally the vesting term. For awards subject to both performance and service-based vesting conditions, the Company recognizes stock-based compensation expense using an accelerated recognition method when it is probable that the performance condition will be achieved. If achievement of the performance condition is not probable, but the award will vest based on the service condition, expense is recognized over the requisite service period. Share-based payments issued to non-employees are recorded at their fair values, and are periodically revalued as the equity instruments vest and are recognized as expense over the related service period in accordance with the provisions of ASC 718 and ASC Topic 505 (ASC 505), Equity . For stock-based awards granted to non-employees, the Company recognizes stock-based compensation expense using an accelerated recognition method. Effective January 1, 2017, the Company adopted ASU 2016-09, Compensation - Stock Compensation, Improvements to Employee Share-Based Payment Accounting . In connection with the adoption of this standard, the Company records actual forfeitures as they occur, rather than estimating forfeitures by applying a forfeiture rate. See Note 11 for a discussion of the assumptions used by the Company in determining the grant date fair value of options granted under the Black-Scholes option pricing model, as well as a summary of the stock option activity under the Company's stock-based compensation plans for the year ended December 31, 2017 . |
Income Taxes | Income Taxes Income taxes are recorded in accordance with ASC Topic 740, Income Taxes (ASC 740), which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are provided, if based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. |
Net Loss Per Share | Net Loss Per Share The Company calculates basic and diluted net loss per common share by dividing the net loss by the weighted-average number of common shares outstanding during the period. For the years ended December 31, 2017 , 2016 and 2015 , the Company has excluded the effects of all potentially dilutive shares, which include outstanding common stock options, warrants for common stock, common stock issuable under the employee stock purchase plan, and restricted stock units, from the weighted-average number of common shares outstanding as their inclusion in the computation for these years would be anti-dilutive due to net losses incurred. |
Comprehensive Loss | Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions, other events, and circumstances from non-owner sources. Comprehensive loss consists of net loss and other comprehensive loss, which includes certain changes in equity that are excluded from net loss. Comprehensive loss has been disclosed in the accompanying consolidated statements of operations and comprehensive loss. Accumulated other comprehensive loss is presented separately on the consolidated balance sheets and consists entirely of unrealized holdings losses on investments as of December 31, 2017 and 2016 . |
Subsequent Events | Subsequent Events The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. Subsequent events have been evaluated as required. The Company has evaluated all subsequent events and determined that there are no material recognized or unrecognized subsequent events requiring disclosure. |
Recently Adopted Accounting Pronouncements | Recently Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. The new standard will be effective for the Company on January 1, 2018. Topic 606 allows for either a full retrospective application, which the standard is applied to all periods presented, or a modified retrospective application, in which the standard is applied to the most current period presented in the financial statements. As of December 31, 2017 , revenue is generated exclusively from the Company's collaboration agreement with Celgene. The Company is currently evaluating the potential impact that Topic 606 may have on its financial position and results of operations as it relates to this single arrangement, and expects to elect the modified retrospective application as its transition method. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), Amendments to the FASB Accounting Standards Codification , which replaces the existing guidance for leases. ASU 2016-02 requires the identification of arrangements that should be accounted for as leases by lessees. In general, for lease arrangements exceeding a twelve month term, these arrangements must now be recognized as assets and liabilities on the balance sheet of the lessee. Under ASU 2016-02, a right-of-use asset and lease obligation will be recorded for all leases, whether operating or financing, while the income statement will reflect lease expense for operating leases and amortization/interest expense for financing leases. The balance sheet amount recorded for existing leases at the date of adoption of ASU 2016-02 must be calculated using the applicable incremental borrowing rate at the date of adoption. In addition, ASU 2016-02 requires the use of the modified retrospective method, which will require adjustment to all comparative periods presented in the consolidated financial statements. This guidance is effective for annual and interim periods beginning after December 15, 2018 and requires retrospective application. The Company is currently assessing the impact that adopting ASU 2016-02 will have on its consolidated financial statements and related disclosures. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows - Restricted Cash (Topic 230) . This new standard requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This guidance is effective for annual and interim reporting periods beginning after December 15, 2017, and requires retrospective application. The Company is currently assessing the impact that adopting ASU 2016-18 will have on its consolidated financial statements and related disclosures. In March 2017, the FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. This new standard shortens the amortization period for certain callable debt securities held at a premium. Specifically, the amendment requires the premium to be amortized to the earliest call date. The amendment does not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The guidance is effective for annual and interim periods beginning after December 15, 2018, and early adoption is permitted. The amendment should be applied on a modified retrospective basis, with the cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company is currently assessing the impact that adopting ASU 2017-08 will have on its consolidated financial statements and related disclosures. |
Summary of Significant Accoun24
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Schedule of Financial Instruments Carried at Fair Value | The following tables set forth the Company's financial instruments carried at fair value using the lowest level of input applicable to each financial instrument as of December 31, 2017 and 2016 (in thousands): December 31, 2017 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 90,702 $ — $ — $ 90,702 Corporate obligations — 158,849 — 158,849 U.S. Treasury securities — 37,813 — 37,813 Certificates of deposit — 12,244 — 12,244 Mortgage and other asset backed securities — 67,888 — 67,888 Restricted cash 1,132 — — 1,132 Total assets $ 91,834 $ 276,794 $ — $ 368,628 Liabilities: Warrants to purchase common stock $ — $ — $ 2,236 $ 2,236 Total liabilities $ — $ — $ 2,236 $ 2,236 December 31, 2016 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 19,818 $ — $ — $ 19,818 Corporate obligations — 88,492 — 88,492 U.S. Treasury securities — 33,968 — 33,968 Certificates of deposit — 23,373 — 23,373 Mortgage and other asset backed securities — 67,599 — 67,599 Restricted cash 946 — — 946 Total assets $ 20,764 $ 213,432 $ — $ 234,196 Liabilities: Warrants to purchase common stock $ — $ — $ 1,244 $ 1,244 Total liabilities $ — $ — $ 1,244 $ 1,244 |
Summary of Changes in the Fair Value of Preferred and Common Stock Warrants | The following table sets forth a summary of changes in the fair value of the Company's common stock warrant liabilities, which represent a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs (in thousands): Year Ended December 31, 2017 2016 Beginning balance $ 1,244 $ 17,187 Change in fair value 992 (7,262 ) Exercises — (8,681 ) Ending balance $ 2,236 $ 1,244 |
Schedule of Estimated Useful Lives of Property and Equipment | Depreciation and amortization is calculated using the straight-line method over the estimated useful lives of the assets, which are as follows: Asset Estimated Useful Life Computer equipment and software 3 years Office and laboratory equipment 3 years Leasehold improvements Shorter of the useful life or remaining lease term |
Schedule of Anti-dilutive Common Stock Equivalents Excluded from the Calculation of Diluted Net Income (Loss) per Share | The following is a summary of the common stock equivalents which were excluded from the calculation of diluted net loss per share for the periods indicated (in thousands): Year Ended December 31, 2017 2016 2015 Outstanding stock options 3,452 3,316 3,191 Common stock warrants 61 64 398 Shares issuable under employee stock purchase plan 18 23 15 Restricted stock units 604 732 521 Total excluded common stock equivalents 4,135 4,135 4,125 |
Property and Equipment, Net (Ta
Property and Equipment, Net (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Property, Plant and Equipment [Abstract] | |
Schedule of Property and Equipment, Net | Property and equipment, net, consists of the following (in thousands): December 31, 2017 2016 Computer equipment and software $ 1,501 $ 1,260 Office equipment 522 519 Laboratory equipment 17,268 13,204 Leasehold improvements 11,501 11,126 Construction in progress 584 849 Total property and equipment 31,376 26,958 Accumulated depreciation and amortization (24,410 ) (21,757 ) Property and equipment, net $ 6,966 $ 5,201 |
Cash, Cash Equivalents and Sh26
Cash, Cash Equivalents and Short-term and Long-term Investments (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Cash and Cash Equivalents [Abstract] | |
Schedule of Available-for-Sale Securities | The following is a summary of cash, cash equivalents and available-for-sale securities as of December 31, 2017 and December 31, 2016 (in thousands): December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 100,150 $ — $ — $ 100,150 Available-for-sale securities: Corporate obligations due in one year or less 99,792 — (219 ) 99,573 Corporate obligations due in more than one year 57,537 — (261 ) 57,276 U.S. Treasury securities due in one year or less 27,987 — (93 ) 27,894 U.S. Treasury securities due in more than one year 9,968 — (48 ) 9,920 Certificates of deposit due in one year or less 10,529 — — 10,529 Certificates of deposit due in more than one year 1,715 — — 1,715 Mortgage and other asset backed securities due in one year or less 39,236 — (155 ) 39,081 Mortgage and other asset backed securities due in more than one year 26,931 — (119 ) 26,812 Total available-for-sale securities $ 273,695 $ — $ (895 ) $ 272,800 Total cash, cash equivalents and available-for-sale securities $ 373,845 $ — $ (895 ) $ 372,950 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 20,950 $ — $ — $ 20,950 Available-for-sale securities: Corporate obligations due in one year or less 45,839 1 (58 ) 45,782 Corporate obligations due in more than one year 42,895 — (185 ) 42,710 U.S. Treasury securities due in one year or less 22,490 — (10 ) 22,480 U.S. Treasury securities due in more than one year 11,541 — (53 ) 11,488 Certificates of deposit due in one year or less 13,562 — — 13,562 Certificates of deposit due in more than one year 9,811 — — 9,811 Mortgage and other asset backed securities due in one year or less 36,948 — (32 ) 36,916 Mortgage and other asset backed securities due in more than one year 30,771 — (88 ) 30,683 Total available-for-sale securities $ 213,857 $ 1 $ (426 ) $ 213,432 Total cash, cash equivalents and available-for-sale securities $ 234,807 $ 1 $ (426 ) $ 234,382 |
Accrued Expenses (Tables)
Accrued Expenses (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Payables and Accruals [Abstract] | |
Schedule of Accrued Expenses | Accrued expenses consist of the following (in thousands): December 31, 2017 2016 Research and development related $ 4,014 $ 5,238 Employee compensation 6,809 4,840 Professional services 1,183 739 Other 2,930 2,432 Total accrued expenses $ 14,936 $ 13,249 |
Warrants (Tables)
Warrants (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Warrants and Rights Note Disclosure [Abstract] | |
Summary of Shares Issuable Upon Exercise of Outstanding Warrants | Below is a summary of the number of shares issuable upon exercise of outstanding warrants and the terms and accounting treatment for the outstanding warrants (in thousands, except per share data): Warrants as of Weighted- Average Exercise Balance Sheet Classification December 31, 2017 December 31, 2016 Price Per Share Expiration December 31, 2017 December 31, 2016 Warrants to purchase common stock 61 61 $ 5.88 June 10, 2020 - July 9, 2020 Liability Liability Warrants to purchase common stock — 4 4.00 - 7.40 March 28, 2017 - December 31, 2017 Equity(1) (2) (3) Equity(1) (2) (3) All warrants 61 65 $ 5.88 ______________________________________________________________________ (1) In March 2017, the warrant holders exercised warrants to purchase 1,187 shares of Common Stock on a net basis, resulting in the issuance of 1,014 shares of Common Stock. (2) In December 2017, the warrant holders exercised warrants to purchase 2,702 shares of Common Stock on a net basis, resulting in the issuance of 2,207 shares of Common Stock. (3) Warrants to purchase common stock were issued in connection with various debt financing transactions that were consummated prior to our initial public offering. |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Commitments and Contingencies Disclosure [Abstract] | |
Schedule of Future Annual Minimum Lease Payments | Future annual minimum lease payments as of December 31, 2017, are as follows (in thousands): 2018 $ 5,551 2019 6,320 2020 6,506 2021 6,191 2022 6,207 2023 4,761 Total $ 35,536 |
Schedule of Future Minimum Sublease Proceeds | Future annual minimum sublease proceeds expected as of December 31, 2017 are as follows (in thousands): 2018 $ 704 Total $ 704 |
Stockholders' Equity (Tables)
Stockholders' Equity (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Stockholders' Equity Note [Abstract] | |
Schedule of Common Stock Reserved for Future Issuance | At December 31, 2017 , the Company has reserved for future issuance the following number of shares of common stock (in thousands): December 31, 2017 Outstanding stock options to purchase common stock 3,452 Outstanding restricted stock units 604 Shares available for future issuance under equity incentive plan 2,763 Warrants to purchase common stock 61 Shares available for future issuance under the employee stock purchase plan 187 Additional shares reserved for unissued, but designated, Preferred Stock 25,000 Total shares of authorized common stock reserved for future issuance 32,067 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Schedule of Total Compensation Cost Recognized for all Stock-based Awards | The Company recognized stock-based compensation expense under the various Plans in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year Ended December 31, 2017 2016 2015 Research and development $ 14,227 $ 8,171 $ 4,852 General and administrative 14,021 10,386 7,223 $ 28,248 $ 18,557 $ 12,075 |
Schedule of Stock Option Valuation Assumptions | The fair value of each option issued to employees was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Year Ended December 31, 2017 2016 2015 Expected volatility 65.7 % 65.1 % 67.0 % Expected term (in years) 6.0 6.0 6.0 Risk-free interest rate 2.13 % 1.69 % 1.67 % Expected dividend yield — % — % — % |
Summary of Stock Option Activity | The following table summarizes the stock option activity under the Company's stock option plans during the year ended December 31, 2017 (in thousands, except per share amounts and years): Number Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2016 3,316 $ 25.96 Granted 701 $ 30.78 Exercised (474 ) $ 8.21 Canceled or forfeited (91 ) $ 34.85 Outstanding at December 31, 2017 3,452 $ 29.14 6.72 $ 46,115 Exercisable at December 31, 2017 2,110 $ 26.78 5.52 $ 33,208 ______________________________________________________ (1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at December 31, 2017 and 2016 . |
Schedule of Restricted Stock Unit Activity | The following table summarizes the restricted stock unit (RSU) activity under the 2013 Plan during the year ended December 31, 2017 : Number of Weighted- Unvested balance at December 31, 2016 182 $ 31.50 Granted 156 $ 32.89 Vested (57 ) $ 30.52 Forfeited (14 ) $ 33.21 Unvested balance at December 31, 2017 267 $ 32.44 |
Performance Shares Units Nonvested Activity | The following table summarizes PSU activity under the 2013 Plan during the year ended December 31, 2017 : Number of Weighted- Unvested balance at December 31, 2016 551 $ 31.57 Granted 28 $ 27.24 Vested (232 ) $ 31.12 Forfeited (10 ) $ 31.09 Unvested balance at December 31, 2017 337 $ 31.53 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Components of the Company's Deferred Tax Assets | The significant components of the Company's deferred tax assets are comprised of the following (in thousands): Year Ended December 31, 2017 2016 Deferred tax assets: U.S. and state net operating loss carryforwards $ 116,812 $ 109,429 Research and development credits 12,548 9,717 Deferred revenue 1,010 1,666 Accruals and other temporary differences 15,287 15,725 Total deferred tax assets 145,657 136,537 Less valuation allowance (145,657 ) (136,537 ) Net deferred tax assets $ — $ — |
Schedule of Effective Income Tax Rate Reconciliation | A reconciliation of income tax expense computed at the statutory federal income tax rate to income taxes as reflected in the consolidated financial statements is as follows: Year Ended December 31, 2017 2016 2015 Federal income tax expense at statutory rate 34.0 % 34.0 % 34.0 % State income tax, net of federal benefit 5.6 % 5.9 % 4.6 % Permanent differences 1.9 % 4.0 % (8.3 )% Research and development credit 1.9 % 3.1 % 1.2 % Tax reform rate change (54.7 )% — % — % Other (0.3 )% (0.1 )% — % Change in valuation allowance 11.6 % (46.9 )% (31.5 )% Effective income tax rate — % — % — % |
Quarterly Financial Data (una33
Quarterly Financial Data (unaudited) (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Schedule of Certain Unaudited Quarterly Financial Information | The following table presents certain unaudited quarterly financial information for the eight quarters in the period ended December 31, 2017 . This information has been prepared on the same basis as the audited financial statements and includes all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the unaudited quarterly results of operations set forth herein. For the Three Months Ended(1) March 31 June 30 September 30 December 31 (in thousands except per share data) 2017 Total revenue $ 3,705 $ 3,057 $ 3,014 $ 3,705 Total costs and expenses 29,563 32,968 28,592 32,341 Loss from operations (25,858 ) (29,911 ) (25,578 ) (28,636 ) Net loss (25,407 ) (29,669 ) (25,451 ) (27,926 ) Basic net loss per share $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) Diluted net loss per share $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) 2016 Total revenue $ 18,201 $ 3,195 $ 3,005 $ 3,369 Total costs and expenses 22,157 22,850 23,513 25,355 Loss from operations (3,956 ) (19,655 ) (20,508 ) (21,986 ) Net income (loss) 5,061 (22,016 ) (20,770 ) (19,288 ) Basic net income (loss) per share $ 0.14 $ (0.59 ) $ (0.55 ) $ (0.51 ) Diluted net income (loss) per share $ 0.13 $ (0.59 ) $ (0.55 ) $ (0.51 ) ______________________________________________________ (1) The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Summary of Significant Accoun34
Summary of Significant Accounting Policies (Details) | 12 Months Ended | ||
Dec. 31, 2017USD ($)segmentstock-based_compensation_plan | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) | |
Segment Information | |||
Number of operating segments | segment | 1 | ||
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] | |||
Marketable securities, realized gain (loss) | $ 0 | $ 0 | $ 0 |
Continuous unrealized loss position, less than twelve months | 193,600,000 | 172,200,000 | |
Continuous unrealized loss position, twelve months or longer, fair value | 67,000,000 | 5,500,000 | |
Continuous unrealized loss position, fair value | 300,000 | 2,000 | |
Concentrations of Credit Risk and Off-Balance Sheet Risk | |||
Off-balance sheet risk, asset | 0 | ||
Off-balance sheet risk, liability | 0 | ||
Fair Value Measurement | |||
Transfers within the hierarchy | 0 | 0 | |
Property and Equipment | |||
Impairment losses | $ 0 | $ 0 | $ 0 |
Stock-Based Compensation | |||
Number of stock-based compensation plans | stock-based_compensation_plan | 2 |
Summary of Significant Accoun35
Summary of Significant Accounting Policies - Schedule of Financial Instruments Carried at Fair Value (Details) - Recurring - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Assets: | ||
Total assets | $ 368,628 | $ 234,196 |
Liabilities: | ||
Total liabilities | 2,236 | 1,244 |
Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 2,236 | 1,244 |
Money Market Funds | ||
Assets: | ||
Total assets | 90,702 | 19,818 |
Corporate Obligations | ||
Assets: | ||
Total assets | 158,849 | 88,492 |
US Treasury Securities | ||
Assets: | ||
Total assets | 37,813 | 33,968 |
Certificates of Deposit | ||
Assets: | ||
Total assets | 12,244 | 23,373 |
Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 67,888 | 67,599 |
Restricted Cash | ||
Assets: | ||
Total assets | 1,132 | 946 |
Level 1 | ||
Assets: | ||
Total assets | 91,834 | 20,764 |
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 1 | Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 1 | Money Market Funds | ||
Assets: | ||
Total assets | 90,702 | 19,818 |
Level 1 | Corporate Obligations | ||
Assets: | ||
Total assets | 0 | 0 |
Level 1 | US Treasury Securities | ||
Assets: | ||
Total assets | 0 | 0 |
Level 1 | Certificates of Deposit | ||
Assets: | ||
Total assets | 0 | 0 |
Level 1 | Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 0 | 0 |
Level 1 | Restricted Cash | ||
Assets: | ||
Total assets | 1,132 | 946 |
Level 2 | ||
Assets: | ||
Total assets | 276,794 | 213,432 |
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 2 | Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 2 | Money Market Funds | ||
Assets: | ||
Total assets | 0 | 0 |
Level 2 | Corporate Obligations | ||
Assets: | ||
Total assets | 158,849 | 88,492 |
Level 2 | US Treasury Securities | ||
Assets: | ||
Total assets | 37,813 | 33,968 |
Level 2 | Certificates of Deposit | ||
Assets: | ||
Total assets | 12,244 | 23,373 |
Level 2 | Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 67,888 | 67,599 |
Level 2 | Restricted Cash | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | ||
Assets: | ||
Total assets | 0 | 0 |
Liabilities: | ||
Total liabilities | 2,236 | 1,244 |
Level 3 | Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 2,236 | 1,244 |
Level 3 | Money Market Funds | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | Corporate Obligations | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | US Treasury Securities | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | Certificates of Deposit | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | Restricted Cash | ||
Assets: | ||
Total assets | $ 0 | $ 0 |
Summary of Significant Accoun36
Summary of Significant Accounting Policies - Summary of Changes in the Fair Value of Preferred and Common Stock Warrants (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Summary of changes in the fair value of the preferred and common stock warrant liability classified within Level 3 of the fair value hierarchy | |||
Beginning balance | $ 1,244 | $ 17,187 | |
Change in fair value | 992 | (7,262) | $ 3,500 |
Exercises | 0 | (8,681) | |
Ending balance | $ 2,236 | $ 1,244 | $ 17,187 |
Summary of Significant Accoun37
Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Details) | 12 Months Ended |
Dec. 31, 2017 | |
Computer Equipment and Software | |
Property and Equipment | |
Estimated useful life | 3 years |
Office and laboratory equipment | |
Property and Equipment | |
Estimated useful life | 3 years |
Summary of Significant Accoun38
Summary of Significant Accounting Policies - Schedule of Anti-dilutive Common Stock Equivalents Excluded from the Calculation of Diluted Net Income (Loss) per Share (Details) - shares shares in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 4,135 | 4,135 | 4,125 |
Stock Options | |||
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 3,452 | 3,316 | 3,191 |
Common Stock Warrants | |||
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 61 | 64 | 398 |
Shares issuable under employee stock purchase plan | |||
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 18 | 23 | 15 |
Restricted Stock Units | |||
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 604 | 732 | 521 |
Property and Equipment, Net - S
Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Property and equipment, net | |||
Total property and equipment | $ 31,376 | $ 26,958 | |
Accumulated depreciation and amortization | (24,410) | (21,757) | |
Property and equipment, net | 6,966 | 5,201 | |
Depreciation and amortization expense | 2,825 | 1,676 | $ 1,176 |
Computer Equipment and Software | |||
Property and equipment, net | |||
Total property and equipment | 1,501 | 1,260 | |
Office Equipment | |||
Property and equipment, net | |||
Total property and equipment | 522 | 519 | |
Laboratory Equipment | |||
Property and equipment, net | |||
Total property and equipment | 17,268 | 13,204 | |
Leasehold Improvements | |||
Property and equipment, net | |||
Total property and equipment | 11,501 | 11,126 | |
Construction in Progress | |||
Property and equipment, net | |||
Total property and equipment | $ 584 | $ 849 |
Restricted Cash (Details)
Restricted Cash (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Restricted Cash | ||
Letters of credit held in the form of certificates of deposits | $ 1,132 | $ 946 |
Certificates of Deposit | Letters of Credit | ||
Restricted Cash | ||
Letters of credit held in the form of certificates of deposits | $ 1,100 | $ 900 |
Cash, Cash Equivalents and Sh41
Cash, Cash Equivalents and Short-term and Long-term Investments - Schedule of Available-for-Sale Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 |
Schedule of Available-for-sale Securities | ||||
Cash and cash equivalents due in 90 days or less | $ 100,150 | $ 20,950 | $ 27,783 | $ 176,460 |
Available-for-sale securities: | ||||
Amortized Cost | 273,695 | 213,857 | ||
Gross Unrealized Gains | 0 | 1 | ||
Gross Unrealized Losses | (895) | (426) | ||
Estimated Fair Value | 272,800 | 213,432 | ||
Total cash, cash equivalents and available for sale securities | ||||
Amortized Cost | 373,845 | 234,807 | ||
Gross Unrealized Gains | 0 | 1 | ||
Gross Unrealized Losses | (895) | (426) | ||
Estimated Fair Value | 372,950 | 234,382 | ||
Corporate Obligations Due in One Year or Less | ||||
Available-for-sale securities: | ||||
Amortized Cost | 99,792 | 45,839 | ||
Gross Unrealized Gains | 0 | 1 | ||
Gross Unrealized Losses | (219) | (58) | ||
Estimated Fair Value | 99,573 | 45,782 | ||
Corporate Obligations Due in More Than One Year | ||||
Available-for-sale securities: | ||||
Amortized Cost | 57,537 | 42,895 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | (261) | (185) | ||
Estimated Fair Value | 57,276 | 42,710 | ||
U.S. Treasury Securities Due in One Year or Less | ||||
Available-for-sale securities: | ||||
Amortized Cost | 27,987 | 22,490 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | (93) | (10) | ||
Estimated Fair Value | 27,894 | 22,480 | ||
U.S. Treasury Securities Due in More Than One Year | ||||
Available-for-sale securities: | ||||
Amortized Cost | 9,968 | 11,541 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | (48) | (53) | ||
Estimated Fair Value | 9,920 | 11,488 | ||
Certificates Of Deposit Due In One Year Or Less | ||||
Available-for-sale securities: | ||||
Amortized Cost | 10,529 | 13,562 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | 0 | 0 | ||
Estimated Fair Value | 10,529 | 13,562 | ||
Certificates Of Deposit Due In More Than One Year | ||||
Available-for-sale securities: | ||||
Amortized Cost | 1,715 | 9,811 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | 0 | 0 | ||
Estimated Fair Value | 1,715 | 9,811 | ||
Mortgage And Other Asset Backed Securities Due In One Year Or Less | ||||
Available-for-sale securities: | ||||
Amortized Cost | 39,236 | 36,948 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | (155) | (32) | ||
Estimated Fair Value | 39,081 | 36,916 | ||
Mortgage And Other Asset Backed Securities Due More Than One Year | ||||
Available-for-sale securities: | ||||
Amortized Cost | 26,931 | 30,771 | ||
Gross Unrealized Gains | 0 | 0 | ||
Gross Unrealized Losses | (119) | (88) | ||
Estimated Fair Value | $ 26,812 | $ 30,683 |
Accrued Expenses - Schedule of
Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Payables and Accruals [Abstract] | ||
Research and development related | $ 4,014 | $ 5,238 |
Employee compensation | 6,809 | 4,840 |
Professional services | 1,183 | 739 |
Other | 2,930 | 2,432 |
Total accrued expenses | $ 14,936 | $ 13,249 |
Warrants - Summary of Shares Is
Warrants - Summary of Shares Issuable Upon Exercise of Outstanding Warrants (Details) - $ / shares | 1 Months Ended | ||||
Dec. 31, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Jul. 31, 2010 | ||
Class of Warrant or Right | |||||
Number of outstanding warrants (in shares) | 61,000 | 65,000 | |||
Weighted-average exercise price per share (in dollars per share) | $ 5.88 | ||||
Number of warrants exercised (in shares) | 2,702 | 1,187 | |||
Stock issued during period for warrants exercsied (in shares) | 2,207 | 1,014 | |||
Expiring between June 10, 2020 to July 9, 2020 | |||||
Class of Warrant or Right | |||||
Number of outstanding warrants (in shares) | 61,000 | 61,000 | |||
Weighted-average exercise price per share (in dollars per share) | $ 5.88 | ||||
Expiring between June 10, 2020 to July 9, 2020 | Maximum | |||||
Class of Warrant or Right | |||||
Number of outstanding warrants (in shares) | 871,580 | ||||
Expiring between March 28, 2017 to December 31, 2017 | |||||
Class of Warrant or Right | |||||
Number of outstanding warrants (in shares) | [1],[2],[3] | 0 | 4,000 | ||
Expiring between March 28, 2017 to December 31, 2017 | Minimum | |||||
Class of Warrant or Right | |||||
Weighted-average exercise price per share (in dollars per share) | [1],[2],[3] | $ 4 | |||
Expiring between March 28, 2017 to December 31, 2017 | Maximum | |||||
Class of Warrant or Right | |||||
Weighted-average exercise price per share (in dollars per share) | [1],[2],[3] | $ 7.40 | |||
[1] | In December 2017, the warrant holders exercised warrants to purchase 2,702 shares of Common Stock on a net basis, resulting in the issuance of 2,207 shares of Common Stock. | ||||
[2] | In March 2017, the warrant holders exercised warrants to purchase 1,187 shares of Common Stock on a net basis, resulting in the issuance of 1,014 shares of Common Stock. | ||||
[3] | Warrants to purchase common stock were issued in connection with various debt financing transactions that were consummated prior to our initial public offering. |
Warrants (Details)
Warrants (Details) - USD ($) $ in Thousands | Jul. 31, 2010 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Class of Warrant or Right | ||||
Number of outstanding warrants (in shares) | 61,000 | 65,000 | ||
Increase (decrease) in fair value | $ 992 | $ (7,262) | $ 3,500 | |
Expiring between June 10, 2020 to July 9, 2020 | ||||
Class of Warrant or Right | ||||
Number of outstanding warrants (in shares) | 61,000 | 61,000 | ||
Expiration period | 10 years | |||
Maximum | Expiring between June 10, 2020 to July 9, 2020 | ||||
Class of Warrant or Right | ||||
Number of outstanding warrants (in shares) | 871,580 |
Commitments and Contingencies45
Commitments and Contingencies (Details) - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Loss Contingencies | |||
Rent expense | $ 4,800,000 | $ 3,800,000 | $ 3,400,000 |
Sublease revenue | 300,000 | 0 | $ 0 |
Operating lease loss | 100,000 | ||
Collaborative Arrangement, Co-promotion | |||
Loss Contingencies | |||
Amounts due | $ 0 | $ 0 |
Commitments and Contingencies -
Commitments and Contingencies - Schedule of Future Annual Minimum Lease Payments (Details) $ in Thousands | Dec. 31, 2017USD ($) |
Commitments and Contingencies Disclosure [Abstract] | |
2,018 | $ 5,551 |
2,019 | 6,320 |
2,020 | 6,506 |
2,021 | 6,191 |
2,022 | 6,207 |
2,023 | 4,761 |
Total | $ 35,536 |
Commitments and Contingencies S
Commitments and Contingencies Schedule of Future Minimum Sublease Proceeds (Details) $ in Thousands | Dec. 31, 2017USD ($) |
Commitments and Contingencies Disclosure [Abstract] | |
2,018 | $ 704 |
Total | $ 704 |
Stockholders' Equity (Details)
Stockholders' Equity (Details) $ / shares in Units, $ in Thousands | Oct. 04, 2017shares | Sep. 25, 2017USD ($)$ / sharesshares | Jan. 11, 2016USD ($)$ / sharesshares | Dec. 31, 2017USD ($)vote$ / sharesshares | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) |
Common stock | ||||||
Public offering share amount (in shares) | shares | 3,750,000 | |||||
Price per share (in dollars per share) | $ / shares | $ 40 | |||||
Aggregate net proceeds from the offering | $ | $ 140,300 | |||||
Shares issued (in dollars per share) | $ / shares | $ 37 | |||||
Proceeds from issuance of common stock from public offering, net of issuance costs | $ | $ 215,800 | $ 215,802 | $ 140,697 | $ (47) | ||
Preferred stock (in shares) | shares | 25,000,000 | |||||
Number of votes for each share of common stock held | vote | 1 | |||||
Dividends declared on common stock (in dollars per share) | $ / shares | $ 0 | |||||
Common Stock | ||||||
Common stock | ||||||
Issuance of common stock (in shares) | shares | 810,810 | 5,405,406 |
Stockholders' Equity - Schedule
Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details) shares in Thousands | Dec. 31, 2017shares |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 32,067 |
Conversion of Preferred Stock | Unissued, but Designated, Preferred Stock | |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 25,000 |
Common Stock Warrants | |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 61 |
Stock Compensation Plan | |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 3,452 |
Restricted Stock | |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 604 |
Stock Options | |
Common stock | |
Total shares of authorized common stock reserved for future issuance (in shares) | 2,763 |
Significant Agreements - Sotate
Significant Agreements - Sotatercept Agreement (Details) | Sep. 24, 2013USD ($) | Jan. 01, 2013 | Feb. 20, 2008USD ($)discovery_stage_compound | Dec. 31, 2017USD ($) | Aug. 02, 2011USD ($) |
Research and Development Funding and Milestones | Amended Sotatercept Agreement | Collaboration Arrangement | Sotatercept | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Payments received | $ 44,200,000 | ||||
Celgene | Original Sotatercept Agreement | Collaboration Arrangement | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Equity purchased | $ 5,000,000 | ||||
Percentage of development costs for which collaborator is responsible | 100.00% | ||||
Celgene | Original Sotatercept Agreement | Collaboration Arrangement | Discovery Stage Compounds | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Number of license options granted | discovery_stage_compound | 3 | ||||
Celgene | Nonrefundable Upfront Payments | Original Sotatercept Agreement | Collaboration Arrangement | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Payments received | $ 45,000,000 | ||||
Clinical Milestones | Celgene | Restated Sotatercept Agreement | Sotatercept | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Milestone payment receivable on commencement of trial or study | $ 10,000,000 | ||||
Common Stock | Celgene | Original Sotatercept Agreement | Collaboration Arrangement | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Equity purchased | $ 10,000,000 | ||||
Maximum | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Discovery Stage Compounds | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Collaborative arrangement option fees potential | $ 30,000,000 | ||||
Maximum | Clinical Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Discovery Stage Compounds | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | 25,500,000 | ||||
Maximum | Clinical Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Sotatercept | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | 27,000,000 | ||||
Maximum | Regulatory Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Discovery Stage Compounds | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | 142,500,000 | ||||
Maximum | Regulatory Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Sotatercept | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | 190,000,000 | ||||
Maximum | Commercial Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Discovery Stage Compounds | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | 150,000,000 | ||||
Maximum | Commercial Milestones | Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | Sotatercept | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Contingent milestone payments | $ 150,000,000 |
Significant Agreements - Luspat
Significant Agreements - Luspatercept Agreement (Details) - Luspatercept Agreement - USD ($) | Jan. 01, 2013 | Feb. 20, 2008 | Dec. 31, 2016 | Feb. 29, 2016 | Aug. 31, 2011 | Dec. 31, 2011 | Dec. 31, 2017 |
Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Percentage of development costs for which collaborator is responsible | 100.00% | ||||||
Celgene | Nonrefundable Upfront Payments | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Payments received | $ 25,000,000 | ||||||
Celgene | Nonrefundable Upfront Payments | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Payments received | 25,000,000 | ||||||
Celgene | Research and Development Funding and Milestones | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Payments received | $ 99,400,000 | ||||||
Clinical Milestones | Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Payments received | $ 15,000,000 | $ 15,000,000 | $ 7,500,000 | ||||
Clinical Milestones | Maximum | Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Potential milestone payments receivable | 32,500,000 | ||||||
Regulatory Milestones | Maximum | Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Potential milestone payments receivable | 105,000,000 | ||||||
Commercial Milestones | Maximum | Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Potential milestone payments receivable | $ 80,000,000 | ||||||
Luspatercept | Celgene | Collaboration Arrangement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Potential royalty rate (as a percent) | 20.00% | ||||||
Luspatercept | Investor | Clinical Milestones | Collaboration, License, and Option Agreement | |||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||
Milestone payment receivable on commencement of trial or study | $ 25,000,000 |
Significant Agreements - Both A
Significant Agreements - Both Agreements and Accounting Analysis (Details) - USD ($) $ in Thousands | Jan. 01, 2013 | Feb. 20, 2008 | Dec. 31, 2016 | Feb. 29, 2016 | Aug. 31, 2011 | Dec. 31, 2017 | Sep. 30, 2017 | [1] | Jun. 30, 2017 | [1] | Mar. 31, 2017 | [1] | Dec. 31, 2016 | Sep. 30, 2016 | [1] | Jun. 30, 2016 | [1] | Mar. 31, 2016 | [1] | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2012 | Dec. 31, 2011 | ||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Residual consideration recognized | $ 3,705 | [1] | $ 3,014 | $ 3,057 | $ 3,705 | $ 3,369 | [1] | $ 3,005 | $ 3,195 | $ 18,201 | $ 13,481 | $ 27,771 | $ 18,097 | |||||||||||||
Difference between the estimated payments and the estimated selling prices | $ 3,704 | $ 3,161 | $ 3,704 | 3,161 | 3,704 | |||||||||||||||||||||
Cost-sharing, net | 12,940 | 12,221 | 16,913 | |||||||||||||||||||||||
Celgene | Luspatercept Agreement and Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Total arrangement consideration | $ 77,700 | |||||||||||||||||||||||||
Estimated payments for development activities and manufacturing services | 18,000 | |||||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | |||||||||||||||||||||||||
BESP of the undelivered elements | 28,200 | |||||||||||||||||||||||||
Difference between the estimated payments and the estimated selling prices | 10,200 | |||||||||||||||||||||||||
Deferred revenue recognized | 500 | 500 | 1,200 | |||||||||||||||||||||||
Cost-sharing, net | $ 12,900 | $ 12,200 | $ 16,900 | |||||||||||||||||||||||
Celgene | Original Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Deferred revenue | $ 45,000 | 34,700 | ||||||||||||||||||||||||
Delivery period of contract | 15 years | |||||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | |||||||||||||||||||||||||
Celgene | Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Deferred revenue | 34,700 | |||||||||||||||||||||||||
Residual consideration recognized | 49,500 | |||||||||||||||||||||||||
Celgene | Luspatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | |||||||||||||||||||||||||
Nonrefundable Upfront Payments | Celgene | Original Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Payments received | $ 45,000 | |||||||||||||||||||||||||
Nonrefundable Upfront Payments | Celgene | Luspatercept Agreement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Payments received | 25,000 | |||||||||||||||||||||||||
Nonrefundable Upfront Payments | Celgene | Luspatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Payments received | 25,000 | |||||||||||||||||||||||||
Research and Development Services | Celgene | Luspatercept Agreement and Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
BESP of the undelivered elements | 18,800 | |||||||||||||||||||||||||
Sotatercept Joint Development Committee | Celgene | Luspatercept Agreement and Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
BESP of the undelivered elements | 2,900 | |||||||||||||||||||||||||
ACE 536 Joint Development Committee | Celgene | Luspatercept Agreement and Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
BESP of the undelivered elements | 3,700 | |||||||||||||||||||||||||
Manufacturing Services | Celgene | Luspatercept Agreement and Amended Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
BESP of the undelivered elements | $ 2,800 | |||||||||||||||||||||||||
Clinical Milestones | Celgene | Luspatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||||||
Deferred revenue | $ 2,700 | |||||||||||||||||||||||||
Payments received | $ 15,000 | $ 15,000 | 7,500 | |||||||||||||||||||||||
Deferred revenue recognized | $ 4,800 | |||||||||||||||||||||||||
[1] | The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Significant Agreements - Other
Significant Agreements - Other (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended | |||
May 31, 2014 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2004 | |
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Research and development | $ 89,726 | $ 68,580 | $ 58,404 | ||
License Agreement with a Non-profit Institution | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Research and development | 100 | 100 | 100 | ||
License Agreement With Antibody Technology Company | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Research and development | $ 1,600 | $ 1,000 | $ 1,400 | ||
Common Stock | License Agreement with a Non-profit Institution | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Number of shares issued as compensation for licenses (in shares) | 62,500 | ||||
Fair value of shares issued as compensation for licenses | $ 25 | ||||
Maximum | License Agreement with a Non-profit Institution | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Milestone fees payable as percentage of research and U.S. development progress and sublicensing revenue | 25.00% | ||||
Royalty payable as percentage of net sales | 3.50% | ||||
Minimum | License Agreement with a Non-profit Institution | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Milestone fees payable as percentage of research and U.S. development progress and sublicensing revenue | 10.00% | ||||
Royalty payable as percentage of net sales | 1.00% | ||||
Development Milestones | Sotatercept | Maximum | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Total potential milestone payments | $ 2,000 | ||||
Development Milestones | Luspatercept Agreement | Maximum | Non-collaborative Arrangement Transactions | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Total potential milestone payments | $ 700 | ||||
Additional Research Fees | License Agreement With Antibody Technology Company | |||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Total potential milestone payments | $ 600 | ||||
Collaborative arrangement amount paid and expensed | $ 300 |
Stock-Based Compensation (Detai
Stock-Based Compensation (Details) | Sep. 04, 2013shares | Dec. 31, 2017USD ($)stock-based_compensation_planshares | Dec. 31, 2017USD ($)stock-based_compensation_plan$ / sharesshares | Dec. 31, 2016USD ($)$ / sharesshares | Dec. 31, 2015USD ($)$ / sharesshares |
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Number of stock-based compensations plans | stock-based_compensation_plan | 2 | 2 | |||
Shares reserved for issuance (in shares) | shares | 32,067,000 | 32,067,000 | |||
Stock compensation expense | $ 28,248,000 | $ 18,557,000 | $ 12,075,000 | ||
Increase in valuation allowance | $ 9,100,000 | $ 26,700,000 | $ 20,000,000 | ||
Expected dividend yield | 0.00% | ||||
Estimated forfeiture rate | 0.00% | 2.75% | 4.00% | ||
Shares granted during period (in shares) | shares | 701,000 | ||||
Exercise of stock options (in shares) | shares | 474,000 | ||||
2003 Plan | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Number of shares of common stock which may be granted (in shares) | shares | 0 | 0 | |||
Remaining shares reserved for issuance (in shares) | shares | 155,884 | ||||
2013 Plan | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in shares) | shares | 1,500,000 | ||||
Remaining shares reserved for issuance (in shares) | shares | 2,762,770 | 2,762,770 | |||
Additional shares authorized under new plan (in shares) | shares | 1,344,116 | ||||
Annual increase in shares authorized under plan, shares threshold (in shares) | shares | 3,150,000 | ||||
Percentage threshold of outstanding shares as of December 31 of each year for calculation of annual increase in authorized shares under the plan | 4.00% | ||||
2003 and 2013 Plans | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Expiration period of options | 10 years | ||||
Vesting period of stock options and restricted stock awards | 4 years | ||||
Stock compensation expense | $ 4,900,000 | $ 500,000 | $ 0 | ||
Shares granted during period (in shares) | shares | 701,384 | 1,045,795 | 870,526 | ||
Weighted average grant date fair value (in dollars per share) | $ / shares | $ 18.58 | $ 18.55 | $ 24.29 | ||
Exercise of stock options (in shares) | shares | 474,056 | 885,075 | 837,361 | ||
Total proceeds from options exercised | $ 3,900,000 | $ 5,300,000 | $ 4,000,000 | ||
Aggregate intrinsic value of options exercised | 10,200,000 | 23,800,000 | 25,200,000 | ||
Unrecognized compensation expense related to unvested stock options | 22,800,000 | $ 22,800,000 | |||
Weighted-average period of recognition (in years) | 2 years 4 months 21 days | ||||
2013 ESPP | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in shares) | shares | 275,000 | ||||
Purchase price of common stock expressed as a percentage of the fair value of a share of common stock | 85.00% | ||||
Stock compensation expense | $ 300,000 | 300,000 | $ 300,000 | ||
Employment Agreement with Former Chief Operating Officer | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Incremental compensation cost | $ 3,600,000 | ||||
Restricted Stock Units | 2003 and 2013 Plans | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Vesting period of stock options and restricted stock awards | 3 years | ||||
Restricted Stock Units | Certain Individuals | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Weighted-average period of recognition (in years) | 1 year 8 months 5 days | ||||
Unrecognized compensation expense related to unvested restricted stock units | 5,700,000 | $ 5,700,000 | |||
Performance-Based Restricted Stock Units | Certain Individuals | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Weighted-average period of recognition (in years) | 1 year 5 months 5 days | ||||
Unrecognized compensation expense related to unvested restricted stock units | 4,800,000 | $ 4,800,000 | |||
Accounting Standards Update 2016-09 | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Excess tax benefit, amount | 21,500,000 | ||||
Increase in valuation allowance | 21,500,000 | ||||
Accumulated Deficit | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Effect of adoption of ASU 2016-09 | $ (79,000) | ||||
Accumulated Deficit | Accounting Standards Update 2016-09 | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Effect of adoption of ASU 2016-09 | $ 100,000 | $ 100,000 | |||
Employee Stock Purchase Plan | 2013 ESPP | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in shares) | shares | 186,844 | 186,844 |
Stock-Based Compensation - Sche
Stock-Based Compensation - Schedule of Total Compensation Cost Recognized for All Stock-based Awards (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | $ 28,248 | $ 18,557 | $ 12,075 |
Research and Development | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | 14,227 | 8,171 | 4,852 |
General and Administrative | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | $ 14,021 | $ 10,386 | $ 7,223 |
Stock-Based Compensation - Sc56
Stock-Based Compensation - Schedule of Stock Option Valuation Assumptions (Details) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award | |||
Expected dividend yield | 0.00% | ||
Equity Option | |||
Share-based Compensation Arrangement by Share-based Payment Award | |||
Expected volatility | 65.70% | 65.10% | 67.00% |
Expected term (in years) | 6 years | 6 years | 6 years |
Risk-free interest rate | 2.13% | 1.69% | 1.67% |
Expected dividend yield | 0.00% | 0.00% | 0.00% |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands | 12 Months Ended | |
Dec. 31, 2017USD ($)$ / sharesshares | ||
Number of Grants | ||
Outstanding at beginning of period (in shares) | shares | 3,316 | |
Granted (in shares) | shares | 701 | |
Exercised (in shares) | shares | (474) | |
Canceled or forfeited (in shares) | shares | (91) | |
Outstanding at end of period (in shares) | shares | 3,452 | |
Exercisable (in shares) | shares | 2,110 | |
Weighted- Average Exercise Price Per Share | ||
Outstanding at beginning of period (in dollars per share) | $ / shares | $ 25.96 | |
Granted (in dollars per share) | $ / shares | 30.78 | |
Exercised (in dollars per share) | $ / shares | 8.21 | |
Canceled or forfeited (in dollars per share) | $ / shares | 34.85 | |
Outstanding at end of period (in dollars per share) | $ / shares | 29.14 | |
Exercisable (in dollars per share) | $ / shares | $ 26.78 | |
Weighted- Average Contractual Life (in years) | ||
Outstanding at end of period (in years) | 6 years 8 months 19 days | |
Exercisable (in years) | 5 years 6 months 7 days | |
Aggregate Intrinsic Value | ||
Outstanding at end of period (in dollars) | $ | $ 46,115 | [1] |
Exercisable (in dollars) | $ | $ 33,208 | [1] |
[1] | The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying options and the estimated fair value of the common stock for the options that were in the money at December 31, 2017 and 2016. |
Stock-based Compensation - Sc58
Stock-based Compensation - Schedule of Restricted Stock Unit Activity and Performance-Based Restricted Stock Units (Details) - $ / shares | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Restricted Stock Units | ||
Number of Stock Units | ||
Unvested balance at beginning of period (in units) | 182,000 | |
Granted (in units) | 156,000 | |
Vested (in units) | (57,000) | |
Forfeited (in units) | (14,000) | |
Unvested balance at end of period (in units) | 267,000 | 182,000 |
Weighted- Average Grant Date Fair Value Per Share | ||
Unvested balance at beginning of period (in dollars per share) | $ 31.50 | |
Granted (in dollars per share) | 32.89 | |
Vested (in dollars per share) | 30.52 | |
Forfeited (in dollars per share) | 33.21 | |
Unvested balance at end of period (in dollars per share) | $ 32.44 | $ 31.50 |
Performance-Based Restricted Stock Units | ||
Number of Stock Units | ||
Unvested balance at beginning of period (in units) | 551,000 | |
Granted (in units) | 28,000 | |
Vested (in units) | (232,000) | |
Forfeited (in units) | (10,000) | |
Unvested balance at end of period (in units) | 337,000 | 551,000 |
Weighted- Average Grant Date Fair Value Per Share | ||
Unvested balance at beginning of period (in dollars per share) | $ 31.57 | |
Granted (in dollars per share) | 27.24 | |
Vested (in dollars per share) | 31.12 | |
Forfeited (in dollars per share) | 31.09 | |
Unvested balance at end of period (in dollars per share) | $ 31.53 | $ 31.57 |
Certain Individuals | Performance-Based Restricted Stock Units | ||
Number of Stock Units | ||
Granted (in units) | 550,777,000 |
401(k) Savings Plan (Details)
401(k) Savings Plan (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Retirement Benefits [Abstract] | |||
Matching contribution, amount per employee | $ 7 | $ 7 | $ 5 |
Expenses related to 401(k) Savings Plan | $ 700 | $ 600 | $ 300 |
Income Taxes (Details)
Income Taxes (Details) - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Tax Cuts And Jobs Act Of 2017, provisional income tax expense (benefit) | $ 59,300,000 | ||
State tax expense (benefit) | 32,000 | $ 24,000 | $ 0 |
Loss before income taxes | 108,400,000 | 57,000,000 | 63,900,000 |
Increase in valuation allowance | 9,100,000 | 26,700,000 | $ 20,000,000 |
Federal | |||
Operating loss carryforwards | |||
Net operating loss carryforwards | 438,000,000 | 339,300,000 | |
State | |||
Operating loss carryforwards | |||
Net operating loss carryforwards | 393,600,000 | 293,700,000 | |
Research and development | Federal | |||
Operating loss carryforwards | |||
Tax credit carryforwards | 8,100,000 | 6,700,000 | |
Research and development | State | |||
Operating loss carryforwards | |||
Tax credit carryforwards | $ 5,600,000 | $ 4,500,000 |
Income Taxes Income Taxes - Com
Income Taxes Income Taxes - Components of the Company's Deferred Tax Assets (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Income Tax Disclosure [Abstract] | ||
U.S. and state net operating loss carryforwards | $ 116,812 | $ 109,429 |
Research and development credits | 12,548 | 9,717 |
Deferred revenue | 1,010 | 1,666 |
Accruals and other temporary differences | 15,287 | 15,725 |
Total deferred tax assets | 145,657 | 136,537 |
Less valuation allowance | (145,657) | (136,537) |
Net deferred tax assets | $ 0 | $ 0 |
Income Taxes - Schedule of Effe
Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Abstract] | |||
Federal income tax expense at statutory rate | 34.00% | 34.00% | 34.00% |
State income tax, net of federal benefit | 5.60% | 5.90% | 4.60% |
Permanent differences | 1.90% | 4.00% | (8.30%) |
Research and development credit | 1.90% | 3.10% | 1.20% |
Tax reform rate change | (54.70%) | 0.00% | 0.00% |
Other | (0.30%) | (0.10%) | 0.00% |
Change in valuation allowance | 11.60% | (46.90%) | (31.50%) |
Effective income tax rate | 0.00% | 0.00% | 0.00% |
Related Party Transactions (Det
Related Party Transactions (Details) - USD ($) $ in Millions | Oct. 04, 2017 | Sep. 25, 2017 | Jan. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 |
Celgene | |||||
Related Party Transaction [Line Items] | |||||
Ownership percentage of entity's fully diluted equity | 12.50% | 12.80% | |||
Deferred revenue | $ 3.7 | $ 4.2 | |||
Common Stock | |||||
Related Party Transaction [Line Items] | |||||
Shares purchased by collaborators (in shares) | 810,810 | 5,405,406 | |||
Common Stock | Celgene | |||||
Related Party Transaction [Line Items] | |||||
Shares purchased by collaborators (in shares) | 745,592 | 800,000 |
Quarterly Financial Data (una64
Quarterly Financial Data (unaudited) (Details) - 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 revenue | $ 3,705 | [1] | $ 3,014 | [1] | $ 3,057 | [1] | $ 3,705 | [1] | $ 3,369 | [1] | $ 3,005 | [1] | $ 3,195 | [1] | $ 18,201 | [1] | $ 13,481 | $ 27,771 | $ 18,097 | |
Total costs and expenses | 32,341 | [1] | 28,592 | [1] | 32,968 | [1] | 29,563 | [1] | 25,355 | [1] | 23,513 | [1] | 22,850 | [1] | 22,157 | [1] | 123,464 | 93,877 | 78,976 | |
Income (loss) from operations | (28,636) | [1] | (25,578) | [1] | (29,911) | [1] | (25,858) | [1] | (21,986) | [1] | (20,508) | [1] | (19,655) | [1] | (3,956) | [1] | (109,983) | (66,106) | (60,879) | |
Net loss | $ (27,926) | [1] | $ (25,451) | [1] | $ (29,669) | [1] | $ (25,407) | [1] | $ (19,288) | [1] | $ (20,770) | [1] | $ (22,016) | [1] | $ 5,061 | [1] | $ (108,454) | $ (57,014) | $ (63,894) | |
Basic net income (loss) per share (in dollars per share) | [1] | $ (0.62) | $ (0.65) | $ (0.77) | $ (0.66) | $ (0.51) | $ (0.55) | $ (0.59) | $ 0.14 | |||||||||||
Diluted net income (loss) per share (in dollars per share) | [1] | $ (0.62) | $ (0.65) | $ (0.77) | $ (0.66) | $ (0.51) | $ (0.55) | $ (0.59) | $ 0.13 | |||||||||||
[1] | The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |