Document and Entity Information
Document and Entity Information - USD ($) $ in Billions | 12 Months Ended | ||
Dec. 31, 2018 | Jan. 31, 2019 | Jun. 30, 2018 | |
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, 2018 | ||
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 | $ 1.6 | ||
Entity Common Stock, Shares Outstanding | 51,690,462 | ||
Entity Small Business | false | ||
Entity Emerging Growth Company | false | ||
Entity Shell Company | false | ||
Document Fiscal Year Focus | 2,018 | ||
Document Fiscal Period Focus | FY |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 144,052 | $ 100,150 |
Short-term investments | 147,260 | 177,077 |
Collaboration receivables (all amounts are with a related party) | 7,039 | 3,570 |
Prepaid expenses and other current assets | 7,662 | 4,446 |
Total current assets | 306,013 | 285,243 |
Property and equipment, net | 7,106 | 6,966 |
Long-term investments | 0 | 95,723 |
Restricted cash | 1,597 | 1,132 |
Other assets | 105 | 113 |
Total assets | 314,821 | 389,177 |
Current liabilities: | ||
Accounts payable | 419 | 1,086 |
Accrued expenses | 18,209 | 14,936 |
Deferred revenue | 0 | 541 |
Deferred rent | 284 | 182 |
Total current liabilities | 18,912 | 16,745 |
Deferred revenue, net of current portion | 0 | 3,161 |
Deferred rent, net of current portion | 2,381 | 1,818 |
Warrants to purchase common stock | 1,491 | 2,236 |
Total liabilities | 22,784 | 23,960 |
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; 46,260,747 and 45,261,175 shares issued and outstanding at December 31, 2018 and 2017, respectively | 47 | 46 |
Additional paid-in capital | 879,099 | 839,090 |
Accumulated deficit | (586,549) | (473,024) |
Accumulated other comprehensive loss | (560) | (895) |
Total stockholders' equity | 292,037 | 365,217 |
Total liabilities and stockholders' equity | $ 314,821 | $ 389,177 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2018 | Dec. 31, 2017 |
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) | 46,260,747 | 45,261,175 |
Common stock, shares outstanding (in shares) | 46,260,747 | 45,261,175 |
Consolidated Statements of Oper
Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Collaboration revenue: | |||
Revenue | $ 13,991,000 | $ 13,481,000 | $ 27,771,000 |
Costs and expenses: | |||
Research and development | 103,902,000 | 89,726,000 | 68,580,000 |
General and administrative | 34,503,000 | 33,738,000 | 25,297,000 |
Total costs and expenses | 138,405,000 | 123,464,000 | 93,877,000 |
Loss from operations | (124,414,000) | (109,983,000) | (66,106,000) |
Other (expense) income, net | (52,000) | (992,000) | 7,262,000 |
Interest income | 5,568,000 | 2,553,000 | 1,854,000 |
Total other income, net | 5,516,000 | 1,561,000 | 9,116,000 |
Loss before income taxes | (118,898,000) | (108,422,000) | (56,990,000) |
Income tax benefit (provision) | 27,000 | (32,000) | (24,000) |
Net loss | (118,871,000) | (108,454,000) | (57,014,000) |
Other comprehensive loss: | |||
Net unrealized holding gains (losses) on short- and long-term investments during the period net of tax of $95 thousand, zero, and zero for the years ended December 31, 2018, 2017, and 2016, respectively | 335,000 | (470,000) | (205,000) |
Comprehensive loss | $ (118,536,000) | $ (108,924,000) | $ (57,219,000) |
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share) | $ (2.59) | $ (2.68) | $ (1.52) |
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders-basic and diluted (in shares) | 45,898 | 40,420 | 37,430 |
License and milestone | |||
Collaboration revenue: | |||
Revenue | $ 0 | $ 541,356 | $ 15,549,968 |
Cost Sharing | |||
Collaboration revenue: | |||
Revenue | $ 13,991,000 | $ 12,940,000 | $ 12,221,000 |
Consolidated Statements of Op_2
Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Statement [Abstract] | |||
Unrealized holding gain (loss) arising during period, tax | $ 95 | $ 0 | $ 0 |
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, 2015 | $ 109,263 | $ 34 | $ 416,926 | $ (307,477) | $ (220) |
Stockholders' equity beginning 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] | |||||
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) | 474,056 | ||||
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 (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 | ||||
AOCI Attributable to Parent, Net of Tax [Roll Forward] | |||||
Effect of adoption of ASU | 79 | (79) | |||
Stock-based compensation | 24,569 | 24,569 | |||
Exercise of stock options | $ 15,931 | $ 1 | 15,930 | ||
Exercise of stock options (in shares) | 780,000 | 779,711 | |||
Vesting of restricted stock units | $ (731) | (731) | |||
Vesting of restricted stock units (in shares) | 170,516 | ||||
Issuance of common stock related to ESPP | 1,085 | 1,085 | |||
Issuance of common stock related to ESPP (in shares) | 30,896 | ||||
Net exercise of warrants to purchase common stock | 797 | 797 | |||
Net exercise of warrants to purchase common stock (in shares) | 18,449 | ||||
Net exercise of warrants to purchase common stock | 335 | 335 | |||
Net loss | (118,871) | (118,871) | |||
Stockholders' equity ending balance at Dec. 31, 2018 | $ 292,037 | $ 47 | $ 879,099 | $ (586,549) | $ (560) |
Stockholders' equity ending balance (in shares) at Dec. 31, 2018 | 46,260,747 |
Consolidated Statements of St_2
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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Operating Activities | |||
Net loss | $ (118,871) | $ (108,454) | $ (57,014) |
Adjustments to reconcile net loss to net cash used in operating activities: | |||
Depreciation and amortization | 3,747 | 2,825 | 1,676 |
Stock-based compensation | 24,569 | 28,248 | 18,557 |
Change in fair value of warrants | 52 | 992 | (7,262) |
Other non-cash items | 357 | 176 | (8) |
Changes in assets and liabilities: | |||
Prepaid expenses and other current assets | (2,986) | (675) | (1,411) |
Collaboration receivables (all amounts are with a related party) | (3,470) | (336) | 394 |
Accounts payable | (673) | (504) | 644 |
Accrued expenses | 1,904 | 1,493 | 524 |
Deferred revenue | 0 | (543) | (549) |
Deferred rent | 665 | 234 | (96) |
Net cash used in operating activities | (94,706) | (76,544) | (44,545) |
Investing Activities | |||
Purchase of investments | (73,570) | (179,935) | (218,314) |
Proceeds from sales and maturities of investments | 199,087 | 119,965 | 112,889 |
Purchases of property and equipment | (2,590) | (4,396) | (3,380) |
Net cash provided by (used in) investing activities | 122,927 | (64,366) | (108,805) |
Financing Activities | |||
Proceeds from issuance of common stock from public offering, net of issuance costs | 0 | 215,802 | 140,697 |
Payments for withholding taxes on restricted stock units | (731) | (226) | 0 |
Proceeds from issuances of common stock related to employee stock purchase plan | 1,085 | 827 | 658 |
Proceeds from exercise of stock options and warrants to purchase common stock | 15,931 | 3,893 | 5,312 |
Payments for capital lease expenditures | (139) | 0 | 0 |
Net cash provided by financing activities | 16,146 | 220,296 | 146,667 |
Net increase (decrease) in cash, cash equivalents and restricted cash | 44,367 | 79,386 | (6,683) |
Cash, cash equivalents and restricted cash at beginning of year | 101,282 | 21,896 | 28,579 |
Cash, cash equivalents and restricted cash at end of year | 145,649 | 101,282 | 21,896 |
Supplemental Disclosure of Non-Cash Investing and Financing Activities: | |||
Reclassification of warrant liability to additional paid-in capital | 797 | 0 | 8,682 |
Capitalized follow-on public offering costs included in accrued expenses | 221 | 0 | 0 |
Purchase of property and equipment included in accounts payable and accrued expenses | $ 1,159 | $ 194 | $ 397 |
Nature of Business
Nature of Business | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 | |
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, 2018 or 2017 . 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, as well as marketable securities with a remaining maturity of 90 days or less. 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, 2018 and 2017 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, 2018 , 2017 and 2016 . 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, 2018 and December 31, 2017 was $51.2 million and $193.6 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, 2018 and December 31, 2017 was $94.3 million and $67.0 million , respectively. The aggregate unrealized loss for those securities in an unrealized loss position for more than twelve months was $0.4 million and $0.3 million , 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, 2018 and December 31, 2017 . 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, 2018 and 2017 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, 2018 and 2017 (in thousands): December 31, 2018 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 74,023 $ — $ — $ 74,023 Corporate obligations — 128,920 — 128,920 U.S. Treasury securities — 56,978 — 56,978 Certificates of deposit — 1,715 — 1,715 Mortgage and other asset backed securities — 26,874 — 26,874 Restricted cash 1,597 — — 1,597 Total assets $ 75,620 $ 214,487 $ — $ 290,107 Liabilities: Warrants to purchase common stock $ — $ — $ 1,491 $ 1,491 Total liabilities $ — $ — $ 1,491 $ 1,491 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 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, 2018 and 2017 . 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, 2018 2017 Beginning balance $ 2,236 $ 1,244 Change in fair value 52 992 Exercises (797 ) — Ending balance $ 1,491 $ 2,236 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, 2018 , and December 31, 2017 the Black-Scholes option pricing model was used, and at December 31, 2016 , the Monte Carlo simulation framework 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, 2018 or 2017 . 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, 2018 , 2017 and 2016 . Accrued Clinical Trial Expenses The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which includes the conduct of clinical trials. The Company records the estimated costs of clinical trial activities based upon the estimated amount of services provided and includes the costs incurred but not yet invoiced within accrued liabilities on the balance sheet and within research and development expense in the consolidated statements of operations and comprehensive loss. These costs can be a significant component of the Company's research and development expenses. The Company estimates the amount of services provided and efforts expended pursuant to quotes and contracts with third parties, as well as discussion with internal personnel and external service providers as to the progress of the services and the agreed-upon fee to be paid for such services. The Company makes significant judgments and estimates in determining the accrued balance in each reporting period. As actual costs become known, it adjusts its accrued estimates. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed, the number of subjects enrolled, and the rate of enrollment may vary from its estimates and could result in the Company reporting amounts that are too high or too low in a particular period. The Company's accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from contract research organizations and third-party service providers. To date, the Company has not experienced any material differences between accrued costs and actual costs incurred. Revenue Recognition Effective January 1, 2018, the Company adopted Accounting Standards Codification Topic 606, Revenue from Contracts with Customers , (ASC 606), using the modified retrospective transition method. Under this method, results for reporting periods beginning January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605. The Company has primarily generated revenue through collaboration, license and research arrangements, which are within the scope of ASC 606, with collaboration partners for the development and commercialization of therapeutic candidates. The arrangements generally contain performance obligations, which may include (1) licenses, or options to obtain licenses, to the Company's technology, (2) research and development activities performed for the collaboration partners (3) participation on joint development committees (JDCs), 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, exercises of options, and royalties on future product sales. 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. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets, including collaboration receivables. To determine revenue recognition for arrangements within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Depending on the nature of the performance obligation these assessments require management to make significant judgments and estimates. Exclusive Licenses If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred and the customer is able to use and benefit from the license. In order to assess whether the license is distinct, the Company considers the capabilities of the collaboration partner and the availability of the necessary expertise in the general marketplace to determine whether the collaboration partner can benefit from the license for its intended purpose without the receipt of the remaining elements. For licenses determined not to be distinct the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement. Research and Development Services The promises under the Company’s collaboration and license agreements generally include research and development services to be performed by the Company on behalf of the collaboration partner. As the provision of research and development services is a part of the Company’s central operations, when the Company is principally responsible for the performance of these services under the agreements, the Company recognizes revenue on a gross basis for research and development services in accordance with the ASC 606 framework described above. Customer Options The Company's agreements may contain options which provide the collaboration partner the right to obtain additional licenses. If an arrangement is determined to contain customer options, the goods and services underlying the customer options are not considered to be performance obligations at the inception of the arrangement, and the associated option fees are not included in the transaction price. The Company evaluates the customer options to determine if they represent material rights, which may include options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised. Milestone Payments At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the respective milestone in making this assessment. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. If a milestone or other variable consideration relates specifically to the Company's efforts to satisfy a single performance obligation or to a specific outcome from satisfying the performance obligation, the Company generally allocates the milestone amount entirely to that performance obligation. Royalties For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. 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, 2018 , 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. In July 2018, the Company early adopted ASU 2018-07, which expands the scope of Topic 718 to include share-based payments to non-employees. In connection with the adoption of this standard, the Company changed its accounting policy to establish the fair value of awards to non-employees at adoption date for existing awards and at grant date for new awards, rather than to mark such awards to market through the vesting period of the award. Additionally under the new guidance, the Company will use qualitative factors, such as exercise behavior and expected term to establish the term of the awards, rather than using contractual term, when valuing the awards. Forfeitures will be recognized as they occur. Upon adoption, a cumulative adjustment of $1.6 million was booked to increase retained earnings for the impact to the Company's outstanding awards to non-employees. The provisions of the standard were adopted prospectively and prior periods were not retrospectively adjusted. 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, 2018 . Income Taxes Income taxes are recorded in accordance with ASC Topic 740, Income Taxes (ASC 740), which prov |
Property and Equipment, Net
Property and Equipment, Net | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 2017 Computer equipment and software $ 1,712 $ 1,501 Office equipment 672 522 Laboratory equipment 19,948 17,268 Leasehold improvements 11,668 11,501 Construction in progress 1,139 584 Total property and equipment 35,139 31,376 Accumulated depreciation and amortization (28,033 ) (24,410 ) Property and equipment, net $ 7,106 $ 6,966 Depreciation and amortization expense was $3.7 million , $2.8 million and $1.7 million for the years ending December 31, 2018 , 2017 and 2016 , respectively. |
Restricted Cash
Restricted Cash | 12 Months Ended |
Dec. 31, 2018 | |
Cash and Cash Equivalents [Abstract] | |
Restricted Cash | Restricted Cash On January 1, 2018, the Company adopted 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. As a result of the adoption, there was no impact to cash flows from investing or financing activities for the year ended December 31, 2018 , 2017 , and 2016 . The $1.1 million of restricted cash related to collateral for the Company's facility lease obligation and its credit cards, which was previously reported as an adjustment to net loss in cash flows used in operating activities for the year ended December 31, 2017 and 2016 is no longer presented within the net change in cash, cash equivalents and restricted cash, as it is considered part of cash, cash equivalents and restricted cash. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheet that sum to the total of the same such amounts shown in the statement of cash flows (in thousands): December 31, 2018 2017 2016 Cash and cash equivalents $ 144,052 $ 100,150 $ 20,950 Restricted cash 1,597 1,132 946 Total cash, cash equivalents and restricted cash shown in the statement of cash flows 145,649 101,282 21,896 As of December 31, 2018 , 2017 , and 2016 , the Company maintained letters of credit totaling $1.6 million , $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, 2018 | |
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, 2018 and December 31, 2017 (in thousands): December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 144,064 $ — $ (12 ) $ 144,052 Available-for-sale securities: Corporate obligations due in one year or less 73,671 — (267 ) 73,404 U.S. Treasury securities due in one year or less 45,346 — (79 ) 45,267 Certificates of deposit due in one year or less 1,715 — — 1,715 Mortgage and other asset backed securities due in one year or less 26,982 — (108 ) 26,874 Total available-for-sale securities $ 147,714 $ — $ (454 ) $ 147,260 Total cash, cash equivalents and available-for-sale securities $ 291,778 $ — $ (466 ) $ 291,312 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 |
Accrued Expenses
Accrued Expenses | 12 Months Ended |
Dec. 31, 2018 | |
Payables and Accruals [Abstract] | |
Accrued Expenses | Accrued Expenses Accrued expenses consist of the following (in thousands): December 31, 2018 2017 Research and development related $ 8,144 $ 4,014 Employee compensation 7,975 6,809 Professional services 621 1,183 Accrued purchases 351 150 Other 1,118 2,780 Total accrued expenses $ 18,209 $ 14,936 |
Warrants
Warrants | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 December 31, 2017 Price Per Share Expiration December 31, 2018 December 31, 2017 Warrants to purchase common stock 39 61 $ 5.88 June 10, 2020 - July 9, 2020 Liability (1) Liability (1) All warrants 39 61 $ 5.88 ______________________________________________________________________ (1) In January 2018, the warrant holders exercised warrants to purchase 21,258 shares of Common Stock on a net basis, resulting in the issuance of 18,449 shares of Common Stock. Upon issuance 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 $0.1 million , $1.0 million and $(7.3) 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, 2018 , 2017 and 2016 . 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, 2018 . |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2018 | |
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 $5.8 million , $4.8 million and $3.8 million were incurred during the years ended December 31, 2018 , 2017 and 2016 , respectively. Future annual minimum lease payments as of December 31, 2018 , are as follows (in thousands): 2019 $ 8,195 2020 8,438 2021 8,180 2022 8,256 2023 6,333 Total $ 39,402 In July 2017, the Company entered into a sublease for 11,825 square feet of office and lab space at 99 Erie Street in Cambridge Massachusetts beginning on August 1, 2017. In January 2018 the subtenant exercised their right to extend the sublease through December 31, 2018. In December 2018, the Company entered into a new sublease agreement with a new subtenant, which commences upon the original subtenant vacating the facility. The new subtenant will pay rent on the lease through March 31, 2020. Sublease income of approximately $0.7 million , $0.3 million , and zero was recorded during the years ended December 31, 2018 , 2017 and 2016 , respectively. Future annual minimum sublease proceeds expected as of December 31, 2018 are as follows (in thousands): 2019 $ 717 2020 198 Total $ 915 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, 2018 , 2017 and 2016 , 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, 2018 and 2017 , 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, 2018 | |
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 . On January 18, 2019, the Company completed the sale of 5,348,838 shares of common stock at a public offering price of $43.00 per share, resulting in net proceeds to the Company of approximately $215.8 million . In connection with the January 2019 public offering, on February 12, 2019, the underwriters fully exercised their option to purchase an additional 802,325 shares of common stock. The total net proceeds to the Company from the January 2019 public offering and the underwriters' exercise of their option to purchase additional shares of common stock was $248.2 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, 2018 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, 2018 . Common Stock Reserved for Future Issuance At December 31, 2018 , the Company has reserved for future issuance the following number of shares of common stock (in thousands): December 31, 2018 Outstanding stock options to purchase common stock 3,513 Outstanding restricted stock units 608 Shares available for future issuance under equity incentive plan 3,556 Warrants to purchase common stock 39 Shares available for future issuance under the employee stock purchase plan 156 Additional shares reserved for unissued, but designated, Preferred Stock 25,000 Total shares of authorized common stock reserved for future issuance 32,872 |
Significant Agreements
Significant Agreements | 12 Months Ended |
Dec. 31, 2018 | |
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. 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 as agreed in the budget between the Company and Celgene; • 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, 2018 , the Company has received $44.5 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 as agreed in the budget between the Company and Celgene; • 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; Additionally, from time to time the Company may elect to conduct additional activities to support luspatercept at its own expense. 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, 2018 , the Company has received $109.6 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 The Company accounted for the Restated Sotatercept Agreement and Luspatercept Agreement ander ASC 606, effective January 1, 2018. The Company identified the following material promises under the Restated Sotatercept Agreement and Luspatercept Agreement: (1) licenses to develop and commercialize sotatercept and luspatercept; (2) performance of research and development services; (3) participation in the JDCs; and (4) the performance of the manufacturing services. The Company determined that the licenses to sotatercept and luspatercept technology, the research and development activities, participation in the JDCs and the manufacturing services are each distinct performance obligations. The option rights to future products related to the treatment of anemia under the Luspatercept Agreement are not considered to represent a material right as this right is a protective provision akin to exclusivity and does not represent a customer option to receive the rights or services at a discount. In addition, the Company is under no obligation to discover, develop, or deliver any new compounds that modulate anemia. Therefore, the option right under the Luspatercept Agreement is not a performance obligation. Commercialization support for each of sotatercept and luspatercept is considered to be a participatory right and not a performance obligation. The Company concluded that services provided for the extension studies do not represent a contract modification or a performance obligation but rather a separate services arrangement, which is accounted for as a separate contract. Each study includes one promise, the completion of the study, which is distinct from the performance obligations in the Restated Sotatercept Agreement and Luspatercept Agreement that is satisfied over time, and the consideration for each study approximates the stand-alone selling price. Revenue is recognized as the services for each study are provided. The most significant change in the Company’s accounting policy relates to the recognition of milestone revenue. Prior to January 1, 2018, the Company recognized revenue in accordance with ASC 605, Revenue Recognition. At the inception of each arrangement that included milestone payments, the Company evaluated, with respect to each milestone, whether the milestone was substantive and at-risk. The Company evaluated 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 recognized the payment as license and milestone revenue. For milestones that were not deemed substantive and at-risk, where payment was reasonably assured, the Company recognized the milestone payment over the remaining service period. Under ASC 606, future potential milestone payments were excluded from the transaction price as they are still subject to completion of on-going clinical studies or other risks that are outside of the Company's control and therefore the risk of significant reversal has not been resolved. The next likely clinical milestone payment for luspatercept would be $25.0 million and result from U.S. Food and Drug Administration (FDA) or European Medicines Agency (EMA) acceptance of a Biologics Licensing Application or equivalent for luspatercept in either myelodysplastic syndromes or beta-thalassemia. The Company and Celgene are planning regulatory application submissions for luspatercept in the United States in April 2019 and in Europe in the first half of 2019. Following application submission, the FDA will determine the acceptance of the application for "filing" by 60 days from the submission date. Similarly, the EMA will validate the application within 10 days of submission. In accordance with the Company's accounting policy regarding revenue recognition as described in Note 2, the revenue associated with this milestone will be recognized once it is probable that the applications are accepted for review by either the FDA or EMA. Milestone payments that are not within the control of the Company or the licensee are not considered probable of being achieved until those approvals are received. The acceptance of the application is not within the control of the Company or the licensee, and therefore, as of December 31, 2018 , the Company cannot determine if it is probable that a regulatory agency will accept the application. The transaction price includes the following payments received under the Restated Sotatercept and Luspatercept Agreement through the adoption date of December 31, 2017 for a total of $192.3 million , as follows: • $25.0 million upfront fee in connection with the closing of the Luspatercept Agreement; • $45.0 million of nonrefundable, upfront license and option payments in connection with the closing of the Original and Amended Sotatercept Agreements; • $14.9 million received for sotatercept development and manufacturing activities; • $47.9 million received for luspatercept development and manufacturing activities; and • $59.5 million milestone payments pursuant to the agreements. The Company allocated the total transaction price to the identified performance obligations (both satisfied and unsatisfied) using the estimated standalone selling price of each performance obligation as of the adoption date of ASC 606. The Company’s estimate of the standalone selling price requires judgment, in particular in estimating the value of the license rights for luspatercept and sotatercept, which includes assumptions over the projected revenues and expenses, probability of technical and regulatory success and appropriate discount rates. As of the ASC 606 adoption date, the only remaining undelivered element is participation in the JDC for which there was a deferred revenue balance of $3.7 million . The transaction price allocated to participation in the JDC based on the established standalone selling price of all performance obligations was de minimis as the sotatercept and luspatercept licenses carried the most significant portion of the value included in the agreements, and the Company's remaining effort on the JDC is minimal. As a result of adopting ASC 606 on January 1, 2018, the Company has recorded a cumulative-effect reduction to opening accumulated deficit of $3.7 million as of January 1, 2018 and a corresponding decrease to deferred revenue, of which $0.5 million was recorded to current deferred revenue and $3.2 million was recorded to long-term deferred revenue. License and milestone revenue for the year ended December 31, 2018 was zero , as compared to the $0.5 million that would have been recorded under ASC 605. Deferred revenue as of December 31, 2018 was zero under ASC 606, as compared to a balance of $3.2 million , which would have resulted under ASC 605. Through December 31, 2018 , under all Celgene arrangements the Company has received net cost-share payments and milestones of $109.6 million and $44.5 million for luspatercept and sotatercept, respectively. The Company recorded net cost-sharing revenue of $14.0 million , $12.9 million , and $12.2 million during the years ended December 31, 2018 , 2017 , and 2016 , 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, 2018 , 2017 and 2016 , 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, 2018 , 2017 , and 2016 , the Company expensed milestones and fees totaling $0.1 million , $1.6 million , and $1.0 million , which is recorded as research and development expense. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Stock-Based Compensation | Stock-Based Compensation At December 31, 2018 , 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 3,555,548 at December 31, 2018 . 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 $0.4 million , $0.3 million , and $0.3 million of stock-based compensation expense during the years ended December 31, 2018 , 2017 , and 2016 , respectively related to the 2013 ESPP. The number of shares available for future issuance was 155,948 at December 31, 2018 . 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, 2018 , 2017 and 2016 , the Company recognized $2.4 million , $4.9 million , and $0.5 million , respectively, of stock-based compensation expense related to the agreement. 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, 2018 2017 2016 Research and development $ 12,669 $ 14,227 $ 8,171 General and administrative 11,900 14,021 10,386 $ 24,569 $ 28,248 $ 18,557 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, 2018 2017 2016 Expected volatility 62.8 % 65.7 % 65.1 % Expected term (in years) 6.0 6.0 6.0 Risk-free interest rate 2.70 % 2.13 % 1.69 % 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 , zero , and 3% for the years ended December 31, 2018 , 2017 , and 2016 , 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, 2018 (in thousands, except per share amounts and years): Number (in thousands) Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2017 3,452 $ 29.14 Granted 942 $ 42.30 Exercised (780 ) $ 20.43 Canceled or forfeited (101 ) $ 36.05 Outstanding at December 31, 2018 3,513 $ 34.40 7.31 $ 33,442 Exercisable at December 31, 2018 2,007 $ 31.86 6.35 $ 23,561 ______________________________________________________ (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, 2018 . During the years ended December 31, 2018 , 2017 and 2016 , the Company granted stock options to purchase an aggregate of 942,271 , 701,384 , and 1,045,795 shares of its common stock, respectively, with weighted-average grant date fair values of $25.05 , $18.58 , and $18.55 , respectively. During the years ended December 31, 2018 , 2017 and 2016 , current and former employees of the Company exercised a total of 779,711 , 474,056 , and 885,075 options, respectively, resulting in total proceeds of $15.9 million , $3.9 million , and $5.3 million , respectively. The aggregate intrinsic value of options exercised during the years ended December 31, 2018 , 2017 , and 2016 , under the Company's stock option plans, was $19.3 million , $10.2 million , and $23.8 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, 2018 , there was $29.2 million of unrecognized compensation expense that is expected to be recognized over a weighted-average period of 2.40 years. Restricted Stock Units The following table summarizes the restricted stock unit (RSU) activity under the 2013 Plan during the year ended December 31, 2018 : Number of Weighted- Unvested balance at December 31, 2017 267 $ 32.44 Granted 239 $ 38.83 Vested (104 ) $ 31.58 Forfeited (30 ) $ 35.49 Unvested balance at December 31, 2018 372 $ 36.53 At December 31, 2018 , there was approximately $9.5 million of related unrecognized compensation cost which the Company expects to recognize over a remaining weighted-average period of 1.85 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, 2018 : Number of Weighted- Unvested balance at December 31, 2017 337 $ 31.53 Granted — $ — Vested (83 ) $ 31.93 Forfeited (18 ) $ 31.09 Unvested balance at December 31, 2018 236 $ 31.42 As of December 31, 2018 , there was approximately $1.3 million of related unrecognized compensation cost which the Company expects to recognize over a remaining weighted-average period of 0.50 years. |
401(k) Savings Plan
401(k) Savings Plan | 12 Months Ended |
Dec. 31, 2018 | |
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 2018 , 2017 , and 2016 , the Board approved matching contributions of up to $8,500 , $7,000 , and $7,000 , 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 $1.1 million , $0.7 million , and $0.6 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively, and have been recorded in the consolidated statement of operations and comprehensive loss. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2018 | |
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, legislation commonly known as the Tax Cuts and Jobs Act (the Tax Act) was signed into law. The Tax Act, among other things, reduces the U.S. federal corporate tax rate from 35% to 21%, requires taxpayers to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. The Company does not currently have any foreign subsidiaries and the international aspects of the Tax Act are not applicable. In connection with the Tax Act, the Company remeasured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. The remeasurement of the Company's deferred tax balance was primarily offset by application of its valuation allowance. As of December 31, 2018 , the Company had completed its accounting for all of the tax effects of the enactment of the Act, including the effects on its existing deferred tax balances. The Company has not recognized any material adjustment to the provisional estimate that was previously recorded related to the Act. Deferred tax assets and valuation allowance The Company recorded a tax benefit of $27,000 for the year ended December 31, 2018 , related to the realization of current year losses that offset unrealized gains, recognized in other comprehensive income, from our investment portfolio. The Company recognized current income tax expense of $32,000 and $24,000 , for the years ended December 31, 2017 and 2016 , respectively, related state income taxes on its interest income. The Company's loss before income taxes was $118.9 million , $108.4 million and $57.0 million for the years ended December 31, 2018 , 2017 and 2016 , 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, 2018 2017 Deferred tax assets: U.S. and state net operating loss carryforwards $ 149,170 $ 116,812 Research and development credits 16,340 12,548 Deferred revenue — 1,010 Accruals and other temporary differences 17,445 15,287 Total deferred tax assets 182,955 145,657 Less valuation allowance (182,955 ) (145,657 ) 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, 2018 and 2017 . The valuation allowance increased by $37.3 million , $9.1 million , and $26.7 million during the years ended December 31, 2018 , 2017 , and 2016 , respectively, due primarily to the generation of net operating losses during these periods, and the tax reform rate change during the year ended December 31, 2017 . 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, 2018 2017 2016 Federal income tax expense at statutory rate 21.0 % 34.0 % 34.0 % State income tax, net of federal benefit 7.0 % 5.6 % 5.9 % Permanent differences 2.0 % 1.9 % 4.0 % Research and development credit 3.2 % 1.9 % 3.1 % Tax reform rate change — % (54.7 )% — % Other (0.6 )% (0.3 )% (0.1 )% Change in valuation allowance (32.6 )% 11.6 % (46.9 )% Effective income tax rate — % — % — % As of December 31, 2018 and 2017 , the Company had U.S. federal net operating loss carryforwards of $556.0 million and $438.0 million , respectively, which may be available to offset future taxable income. Federal net operating loss carryforwards of $438.0 million will expire at various dates from 2023 through 2037. $118.0 million of the federal net operating loss carryforward can be carried forward indefinitely. As of December 31, 2018 and 2017 , the Company also had U.S. state net operating loss carryforwards of $515.0 million and $393.6 million , respectively, which may be available to offset future income tax liabilities and expire at various dates through 2038 . As of December 31, 2018 and 2017 , the Company had federal research and development and orphan drug tax credit carryforwards of $10.7 million and $8.1 million , respectively, available to reduce future tax liabilities which expire at various dates through 2038 . As of December 31, 2018 and 2017 , the Company had state research and development tax credit carryforwards of approximately $7.1 million and $5.6 million , respectively, available to reduce future tax liabilities which expire at various dates through 2033 . 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, 2018 and 2017 , 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, 2018 , 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, 2018 and 2017 . 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, 2015 through December 31, 2018 . 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, 2018 | |
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 12.2% and 12.5% of the Company's fully diluted equity as of December 31, 2018 and 2017 , respectively. During the years ended December 31, 2018 , 2017 and 2016 , all revenue recognized by the Company was recognized under the Celgene collaboration agreement and as of December 31, 2018 and 2017 , the Company had zero and $3.7 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, 2018 | |
Quarterly Financial Information Disclosure [Abstract] | |
Quarterly Financial Data (unaudited) | Quarterly Financial Data (unaudited) The following table presents certain unaudited quarterly financial information for the previous eight quarters. 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) 2018 Total revenue $ 3,232 $ 3,685 $ 3,258 $ 3,816 Total costs and expenses 30,872 33,591 33,320 40,622 Loss from operations (27,640 ) (29,906 ) (30,062 ) (36,806 ) Net loss (26,219 ) (28,938 ) (28,979 ) (34,734 ) Net loss per share- basic and diluted $ (0.58 ) $ (0.63 ) $ (0.63 ) $ (0.75 ) 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 income (loss) (25,407 ) (29,669 ) (25,451 ) (27,926 ) Net loss per share- basic and diluted $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) ______________________________________________________ (1) The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Summary of Significant Accoun_2
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2018 | |
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, as well as marketable securities with a remaining maturity of 90 days or less. 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, 2018 and 2017 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, 2018 , 2017 and 2016 . 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, 2018 and 2017 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, 2018 and 2017 (in thousands): December 31, 2018 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 74,023 $ — $ — $ 74,023 Corporate obligations — 128,920 — 128,920 U.S. Treasury securities — 56,978 — 56,978 Certificates of deposit — 1,715 — 1,715 Mortgage and other asset backed securities — 26,874 — 26,874 Restricted cash 1,597 — — 1,597 Total assets $ 75,620 $ 214,487 $ — $ 290,107 Liabilities: Warrants to purchase common stock $ — $ — $ 1,491 $ 1,491 Total liabilities $ — $ — $ 1,491 $ 1,491 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 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, 2018 and 2017 . 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, 2018 2017 Beginning balance $ 2,236 $ 1,244 Change in fair value 52 992 Exercises (797 ) — Ending balance $ 1,491 $ 2,236 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, 2018 , and December 31, 2017 the Black-Scholes option pricing model was used, and at December 31, 2016 , the Monte Carlo simulation framework 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, 2018 or 2017 . |
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. |
Accrued Clinical Trail Expenses/Research and Development Expenses | Accrued Clinical Trial Expenses The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which includes the conduct of clinical trials. The Company records the estimated costs of clinical trial activities based upon the estimated amount of services provided and includes the costs incurred but not yet invoiced within accrued liabilities on the balance sheet and within research and development expense in the consolidated statements of operations and comprehensive loss. These costs can be a significant component of the Company's research and development expenses. The Company estimates the amount of services provided and efforts expended pursuant to quotes and contracts with third parties, as well as discussion with internal personnel and external service providers as to the progress of the services and the agreed-upon fee to be paid for such services. The Company makes significant judgments and estimates in determining the accrued balance in each reporting period. As actual costs become known, it adjusts its accrued estimates. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed, the number of subjects enrolled, and the rate of enrollment may vary from its estimates and could result in the Company reporting amounts that are too high or too low in a particular period. The Company's accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from contract research organizations and third-party service providers. To date, the Company has not experienced any material differences between accrued costs and actual costs incurred. 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. |
Revenue Recognition | Revenue Recognition Effective January 1, 2018, the Company adopted Accounting Standards Codification Topic 606, Revenue from Contracts with Customers , (ASC 606), using the modified retrospective transition method. Under this method, results for reporting periods beginning January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605. The Company has primarily generated revenue through collaboration, license and research arrangements, which are within the scope of ASC 606, with collaboration partners for the development and commercialization of therapeutic candidates. The arrangements generally contain performance obligations, which may include (1) licenses, or options to obtain licenses, to the Company's technology, (2) research and development activities performed for the collaboration partners (3) participation on joint development committees (JDCs), 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, exercises of options, and royalties on future product sales. 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. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets, including collaboration receivables. To determine revenue recognition for arrangements within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Depending on the nature of the performance obligation these assessments require management to make significant judgments and estimates. Exclusive Licenses If the license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred and the customer is able to use and benefit from the license. In order to assess whether the license is distinct, the Company considers the capabilities of the collaboration partner and the availability of the necessary expertise in the general marketplace to determine whether the collaboration partner can benefit from the license for its intended purpose without the receipt of the remaining elements. For licenses determined not to be distinct the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement. Research and Development Services The promises under the Company’s collaboration and license agreements generally include research and development services to be performed by the Company on behalf of the collaboration partner. As the provision of research and development services is a part of the Company’s central operations, when the Company is principally responsible for the performance of these services under the agreements, the Company recognizes revenue on a gross basis for research and development services in accordance with the ASC 606 framework described above. Customer Options The Company's agreements may contain options which provide the collaboration partner the right to obtain additional licenses. If an arrangement is determined to contain customer options, the goods and services underlying the customer options are not considered to be performance obligations at the inception of the arrangement, and the associated option fees are not included in the transaction price. The Company evaluates the customer options to determine if they represent material rights, which may include options to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the relative standalone selling price, which is determined based on the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised. Milestone Payments At the inception of each arrangement that includes milestone payments, the Company evaluates whether the milestones are considered probable of being achieved and estimates the amount to be included in the transaction price using the most likely amount method. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the respective milestone in making this assessment. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. If a milestone or other variable consideration relates specifically to the Company's efforts to satisfy a single performance obligation or to a specific outcome from satisfying the performance obligation, the Company generally allocates the milestone amount entirely to that performance obligation. Royalties For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. |
Stock-Based Compensation | Stock-Based Compensation At December 31, 2018 , 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. In July 2018, the Company early adopted ASU 2018-07, which expands the scope of Topic 718 to include share-based payments to non-employees. In connection with the adoption of this standard, the Company changed its accounting policy to establish the fair value of awards to non-employees at adoption date for existing awards and at grant date for new awards, rather than to mark such awards to market through the vesting period of the award. Additionally under the new guidance, the Company will use qualitative factors, such as exercise behavior and expected term to establish the term of the awards, rather than using contractual term, when valuing the awards. Forfeitures will be recognized as they occur. |
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, 2018 , 2017 and 2016 , the Company has excluded the effects of all potentially dilutive shares, which include outstanding common stock options, warrants to purchase 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, 2018 and 2017 . |
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, other than the January 2019 public offering of common stock as discussed in Note 9 and elsewhere in this Annual Report on Form 10-K. |
Recent Accounting Pronouncements - Not Yet Adopted | Recent Accounting Pronouncements - Not Yet Adopted 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 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. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018 and requires modified retrospective method in which the new guidance is applied on the date of the initial application. In July 2018, the FASB issued ASU 2018-11, Leases - Targeted Improvements , intended to ease the implementation of the new lease standard for financial statement preparers by, among other things, allowing for an additional transition method. In lieu of presenting transition requirements to comparative periods, as previously required, an entity may now elect to show a cumulative effect adjustment on the date of adoption without the requirement to recast prior financial statements or disclosures presented in accordance with ASU 2016-02. The Company expects to adopt the new standard and elect to use the cumulative effect adjustment transition option effective January 1, 2019, which will be the initial date of application. The Company currently expects to elect the available package of practical expedients which allows the Company to not reassess previous accounting conclusions around whether arrangements are or contain leases, the classification of leases, and the treatment of initial direct costs. The Company also expects it will make an accounting policy election to keep leases with an initial term of 12 months or less off of the balance sheet. The Company is continuing to assess the impact that adopting the new standard and its amendments will have on its consolidated financial statements and related disclosures. In preparation for adoption of the standard, the Company is in the process of implementing internal controls to enable the preparation of financial information including the assessment of the impact of the standard. The adoption of the new standard is expected to result in the recognition of additional lease liabilities and right-of-use assets as of January 1, 2019 which will have a material impact to the Company’s consolidated balance sheets. |
Summary of Significant Accoun_3
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 and 2017 (in thousands): December 31, 2018 Quoted Prices Significant Other Significant Total Assets: Money market funds $ 74,023 $ — $ — $ 74,023 Corporate obligations — 128,920 — 128,920 U.S. Treasury securities — 56,978 — 56,978 Certificates of deposit — 1,715 — 1,715 Mortgage and other asset backed securities — 26,874 — 26,874 Restricted cash 1,597 — — 1,597 Total assets $ 75,620 $ 214,487 $ — $ 290,107 Liabilities: Warrants to purchase common stock $ — $ — $ 1,491 $ 1,491 Total liabilities $ — $ — $ 1,491 $ 1,491 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 |
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, 2018 2017 Beginning balance $ 2,236 $ 1,244 Change in fair value 52 992 Exercises (797 ) — Ending balance $ 1,491 $ 2,236 |
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, 2018 2017 2016 Outstanding stock options 3,513 3,452 3,316 Common stock warrants 39 61 64 Shares issuable under employee stock purchase plan 18 18 23 Restricted stock units 608 604 732 Total excluded common stock equivalents 4,178 4,135 4,135 |
Property and Equipment, Net (Ta
Property and Equipment, Net (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Property, Plant and Equipment [Abstract] | |
Schedule of Property and Equipment, Net | Property and equipment, net, consists of the following (in thousands): December 31, 2018 2017 Computer equipment and software $ 1,712 $ 1,501 Office equipment 672 522 Laboratory equipment 19,948 17,268 Leasehold improvements 11,668 11,501 Construction in progress 1,139 584 Total property and equipment 35,139 31,376 Accumulated depreciation and amortization (28,033 ) (24,410 ) Property and equipment, net $ 7,106 $ 6,966 |
Restricted Cash (Tables)
Restricted Cash (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Cash and Cash Equivalents [Abstract] | |
Restrictions on Cash and Cash Equivalents [Table Text Block] | The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheet that sum to the total of the same such amounts shown in the statement of cash flows (in thousands): December 31, 2018 2017 2016 Cash and cash equivalents $ 144,052 $ 100,150 $ 20,950 Restricted cash 1,597 1,132 946 Total cash, cash equivalents and restricted cash shown in the statement of cash flows 145,649 101,282 21,896 |
Cash, Cash Equivalents and Sh_2
Cash, Cash Equivalents and Short-term and Long-term Investments (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 and December 31, 2017 (in thousands): December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Cash and cash equivalents due in 90 days or less $ 144,064 $ — $ (12 ) $ 144,052 Available-for-sale securities: Corporate obligations due in one year or less 73,671 — (267 ) 73,404 U.S. Treasury securities due in one year or less 45,346 — (79 ) 45,267 Certificates of deposit due in one year or less 1,715 — — 1,715 Mortgage and other asset backed securities due in one year or less 26,982 — (108 ) 26,874 Total available-for-sale securities $ 147,714 $ — $ (454 ) $ 147,260 Total cash, cash equivalents and available-for-sale securities $ 291,778 $ — $ (466 ) $ 291,312 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 |
Accrued Expenses (Tables)
Accrued Expenses (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Payables and Accruals [Abstract] | |
Schedule of Accrued Expenses | Accrued expenses consist of the following (in thousands): December 31, 2018 2017 Research and development related $ 8,144 $ 4,014 Employee compensation 7,975 6,809 Professional services 621 1,183 Accrued purchases 351 150 Other 1,118 2,780 Total accrued expenses $ 18,209 $ 14,936 |
Warrants (Tables)
Warrants (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 December 31, 2017 Price Per Share Expiration December 31, 2018 December 31, 2017 Warrants to purchase common stock 39 61 $ 5.88 June 10, 2020 - July 9, 2020 Liability (1) Liability (1) All warrants 39 61 $ 5.88 ______________________________________________________________________ (1) In January 2018, the warrant holders exercised warrants to purchase 21,258 shares of Common Stock on a net basis, resulting in the issuance of 18,449 shares of Common Stock. |
Commitments and Contingencies (
Commitments and Contingencies (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Commitments and Contingencies Disclosure [Abstract] | |
Schedule of Future Annual Minimum Lease Payments | Future annual minimum lease payments as of December 31, 2018 , are as follows (in thousands): 2019 $ 8,195 2020 8,438 2021 8,180 2022 8,256 2023 6,333 Total $ 39,402 |
Schedule of Future Minimum Sublease Proceeds | Future annual minimum sublease proceeds expected as of December 31, 2018 are as follows (in thousands): 2019 $ 717 2020 198 Total $ 915 |
Stockholders' Equity (Tables)
Stockholders' Equity (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Stockholders' Equity Note [Abstract] | |
Schedule of Common Stock Reserved for Future Issuance | At December 31, 2018 , the Company has reserved for future issuance the following number of shares of common stock (in thousands): December 31, 2018 Outstanding stock options to purchase common stock 3,513 Outstanding restricted stock units 608 Shares available for future issuance under equity incentive plan 3,556 Warrants to purchase common stock 39 Shares available for future issuance under the employee stock purchase plan 156 Additional shares reserved for unissued, but designated, Preferred Stock 25,000 Total shares of authorized common stock reserved for future issuance 32,872 |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Schedule of 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, 2018 2017 2016 Research and development $ 12,669 $ 14,227 $ 8,171 General and administrative 11,900 14,021 10,386 $ 24,569 $ 28,248 $ 18,557 |
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, 2018 2017 2016 Expected volatility 62.8 % 65.7 % 65.1 % Expected term (in years) 6.0 6.0 6.0 Risk-free interest rate 2.70 % 2.13 % 1.69 % 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, 2018 (in thousands, except per share amounts and years): Number (in thousands) Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2017 3,452 $ 29.14 Granted 942 $ 42.30 Exercised (780 ) $ 20.43 Canceled or forfeited (101 ) $ 36.05 Outstanding at December 31, 2018 3,513 $ 34.40 7.31 $ 33,442 Exercisable at December 31, 2018 2,007 $ 31.86 6.35 $ 23,561 ______________________________________________________ (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, 2018 . |
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, 2018 : Number of Weighted- Unvested balance at December 31, 2017 267 $ 32.44 Granted 239 $ 38.83 Vested (104 ) $ 31.58 Forfeited (30 ) $ 35.49 Unvested balance at December 31, 2018 372 $ 36.53 |
Performance Shares Units Nonvested Activity | The following table summarizes PSU activity under the 2013 Plan during the year ended December 31, 2018 : Number of Weighted- Unvested balance at December 31, 2017 337 $ 31.53 Granted — $ — Vested (83 ) $ 31.93 Forfeited (18 ) $ 31.09 Unvested balance at December 31, 2018 236 $ 31.42 |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
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, 2018 2017 Deferred tax assets: U.S. and state net operating loss carryforwards $ 149,170 $ 116,812 Research and development credits 16,340 12,548 Deferred revenue — 1,010 Accruals and other temporary differences 17,445 15,287 Total deferred tax assets 182,955 145,657 Less valuation allowance (182,955 ) (145,657 ) 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, 2018 2017 2016 Federal income tax expense at statutory rate 21.0 % 34.0 % 34.0 % State income tax, net of federal benefit 7.0 % 5.6 % 5.9 % Permanent differences 2.0 % 1.9 % 4.0 % Research and development credit 3.2 % 1.9 % 3.1 % Tax reform rate change — % (54.7 )% — % Other (0.6 )% (0.3 )% (0.1 )% Change in valuation allowance (32.6 )% 11.6 % (46.9 )% Effective income tax rate — % — % — % |
Quarterly Financial Data (una_2
Quarterly Financial Data (unaudited) (Tables) | 12 Months Ended |
Dec. 31, 2018 | |
Quarterly Financial Information Disclosure [Abstract] | |
Schedule of Certain Unaudited Quarterly Financial Information | The following table presents certain unaudited quarterly financial information for the previous eight quarters. 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) 2018 Total revenue $ 3,232 $ 3,685 $ 3,258 $ 3,816 Total costs and expenses 30,872 33,591 33,320 40,622 Loss from operations (27,640 ) (29,906 ) (30,062 ) (36,806 ) Net loss (26,219 ) (28,938 ) (28,979 ) (34,734 ) Net loss per share- basic and diluted $ (0.58 ) $ (0.63 ) $ (0.63 ) $ (0.75 ) 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 income (loss) (25,407 ) (29,669 ) (25,451 ) (27,926 ) Net loss per share- basic and diluted $ (0.66 ) $ (0.77 ) $ (0.65 ) $ (0.62 ) ______________________________________________________ (1) The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Summary of Significant Accoun_4
Summary of Significant Accounting Policies (Details) | 12 Months Ended | |||
Dec. 31, 2018USD ($)segmentstock-based_compensation_plan | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Jan. 01, 2018USD ($) | |
Segment Information | ||||
Number of operating segments | segment | 1 | |||
Debt Securities, Available-for-sale, Unrealized Loss Position [Abstract] | ||||
Marketable securities, realized gain (loss) | $ 0 | $ 0 | $ 0 | |
Continuous unrealized loss position, less than twelve months | 51,200,000 | 193,600,000 | ||
Continuous unrealized loss position, twelve months or longer, fair value | 94,300,000 | 67,000,000 | ||
Continuous unrealized loss position, fair value | 400,000 | 300,000 | ||
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 | |||
Accumulated Deficit | ||||
Stock-Based Compensation | ||||
Effect of adoption of ASU | $ (79,000) | |||
Accumulated Deficit | Accounting Standards Update 2018-07 | ||||
Stock-Based Compensation | ||||
Effect of adoption of ASU | $ 1,641,000 |
Summary of Significant Accoun_5
Summary of Significant Accounting Policies - Schedule of Financial Instruments Carried at Fair Value (Details) - Recurring - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Assets: | ||
Total assets | $ 290,107 | $ 368,628 |
Liabilities: | ||
Total liabilities | 1,491 | 2,236 |
Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 1,491 | 2,236 |
Money Market Funds | ||
Assets: | ||
Total assets | 74,023 | 90,702 |
Corporate Obligations | ||
Assets: | ||
Total assets | 128,920 | 158,849 |
US Treasury Securities | ||
Assets: | ||
Total assets | 56,978 | 37,813 |
Certificates of Deposit | ||
Assets: | ||
Total assets | 1,715 | 12,244 |
Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 26,874 | 67,888 |
Restricted Cash | ||
Assets: | ||
Total assets | 1,597 | 1,132 |
Level 1 | ||
Assets: | ||
Total assets | 75,620 | 91,834 |
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 1 | Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 0 | 0 |
Level 1 | Money Market Funds | ||
Assets: | ||
Total assets | 74,023 | 90,702 |
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 | 1,597 | 1,132 |
Level 2 | ||
Assets: | ||
Total assets | 214,487 | 276,794 |
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 | 128,920 | 158,849 |
Level 2 | US Treasury Securities | ||
Assets: | ||
Total assets | 56,978 | 37,813 |
Level 2 | Certificates of Deposit | ||
Assets: | ||
Total assets | 1,715 | 12,244 |
Level 2 | Mortgage and Other Asset-Backed Securities | ||
Assets: | ||
Total assets | 26,874 | 67,888 |
Level 2 | Restricted Cash | ||
Assets: | ||
Total assets | 0 | 0 |
Level 3 | ||
Assets: | ||
Total assets | 0 | 0 |
Liabilities: | ||
Total liabilities | 1,491 | 2,236 |
Level 3 | Common Stock Warrants | ||
Liabilities: | ||
Total liabilities | 1,491 | 2,236 |
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 Accoun_6
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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
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 | $ 2,236 | $ 1,244 | |
Change in fair value | 52 | 992 | $ (7,300) |
Exercises | (797) | 0 | |
Ending balance | $ 1,491 | $ 2,236 | $ 1,244 |
Summary of Significant Accoun_7
Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Details) | 12 Months Ended |
Dec. 31, 2018 | |
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 Accoun_8
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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Net Income (Loss) Per Share | |||
Anti-dilutive common stock equivalents excluded from the calculation of diluted net income (loss) per share (in shares) | 4,178 | 4,135 | 4,135 |
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) | 3,513 | 3,452 | 3,316 |
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) | 39 | 61 | 64 |
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 | 18 | 23 |
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) | 608 | 604 | 732 |
Property and Equipment, Net - S
Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Property and equipment, net | |||
Total property and equipment | $ 35,139 | $ 31,376 | |
Accumulated depreciation and amortization | (28,033) | (24,410) | |
Property and equipment, net | 7,106 | 6,966 | |
Depreciation and amortization expense | 3,747 | 2,825 | $ 1,676 |
Computer Equipment and Software | |||
Property and equipment, net | |||
Total property and equipment | 1,712 | 1,501 | |
Office Equipment | |||
Property and equipment, net | |||
Total property and equipment | 672 | 522 | |
Laboratory Equipment | |||
Property and equipment, net | |||
Total property and equipment | 19,948 | 17,268 | |
Leasehold Improvements | |||
Property and equipment, net | |||
Total property and equipment | 11,668 | 11,501 | |
Construction in Progress | |||
Property and equipment, net | |||
Total property and equipment | $ 1,139 | $ 584 |
Restricted Cash - Narrative (De
Restricted Cash - Narrative (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 |
Restricted Cash | |||
Letters of credit held in the form of certificates of deposits | $ 1,597 | $ 1,132 | $ 946 |
Certificates of Deposit | Letters of Credit | |||
Restricted Cash | |||
Letters of credit held in the form of certificates of deposits | $ 1,600 | $ 1,100 | $ 900 |
Restricted Cash (Details)
Restricted Cash (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Cash and Cash Equivalents [Abstract] | ||||
Cash and cash equivalents | $ 144,052 | $ 100,150 | $ 20,950 | |
Restricted cash | 1,597 | 1,132 | 946 | |
Total cash, cash equivalents and restricted cash shown in the statement of cash flows | $ 145,649 | $ 101,282 | $ 21,896 | $ 28,579 |
Cash, Cash Equivalents and Sh_3
Cash, Cash Equivalents and Short-term and Long-term Investments - Schedule of Available-for-Sale Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 |
Schedule of Available-for-sale Securities | |||
Cash and cash equivalents, amortized cost | $ 144,064 | $ 100,150 | |
Gross Unrealized Losses | (12) | 0 | |
Cash and cash equivalents due in 90 days or less | 144,052 | 100,150 | $ 20,950 |
Available-for-sale securities: | |||
Amortized Cost | 147,714 | 273,695 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | 454 | 895 | |
Estimated Fair Value | 147,260 | 272,800 | |
Total cash, cash equivalents and available for sale securities | |||
Amortized Cost | 291,778 | 373,845 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | (466) | (895) | |
Estimated Fair Value | 291,312 | 372,950 | |
Corporate Obligations Due in One Year or Less | |||
Available-for-sale securities: | |||
Amortized Cost | 73,671 | 99,792 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | 267 | 219 | |
Estimated Fair Value | 73,404 | 99,573 | |
Corporate Obligations Due in More Than One Year | |||
Available-for-sale securities: | |||
Amortized Cost | 57,537 | ||
Gross Unrealized Gains | 0 | ||
Gross Unrealized Losses | 261 | ||
Estimated Fair Value | 57,276 | ||
U.S. Treasury Securities Due in One Year or Less | |||
Available-for-sale securities: | |||
Amortized Cost | 45,346 | 27,987 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | 79 | 93 | |
Estimated Fair Value | 45,267 | 27,894 | |
U.S. Treasury Securities Due in More Than One Year | |||
Available-for-sale securities: | |||
Amortized Cost | 9,968 | ||
Gross Unrealized Gains | 0 | ||
Gross Unrealized Losses | 48 | ||
Estimated Fair Value | 9,920 | ||
Certificates Of Deposit Due In One Year Or Less | |||
Available-for-sale securities: | |||
Amortized Cost | 1,715 | 10,529 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | 0 | 0 | |
Estimated Fair Value | 1,715 | 10,529 | |
Certificates Of Deposit Due In More Than One Year | |||
Available-for-sale securities: | |||
Amortized Cost | 1,715 | ||
Gross Unrealized Gains | 0 | ||
Gross Unrealized Losses | 0 | ||
Estimated Fair Value | 1,715 | ||
Mortgage And Other Asset Backed Securities Due In One Year Or Less | |||
Available-for-sale securities: | |||
Amortized Cost | 26,982 | 39,236 | |
Gross Unrealized Gains | 0 | 0 | |
Gross Unrealized Losses | 108 | 155 | |
Estimated Fair Value | $ 26,874 | 39,081 | |
Mortgage And Other Asset Backed Securities Due More Than One Year | |||
Available-for-sale securities: | |||
Amortized Cost | 26,931 | ||
Gross Unrealized Gains | 0 | ||
Gross Unrealized Losses | 119 | ||
Estimated Fair Value | $ 26,812 |
Accrued Expenses - Schedule of
Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Payables and Accruals [Abstract] | ||
Research and development related | $ 8,144 | $ 4,014 |
Employee compensation | 7,975 | 6,809 |
Professional services | 621 | 1,183 |
Accrued purchases | 351 | 150 |
Other | 1,118 | 2,780 |
Total accrued expenses | $ 18,209 | $ 14,936 |
Warrants - Summary of Shares Is
Warrants - Summary of Shares Issuable Upon Exercise of Outstanding Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands | 1 Months Ended | 12 Months Ended | ||
Jan. 31, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Class of Warrant or Right | ||||
Number of outstanding warrants (in shares) | 39,000 | 61,000 | ||
Weighted-average exercise price per share (in dollars per share) | $ 5.88 | |||
Number of warrants exercised (in shares) | 21,258 | |||
Stock issued during period for warrants exercsied (in shares) | 18,449 | |||
Increase (decrease) in fair value | $ 52 | $ 992 | $ (7,300) | |
Expiring between June 10, 2020 to July 9, 2020 | ||||
Class of Warrant or Right | ||||
Number of outstanding warrants (in shares) | 39,000 | 61,000 | ||
Weighted-average exercise price per share (in dollars per share) | $ 5.88 |
Commitments and Contingencies_2
Commitments and Contingencies (Details) | 12 Months Ended | |||
Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Jul. 31, 2017ft² | |
Loss Contingencies | ||||
Rent expense | $ 5,800,000 | $ 4,800,000 | $ 3,800,000 | |
Sublease revenue | 700,000 | 300,000 | $ 0 | |
Collaborative Arrangement, Co-promotion | ||||
Loss Contingencies | ||||
Amounts due | $ 0 | $ 0 | ||
99 Erie Street, Cambridge, Massachusetts | ||||
Loss Contingencies | ||||
Area of Real Estate Property | ft² | 11,825 |
Commitments and Contingencies -
Commitments and Contingencies - Schedule of Future Annual Minimum Lease Payments (Details) $ in Thousands | Dec. 31, 2018USD ($) |
Commitments and Contingencies Disclosure [Abstract] | |
2,019 | $ 8,195 |
2,020 | 8,438 |
2,021 | 8,180 |
2,022 | 8,256 |
2,023 | 6,333 |
Total | $ 39,402 |
Commitments and Contingencies S
Commitments and Contingencies Schedule of Future Minimum Sublease Proceeds (Details) $ in Thousands | Dec. 31, 2018USD ($) |
Commitments and Contingencies Disclosure [Abstract] | |
2,019 | $ 717 |
2,020 | 198 |
Total | $ 915 |
Stockholders' Equity (Details)
Stockholders' Equity (Details) $ / shares in Units, $ in Thousands | Feb. 12, 2019USD ($) | Jan. 18, 2019USD ($)$ / sharesshares | Oct. 04, 2017shares | Sep. 25, 2017USD ($)$ / sharesshares | Jan. 11, 2016USD ($)$ / sharesshares | Dec. 31, 2018USD ($)vote$ / sharesshares | Dec. 31, 2017USD ($)shares | Dec. 31, 2016USD ($) |
Common stock | ||||||||
Public offering share amount (in shares) | 3,750,000 | |||||||
Price per share (in dollars per share) | $ / shares | $ 37 | $ 40 | ||||||
Aggregate net proceeds from the offering | $ | $ 140,300 | |||||||
Proceeds from issuance of common stock from public offering, net of issuance costs | $ | $ 215,800 | $ 0 | $ 215,802 | $ 140,697 | ||||
Preferred stock (in shares) | 25,000,000 | |||||||
Preferred stock, shares issued (in shares) | 0 | 0 | ||||||
Preferred stock, shares outstanding (in shares) | 0 | 0 | ||||||
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 | ||||||||
Public offering share amount (in shares) | 810,810 | 5,405,406 | ||||||
Subsequent Event | ||||||||
Common stock | ||||||||
Price per share (in dollars per share) | $ / shares | $ 43 | |||||||
Proceeds from issuance of common stock from public offering, net of issuance costs | $ | $ 248,200 | $ 215,800 | ||||||
Subsequent Event | Common Stock | ||||||||
Common stock | ||||||||
Public offering share amount (in shares) | 5,348,838 | |||||||
Number of additional shares available for purchase (in shares) | 802,325 |
Stockholders' Equity - Schedule
Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details) - shares | Dec. 31, 2018 | Sep. 04, 2013 |
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 32,872,000 | |
Conversion of Preferred Stock | Unissued, but Designated, Preferred Stock | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 25,000,000 | |
Common Stock Warrants | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 39,000 | |
Stock Compensation Plan | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 3,513,000 | |
Restricted Stock | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 608,000 | |
Stock Options | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 3,556,000 | |
2013 ESPP | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 275,000 | |
2013 ESPP | Employee Stock Purchase Plan | ||
Common stock | ||
Total shares of authorized common stock reserved for future issuance (in shares) | 155,948 |
Significant Agreements - Sotate
Significant Agreements - Sotatercept Agreement (Details) | Sep. 24, 2013USD ($) | Jan. 01, 2013 | Feb. 20, 2008USD ($)discovery_stage_compound | Dec. 31, 2018USD ($) | Sep. 30, 2018USD ($) | [1] | Jun. 30, 2018USD ($) | [1] | Mar. 31, 2018USD ($) | [1] | Dec. 31, 2017USD ($) | [1] | Sep. 30, 2017USD ($) | [1] | Jun. 30, 2017USD ($) | [1] | Mar. 31, 2017USD ($) | [1] | Dec. 31, 2018USD ($) | Dec. 31, 2017USD ($) | Dec. 31, 2016USD ($) | Aug. 02, 2011USD ($) | |
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Revenue | $ 3,816,000 | [1] | $ 3,258,000 | $ 3,685,000 | $ 3,232,000 | $ 3,705,000 | $ 3,014,000 | $ 3,057,000 | $ 3,705,000 | $ 13,991,000 | $ 13,481,000 | $ 27,771,000 | |||||||||||
Original Sotatercept Agreement | Collaboration Arrangement | Upfront License and Option Payments | |||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Revenue | $ 45,000,000 | $ 45,000,000 | |||||||||||||||||||||
Celgene | Original Sotatercept Agreement | Collaboration Arrangement | |||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | ||||||||||||||||||||||
Equity purchased | $ 5,000,000 | ||||||||||||||||||||||
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 | ||||||||||||||||||||||
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 | 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 | ||||||||||||||||||||||
Investor | Collaboration, License, and Option Agreement | Sotatercept | |||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Payments received | $ 44,500,000 | ||||||||||||||||||||||
Investor | Collaboration, License, and Option Agreement | Restated Sotatercept Agreement | |||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | ||||||||||||||||||||||
Investor | Weighted Average | Collaboration, License, and Option Agreement | Restated Sotatercept Agreement | |||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||||||||||||||||||||
Potential royalty rate (as a percent) | 20.00% | ||||||||||||||||||||||
[1] | The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Significant Agreements - Luspat
Significant Agreements - Luspatercept Agreement (Details) - USD ($) | Jan. 01, 2013 | Feb. 20, 2008 | Aug. 31, 2011 | Dec. 31, 2018 | Sep. 30, 2018 | [1] | Jun. 30, 2018 | [1] | Mar. 31, 2018 | [1] | Dec. 31, 2017 | [1] | Sep. 30, 2017 | [1] | Jun. 30, 2017 | [1] | Mar. 31, 2017 | [1] | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 3,816,000 | [1] | $ 3,258,000 | $ 3,685,000 | $ 3,232,000 | $ 3,705,000 | $ 3,014,000 | $ 3,057,000 | $ 3,705,000 | $ 13,991,000 | $ 13,481,000 | $ 27,771,000 | ||||||||||
Luspatercept Agreement | Celgene | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Percentage of development costs for which collaborator is responsible | 100.00% | |||||||||||||||||||||
Clinical Milestones | Maximum | Luspatercept Agreement | Celgene | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Potential milestone payments receivable | $ 32,500,000 | |||||||||||||||||||||
Regulatory Milestones | Maximum | Luspatercept Agreement | Celgene | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Potential milestone payments receivable | 105,000,000 | |||||||||||||||||||||
Commercial Milestones | Maximum | Luspatercept Agreement | Celgene | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Potential milestone payments receivable | 80,000,000 | |||||||||||||||||||||
Nonrefundable Upfront Payments | Luspatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 25,000,000 | $ 25,000,000 | ||||||||||||||||||||
Luspatercept | Luspatercept Agreement | Celgene | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Potential royalty rate (as a percent) | 20.00% | |||||||||||||||||||||
Luspatercept | Investor | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Payments received | 109,600,000 | |||||||||||||||||||||
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 | 25,000,000 | ||||||||||||||||||||
Luspatercept | Investor | Clinical Milestones | Luspatercept Agreement | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Milestone payment receivable on commencement of trial or study | $ 25,000,000 | $ 25,000,000 | ||||||||||||||||||||
[1] | The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Significant Agreements - Both A
Significant Agreements - Both Agreements and Accounting Analysis (Details) - USD ($) | Feb. 20, 2008 | Aug. 31, 2011 | Dec. 31, 2018 | Sep. 30, 2018 | [1] | Jun. 30, 2018 | [1] | Mar. 31, 2018 | [1] | Dec. 31, 2017 | Sep. 30, 2017 | [1] | Jun. 30, 2017 | [1] | Mar. 31, 2017 | [1] | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Jan. 01, 2018 | ||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 3,816,000 | [1] | $ 3,258,000 | $ 3,685,000 | $ 3,232,000 | $ 3,705,000 | [1] | $ 3,014,000 | $ 3,057,000 | $ 3,705,000 | $ 13,991,000 | $ 13,481,000 | $ 27,771,000 | |||||||||
Deferred revenue | 0 | 0 | ||||||||||||||||||||
Deferred revenue | 0 | 541,000 | 0 | 541,000 | ||||||||||||||||||
Difference between the estimated payments and the estimated selling prices | 0 | $ 3,161,000 | 0 | 3,161,000 | ||||||||||||||||||
Luspatercept Agreement and Amended Sotatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 192,300,000 | |||||||||||||||||||||
Deferred revenue | $ 3,700,000 | |||||||||||||||||||||
Luspatercept | Investor | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Payments received | 109,600,000 | |||||||||||||||||||||
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 | 25,000,000 | ||||||||||||||||||||
Luspatercept | Investor | Clinical Milestones | Luspatercept Agreement | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Milestone payment receivable on commencement of trial or study | 25,000,000 | 25,000,000 | ||||||||||||||||||||
Nonrefundable Upfront Payments | Luspatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 25,000,000 | 25,000,000 | ||||||||||||||||||||
Upfront License and Option Payments | Original Sotatercept Agreement | Collaboration Arrangement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 45,000,000 | 45,000,000 | ||||||||||||||||||||
Development and Manufacturing Activities | Luspatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 47,900,000 | |||||||||||||||||||||
Development and Manufacturing Activities | Amended Sotatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 14,900,000 | |||||||||||||||||||||
Milestone Achievements | Luspatercept Agreement and Amended Sotatercept Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 59,500,000 | |||||||||||||||||||||
License and milestone | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 0 | 541,356 | 15,549,968 | |||||||||||||||||||
Sotatercept | Investor | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Payments received | 44,500,000 | |||||||||||||||||||||
Cost Sharing | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 13,991,000 | 12,940,000 | 12,221,000 | |||||||||||||||||||
Cost Sharing | Investor | Collaboration, License, and Option Agreement | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | 14,000,000 | $ 12,900,000 | $ 12,200,000 | |||||||||||||||||||
Calculated under Revenue Guidance in Effect before Topic 606 | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Deferred revenue | $ 3,200,000 | 3,200,000 | ||||||||||||||||||||
Calculated under Revenue Guidance in Effect before Topic 606 | License and milestone | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Revenue | $ 500,000 | |||||||||||||||||||||
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | ||||||||||||||||||||||
Collaborative Arrangements and Non-collaborative Arrangement Transactions | ||||||||||||||||||||||
Deferred revenue | 500,000 | |||||||||||||||||||||
Difference between the estimated payments and the estimated selling prices | $ 3,200,000 | |||||||||||||||||||||
[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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2004 | |
Collaborative Arrangements and Non-collaborative Arrangement Transactions | |||||
Research and development | $ 103,902 | $ 89,726 | $ 68,580 | ||
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 | $ 100 | $ 1,600 | $ 1,000 | ||
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, 2018USD ($)stock-based_compensation_planshares | Dec. 31, 2018USD ($)stock-based_compensation_plan$ / sharesshares | Dec. 31, 2017USD ($)$ / sharesshares | Dec. 31, 2016USD ($)$ / 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) | 32,872,000 | 32,872,000 | |||
Stock compensation expense | $ | $ 24,569,000 | $ 28,248,000 | $ 18,557,000 | ||
Expected dividend yield | 0.00% | ||||
Estimated forfeiture rate | 0.00% | 0.00% | 3.00% | ||
Shares granted during period (in shares) | 942,000 | ||||
Exercise of stock options (in shares) | 780,000 | ||||
2003 Plan | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Number of shares of common stock which may be granted (in shares) | 0 | 0 | |||
Remaining shares reserved for issuance (in shares) | 155,884 | ||||
2013 Plan | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in shares) | 1,500,000 | ||||
Remaining shares reserved for issuance (in shares) | 3,555,548 | 3,555,548 | |||
Additional shares authorized under new plan (in shares) | 1,344,116 | ||||
Annual increase in shares authorized under plan, shares threshold (in 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 | $ | $ 2,400,000 | $ 4,900,000 | $ 500,000 | ||
Shares granted during period (in shares) | 942,271 | 701,384 | 1,045,795 | ||
Weighted average grant date fair value (in dollars per share) | $ / shares | $ 25.05 | $ 18.58 | $ 18.55 | ||
Exercise of stock options (in shares) | 779,711 | 474,056 | 885,075 | ||
Total proceeds from options exercised | $ | $ 15,900,000 | $ 3,900,000 | $ 5,300,000 | ||
Aggregate intrinsic value of options exercised | $ | 19,300,000 | 10,200,000 | 23,800,000 | ||
Unrecognized compensation expense related to unvested stock options | $ | 29,200,000 | $ 29,200,000 | |||
Weighted-average period of recognition (in years) | 2 years 4 months 24 days | ||||
2013 ESPP | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in 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 | $ | $ 400,000 | $ 300,000 | $ 300,000 | ||
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 10 months 6 days | ||||
Unrecognized compensation expense related to unvested restricted stock units | $ | 9,500,000 | $ 9,500,000 | |||
Performance-Based Restricted Stock Units | Certain Individuals | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Weighted-average period of recognition (in years) | 6 months | ||||
Unrecognized compensation expense related to unvested restricted stock units | $ | $ 1,300,000 | $ 1,300,000 | |||
Employee Stock Purchase Plan | 2013 ESPP | |||||
Share-based Compensation Arrangement by Share-based Payment Award | |||||
Shares reserved for issuance (in shares) | 155,948 | 155,948 |
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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | $ 24,569 | $ 28,248 | $ 18,557 |
Research and Development | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | 12,669 | 14,227 | 8,171 |
General and Administrative | |||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
Total compensation cost recognized | $ 11,900 | $ 14,021 | $ 10,386 |
Stock-Based Compensation - Sc_2
Stock-Based Compensation - Schedule of Stock Option Valuation Assumptions (Details) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
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 | 62.80% | 65.70% | 65.10% |
Expected term (in years) | 6 years | 6 years | 6 years |
Risk-free interest rate | 2.70% | 2.13% | 1.69% |
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, 2018USD ($)$ / sharesshares | ||
Number of Grants (in thousands) | ||
Outstanding at beginning of period (in shares) | shares | 3,452 | |
Granted (in shares) | shares | 942 | |
Exercised (in shares) | shares | (780) | |
Canceled or forfeited (in shares) | shares | (101) | |
Outstanding at end of period (in shares) | shares | 3,513 | |
Exercisable (in shares) | shares | 2,007 | |
Weighted- Average Exercise Price Per Share | ||
Outstanding at beginning of period (in dollars per share) | $ / shares | $ 29.14 | |
Granted (in dollars per share) | $ / shares | 42.30 | |
Exercised (in dollars per share) | $ / shares | 20.43 | |
Canceled or forfeited (in dollars per share) | $ / shares | 36.05 | |
Outstanding at end of period (in dollars per share) | $ / shares | 34.40 | |
Exercisable (in dollars per share) | $ / shares | $ 31.86 | |
Weighted- Average Contractual Life (in years) | ||
Outstanding at end of period (in years) | 7 years 3 months 22 days | |
Exercisable (in years) | 6 years 4 months 6 days | |
Aggregate Intrinsic Value | ||
Outstanding at end of period (in dollars) | $ | $ 33,442 | [1] |
Exercisable (in dollars) | $ | $ 23,561 | [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, 2018. |
Stock-based Compensation - Sc_3
Stock-based Compensation - Schedule of Restricted Stock Unit Activity and Performance-Based Restricted Stock Units (Details) shares in Thousands | 12 Months Ended |
Dec. 31, 2018$ / sharesshares | |
Restricted Stock Units | |
Number of Stock Units (in thousands) | |
Unvested balance at beginning of period (in units) | shares | 267 |
Granted (in units) | shares | 239 |
Vested (in units) | shares | (104) |
Forfeited (in units) | shares | (30) |
Unvested balance at end of period (in units) | shares | 372 |
Weighted- Average Grant Date Fair Value Per Share | |
Unvested balance at beginning of period (in dollars per share) | $ / shares | $ 32.44 |
Granted (in dollars per share) | $ / shares | 38.83 |
Vested (in dollars per share) | $ / shares | 31.58 |
Forfeited (in dollars per share) | $ / shares | 35.49 |
Unvested balance at end of period (in dollars per share) | $ / shares | $ 36.53 |
Performance-Based Restricted Stock Units | |
Number of Stock Units (in thousands) | |
Unvested balance at beginning of period (in units) | shares | 337 |
Granted (in units) | shares | 0 |
Vested (in units) | shares | (83) |
Forfeited (in units) | shares | (18) |
Unvested balance at end of period (in units) | shares | 236 |
Weighted- Average Grant Date Fair Value Per Share | |
Unvested balance at beginning of period (in dollars per share) | $ / shares | $ 31.53 |
Granted (in dollars per share) | $ / shares | 0 |
Vested (in dollars per share) | $ / shares | 31.93 |
Forfeited (in dollars per share) | $ / shares | 31.09 |
Unvested balance at end of period (in dollars per share) | $ / shares | $ 31.42 |
401(k) Savings Plan (Details)
401(k) Savings Plan (Details) - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Retirement Benefits [Abstract] | |||
Matching contribution, amount per employee | $ 8,500 | $ 7,000 | $ 7,000 |
Expenses related to 401(k) Savings Plan | $ 1,100,000 | $ 700,000 | $ 600,000 |
Income Taxes (Details)
Income Taxes (Details) - USD ($) | 12 Months Ended | ||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Tax Disclosure [Abstract] | |||
State tax expense (benefit) | $ 32,000 | $ 24,000 | |
Loss before income taxes | $ 118,900,000 | 108,400,000 | 57,000,000 |
Increase in valuation allowance | 37,300,000 | 9,100,000 | $ 26,700,000 |
Income tax penalties and interest accrued | 0 | 0 | |
Income tax penalties and interest expense | 0 | 0 | |
Operating loss carryforwards | |||
Income Tax benefit from realized current year losses offset by unrealized gains | (27,000) | ||
Operating loss carryforwards, subject to expiration | 438,000,000 | ||
Federal | |||
Operating loss carryforwards | |||
Net operating loss carryforwards | 556,000,000 | 438,000,000 | |
Operating loss carryforwards, not subject to expiration | 118,000,000 | ||
State | |||
Operating loss carryforwards | |||
Net operating loss carryforwards | 515,000,000 | 393,600,000 | |
Research and development | Federal | |||
Operating loss carryforwards | |||
Tax credit carryforwards | 10,700,000 | 8,100,000 | |
Research and development | State | |||
Operating loss carryforwards | |||
Tax credit carryforwards | $ 7,100,000 | $ 5,600,000 |
Income Taxes Income Taxes - Com
Income Taxes Income Taxes - Components of the Company's Deferred Tax Assets (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 |
Income Tax Disclosure [Abstract] | ||
U.S. and state net operating loss carryforwards | $ 149,170 | $ 116,812 |
Research and development credits | 16,340 | 12,548 |
Deferred revenue | 0 | 1,010 |
Accruals and other temporary differences | 17,445 | 15,287 |
Total deferred tax assets | 182,955 | 145,657 |
Less valuation allowance | (182,955) | (145,657) |
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, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Income Tax Disclosure [Abstract] | |||
Federal income tax expense at statutory rate | 21.00% | 34.00% | 34.00% |
State income tax, net of federal benefit | 7.00% | 5.60% | 5.90% |
Permanent differences | 2.00% | 1.90% | 4.00% |
Research and development credit | 3.20% | 1.90% | 3.10% |
Tax reform rate change | 0.00% | (54.70%) | 0.00% |
Other | (0.60%) | (0.30%) | (0.10%) |
Change in valuation allowance | (32.60%) | 11.60% | (46.90%) |
Effective income tax rate | 0.00% | 0.00% | 0.00% |
Related Party Transactions (Det
Related Party Transactions (Details) - USD ($) | Sep. 25, 2017 | Jan. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 |
Related Party Transaction [Line Items] | ||||
Deferred revenue | $ 0 | |||
Celgene | ||||
Related Party Transaction [Line Items] | ||||
Deferred revenue | $ 0 | $ 3,700,000 | ||
Common Stock | Celgene | ||||
Related Party Transaction [Line Items] | ||||
Shares purchased by collaborators (in shares) | 745,592 | 800,000 | ||
Celgene | Celgene | ||||
Related Party Transaction [Line Items] | ||||
Ownership percentage of entity's fully diluted equity | 12.20% | 12.50% |
Quarterly Financial Data (una_3
Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||||||||||
Dec. 31, 2018 | [1] | Sep. 30, 2018 | [1] | Jun. 30, 2018 | [1] | Mar. 31, 2018 | [1] | Dec. 31, 2017 | [1] | Sep. 30, 2017 | [1] | Jun. 30, 2017 | [1] | Mar. 31, 2017 | [1] | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
Quarterly Financial Information Disclosure [Abstract] | |||||||||||||||||||
Revenue | $ 3,816 | $ 3,258 | $ 3,685 | $ 3,232 | $ 3,705 | $ 3,014 | $ 3,057 | $ 3,705 | $ 13,991 | $ 13,481 | $ 27,771 | ||||||||
Total costs and expenses | 40,622 | 33,320 | 33,591 | 30,872 | 32,341 | 28,592 | 32,968 | 29,563 | 138,405 | 123,464 | 93,877 | ||||||||
Income (loss) from operations | (36,806) | (30,062) | (29,906) | (27,640) | (28,636) | (25,578) | (29,911) | (25,858) | (124,414) | (109,983) | (66,106) | ||||||||
Net loss | $ (34,734) | $ (28,979) | $ (28,938) | $ (26,219) | $ (27,926) | $ (25,451) | $ (29,669) | $ (25,407) | $ (118,871) | $ (108,454) | $ (57,014) | ||||||||
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share) | $ (0.75) | $ (0.63) | $ (0.63) | $ (0.58) | $ (0.62) | $ (0.65) | $ (0.77) | $ (0.66) | $ (2.59) | $ (2.68) | $ (1.52) | ||||||||
[1] | The amounts were computed independently for each quarter, and the sum of the quarters may not total the annual amounts. |
Uncategorized Items - xlrn-2018
Label | Element | Value |
Accounting Standards Update 2014-09 [Member] | ||
Cumulative Effect of New Accounting Principle in Period of Adoption | us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption | $ 3,705,000 |
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member] | ||
Cumulative Effect of New Accounting Principle in Period of Adoption | us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption | 3,705,000 |
Accounting Standards Update 2018-07 [Member] | Additional Paid-in Capital [Member] | ||
Cumulative Effect of New Accounting Principle in Period of Adoption | us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption | $ (1,641,000) |