Document and Entity Information
Document and Entity Information - shares | 6 Months Ended | |
Jun. 30, 2018 | Aug. 06, 2018 | |
Document And Entity Information [Abstract] | ||
Document Type | 10-Q | |
Amendment Flag | false | |
Document Period End Date | Jun. 30, 2018 | |
Document Fiscal Year Focus | 2,018 | |
Document Fiscal Period Focus | Q2 | |
Trading Symbol | ALRN | |
Entity Registrant Name | AILERON THERAPEUTICS INC | |
Entity Central Index Key | 1,420,565 | |
Current Fiscal Year End Date | --12-31 | |
Entity Filer Category | Non-accelerated Filer | |
Entity Common Stock, Shares Outstanding | 14,737,402 |
Condensed Balance Sheets
Condensed Balance Sheets - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 |
Current assets: | ||
Cash and cash equivalents | $ 11,980 | $ 11,863 |
Investments | 23,811 | 38,889 |
Prepaid expenses and other current assets | 1,390 | 1,000 |
Restricted cash | 25 | 88 |
Total current assets | 37,206 | 51,840 |
Property and equipment, net | 4,123 | 154 |
Restricted cash, non-current | 568 | |
Other assets | 680 | 694 |
Total assets | 42,577 | 52,688 |
Current liabilities: | ||
Accounts payable | 1,583 | 1,600 |
Accrued expenses and other current liabilities | 4,781 | 3,291 |
Total current liabilities | 6,364 | 4,891 |
Construction financing liability, net of current portion | 3,345 | |
Total liabilities | 9,709 | 4,891 |
Commitments and contingencies (Note 9) | ||
Stockholders’ equity: | ||
Preferred stock, $0.001 par value; 5,000,000 shares authorized at June 30, 2018 and December 31, 2017, respectively; no shares issued and outstanding at June 30, 2018 and December 31, 2017 | ||
Common stock, $0.001 par value; 150,000,000 shares authorized at June 30, 2018 and December 31, 2017; 14,737,402 and 14,723,818 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively | 15 | 15 |
Additional paid-in capital | 186,890 | 184,761 |
Accumulated other comprehensive loss | (12) | (33) |
Accumulated deficit | (154,025) | (136,946) |
Total stockholders’ equity | 32,868 | 47,797 |
Total liabilities and stockholders’ equity | $ 42,577 | $ 52,688 |
Condensed Balance Sheets (Paren
Condensed Balance Sheets (Parenthetical) - $ / shares | Jun. 30, 2018 | Dec. 31, 2017 |
Statement Of Financial Position [Abstract] | ||
Preferred stock, par value | $ 0.001 | $ 0.001 |
Preferred stock, shares authorized | 5,000,000 | 5,000,000 |
Preferred stock, shares issued | 0 | 0 |
Preferred stock, shares outstanding | 0 | 0 |
Common stock, par value | $ 0.001 | $ 0.001 |
Common stock, shares authorized | 150,000,000 | 150,000,000 |
Common stock, shares issued | 14,737,402 | 14,723,818 |
Common stock, shares outstanding | 14,737,402 | 14,723,818 |
Condensed Statements of Operati
Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Income Statement [Abstract] | ||||
Revenue | $ 0 | $ 0 | $ 0 | $ 0 |
Operating expenses: | ||||
Research and development | 5,320 | 3,161 | 10,166 | 6,103 |
General and administrative | 4,339 | 1,791 | 7,256 | 3,438 |
Total operating expenses | 9,659 | 4,952 | 17,422 | 9,541 |
Loss from operations | (9,659) | (4,952) | (17,422) | (9,541) |
Interest income | 168 | 29 | 343 | 61 |
Net loss | (9,491) | (4,923) | (17,079) | (9,480) |
Accretion of redeemable convertible preferred stock to redemption value | (21) | 0 | (41) | |
Net loss attributable to common stockholders | $ (9,491) | $ (4,944) | $ (17,079) | $ (9,521) |
Net loss per share attributable to common stockholders—basic and diluted | $ (0.64) | $ (10.98) | $ (1.16) | $ (21.56) |
Weighted average common shares outstanding—basic and diluted | 14,737,236 | 450,495 | 14,734,775 | 441,661 |
Comprehensive loss: | ||||
Net loss | $ (9,491) | $ (4,923) | $ (17,079) | $ (9,480) |
Other comprehensive loss: | ||||
Unrealized gain on investments, net of tax of $0 | 38 | 21 | ||
Total other comprehensive loss | 38 | 21 | ||
Total comprehensive loss | $ (9,453) | $ (4,923) | $ (17,058) | $ (9,480) |
Condensed Statements of Operat5
Condensed Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Income Statement [Abstract] | ||||
Unrealized gain on investments, tax | $ 0 | $ 0 | $ 0 | $ 0 |
Condensed Statements of Cash Fl
Condensed Statements of Cash Flows - USD ($) $ in Thousands | 6 Months Ended | |
Jun. 30, 2018 | Jun. 30, 2017 | |
Cash flows from operating activities: | ||
Net loss | $ (17,079) | $ (9,480) |
Adjustments to reconcile net loss to net cash used in operating activities: | ||
Depreciation and amortization expense | 82 | 45 |
Net amortization of premiums and discounts on investments | (93) | |
Stock-based compensation expense | 2,101 | 469 |
Change in deferred rent | (11) | (11) |
Changes in operating assets and liabilities: | ||
Prepaid expenses and other current assets | 141 | (291) |
Other assets | 15 | 59 |
Accounts payable | (22) | (500) |
Accrued expenses and other current liabilities | 481 | 252 |
Net cash used in operating activities | (14,385) | (9,457) |
Cash flows from investing activities: | ||
Purchases of property and equipment | (213) | (47) |
Purchases of investments | (20,763) | (8,747) |
Proceeds from sales or maturities of investments | 35,955 | 6,800 |
Net cash provided by (used in) investing activities | 14,979 | (1,994) |
Cash flows from financing activities: | ||
Proceeds from issuance of redeemable convertible preferred stock, net of issuance costs | 472 | |
Proceeds from exercise of stock options | 28 | 80 |
Payments of initial public offering costs | (419) | |
Net cash provided by financing activities | 28 | 133 |
Net increase (decrease) in cash, cash equivalents and restricted cash | 622 | (11,318) |
Cash, cash equivalents and restricted cash at beginning of period | 11,951 | 20,715 |
Cash, cash equivalents and restricted cash at end of period | 12,573 | 9,397 |
Supplemental disclosure of non-cash financing activities: | ||
Accretion of redeemable convertible preferred stock to redemption value | 0 | 41 |
Deferred offering costs included in accounts payable and accrued expenses | $ 1,803 | |
Capitalization of construction-in-progress related to facility lease obligation | 3,940 | |
Fixed asset addition included in accounts payable and accrued expenses | $ 1,025 |
Nature of the Business and Basi
Nature of the Business and Basis of Presentation | 6 Months Ended |
Jun. 30, 2018 | |
Accounting Policies [Abstract] | |
Nature of the Business and Basis of Presentation | 1. Nature of the Business and Basis of Presentation Aileron Therapeutics, Inc. (“Aileron” or the “Company”) is a clinical-stage biopharmaceutical company that is focused on developing and commercializing a novel class of therapeutics called stapled peptides. The Company’s lead product candidate, ALRN-6924, targets the tumor suppressor p53 for the treatment of a wide variety of cancers. ALRN-6924 reactivates p53-mediated tumor suppression by targeting the two primary p53 suppressor proteins, MDMX and MDM2. ALRN-6924 was in multiple clinical trials as of June 30, 2018 and December 31, 2017. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure, and extensive compliance-reporting capabilities. The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary governmental regulatory approval or that any approved products will be commercially viable. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its key employees and consultants. The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Reverse Stock Split On June 16, 2017, in connection with its initial public offering of its common stock (“IPO”), the Company effected a one-for-9.937 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s redeemable convertible preferred stock (see Note 6). Accordingly, all common share and per share amounts for all periods presented in the accompanying financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and the associated adjustment of the preferred stock conversion ratios. Initial Public Offering On June 28, 2017, the Company’s registration statement on Form S-1 relating to its IPO was declared effective by the Securities and Exchange Commission (“SEC”). In the IPO, which closed on July 5, 2017, the Company issued and sold 3,750,000 shares of common stock at a public offering price of $15.00 per share for net proceeds of $50,009 after deducting underwriting discounts and commissions of $3,937 and offering expenses of $2,304. Upon the closing of the IPO, all 106,114,520 shares of redeemable convertible preferred stock then outstanding converted into an aggregate of 10,509,774 common shares. Liquidity In accordance with Accounting Standards Update (“ASU”) No. 2014-15, Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern The Company’s financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. Through June 30, 2018, the Company has funded its operations with net proceeds of $50,009 from its IPO, $131,211 from sales of preferred stock and $34,910 from a collaboration agreement. As of June 30, 2018, the Company had cash, cash equivalents and investments of $35,791. The Company has incurred losses and negative cash flows from operations and had an accumulated deficit of $154,025 as of June 30, 2018. The Company expects to continue to generate losses for the foreseeable future. As of August 7, 2018, the date of issuance of these unaudited interim condensed financial statements, the Company expects that its cash, cash equivalents and investments of $35,791 as of June 30, 2018 will be sufficient to fund its operating expenses and capital expenditure requirements through at least the next twelve months. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. Although the Company has been successful in raising capital in the past, there is no assurance that it will be successful in obtaining such additional financing on terms acceptable to the Company, if at all. To execute its business plans, the Company will need substantial funding to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations through the sale of common stock in public offering and/or private placements, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain financing on acceptable terms or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion plans or commercialization efforts, which could adversely affect its business prospects. |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 6 Months Ended |
Jun. 30, 2018 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | 2. Summary of Significant Accounting Policies 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 of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock and stock-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates. Unaudited Interim Financial Information The accompanying unaudited condensed financial statements as of June 30, 2018 and for the six months ended June 30, 2018 and 2017 have been prepared by the Company, pursuant to the rules and regulations of the SEC for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 that was filed with the SEC on April 2, 2018. The unaudited interim condensed financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2018, the results of its operations for the three and six months ended June 30, 2018 and 2017 and its cash flows for the six months ended June 30, 2018 and 2017. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2018 and 2017 are unaudited. The results for the six months ended June 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2017 has been derived from the Company’s audited financial statements for the year ended December 31, 2017 previously filed with the SEC. Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents. Cash equivalents, which consist of money market accounts, corporate notes and commercial paper, are stated at fair value. Restricted Cash As of June 30, 2018, current restricted cash of $25 consisted entirely of cash deposited in a separate restricted bank account as a security deposit for the Company’s corporate credit cards. As of December 31, 2017, current restricted cash consisted of $25 of cash deposited in a separate restricted bank account as a security deposit for the Company’s corporate credit cards and $63 of cash deposited in a separate restricted bank account as a security deposit for the lease of the Company’s facility. As of June 30, 2018, non-current restricted cash consisted of $568 of cash deposited in a separate restricted bank account as a security deposit for Investments The Company classifies its available-for-sale investments as current assets on the balance sheet if they mature within one year from the balance sheet date. The Company classifies all of its investments as available-for-sale securities. The Company’s investments are measured and reported at fair value using quoted prices in active markets for similar securities or using other inputs that are observable or can be corroborated by observable market data. Unrealized gains and losses on available-for-sale securities are reported as accumulated other comprehensive income (loss), which is a separate component of stockholders’ equity (deficit). The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the statements of operations and comprehensive loss. The Company evaluates its investments with unrealized losses for other-than-temporary impairment. When assessing investments for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary”, the Company reduces the investment to fair value through a charge to the statements of operations and comprehensive loss. No such adjustments were necessary during the periods presented. Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and investments are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair value due to the short-term nature of these liabilities. Net Income (Loss) per Share The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting income (loss) per share attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options to purchase common stock and shares of redeemable convertible preferred stock are considered potential dilutive common shares. The Company’s redeemable convertible preferred stock contractually entitled the holders of such shares to participate in dividends but contractually did not require the holders of such stock to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers , Revenue from Contract with Customers: Principal versus Agent Considerations Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. The adoption of these standards did not have an impact on the Company’s financial position, results of operations or cash flows as the Company does not currently have any revenue generating arrangements. In November 2016, the FASB issued ASU No. 2016-18, Restricted Cash Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments Compensation – Stock Compensation Scope of Modification Accounting Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases Leases Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption. |
Fair Value of Financial Assets
Fair Value of Financial Assets | 6 Months Ended |
Jun. 30, 2018 | |
Fair Value Disclosures [Abstract] | |
Fair Value of Financial Assets | 3. Fair Value of Financial Assets The following tables present information about the Company’s assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of June 30, 2018 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 8,975 $ — $ — $ 8,975 Commercial paper — 1,495 — 1,495 Investments: Corporate notes — 10,226 — 10,226 Commercial paper — 13,585 — 13,585 $ 8,975 $ 25,306 $ — $ 34,281 Fair Value Measurements as of December 31, 2017 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 10,509 $ — $ — $ 10,509 Investments: Corporate notes — 25,710 — 25,710 Commercial paper — 13,179 — 13,179 $ 10,509 $ 38,889 $ — $ 49,398 As of June 30, 2018 and December 31, 2017, the Company’s cash equivalents and investments were invested in money market funds, corporate notes and commercial paper and were valued based on Level 1 and Level 2 inputs. In determining the fair value of its corporate notes and commercial paper at each date presented above, the Company relied on quoted prices for similar securities in active markets or using other inputs that are observable or can be corroborated by observable market data. The Company’s cash equivalents have original maturities of less than 90 days from the date of purchase. All available-for-sale investments have contractual maturities of less than one year. During the six months ended June 30, 2018 and the year ended December 31, 2017, there were no transfers between Level 1, Level 2 and Level 3. |
Investments
Investments | 6 Months Ended |
Jun. 30, 2018 | |
Investments Debt And Equity Securities [Abstract] | |
Investments | 4. Investments As of June 30, 2018 and December 31, 2017, the fair value of available-for-sale investments by type of security was as follows: June 30, 2018 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Investments: Corporate notes $ 10,235 $ — $ (9 ) $ 10,226 Commercial paper 13,588 — (3 ) 13,585 $ 23,823 $ — $ (12 ) $ 23,811 December 31, 2017 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Investments: Corporate notes $ 25,733 $ — $ (23 ) $ 25,710 Commercial paper 13,189 — (10 ) 13,179 $ 38,922 $ — $ (33 ) $ 38,889 |
Accrued Expenses and Other Curr
Accrued Expenses and Other Current Liabilities | 6 Months Ended |
Jun. 30, 2018 | |
Payables And Accruals [Abstract] | |
Accrued Expenses and Other Current Liabilities | 5. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: June 30, 2018 December 31, 2017 External research and development services $ 1,694 $ 1,284 Construction-in-progress related to facility lease obligation 1,020 — Payroll and payroll-related costs 846 1,120 Accrued severance 508 — Professional fees 458 536 Other 255 351 $ 4,781 $ 3,291 |
Redeemable Convertible Preferre
Redeemable Convertible Preferred Stock | 6 Months Ended |
Jun. 30, 2018 | |
Equity [Abstract] | |
Redeemable Convertible Preferred Stock | 6. Redeemable Convertible Preferred Stock Prior to the closing of the Company’s IPO in July 2017, the Company had shares of redeemable convertible preferred stock outstanding, including shares of Series A, Series A-1, Series B, Series C-1 and Series C-2 redeemable convertible preferred stock (collectively, the “Junior Preferred Stock”) and Series D, Series D-1, Series E, Series E-1, Series E-2, Series E-3 and Series F redeemable convertible preferred stock (collectively, the “Senior Preferred Stock” and, together with the Junior Preferred Stock, the “Redeemable Preferred Stock”). The Redeemable Preferred Stock is classified outside of stockholders’ equity (deficit) because the shares contain redemption features that are not solely within the control of the Company. In February 2017, the Company issued 483,501 shares of Series F redeemable convertible preferred stock (the “Series F preferred stock”) at a price of $1.36 per share, resulting in proceeds of $626, net of issuance costs of $32. Pursuant to the amended Series F preferred stock purchase agreement, holders of 4,411,765 shares of Series E-1 preferred stock that participated in the February 2017 closing elected to convert their shares of Series E-1 preferred stock into 4,411,765 shares of Series E-3 preferred stock. The Company determined that the conversion of shares of preferred stock that occurred in February 2017 represented modifications of these securities for accounting purposes; however, the modifications did not result in the recognition of a deemed dividend for accounting purposes because the modifications did not result in a transfer of value from common stockholders to preferred stockholders. Pursuant to the terms of the amended Series F preferred stock purchase agreement, if the second tranche closing did not occur prior to the closing of the Company’s initial public offering of common stock, then, immediately prior to such closing, the purchasers of the Series F preferred stock would be required to purchase a number of shares of the Company’s common stock equal to $11,516 divided by the price per share paid by the public in the initial public offering in a concurrent private offering. This requirement to purchase shares immediately prior to the closing of the Company’s initial public offering could be waived in whole or in part by the Company’s board of directors. On June 15, 2017, the Company’s board of directors waived in whole, effective immediately prior to the closing of the Company’s IPO, the requirement of the purchasers of Series F preferred stock to purchase shares of the Company’s common stock in a concurrent private offering in connection with the Company’s initial public offering. Upon the closing of the Company’s IPO on July 5, 2017, all shares of the Redeemable Preferred Stock converted into an aggregate of 10,509,774 shares of common stock. As of June 30, 2018, there were no shares of Redeemable Preferred Stock authorized, issued or outstanding. |
Stock-Based Awards
Stock-Based Awards | 6 Months Ended |
Jun. 30, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Stock-Based Awards | 7. Stock-Based Awards 2017 Stock Incentive Plan The Company’s 2017 Stock Incentive Plan (the “2017 Plan”) was approved by the Company’s stockholders on June 16, 2017 and became effective on June 28, 2017. Under the 2017 Plan, the Company may grant incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, awards of restricted stock units and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors are eligible to receive awards under the 2017 Plan; however, incentive stock options may only be granted to employees. The 2017 Plan is administered by the board of directors or, at the discretion of the board of directors, by a committee of the board. The number of shares of common stock covered by options and the date those options become exercisable, type of options to be granted, exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the 2017 Plan with service-based vesting conditions generally vest over four years and may not have a duration in excess of ten years, although options have been granted with vesting terms of less than four years. The total number of shares of common stock that may be issued under the 2017 Plan was 2,579,341 as of June 30, 2018, of which 1,501,886 shares remained available for grant. The Company initially reserved During the six months ended June 30, 2018, pursuant to the terms of the 2017 Plan, the Company granted options to employees and directors to purchase 271,000 shares of common stock at a weighted average exercise price of $7.01 per share. Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards. The exercise price for stock options granted may not be less than the fair market value of the common stock as of the date of grant. 2017 Employee Stock Purchase Plan On June 16, 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which became effective on June 28, 2017. A total of 150,000 shares of common stock were initially reserved for issuance under this plan. The number of shares of common stock that may be issued under the 2017 ESPP will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 622,408 shares, (ii) 1% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. On January 1, 2018, the Company’s board of directors determined not to increase the number of shares of common stock that may be issued under the 2017 ESPP. 2016 Stock Incentive Plan The Company’s 2016 Stock Incentive Plan (the “2016 Plan”) provided for the Company to grant incentive stock options or nonqualified stock options, restricted stock, restricted stock units and other equity awards to employees, directors and consultants of the Company. The 2016 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the 2016 Plan with service-based vesting conditions vest over four years and expire after ten years. In connection with the IPO, the board of directors determined to grant no further awards under the 2016 Plan. No stock options or other awards have been made under the 2016 Plan since the adoption of the 2017 Plan. Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards under the 2017 Plan. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards under the 2017 Plan. 2006 Stock Incentive Plan The Company’s 2006 Stock Incentive Plan, as amended, (the “2006 Plan”) provided for the Company to grant incentive stock options or nonqualified stock options, restricted stock, restricted stock units and other equity awards to employees, directors and consultants of the Company. The 2006 Plan was administered by the board of directors or, at the discretion of the board of directors, by a committee of the board. The exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the 2006 Plan with service-based vesting conditions generally vest over four years and expire after ten years, although options have been granted with vesting terms of less than four years. The 2006 Plan expired in 2016. Since its expiration no further awards have been granted under the 2006 Plan. Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards under the 2017 Plan. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards under the 2017 Plan. Stock Option Valuation The assumptions that the Company used to determine the grant-date fair value of the stock options granted to employees and directors during the six months ended June 30, 2018 and 2017 were as follows, presented on a weighted average basis: Six Months Ended June 30, 2018 Six Months Ended June 30, 2017 Risk-free interest rate 2.75 % 2.19 % Expected term (in years) 6.2 6.1 Expected volatility 76.0 % 80.2 % Expected dividend yield 0 % 0 % Stock Options The following table summarizes the Company’s stock option activity since January 1, 2018: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in years) Outstanding at December 31, 2017 2,096,233 $ 8.02 8.0 $ 7,332 Granted 271,000 7.01 Exercised (13,584 ) 2.03 Forfeited (315,887 ) 9.06 Outstanding at June 30, 2018 2,037,762 $ 7.77 6.6 $ 875 Options exercisable at June 30, 2018 1,045,177 $ 5.73 4.1 $ 858 Options vested and expected to vest at June 30, 2018 2,004,599 $ 7.73 6.6 $ 875 Options exercisable at December 31, 2017 784,190 $ 4.71 6.0 $ 4,667 Options vested and expected to vest at December 31, 2017 2,030,629 $ 7.96 7.9 $ 7,198 The weighted average grant-date fair value of stock options granted during the six months ended June 30, 2018 and 2017 was $4.79 and $5.98, respectively. The aggregate fair value of stock options that vested during the six months ended June 30, 2018 and 2017 was $1,812 and $412, respectively. The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the six months ended June 30, 2018 and 2017 was $93 and $126, respectively. Stock-Based Compensation The Company recorded stock-based compensation expense related to stock options in the following expense categories of its statements of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Research and development expenses $ 240 $ 131 $ 510 $ 205 General and administrative expenses 1,093 142 1,591 264 $ 1,333 $ 273 $ 2,101 $ 469 As of June 30, 2018, the Company had an aggregate of $6,046 of unrecognized stock-based compensation expense, which it expects to recognize over a weighted average period of 2.8 years. In May 2018, the Company modified certain equity awards in connection with a separation agreement with its former Chief Executive Officer. The modification included acceleration of vesting of stock options to purchase 80,822 shares of common stock and an extension of the post-termination exercise period for vested options from 90 days to up to two years. In connection with this modification, the Company recorded an incremental compensation charge of $612 during the three and six months ended June 30, 2018. |
Net Loss per Share
Net Loss per Share | 6 Months Ended |
Jun. 30, 2018 | |
Earnings Per Share [Abstract] | |
Net Loss per Share | 8. Net Loss per Share Basic and diluted net loss per share attributable to common stockholders was calculated as follows : Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator: Net loss $ (9,491 ) $ (4,923 ) $ (17,079 ) $ (9,480 ) Accretion of redeemable convertible preferred stock to redemption value — (21 ) 0 (41 ) Net loss attributable to common stockholders $ (9,491 ) $ (4,944 ) $ (17,079 ) $ (9,521 ) Denominator: Weighted average common shares outstanding—basic and diluted. 14,737,236 450,495 14,734,775 441,661 Net loss per share attributable to common stockholders—basic and diluted $ (0.64 ) $ (10.98 ) $ (1.16 ) $ (21.56 ) The Company’s potential dilutive securities, which include stock options and redeemable convertible preferred stock, have been excluded from the computation of diluted net loss per share attributable to common stockholders whenever the effect of including them would be to reduce the net loss per share. In periods where there is a net loss, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The following potential shares of common stock, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Three and Six Months Ended June 30, 2018 2017 Stock options to purchase common stock 2,037,762 1,444,314 Redeemable convertible preferred stock (as converted to common stock) — 10,509,774 2,037,762 11,954,088 |
Commitments and Contingencies
Commitments and Contingencies | 6 Months Ended |
Jun. 30, 2018 | |
Commitments And Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | 9. Commitments and Contingencies Operating Lease Facility Leases On April 4, 2018, a lease agreement (the “Lease”) entered into between the Company and 480 Arsenal Group LLC became effective. The Lease is for approximately 18,609 square feet of office and lab space in Watertown, Massachusetts. The Lease has an initial term of eight years and provides the Company with an option to extend the Lease term for one additional five-year period. The future minimum rent commitment for the initial eight-year term is approximately $8,771. In addition to rent, the Lease requires the Company to pay additional amounts for taxes, insurance, maintenance and other operating expenses. The Company was required to provide a $568 security deposit, which the Company provided in the form of a letter of credit in the favor of the landlord which is included as non-current restricted cash on the balance sheet as of June 30, 2018. The Company is not the legal owner of the leased space. However, in accordance with ASC 840, Leases Additionally, construction costs incurred as part of the build-out and tenant improvements will be capitalized within property, plant and equipment, net. Rental payments made under the Lease will be allocated to imputed ground rent, interest expense and the build-to-suit facility lease obligation, based on the implicit rate of the build-to-suit facility lease obligation. The build-to-suit facility lease obligation was $3,345 as of June 30, 2018. 281 Albany Street In February 2010, the Company entered into an operating lease agreement for office and laboratory space in Cambridge, Massachusetts, which, as amended, expires in August 2018. Upon entering into the agreement, the Company was required to maintain a security deposit which was recorded as restricted cash on the Company’s balance sheet. The agreement requires future minimum lease payments for the year ending December 31, 2018 of $85. The Company recognizes rent expense on a straight-line basis over the lease period and has recorded deferred rent for rent expense incurred but not yet paid. Rental expense under operating leases totaled $211 and $120 for the three months ended June 30, 2018 and 2017, respectively and $339 and $239 for the six months ended June 30, 2018 and 2017, respectively. Intellectual Property Licenses Harvard and Dana-Farber Agreement In August 2006, the Company entered into an exclusive license agreement with President and Fellows of Harvard College (“Harvard”) and Dana-Farber Cancer Institute (“DFCI”). The agreement granted the Company an exclusive worldwide license, with the right to sublicense, under specified patents and patent applications to develop, obtain regulatory approval for and commercialize specified product candidates based on stapled peptides. Under the agreement, the Company is obligated to use commercially reasonable efforts to develop and commercialize one or more licensed products and to achieve specified milestone events by specified dates. In connection with entering into the agreement, the Company paid an upfront license fee and issued to Harvard and DFCI shares of its common stock. In February 2010, the agreement was amended and restated (the “Harvard/DFCI agreement”) under which additional patent rights were added to the scope of the license agreement and the annual license maintenance fees were increased. Under the Harvard/DFCI agreement, the Company is obligated to make aggregate milestones payments of up to $7,700 per licensed therapeutic product upon the Company’s achievement of specified clinical, regulatory and sales milestones with respect to such product and up to $700 per licensed diagnostic product upon the Company’s achievement of specified regulatory and sales milestones with respect to such product. In addition, the Company is obligated to pay royalties of low single-digit percentages on annual net sales of licensed products sold by the Company, its affiliates or its sublicensees. The royalties are payable on a product-by-product and country-by-country basis and may be reduced in specified circumstances. In addition, the agreement obligates the Company to pay a percentage, up to the mid-twenties, of fees received by the Company in connection with its sublicense of the licensed products. In accordance with the terms of the agreement, the Company’s sublicense payment obligations may be subject to specified reductions. The Harvard/DFCI agreement requires the Company to pay annual license maintenance fees of $145 each year. Any payments made in connection with the annual license maintenance fees will be credited against any royalties due. The Company As of June 30, 2018, the Company had not developed a commercial product using the licensed technologies and no royalties under the agreement had been paid or were due. Under the Harvard/DFCI agreement, the Company is responsible for all patent expenses related to the prosecution and maintenance of the licensed patents and applications in-licensed under the agreement as well as cost reimbursement of amounts incurred for all documented patent-related expenses. The agreement will expire on a product-by-product and country-by-country basis upon the last to expire of any valid patent claim pertaining to licensed products covered under the agreement. Umicore Agreement In December 2006, the Company entered into a license agreement with Materia, Inc. (“Materia”), under which it was granted a non-exclusive worldwide license, with the right to sublicense, under specified patent and patent applications to utilize Materia’s catalysts to develop, obtain regulatory approval for and commercialize specified peptides owned or controlled by Materia and the right to manufacture specified compositions owned or controlled by Materia. In February 2017, Materia assigned the license agreement (the “Umicore agreement”) to Umicore Precious Metals Chemistry USA, LLC (“Umicore”), and Umicore agreed to continue to supply the Company under the agreement. Under the Umicore agreement, the Company is obligated to make aggregate milestone payments to Umicore of up to $6,400 upon the Company’s achievement of specified clinical, regulatory and sales milestones with respect to each licensed product. In addition, the Company is obligated to pay tiered royalties ranging in the low single-digit percentages on annual net sales of licensed products sold by the Company or its sublicensees. The royalties are payable on a product-by-product and country-by-country basis, and may be reduced in specified circumstances. The Umicore agreement requires the Company to pay annual license fees of $50. The Company did not incur any license fees during the three and six months ended June 30, 2018 and 2017, respectively. In addition, the Company did not make any milestone payments during the three and six months ended June 30, 2018 and 2017. During the six months ended June 30, 2018, no milestones were achieved and no liabilities for additional milestone payments were recorded in the Company’s financial statements. The agreement expires upon the expiration of the Company’s obligation to pay royalties in each territory covered under the agreement. Scripps Agreement In October 2010, the Company entered into a patent license agreement (the “Scripps agreement”) with The Scripps Research Institute (“Scripps”) under which it was granted a license, with the right to sublicense, for the exclusive worldwide rights to utilize Scripps’ “Click” chemistry for therapeutics and non-exclusive worldwide rights for diagnostics with the Company’s stabilized peptide and protein technology platforms. Under the agreement, the Company is obligated to make aggregate milestone payments to Scripps of up to $1,900 for each licensed peptide product and up to $950 for each licensed protein product upon achieving of specified clinical, regulatory and commercial milestones. In addition, the Company is obligated to pay tiered royalties ranging in the low single-digit percentages on annual net sales of licensed products sold by the Company or its sublicensees. The royalties are payable on a product-by-product and country-by-country basis. The Scripps agreement requires the Company to pay annual license fees of $50. The Company did not incur any license fees during the three and six months ended June 30, 2018 and 2017, respectively. As of June 30, 2018, no milestones had been achieved and no liabilities for milestone payments had been recorded in the Company’s financial statements. As of June 30, 2018, the Company had not developed a commercial product using the licensed technologies and no royalties under the agreement had been paid or were due. The agreement expires upon expiration of the last of any patent rights covered under the agreement. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position, results of operations or cash flows, and it had not accrued any liabilities related to such obligations in its financial statements as of June 30, 2018 or December 31, 2017. |
Income Taxes
Income Taxes | 6 Months Ended |
Jun. 30, 2018 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | 10. Income Taxes The Company did not provide for any income taxes for the three and six months ended June 30, 2018 and 2017. The Company has evaluated the positive and negative evidence bearing upon the realizability of its U.S. net deferred tax assets. As required by the provisions of ASC 740, Income Taxes, management has determined that it is more-likely-than-not that the Company will not utilize the benefits of federal and state U.S. net deferred tax assets for financial reporting purposes. Accordingly, the net deferred tax assets are subject to a valuation allowance at June 30, 2018 and December 31, 2017. |
Summary of Significant Accoun17
Summary of Significant Accounting Policies (Policies) | 6 Months Ended |
Jun. 30, 2018 | |
Accounting Policies [Abstract] | |
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 of revenue and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock and stock-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates. |
Unaudited Interim Financial Information | Unaudited Interim Financial Information The accompanying unaudited condensed financial statements as of June 30, 2018 and for the six months ended June 30, 2018 and 2017 have been prepared by the Company, pursuant to the rules and regulations of the SEC for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 that was filed with the SEC on April 2, 2018. The unaudited interim condensed financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2018, the results of its operations for the three and six months ended June 30, 2018 and 2017 and its cash flows for the six months ended June 30, 2018 and 2017. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2018 and 2017 are unaudited. The results for the six months ended June 30, 2018 are not necessarily indicative of results to be expected for the year ending December 31, 2018, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2017 has been derived from the Company’s audited financial statements for the year ended December 31, 2017 previously filed with the SEC. |
Cash Equivalents | Cash Equivalents The Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents. Cash equivalents, which consist of money market accounts, corporate notes and commercial paper, are stated at fair value. |
Restricted Cash | Restricted Cash As of June 30, 2018, current restricted cash of $25 consisted entirely of cash deposited in a separate restricted bank account as a security deposit for the Company’s corporate credit cards. As of December 31, 2017, current restricted cash consisted of $25 of cash deposited in a separate restricted bank account as a security deposit for the Company’s corporate credit cards and $63 of cash deposited in a separate restricted bank account as a security deposit for the lease of the Company’s facility. As of June 30, 2018, non-current restricted cash consisted of $568 of cash deposited in a separate restricted bank account as a security deposit for |
Investments | Investments The Company classifies its available-for-sale investments as current assets on the balance sheet if they mature within one year from the balance sheet date. The Company classifies all of its investments as available-for-sale securities. The Company’s investments are measured and reported at fair value using quoted prices in active markets for similar securities or using other inputs that are observable or can be corroborated by observable market data. Unrealized gains and losses on available-for-sale securities are reported as accumulated other comprehensive income (loss), which is a separate component of stockholders’ equity (deficit). The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense) within the statements of operations and comprehensive loss. The Company evaluates its investments with unrealized losses for other-than-temporary impairment. When assessing investments for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other than temporary”, the Company reduces the investment to fair value through a charge to the statements of operations and comprehensive loss. No such adjustments were necessary during the periods presented. |
Fair Value Measurements | Fair Value Measurements Certain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable. • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and investments are carried at fair value, determined according to the fair value hierarchy described above (see Note 3). The carrying values of the Company’s accounts payable and accrued expenses approximate their fair value due to the short-term nature of these liabilities. |
Net Income (Loss) per Share | Net Income (Loss) per Share The Company follows the two-class method when computing net income (loss) per share as the Company has issued shares that meet the definition of participating securities. The two-class method determines net income (loss) per share for each class of common and participating securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to be allocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had been distributed. Basic net income (loss) per share attributable to common stockholders is computed by dividing the net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period. Diluted net income (loss) attributable to common stockholders is computed by adjusting income (loss) per share attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common stockholders is computed by dividing the diluted net income (loss) attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, including potential dilutive common shares. For purpose of this calculation, outstanding options to purchase common stock and shares of redeemable convertible preferred stock are considered potential dilutive common shares. The Company’s redeemable convertible preferred stock contractually entitled the holders of such shares to participate in dividends but contractually did not require the holders of such stock to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable to common stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive. |
Recently Adopted Accounting Pronouncements | Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers Revenue from Contracts with Customers , Revenue from Contract with Customers: Principal versus Agent Considerations Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. The adoption of these standards did not have an impact on the Company’s financial position, results of operations or cash flows as the Company does not currently have any revenue generating arrangements. In November 2016, the FASB issued ASU No. 2016-18, Restricted Cash Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments Compensation – Stock Compensation Scope of Modification Accounting |
Recently Issued Accounting Pronouncements | Recently Issued Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, Leases Leases Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption. |
Fair Value of Financial Assets
Fair Value of Financial Assets (Tables) | 6 Months Ended |
Jun. 30, 2018 | |
Fair Value Disclosures [Abstract] | |
Summary of Assets Measured at Fair Value on Recurring Basis | The following tables present information about the Company’s assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of June 30, 2018 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 8,975 $ — $ — $ 8,975 Commercial paper — 1,495 — 1,495 Investments: Corporate notes — 10,226 — 10,226 Commercial paper — 13,585 — 13,585 $ 8,975 $ 25,306 $ — $ 34,281 Fair Value Measurements as of December 31, 2017 using: Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 10,509 $ — $ — $ 10,509 Investments: Corporate notes — 25,710 — 25,710 Commercial paper — 13,179 — 13,179 $ 10,509 $ 38,889 $ — $ 49,398 |
Investments (Tables)
Investments (Tables) | 6 Months Ended |
Jun. 30, 2018 | |
Investments Debt And Equity Securities [Abstract] | |
Summary of Fair Value of Available for Sale Investments | As of June 30, 2018 and December 31, 2017, the fair value of available-for-sale investments by type of security was as follows: June 30, 2018 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Investments: Corporate notes $ 10,235 $ — $ (9 ) $ 10,226 Commercial paper 13,588 — (3 ) 13,585 $ 23,823 $ — $ (12 ) $ 23,811 December 31, 2017 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Investments: Corporate notes $ 25,733 $ — $ (23 ) $ 25,710 Commercial paper 13,189 — (10 ) 13,179 $ 38,922 $ — $ (33 ) $ 38,889 |
Accrued Expenses and Other Cu20
Accrued Expenses and Other Current Liabilities (Tables) | 6 Months Ended |
Jun. 30, 2018 | |
Payables And Accruals [Abstract] | |
Summary of Accrued Expenses and Other Current Liabilities | Accrued expenses and other current liabilities consisted of the following: June 30, 2018 December 31, 2017 External research and development services $ 1,694 $ 1,284 Construction-in-progress related to facility lease obligation 1,020 — Payroll and payroll-related costs 846 1,120 Accrued severance 508 — Professional fees 458 536 Other 255 351 $ 4,781 $ 3,291 |
Stock-Based Awards (Tables)
Stock-Based Awards (Tables) | 6 Months Ended |
Jun. 30, 2018 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |
Valuation Assumptions of Stock Options Granted | The assumptions that the Company used to determine the grant-date fair value of the stock options granted to employees and directors during the six months ended June 30, 2018 and 2017 were as follows, presented on a weighted average basis: Six Months Ended June 30, 2018 Six Months Ended June 30, 2017 Risk-free interest rate 2.75 % 2.19 % Expected term (in years) 6.2 6.1 Expected volatility 76.0 % 80.2 % Expected dividend yield 0 % 0 % |
Summary of Stock Option Activity | The following table summarizes the Company’s stock option activity since January 1, 2018: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (in years) Outstanding at December 31, 2017 2,096,233 $ 8.02 8.0 $ 7,332 Granted 271,000 7.01 Exercised (13,584 ) 2.03 Forfeited (315,887 ) 9.06 Outstanding at June 30, 2018 2,037,762 $ 7.77 6.6 $ 875 Options exercisable at June 30, 2018 1,045,177 $ 5.73 4.1 $ 858 Options vested and expected to vest at June 30, 2018 2,004,599 $ 7.73 6.6 $ 875 Options exercisable at December 31, 2017 784,190 $ 4.71 6.0 $ 4,667 Options vested and expected to vest at December 31, 2017 2,030,629 $ 7.96 7.9 $ 7,198 |
Summary of Stock Based Compensation Expense | The Company recorded stock-based compensation expense related to stock options in the following expense categories of its statements of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Research and development expenses $ 240 $ 131 $ 510 $ 205 General and administrative expenses 1,093 142 1,591 264 $ 1,333 $ 273 $ 2,101 $ 469 |
Net Loss per Share (Tables)
Net Loss per Share (Tables) | 6 Months Ended |
Jun. 30, 2018 | |
Earnings Per Share [Abstract] | |
Basic and Diluted Net Loss per Share Attributable to Common Stockholders | Basic and diluted net loss per share attributable to common stockholders was calculated as follows : Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Numerator: Net loss $ (9,491 ) $ (4,923 ) $ (17,079 ) $ (9,480 ) Accretion of redeemable convertible preferred stock to redemption value — (21 ) 0 (41 ) Net loss attributable to common stockholders $ (9,491 ) $ (4,944 ) $ (17,079 ) $ (9,521 ) Denominator: Weighted average common shares outstanding—basic and diluted. 14,737,236 450,495 14,734,775 441,661 Net loss per share attributable to common stockholders—basic and diluted $ (0.64 ) $ (10.98 ) $ (1.16 ) $ (21.56 ) |
Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share | The following potential shares of common stock, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Three and Six Months Ended June 30, 2018 2017 Stock options to purchase common stock 2,037,762 1,444,314 Redeemable convertible preferred stock (as converted to common stock) — 10,509,774 2,037,762 11,954,088 |
Nature of the Business and Ba23
Nature of the Business and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands | Jul. 05, 2017USD ($)$ / sharesshares | Jun. 16, 2017 | Jun. 30, 2018USD ($)shares | Jun. 30, 2017USD ($) | Dec. 31, 2017USD ($) |
Class of Stock [Line Items] | |||||
Offering expenses | $ 419 | ||||
Redeemable convertible preferred stock, outstanding (in shares) | shares | 0 | ||||
Proceeds from collaboration agreement | $ 34,910 | ||||
Cash, cash equivalents and investments | 35,791 | ||||
Accumulated deficit | (154,025) | $ (136,946) | |||
Preferred Stock [Member] | |||||
Class of Stock [Line Items] | |||||
Proceeds from sales of stock | $ 131,211 | ||||
IPO [Member] | Redeemable Convertible Preferred Stock [Member] | |||||
Class of Stock [Line Items] | |||||
Redeemable convertible preferred stock, outstanding (in shares) | shares | 106,114,520 | ||||
Common Stock [Member] | IPO [Member] | |||||
Class of Stock [Line Items] | |||||
Reverse stock split description | one-for-9.937 reverse stock split | ||||
Reverse stock split ratio | 0.100634 | ||||
Stock issued and sold | shares | 3,750,000 | ||||
Share price | $ / shares | $ 15 | ||||
Net proceeds from issuance of initial public offering | $ 50,009 | ||||
Underwriting discounts and commissions incurred | 3,937 | ||||
Offering expenses | $ 2,304 | ||||
Number of common shares issued on conversion of redeemable convertible preferred stock | shares | 10,509,774 |
Summary of Significant Accoun24
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 |
Summary Of Significant Accounting Policies [Line Items] | ||
Restricted cash, current | $ 25 | $ 88 |
Restricted cash, non-current | 568 | |
Security Deposit Related to Credit Card Accounts [Member] | ||
Summary Of Significant Accounting Policies [Line Items] | ||
Restricted cash, current | 25 | 25 |
Security Deposit Related to Lease Facility [Member] | ||
Summary Of Significant Accounting Policies [Line Items] | ||
Restricted cash, current | $ 63 | |
Restricted cash, non-current | $ 568 |
Fair Value of Financial Asset25
Fair Value of Financial Assets - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) - Recurring [Member] - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Total assets | $ 34,281 | $ 49,398 |
Corporate Notes [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Investments | 10,226 | 25,710 |
Commercial Paper [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Investments | 13,585 | 13,179 |
Level 1 [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Total assets | 8,975 | 10,509 |
Level 2 [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Total assets | 25,306 | 38,889 |
Level 2 [Member] | Corporate Notes [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Investments | 10,226 | 25,710 |
Level 2 [Member] | Commercial Paper [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Investments | 13,585 | 13,179 |
Money Market Funds [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Cash equivalents | 8,975 | 10,509 |
Money Market Funds [Member] | Level 1 [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Cash equivalents | 8,975 | $ 10,509 |
Commercial Paper [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Cash equivalents | 1,495 | |
Commercial Paper [Member] | Level 2 [Member] | ||
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | ||
Cash equivalents | $ 1,495 |
Fair Value of Financial Asset26
Fair Value of Financial Assets - Additional Information (Detail) - USD ($) | 6 Months Ended | 12 Months Ended |
Jun. 30, 2018 | Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | ||
Available-for-sale investments, maximum contractual maturity period | 1 year | |
Fair value, assets transfers from Level 1 to Level 2 | $ 0 | $ 0 |
Fair value, assets transfers from Level 2 to Level 1 | 0 | 0 |
Fair Value, assets transfers into (out of) Level 3 | $ 0 | $ 0 |
Investments - Summary of Fair V
Investments - Summary of Fair Value of Available for Sale Investments (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 |
Schedule of Available-for-sale Securities [Line Items] | ||
Investments, Amortized Cost | $ 23,823 | $ 38,922 |
Investments, Gross Unrealized Loss | (12) | (33) |
Investments, Fair Value | 23,811 | 38,889 |
Corporate Notes [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Investments, Amortized Cost | 10,235 | 25,733 |
Investments, Gross Unrealized Loss | (9) | (23) |
Investments, Fair Value | 10,226 | 25,710 |
Commercial Paper [Member] | ||
Schedule of Available-for-sale Securities [Line Items] | ||
Investments, Amortized Cost | 13,588 | 13,189 |
Investments, Gross Unrealized Loss | (3) | (10) |
Investments, Fair Value | $ 13,585 | $ 13,179 |
Accrued Expenses and Other Cu28
Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 |
Payables And Accruals [Abstract] | ||
External research and development services | $ 1,694 | $ 1,284 |
Construction-in-progress related to facility lease obligation | 1,020 | |
Payroll and payroll-related costs | 846 | 1,120 |
Accrued severance | 508 | |
Professional fees | 458 | 536 |
Other | 255 | 351 |
Total accrued expenses and other current liabilities | $ 4,781 | $ 3,291 |
Redeemable Convertible Prefer29
Redeemable Convertible Preferred Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | Jul. 05, 2017 | Feb. 28, 2017 | Jun. 30, 2018 | Jun. 30, 2017 |
Temporary Equity [Line Items] | ||||
Preferred stock issuance costs, paid | $ 419 | |||
Redeemable convertible preferred stock, authorized (in shares) | 0 | |||
Redeemable convertible preferred stock, issued (in shares) | 0 | |||
Redeemable convertible preferred stock, outstanding (in shares) | 0 | |||
IPO [Member] | ||||
Temporary Equity [Line Items] | ||||
Initial public offering closing date | Jul. 5, 2017 | |||
IPO [Member] | Common Stock [Member] | ||||
Temporary Equity [Line Items] | ||||
Preferred stock shares issued, price per share | $ 15 | |||
Preferred stock issuance costs, paid | $ 2,304 | |||
Number of common shares issued on conversion of redeemable convertible preferred stock | 10,509,774 | |||
Series F Redeemable Convertible Preferred Stock [Member] | ||||
Temporary Equity [Line Items] | ||||
Preferred stock shares issued | 483,501 | |||
Preferred stock shares issued, price per share | $ 1.36 | |||
Proceeds from issuance of redeemable convertible preferred stock | $ 626 | |||
Preferred stock issuance costs, paid | 32 | |||
Stock purchase agreement, aggregate purchase price | $ 11,516 | |||
Series E-1 Redeemable Convertible Preferred Stock [Member] | ||||
Temporary Equity [Line Items] | ||||
Preferred stock shares converted | 4,411,765 | |||
Series E-3 Redeemable Convertible Preferred Stock [Member] | ||||
Temporary Equity [Line Items] | ||||
Preferred stock shares issued on conversion | 4,411,765 |
Stock-Based Awards - Additional
Stock-Based Awards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | Jun. 16, 2017 | May 31, 2018 | Jun. 30, 2018 | Jun. 30, 2018 | Jun. 30, 2017 | Jan. 01, 2018 |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Common stock, weighted average exercise price per share | $ 7.01 | |||||
Weighted average grant-date fair value of stock options | $ 4.79 | $ 5.98 | ||||
Aggregate fair value of stock options vested | $ 1,812 | $ 412 | ||||
Aggregate intrinsic value of stock options exercised | 93 | $ 126 | ||||
Aggregate unrecognized stock-based compensation expense | $ 6,046 | $ 6,046 | ||||
Unrecognized stock-based compensation expense, weighted average period expects for recognition | 2 years 9 months 18 days | |||||
Chief Executive Officer [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Acceleration of vesting of stock options to purchase shares of common stock | 80,822 | |||||
Incremental compensation charge | $ 612 | $ 612 | ||||
2017 Stock Incentive Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 4 years | |||||
Number of shares, available for grant | 2,579,341 | 2,579,341 | ||||
Number of shares remained available for grant | 1,501,886 | 1,501,886 | ||||
Stock reserved for future issuance | 1,244,816 | 1,244,816 | 588,953 | |||
Maximum annual increase in common stock reserved for future issuance | 1,244,816 | |||||
Percentage of common stock shares outstanding | 4.00% | |||||
Options to purchase | 271,000 | |||||
Common stock, weighted average exercise price per share | $ 7.01 | |||||
2016 Stock Incentive Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 4 years | |||||
Stock option expiration period | 10 years | |||||
2016 Stock Incentive Plan [Member] | Common Stock [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock reserved for future issuance | 424,601 | 424,601 | ||||
2017 Employee Stock Purchase Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock reserved for future issuance | 150,000 | 0 | ||||
Maximum annual increase in common stock reserved for future issuance | 622,408 | |||||
Percentage of common stock shares outstanding | 1.00% | |||||
Stock incentive plan description | On June 16, 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which became effective on June 28, 2017. A total of 150,000 shares of common stock were initially reserved for issuance under this plan. The number of shares of common stock that may be issued under the 2017 ESPP will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 622,408 shares, (ii) 1% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. On January 1, 2018, the Company’s board of directors determined not to increase the number of shares of common stock that may be issued under the 2017 ESPP. | |||||
2006 Stock Incentive Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 4 years | |||||
Stock option expiration period | 10 years | |||||
Stock incentive plan termination year | 2,016 | |||||
Maximum [Member] | Chief Executive Officer [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 2 years | |||||
Maximum [Member] | 2017 Stock Incentive Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 4 years | |||||
Stock option expiration period | 10 years | |||||
Maximum [Member] | 2006 Stock Incentive Plan [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 4 years | |||||
Minimum [Member] | Chief Executive Officer [Member] | ||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||||
Stock option granted vesting period | 90 days |
Stock-Based Awards - Valuation
Stock-Based Awards - Valuation Assumptions of Stock Options Granted (Detail) | 6 Months Ended | |
Jun. 30, 2018 | Jun. 30, 2017 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | ||
Risk-free interest rate | 2.75% | 2.19% |
Expected term (in years) | 6 years 2 months 12 days | 6 years 1 month 6 days |
Expected volatility | 76.00% | 80.20% |
Expected dividend yield | 0.00% | 0.00% |
Stock-Based Awards - Summary of
Stock-Based Awards - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands | 6 Months Ended | 12 Months Ended |
Jun. 30, 2018 | Dec. 31, 2017 | |
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | ||
Number of Shares, Beginning balance | 2,096,233 | |
Number of Shares, Granted | 271,000 | |
Number of Shares, Exercised | (13,584) | |
Number of Shares, Forfeited | (315,887) | |
Number of Shares, Ending balance | 2,037,762 | 2,096,233 |
Number of Shares, Options exercisable | 1,045,177 | 784,190 |
Number of Shares, Options vested and expected to vest | 2,004,599 | 2,030,629 |
Weighted Average Exercise Price, Beginning balance | $ 8.02 | |
Weighted Average Exercise Price, Granted | 7.01 | |
Weighted Average Exercise Price, Exercised | 2.03 | |
Weighted Average Exercise Price, Forfeited | 9.06 | |
Weighted Average Exercise Price, Ending balance | 7.77 | $ 8.02 |
Weighted Average Exercise Price, Options exercisable | 5.73 | 4.71 |
Weighted Average Exercise Price, Options vested and expected to vest | $ 7.73 | $ 7.96 |
Weighted-Average Remaining Contractual Term, Outstanding | 6 years 7 months 6 days | 8 years |
Weighted Average Remaining Contractual Term, Options exercisable | 4 years 1 month 6 days | 6 years |
Weighted Average Remaining Contractual Term, Options vested and expected to vest | 6 years 7 months 6 days | 7 years 10 months 24 days |
Aggregate Intrinsic Value | $ 875 | $ 7,332 |
Aggregate Intrinsic Value, Options exercisable | 858 | 4,667 |
Aggregate Intrinsic Value, Options vested and expected to vest | $ 875 | $ 7,198 |
Stock-Based Awards - Summary 33
Stock-Based Awards - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Stock-based compensation expense | $ 1,333 | $ 273 | $ 2,101 | $ 469 |
Research and Development [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Stock-based compensation expense | 240 | 131 | 510 | 205 |
General and Administrative [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Stock-based compensation expense | $ 1,093 | $ 142 | $ 1,591 | $ 264 |
Net Loss per Share - Basic and
Net Loss per Share - Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Numerator: | ||||
Net loss | $ (9,491) | $ (4,923) | $ (17,079) | $ (9,480) |
Accretion of redeemable convertible preferred stock to redemption value | (21) | 0 | (41) | |
Net loss attributable to common stockholders | $ (9,491) | $ (4,944) | $ (17,079) | $ (9,521) |
Denominator: | ||||
Weighted average common shares outstanding—basic and diluted | 14,737,236 | 450,495 | 14,734,775 | 441,661 |
Net loss per share attributable to common stockholders—basic and diluted | $ (0.64) | $ (10.98) | $ (1.16) | $ (21.56) |
Net Loss per Share - Summary of
Net Loss per Share - Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share (Detail) - shares | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Potential common shares excluded from calculation of diluted net loss per share | 2,037,762 | 11,954,088 | 2,037,762 | 11,954,088 |
Redeemable Convertible Preferred Stock [Member] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Potential common shares excluded from calculation of diluted net loss per share | 10,509,774 | 10,509,774 | ||
Stock Options to Purchase Common Stock [Member] | ||||
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
Potential common shares excluded from calculation of diluted net loss per share | 2,037,762 | 1,444,314 | 2,037,762 | 1,444,314 |
Commitments and Contingencies -
Commitments and Contingencies - Additional Information (Detail) | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended | 96 Months Ended | 102 Months Ended | |||||
Oct. 31, 2010USD ($) | Feb. 28, 2010USD ($) | Jun. 30, 2018USD ($) | Jun. 30, 2017USD ($) | Jun. 30, 2018USD ($)Milestone | Jun. 30, 2017USD ($) | Dec. 31, 2016USD ($) | Dec. 31, 2017USD ($) | Jun. 30, 2018USD ($) | Apr. 04, 2018USD ($)ft² | Dec. 31, 2006USD ($) | |
Other Commitments [Line Items] | |||||||||||
Property and equipment, net | $ 4,123,000 | $ 4,123,000 | $ 154,000 | $ 4,123,000 | |||||||
Harvard and Dana-Farber Agreement [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Milestone payments | 0 | $ 0 | $ 0 | $ 0 | |||||||
Milestones achieved | Milestone | 0 | ||||||||||
Additional liabilities for milestone payments | 0 | $ 0 | 0 | ||||||||
Non-refundable cash payment | $ 4,428,000 | 4,573,000 | |||||||||
Payments for royalties | 0 | ||||||||||
Harvard and Dana-Farber Agreement [Member] | Therapeutic Product [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Aggregate milestones payments | $ 7,700,000 | ||||||||||
Harvard and Dana-Farber Agreement [Member] | Diagnostic Product [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Aggregate milestones payments | 700,000 | ||||||||||
Harvard and Dana-Farber Agreement [Member] | License and Maintenance [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | $ 145,000 | ||||||||||
Harvard and Dana-Farber Agreement [Member] | License [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | 145,000 | 145,000 | |||||||||
Umicore Agreement [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Aggregate milestones payments | $ 6,400,000 | ||||||||||
Milestone payments | 0 | 0 | $ 0 | 0 | |||||||
Milestones achieved | Milestone | 0 | ||||||||||
Additional liabilities for milestone payments | 0 | $ 0 | 0 | ||||||||
Umicore Agreement [Member] | License and Maintenance [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | $ 50,000 | ||||||||||
Umicore Agreement [Member] | License [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | 0 | 0 | $ 0 | 0 | |||||||
Scripps Agreement [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Milestones achieved | Milestone | 0 | ||||||||||
Additional liabilities for milestone payments | 0 | $ 0 | 0 | ||||||||
Payments for royalties | 0 | ||||||||||
Scripps Agreement [Member] | License and Maintenance [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | $ 50,000 | ||||||||||
Scripps Agreement [Member] | License [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Annual license maintenance fees | 0 | 0 | 0 | 0 | |||||||
Scripps Agreement [Member] | Peptide Product [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Aggregate milestones payments | 1,900,000 | ||||||||||
Scripps Agreement [Member] | Protein Product [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Aggregate milestones payments | $ 950,000 | ||||||||||
Letter of Credit [Member] | Non-current Restricted Cash [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Security deposit provided to landlord | 568,000 | 568,000 | 568,000 | ||||||||
Cambridge, Massachusetts [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Rental expense under operating leases | 211,000 | $ 120,000 | 339,000 | $ 239,000 | |||||||
Build-to-suit Facility [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Property and equipment, net | 3,719,000 | 3,719,000 | 3,719,000 | ||||||||
Lease obligation | 3,345,000 | $ 3,345,000 | 3,345,000 | ||||||||
Lease Agreements [Member] | Office and Lab Space [Member] | Watertown, Massachusetts [Member] | 480 Arsenal Group LLC [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Area of land | ft² | 18,609 | ||||||||||
Lease initial term | 8 years | ||||||||||
Lease option to extend, description | The Lease has an initial term of eight years and provides the Company with an option to extend the Lease term for one additional five-year period. | ||||||||||
Lease extension term | 5 years | ||||||||||
Future minimum rent commitment | $ 8,771,000 | ||||||||||
Operating Lease Agreement [Member] | Cambridge, Massachusetts [Member] | |||||||||||
Other Commitments [Line Items] | |||||||||||
Operating lease expiration | 2018-08 | ||||||||||
Future minimum lease payments, 2018 | $ 85,000 | $ 85,000 | $ 85,000 |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended | ||
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
Income Tax Disclosure [Abstract] | ||||
Income tax expense (benefit) | $ 0 | $ 0 | $ 0 | $ 0 |