Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2016
Summary of Significant Accounting Policies
Use of Estimates	Use of Estimates The preparation of condensed financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed financial statements and accompanying notes. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of deposit to be cash equivalents.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s condensed financial instruments include principally cash and cash equivalents, other current assets, accounts payable, accrued liabilities and debt. The carrying amounts for these condensed financial instruments reported in the balance sheets approximate their fair values. See Note 11 — Fair Value Measurements, for further discussion of fair value.
General and Administrative Expenses	General and Administrative Expenses General and administrative expenses consist primarily of personnel‑related costs, including salaries and share‑based compensation costs, for personnel in functions not directly associated with research and development activities. Other significant costs include legal fees related to intellectual property and corporate matters and professional fees for accounting and other services.
Research and Development Expenses	Research and Development Expenses Research and development expenses consist of costs incurred in performing research and development activities, including compensation for research and development employees, costs associated with preclinical studies and trials, regulatory activities, manufacturing activities to support clinical activities, license fees, non‑legal patent costs, fees paid to external service providers that conduct certain research and development, clinical costs and an allocation of overhead expenses. Research and development costs are expensed as incurred.
Acquired In-Process Research and Development Expenses	Acquired In‑Process Research and Development Expenses The Company includes costs to acquire or in‑license product candidates in acquired in‑process research and development expenses. The Company has acquired the right to develop and commercialize its product candidate gemcabene. These costs are immediately expensed provided that the payments do not also represent processes or activities that would constitute a “business” as defined under GAAP or provided that the product candidate has not achieved regulatory approval for marketing and, and absent obtaining such approval, has no alternative future use. Royalties owed on future sales of any licensed product will be expensed in the period the related revenues are recognized.
Income Taxes	Income Taxes The Company utilizes the liability method of accounting for income taxes as required by Accounting Standards Codification (ASC) 740, Income Taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and the tax basis of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. Currently, there is no provision for income taxes, as the Company has incurred operating losses to date, and a full valuation allowance has been provided on the net deferred tax assets. MLT was treated as a partnership for federal and state income tax purposes. Accordingly, no provision was made for income taxes for periods prior to November 1, 2014, since the Company’s net loss (subject to certain limitations) was passed through to the income tax returns of its members. Upon incorporation on October 30, 2014, the Company became taxed as a corporation.
Share-Based Compensation	Share‑Based Compensation The Company accounts for share‑based compensation in accordance with the provisions of ASC 718, Compensation — Stock Compensation (ASC 718). Accordingly, compensation costs related to equity instruments granted are recognized at the grant‑date fair value. Additionally, under the provisions of ASC 718, the Company is required to include an estimate of the number of awards that will be forfeited in calculating compensation costs, which are recognized over the requisite service period of the awards (typically the vesting period of the awards). Share‑based compensation arrangements to non‑employees are accounted for in accordance with the applicable provisions of ASC 718 and ASC 505, Equity, using a fair value approach. The compensation costs of these arrangements are subject to re‑measurement as the equity instruments vest and are recognized as expense over the related service period (typically the vesting period of the awards).
Common Stock Valuation	Common Stock Valuation Due to the absence of an active market for the Company’s common stock, the Company utilized methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately‑Held Company Equity Securities Issued as Compensation, to estimate the fair value of its common stock. The valuation methodology includes estimates and assumptions that require the Company’s judgment. These estimates and assumptions include a number of objective and subjective factors, including external market conditions affecting the biopharmaceutical industry sector, and the likelihood of achieving a liquidity event, such as an IPO or sale. Significant changes to the key assumptions used in the valuations could result in different fair values of common stock at each valuation date.
Convertible Preferred Stock	Convertible Preferred Stock On March 31, 2015, the Company issued 745,637 shares of Series A convertible preferred stock (the Series A preferred stock). The Series A preferred stock is classified outside of permanent equity, in mezzanine equity, on the Company’s condensed balance sheet. The Company initially records preferred stock that may be redeemed at the option of the holder, or based on the occurrence of events outside of the Company’s control, at the value of the proceeds received. Subsequently, if it is probable that the preferred stock will become redeemable, the Company recognizes changes in the redemption value immediately as they occur and adjusts the carrying amount of the instrument to equal the redemption value at the end of each reporting period. If it is not probable that the preferred stock will become redeemable, the Company does not adjust the carrying value. In the absence of retained earnings, these charges are recorded against additional paid‑in‑capital, if any, and then to accumulated deficit. See Note 7 — Convertible Series A Preferred Stock for further discussion.
Segment Information	Segment Information Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and assessing performance. The Company’s chief operating decision maker is its Chief Executive Officer. The Company’s Chief Executive Officer views the Company’s operations and manages its business in one operating segment, which is the business of development and commercialization of therapeutics for the treatment of dyslipidemia, a serious medical condition that increases the risk of life threatening cardiovascular disease. Accordingly, the Company has a single reporting segment.
Jumpstart Our Business Startups Act Accounting Election	Jumpstart Our Business Startups Act Accounting Election As an emerging growth company under the Jumpstart Our Business Startups Act (JOBS Act), the Company is eligible to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies. The Company has irrevocably elected not to avail itself of this exemption and, therefore, will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2015, the FASB issued ASU 2015‑17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (ASU 2015‑17). The new guidance simplifies the presentation of deferred income taxes by requiring that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. ASU 2015‑17 applies to all entities that present a classified statement of financial position. The current requirement that deferred tax liabilities and assets of a tax‑paying component of an entity be offset and presented as a single amount is not affected by this ASU. For public entities, ASU 2015‑17 is effective for financial statements issued for annual periods beginning after December 15, 2016 with earlier application permitted. The new guidance may be applied either prospectively or retrospectively to all periods presented. The Company adopted this standard effective April 1, 2016 on a retrospective basis for each period presented. The adoption of this standard did not have a material impact on the Company’s financial statements. In January 2016, the FASB issued ASU No. 2016‑01, Financial Instruments — Overall: Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance affects the accounting for equity investments, financial liabilities under the fair value option and the presentation and disclosure requirements of financial instruments. The guidance is effective in the first quarter of fiscal 2019. Early adoption is permitted for the accounting guidance on financial liabilities under the fair value option. The Company is currently evaluating the impact of the new guidance on its financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The objective of this update is to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those annual periods and is to be applied utilizing a modified retrospective approach. The Company is currently evaluating the new guidance to determine the impact it may have on its financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment award transactions including: income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. This ASU is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the requirements of the new guidance and has not yet determined its impact on the Company’s financial statements.