Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation and Use of Estimates The consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and include the accounts of the Company and its wholly owned subsidiaries.
Principles of Consolidation	All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	The preparation of financial statements requires that management make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and related disclosures. Actual results could differ materially from those estimates.
Reclassification	Certain amounts previously reported in the financial statements have been reclassified to conform to the current year presentation. Such reclassifications did not affect net loss, shareholders’ equity or cash flows.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with a maturity from the date of purchase of less than three months to be cash equivalents. The carrying value of the Company’s money market funds is included in cash equivalents and approximates the fair value.
Concentration of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents. The Company invests excess cash in money market accounts. This investment strategy is consistent with the Company’s policy to ensure safety of principal and maintain liquidity.
Property and Equipment	Property and Equipment Property and equipment is stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which range from two to seven years. Amortization of leasehold improvements is recorded over the shorter of the lease term or the estimated useful life of the related assets. Maintenance and repairs are charged to operating expense as incurred. When assets are sold, or otherwise disposed of, the cost and related accumulated depreciation are removed from the accounts, and any gain or loss is included in operating expense. Lease incentives are amortized on a straight-line basis over the lease term as a reduction to rent expense. Leasehold improvements are capitalized and amortized over the shorter of the lease term or expected useful lives.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when all of the following criteria are met: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services have been rendered; (3) the seller’s price to the buyer is fixed or determinable; and (4) collectibility is reasonably assured. The Company has recognized revenue from payments received under a services agreement with a related party. Under the terms of this services agreement, the Company receives payments from this related party for research and development services that the Company provides at a negotiated, arms-length rate.
Research and Development Expenses	Research and Development Expense Research and development expense includes salaries and benefits, facilities and other overhead costs, research-related manufacturing costs, contract service and clinical and preclinical-related service costs performed by clinical research organizations, research institutions and other outside service providers. Research and development expense is expensed as incurred when these expenditures relate to the Company’s research and development efforts and have no alternative future uses. In accordance with certain research and development agreements, the Company is obligated to make certain upfront payments upon execution of the agreement. Advance payments, including nonrefundable amounts, for materials or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized as an expense as the related goods are delivered or the related services are performed. Acquisition or milestone payments that the Company makes in connection with in-licensed technology are expensed as incurred when there is uncertainty in receiving future economic benefits from the licensed technology. The Company considers the future economic benefits from the licensed technology to be uncertain until such licensed technology is incorporated into products that are approved for marketing by the FDA or when other significant risk factors are abated. For accounting purposes, management has viewed future economic benefits for all of the Company’s licensed technology to be uncertain.
Clinical Trial Expenses	Clinical Trial Expenses Payments in connection with the Company’s clinical trials are often made under contracts with multiple contract research organizations that conduct and manage clinical trials on the Company’s behalf. The financial terms of these contracts are subject to negotiation, vary from contract to contract and may result in uneven payment flows. Generally, these contracts set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. Payments under these contracts depend on factors such as the successful enrollment or treatment of patients or the completion of other clinical trial milestones. The Company amortizes prepaid clinical trial costs to expense based on estimates regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Expenses related to clinical trials are accrued based on estimates regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the contracted amounts are modified, the accruals are modified accordingly on a prospective basis. Revisions in the scope of a contract are charged to research and development expense in the period in which the facts that give rise to the revision occur.
Patent Costs	Patent Costs Legal costs in connection with approved patents and patent applications are expensed as incurred, as recoverability of such expenditures is uncertain. These costs are recorded in general and administrative expense in the consolidated statements of operations.
Share-based Compensation	Share-based Compensation The Company accounts for share-based payment arrangements in accordance with Accounting Standards Codification (ASC) 718, Compensation - Stock Compensation and ASC 505-50, Equity - Equity Based Payments to Non-Employees, which requires the recognition of compensation expense, using a fair-value based method, for all costs related to share-based payments, including stock options and restricted stock awards. These standards require companies to estimate the fair value of share-based payment awards on the date of the grant using an option-pricing model. The Company has elected to account for forfeitures as they occur.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method. Deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts and the income tax basis of assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates applicable to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is applied against any deferred tax asset if, based on available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. For uncertain tax positions that meet a “more likely than not” threshold, the Company recognizes the benefit of uncertain tax positions in the consolidated financial statements. The Company’s practice is to recognize interest and penalties, if any, related to uncertain tax positions in income tax expense in the consolidated statements of operations.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated based on the weighted-average number of common shares outstanding, excluding unvested restricted stock awards. Diluted net loss per share is calculated using the weighted-average number of common shares outstanding plus common stock equivalents. Convertible preferred stock, stock options, warrants and unvested restricted stock awards are considered common stock equivalents and are included in the calculation of diluted net loss per share using the treasury stock method when their effect is dilutive. Common stock equivalents are excluded from the calculation of diluted net loss per share when their effect is anti-dilutive.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as a change in equity during a period from transactions and other events and circumstances from non-owner sources.
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. Management views its operations and manages its business in one operating segment.
Fair Value Measurement	Fair Value Measurements The Company follows the provisions of ASC 820-10, Fair Value Measurements and Disclosures, which defines fair value, establishes a framework for measuring fair value in GAAP and requires certain disclosures about fair value measurements. Broadly, the ASC 820-10 framework clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820-10 establishes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value as follows: Level 1) observable inputs such as quoted prices in active markets; Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and Level 3) unobservable inputs in which there is little or no market data, which require us to develop our own assumptions. The hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. Cash equivalents consist of money market accounts with maturities of 90 days or less. Due to the high ratings and short-term nature of these funds, the Company considers the inputs to the value of all cash and cash equivalents as Level 1. The Company’s consolidated financial instruments include cash and cash equivalents, prepaid expenses, accounts payable and accrued expenses. The carrying amounts reported in the balance sheets for cash equivalents, prepaid expenses, accounts payable and accrued expenses approximate fair values because of the short-term nature of these instruments.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standard Update (ASU) 2017-09, Compensation - Stock Compensation (Topic 718), Scope of Modification Accounting. The new standard clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. ASU 2017-09 will be effective for the Company in the first quarter of 2018. Early adoption is permitted, including adoption in an interim period for which financial statements have not yet been issued. The Company plans to adopt the ASU in the first quarter of 2018 and expects the standard to have no material impact on the Company’s financial position or results of operations. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The new standard update clarifies the presentation of restricted cash and cash equivalents, and requires companies to include restricted cash and cash equivalents in the beginning and ending cash and cash equivalents on the statement of cash flows. Additional disclosures will be required to describe the amount and detail of the restriction by balance sheet line item. ASU 2016-18 will be effective for the Company in the first quarter of 2018. The Company plans to adopt the ASU in the first quarter of 2018, which will require inclusion of the Company’s restricted cash balances in cash and cash equivalents on the statement of cash flows with retrospective application of each prior period presented. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The new standard requires lessees to recognize most leases on their balance sheets as lease liabilities with corresponding right-of-use assets and eliminates certain real estate-specific provisions. ASU 2016-02 will be effective for the Company in the first quarter of 2019 and will be adopted with modified retrospective application for the Company's new 10-year lease agreement for its corporate headquarters, which commenced October 30, 2017. This lease will be recognized on the balance sheet as a lease liability with a corresponding right-of-use asset, which will require modified retrospective application back to the fourth quarter of 2017 and for all of 2018. By 2019, all of the Company’s prior existing leases will have ended. Those leases will not require modified retrospective disclosures applied within the consolidated financial statements upon adoption in 2019. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). The new standard is based on the principle that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Since its initial release, the FASB has issued several amendments to the standard, which include clarification of accounting guidance related to identification of performance obligations and principal versus agent considerations. Topic 606 will be effective for the Company in the first quarter of 2018 and allows for a full retrospective or a modified retrospective adoption approach. The Company currently does not have, and has never had any, contracts that are within the scope of Topic 606 or its predecessor guidance, ASC 605 Revenue Recognition. Accordingly, there will not be any retrospective impact to the financial statements upon the adoption of Topic 606, which the Company will implement when it has contracts within its scope. The Company anticipates that initial sales subject to Topic 606 will begin in the first quarter of 2018, and that such sales will be to a limited number of customers, which are pharmaceutical specialty distributors. The Contract Revenue - Related Party reported in our results of operations for 2015 and 2016, which represents expense reimbursements from a related party, will not be impacted by the adoption of the new guidance.