Document and Entity Information Statement [Table] Statement [Line Items] Statement Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Entity Current Reporting Status Entity Filer Category Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Period Focus Condensed Consolidated Balance Sheets Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Available-for-sale Securities, Current Marketable securities Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Assets, Current Total current assets Property, Plant and Equipment, Net Property and equipment, net Assets Total assets Liabilities and Equity [Abstract] Liabilities and Stockholders' Equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Accrued Liabilities, Current Accrued expenses Liabilities, Current Total current liabilities Liabilities Total liabilities Stockholders' Equity Attributable to Parent [Abstract] Stockholders' equity: Preferred Stock, Value, Issued Preferred stock, par value $0.0001 per share authorized: 5,000,000 shares at March 31, 2018 and December 31, 2017; 1,969,797 shares issued and outstanding at March 31, 2018 and December 31, 2017 Common Stock, Value, Issued Common stock, par value $0.0001 per share authorized: 200,000,000 at March 31, 2018 and December 31, 2017; 14,250,726 and 14,227,634 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively Additional Paid in Capital, Common Stock Additional paid-in-capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive loss Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated deficit Stockholders' Equity Attributable to Parent Total stockholders' equity Liabilities and Equity Total liabilities and stockholders' equity Preferred Stock, Par or Stated Value Per Share Preferred stock, par value (in dollars per share) Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Condensed Consolidated Statements of Operations Costs and Expenses [Abstract] Operating expenses: Research and Development Expense (Excluding Acquired in Process Cost) Research and development General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Loss from operations Interest Income, Operating Interest income Net Income (Loss) Available to Common Stockholders, Basic Net loss Net loss Net Loss Earnings Per Share [Abstract] Net loss per common share: Earnings Per Share, Basic and Diluted Basic and diluted net loss per common share (in dollars per share) Weighted Average Number of Shares Outstanding, Basic and Diluted Basic and diluted weighted average number of common shares outstanding Condensed Consolidated Statements of Comprehensive Loss Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Unrealized gain (loss) on available-for-sale securities Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive loss Condensed Consolidated Statements of Cash Flows Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Cash flows from operating activities: Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net loss Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Share-based Compensation Stock-based compensation expense Depreciation, Depletion and Amortization Depreciation and amortization expense Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other current assets Increase (Decrease) in Accounts Payable, Trade Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expense Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used in operating activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Cash flows from investing activities: Payments to Acquire Available-for-sale Securities Purchases of marketable securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Sales and maturities of marketable securities Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment, net of disposals Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash used in investing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Cash flows from financing activities: The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity, net of transaction costs. Proceeds From Issuance Or Sale Of Equity, Net Proceeds from issuance of common and preferred stock, net of transaction costs Net proceeds after deducting commissions and other transactions costs The cash inflow from the additional capital contribution including exercise of common stock options to the entity. Proceeds From Issuance of Common Stock Including Exercise of Common Stock Options Proceeds from issuance of stock, net of transaction costs, including exercise of common stock options Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities Amount of increase (decrease) in cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage; excluding effect from exchange rate change. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Net decrease in cash and cash equivalents Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Organization, Business, and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Organization, Business, and Basis of Presentation Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Summary of Significant Accounting Policies Liquidity And Uncertainties Disclosure Abstract Liquidity and Uncertainties Substantial Doubt about Going Concern [Text Block] Liquidity and Uncertainties Cash, Cash Equivalents and Marketable Securities Cash, Cash Equivalents, and Marketable Securities [Text Block] Cash, Cash Equivalents and Marketable Securities Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Stock-based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-based Compensation Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Consolidation, Policy [Policy Text Block] Principle of Consolidation Use of Estimates, Policy [Policy Text Block] Use of Estimates Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Marketable Securities, Policy [Policy Text Block] Marketable Securities Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value of Financial Instruments Research and Development Expense, Policy [Policy Text Block] Research and Development Costs Disclosure of accounting policy for patents. Patents [Policy Text Block] Patents Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Stock-Based Compensation Income Tax, Policy [Policy Text Block] Income Taxes Comprehensive Income, Policy [Policy Text Block] Comprehensive Loss Earnings Per Share, Policy [Policy Text Block] Basic and Diluted Loss Per Common Share New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Summary of the outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive Cash, Cash Equivalents and Investments [Table Text Block] Summary of cash, cash equivalents and available-for-sale marketable securities Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of stock option activity Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the income statement for the period. This may include the amount of total share-based compensation cost, including the amounts attributable to each share-based compensation plan and any related tax benefits. It includes the reporting line for the costs expensed. Schedule of Share Based Compensation Expense Allocation of Compensation Costs and Recognized Period Costs [Table Text Block] Schedule of stock-based compensation expense Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Schedule of unrecognized stock-based compensation expense Income Taxes Income Taxes The percentage of valuation allowance on the deferred tax assets. Deferred Tax Assets, Percentage Of Valuation Allowance Valuation allowance on deferred tax assets (as a percent) Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities Name [Domain] Antidilutive Securities, Name [Domain] An arrangement whereby an employee or member of the Board of Directors is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement. Employee And Directors Stock Options [Member] Common Stock Options Restricted Stock [Member] Unvested Restricted Common Stock Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Anti-dilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive (in shares) Schedule of Investments [Table] Major Types of Debt and Equity Securities [Axis] Major Types Of Debt And Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Debt securities due within 3 months issued by domestic or foreign corporate business, banks and other entities with a promise of repayment. Corporate Debt Securities2 [Member] Corporate debt securities due within 3 months of date of purchase Corporate Debt Securities [Member] Corporate debt securities due within 1 year of date of purchase Measurement Basis [Axis] Portion At Fair Value Fair Value Disclosure [Member] Portion at Fair Value Measurement [Member] Carrying Reported Amount Fair Value Disclosure [Member] Carrying value Estimate Of Fair Value Fair Value Disclosure [Member] Fair value Fair Value, Hierarchy [Axis] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value Inputs Level1 [Member] Level 1 Fair Value Inputs Level2 [Member] Level 2 Schedule of Investments [Line Items] Cash, Cash Equivalents and Marketable Securities Cash and Cash Equivalents, Fair Value Disclosure Cash and cash equivalents Represents the maturity period from date of purchase to classify an investment as marketable securities. Maturity Period from Date of Purchase to Classify Investment as Marketable Securities Maturity period from date of purchase to classify an investment as marketable securities Available-for-sale Securities, Amortized Cost Basis Marketable securities, cost Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Marketable securities, unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Marketable securities, unrealized losses Available-for-sale Securities Marketable securities, fair value This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings, and cash and cash equivalents. Cash, Cash Equivalents, and Short-term Investments, At Cost Total cash, cash equivalents and marketable securities, Cost This item represents the gross unrealized gains for cash and cash equivalents securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. Cash and Cash Equivalents and Available for Sale Securities, Gross Unrealized Gains Total cash, cash equivalents and marketable securities, Unrealized gains This item represents the gross unrealized losses for cash and cash equivalents securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. Cash and Cash Equivalents and Available for Sale Securities, Gross Unrealized Losses Total cash, cash equivalents and marketable securities, Unrealized losses Cash, Cash Equivalents, and Short-term Investments Total cash, cash equivalents and marketable securities, Fair value Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Stockholders' Equity Represents the number of votes per share that common stockholders are entitled to receive. Common Stock Voting Rights Number Number of votes per share that common stockholders are entitled to receive Sale of Stock [Axis] Sale Of Stock Name Of Transaction [Domain] Sale of Stock [Domain] Over Allotment Option [Member] Additional Shares Represents registered offering. Registered Offering [Member] Registered Offering Counterparty Name [Axis] Repurchase Agreement Counterparty Name [Domain] Counterparty Name [Domain] Represents Goldman Sachs & Co. Goldman Sachs Co [Member] Goldman Sachs & Co. LLC Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements And Nonarrangement Transactions [Member] Arrangements and Non-arrangement Transactions [Domain] Represents Underwriting agreement. Underwriting Agreement [Member] Underwriting Agreement Stock Issued During Period, Shares, New Issues Number of shares sold by the entity Period granted to purchase additional shares. Sale of Stock, Period Granted to Purchase Additional Shares Number of days granted to purchase additional shares Shares Issued, Price Per Share Issue price of stock Stock Issued During Period, Value, New Issues Value of shares sold by the entity Proceeds from Issuance of Common Stock Net proceeds after deducting commissions and other transactions costs Represents information pertaining to private placement offering to sell its securities Securities Purchase Agreement [Member] Purchase Agreement Conversion of Stock, Shares Converted Preferred stock conversion ratio Number of voting rights of preferred stock. Includes eligibility to vote and votes per share owned. Include also, if any, unusual voting rights. Preferred Stock, Number Of Voting Rights Preferred shares number voting rights Represent of Cowen & Co. LLC Member. Cowen Co. Llc [Member] Cowen & Co. LLC Range [Axis] Range [Member] Range [Domain] Maximum [Member] Maximum Represents information pertaining to at-the-market issuance sales agreement for the sale of the entity's common shares. At The Market Issuance Sales Agreement [Member] At-The-Market Issuance Sales Agreement Value of common stock and preferred stock, debt securities and/or warrants, rights or purchase contracts that remain reserved for future issuances under shelf registration with the Securities and Exchange Commission of the United States. Remaining Securities Under Shelf Registration, Value Remaining reserved amount under shelf registration Represents the maximum aggregate offering price the entity may issue and sell shares of its common stock from time to time, at the entity's option, according to at-the-market issuance sales agreement with third party. Common Stock Aggregate Offering Price Maximum aggregate offering price Represents the percentage of gross proceeds payable as commission during the period. Percentage of Gross Proceeds Payable as Commission Percentage of gross proceeds payable as commission Represents number of days of notice period for termination of sales agreement. Sales Agreement Termination Notice Period Days Notice period of termination of sales agreement Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Equity Award [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Unrecognized stock-based compensation expense Stock-based compensation expense Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Expiration period Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Shares available for future issuance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Outstanding at the end of the period (in shares) Outstanding at the beginning of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Exercisable at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Weighted average exercise price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Outstanding at the end of the period (in dollars per share) Outstanding at the beginning of the period (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Options granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Options exercised (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Exercisable at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Additional disclosures Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options Total cash received from stock option exercises Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted-average grant date fair value of options (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Unvested restricted shares outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted average grant date fair value