Document And Entity Information [Abstract] Document Information [Table] Legal Entity [Axis] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Trading Symbol Entity Common Stock, Shares Outstanding Equity [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Accounting Policies [Abstract] Basis of Accounting, Policy [Policy Text Block] Basis of presentation Use of Estimates, Policy [Policy Text Block] Use of Estimates Significant Accounting Policies [Policy Text Block] Significant Accounting Policies Disclosure of accounting policy for Significant Accounting Policies. Statement of Financial Position [Abstract] Statement [Table] Entity [Domain] Statement [Line Items] Assets [Abstract] ASSETS Assets, Current [Abstract] Current assets Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Cash and cash equivalents at the beginning of the period Cash and cash equivalents at the end of the period Marketable Securities, Current, Total Marketable securities, at fair value Accounts Receivable, Net, Current Accounts receivable from collaboration Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Marketable Securities, Noncurrent, Total Marketable securities, at fair value Property, Plant and Equipment, Net Property, plant and equipment, net Property, plant and equipment, net Liabilities and Equity [Abstract] LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities, Current [Abstract] Current liabilities Accounts Payable Accounts payable Contingent License Fee Non Current [Abstract] Contingent license fee Deferred Tax Liabilities, Net, Current Deferred tax liabilities Liabilities, Noncurrent [Abstract] Long-term liabilities Preferred Stock, Value, Issued Preferred stock, $0.001 par value; 5,000,000 shares authorized; 0 shares issued and outstanding Common Stock, Value, Issued Common stock, $0.001 par value; 50,000,000 shares authorized; 20,386,736 and 20,137,974 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively Additional Paid in Capital Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss Retained Earnings (Accumulated Deficit) Accumulated deficit Liabilities Total liabilities Disclosure Of Share-Based Compensation Arrangements By Share-Based Payment Award [Table Text Block] Disclosure of Share-based Compensation Arrangements by Share-based Payment Award Schedule Of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Assumptions for Weighted Average Fair Value of Options Granted Schedule Of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Estimated Future Stock Based Expenses Relating to Unvested Stock Options Nonvested Restricted Stock Shares Activity [Table Text Block] Schedule of Restricted Stock Number of units Class of Stock [Axis] Class of Stock [Domain] Preferred Stock Par Or Stated Value Per Share Preferred stock, par value Preferred Stock Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Common Stock Par Or Stated Value Per Share Common stock, par value Common Stock Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common stock, shares issued Common Stock Shares Outstanding Common stock, shares outstanding Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Option Indexed to Issuer's Equity, Type [Axis] Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding [Roll Forward] Number of Shares Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Option, Outstanding at beginning of period Option, Outstanding at end of period Share-Based Compensation Arrangement By Share-Based Payment Award, Options, Grants In Period, Gross Option, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Option, Exercised Proceeds from the exercise of stock options (in shares) Stock Issued During Period, Shares, Share-based Compensation, Forfeited Option, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Weighted Average Exercise Price Per Share Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Option, Outstanding at beginning of period Option, Outstanding at end of period Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Option, Granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Option, Exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Option, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Total Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Option, Outstanding at beginning of period Option, Outstanding at end of period Share Based Compensation Arrangement By Share Based Payment Award Options Granted In Period Total Intrinsic Value Option, Granted Share Based Compensation Arrangement By Share Based Payment Award Options Granted In Period Total Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Option, Exercised Share Based Compensation Arrangement By Share Based Payment Award Options Forfeited In Period Total Intrinsic Value Option, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Options Forfeited In Period Total Intrinsic Value Range [Axis] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Share Based Compensation Arrangement By Share Based Payment Award, Fair Value Assumptions, Method Used [Line Items] Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items] Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price Exercise price Share-Based Compensation Arrangement By Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected stock price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Risk-free rate of interest Share-Based Compensation Arrangement By Share-Based Payment Award, Fair Value Assumptions, Expected Term Term (years) Stockholders Equity Note [Table] Stockholders Equity Note [Table] Stockholders Equity Note [Line Items] Stockholders Equity Note [Line Items] Stockholders Equity Note [Line Items] Future Stock Based Compensation Expense Current Nine Months Ending December 31, 2018 Amount of required stock based compensation expenses for the next fiscal year following the latest fiscal year. Future Stock Based Compensation Expense Year Two Year Ending December 31, 2019 Future Stock Based Compensation Expense, Year Two Future Stock Based Compensation Expense Year Three Year Ending December 31, 2020 Future Stock Based Compensation Expense, Year Three Award Type [Axis] Equity Award [Domain] Restricted Stock [Member] Class Of Warrant Or Right Outstanding [Abstract] Number of units Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance Beginning of period Ending of period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Number of units, Granted Weighted Average Grant Date Fair Value [Abstract] Weighted average grant price Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Beginning of period Ending of period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted average grant price, Granted Restricted Stock Units (RSUs) [Member] Stock Incentive Plan [Member] 2010 Stock Incentive Plan [Member] Stock Incentive Plan Two Thousand Fourteen [Member] 2014 Stock Incentive Plan [Member] Stock Incentive Plan Two Thousand Fourteen [Member] Equity Interest Type [Axis] Equity Interest Issued or Issuable, Type [Domain] Income Statement Location [Axis] Income Statement Location [Domain] Title of Individual [Axis] Relationship to Entity [Domain] Employees [Member] Employees [Member] Related Party [Axis] Related Party [Domain] Subsidiary, Sale of Stock [Axis] Sale of Stock, Name of Transaction [Domain] Employee Stock [Member] Research and Development Arrangement, Contract to Perform for Others, Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type [Domain] Debt Instrument [Axis] Debt Instrument, Name [Domain] Equity Components [Axis] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Plan [Axis] Common Stock, Capital Shares Reserved for Future Issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Income Statement [Abstract] Research and Development Expense Research and development General and Administrative Expense General and administrative Costs and Expenses Total operating expenses License and Services Revenue Collaboration revenue Interest Income, Other Interest and other income Operating Expenses [Abstract] Operating expenses: Operating Income Loss Loss from operations Nonoperating Income (Expense) [Abstract] Other income (expenses) Commitments and Contingencies Disclosure [Table] Commitments and Contingencies Disclosure [Table] Scenario [Axis] Scenario, Unspecified [Domain] Operating Leases, Rent Expense Statement Of Cash Flows [Abstract] Deferred Revenue Arrangement Type [Axis] Deferred Revenue [Domain] Net Cash Provided by (Used in) Operating Activities [Abstract] Cash flows from operating activities Net Loss Net loss Net loss 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: Depreciation Depreciation and amortization Share Based Compensation Stock-based compensation Marketable Securities, Realized Gain (Loss), Total Realized loss from marketable securities Realized loss from marketable securities Increase (Decrease) in Accounts Receivable Accounts receivable from collaboration Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other current assets Net Cash Provided by (Used in) Operating Activities Net cash (used in) provided by operating activities Net Cash Provided by (Used in) Investing Activities [Abstract] Cash flows from investing activities Payments To Acquire Property Plant and Equipment Purchases of fixed assets Net Cash Provided by (Used in) Financing Activities [Abstract] Cash flows from financing activities Cash and Cash Equivalents Period Increase Decrease Net (decrease) increase in cash and cash equivalents Noncash Investing and Financing Items [Abstract] Supplemental disclosure of cash flow information: Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Total Change in unrealized (loss) gain on marketable securities available-for-sale Statement of Stockholders' Equity [Abstract] Additional Paid-in Capital [Member] Stockholders' Equity Attributable To Parent Balance Total stockholders' equity Balance Shares, Outstanding Balance (in Shares) Balance (in Shares) Stock Issued During Period, Value, Stock Options Exercised Proceeds from the exercise of stock options Organization, Business and Basis Of Presentation [Abstract] Organization Consolidation and Presentation Of Financial Statements Disclosure [Text Block] Nature of Business Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies and Recent Accounting Pronouncements Earnings Per Share, Policy [Policy Text Block] Loss per Share of Common Stock Revenue Recognition, Policy [Policy Text Block] Revenue Recognition New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements Accrued Liabilities, Current Accrued expenses Total accrued expenses Security Deposit Security deposits Intangible Assets, Net (Excluding Goodwill) Intangible assets Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses Increase (Decrease) in Deferred Revenue Deferred revenue Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments, Net of Tax Unrealized loss recognized in accumulated other comprehensive loss before reclassification Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Reclassification adjustment of unrealized loss included in net loss Deferred Revenue, Current Deferred revenue - short-term Plan Name [Axis] Property, Plant and Equipment, Type [Axis] Plan Name [Domain] Property, Plant and Equipment, Type [Domain] plan [Domain] Business Acquisition [Axis] Commitments and Contingencies Commitments and contingencies Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Geographical [Axis] Increase (Decrease) in Security Deposits Security deposits Accrued Offering Cost Related to Issuance of Common Stock Proceeds from the exercise of stock options The amount of offering cost related to the issuance of common stock that were incurred during a noncash or partial noncash transaction. Property, Plant and Equipment [Abstract] Property, Plant and Equipment Disclosure [Text Block] Property, Plant and Equipment, Net Property, Plant and Equipment [Table Text Block] Property, Plant and Equipment Property, Plant and Equipment [Table] Property, Plant and Equipment, Gross Total property, plant and equipment Computer Equipment [Member] Computer hardware and software [Member] Equipment [Member] Lab equipment [Member] Lab equipment [Member] Office Equipment [Member] Office equipment [Member] Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Less: Accumulated depreciation and amortization Property, Plant and Equipment, Useful Life Property, Plant and Equipment [Line Items] Payables and Accruals [Abstract] Accounts Payable and Accrued Liabilities Disclosure [Text Block] Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] Schedule Accrued Expenses Accrued Expenses [Table] Accrued Expenses [Line Items] Accrued Liabilities, Current [Abstract] Accrued expenses: Employee-related Liabilities, Current Salaries, bonuses and employee benefits Accrued Research and Development Expenses Current Research and development expenses Carrying value as of the balance sheet date of obligations incurred through that date and payable for research and development expenses. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Overview [Table] Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options vested and exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Options vested and exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Options vested and exercisable Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Future Stock Based Compensation Expense Year four Year Ending December 31, 2021 the value represents Future Stock Based Compensation Expense Year four. Deferred Compensation Liability [Abstract] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Research and Development Expense [Member] Research and Development Expense [Member] Research and Development [Member] General and Administrative Expense [Member] General and Administrative [Member] Allocated Share-based Compensation Expense Stock based compensation expense Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Stockholders' Equity Attributable to Parent [Abstract] Stockholders' equity Assets, Noncurrent [Abstract] Long-term assets Assets Total assets Goodwill Goodwill (as adjusted) Merger on July 11, 2014 Goodwill As of December 31, 2014 As of December 31, 2015 Assets, Noncurrent, Total Total long-term assets Liabilities and Stockholders Equity Total liabilities and stockholders' equity Deferred Revenue, Noncurrent Deferred revenue - long-term Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive (loss) income Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Trading Securities, Change in Unrealized Holding Gain (Loss) Change in unrealized loss on marketable securities Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Stock-based compensation Accured General And Administrative Expenses Current General and administrative expenses Carrying value as of the balance sheet date of obligations incurred through that date and payable for general and administrative expenses. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer) Investments, Debt and Equity Securities [Abstract] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Marketable Securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of Available-for-sale Securities Reconciliation Schedule Of Available For Sale Securities Fair Value Measurement Categories [Table Text Block] Schedule Of Available For Sale Securities Fair Value Measurement Categories Tabular disclosure of fair value of marketable securities was classified into fair value measurement categories Schedule of Available-for-sale Securities [Table] Investment Type [Axis] Available-for-sale Securities, Amortized Cost Basis, Total Amortized Cost Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Gain Securities or Other Assets Sold under Agreements to Repurchase [Axis] Investments [Domain] Short-term Investments [Member] Other Long-term Investments [Member] Long-term Investments [Member] Schedule of Available-for-sale Securities [Line Items] Assets Sold under Agreements to Repurchase, Type [Domain] Corporate Bond Securities [Member] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Available-for-sale Securities Available-for-sale Securities Fair Value Available For Sale Securities Maturity Term The contractual term to maturity of short-term marketable securities and long-term marketable securities held by the Company. FutureStockBasedCompensationExpenseYearFive Year Ending December 31, 2022 the value represents Future Stock Based Compensation Expense Year five. Lease Arrangement, Type [Axis] Geographical [Domain] Nonoperating Income (Expense) Total other income (expense) Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Warrants To Purchase Common Stock [Member] Options To Purchase Common Stock [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Loss [Member] Retained Earnings [Member] Accumulated Deficit [Member] Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of non-cash activities: Future Stock Based Compensation Expense Total Total Future Stock Based Compensation Expense, Total Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Commitments and Contingencies Disclosure [Line Items] Lease Arrangement, Type [Domain] Equipment Lease [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Option Indexed to Issuer's Equity, Type [Domain] Employee Stock Option [Member] Stock Option [Member] Business Acquisition, Acquiree [Domain] Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Comprehensive Income (Loss), Net of Tax, Attributable to Parent, Total Comprehensive loss Basic and Diluted Net Loss Per Common Share (In Dollars Per Share) Net loss per share, basic and diluted Basic and diluted net loss per common share Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted average common shares outstanding, basic and diluted Licenses Revenue Development Milestone Payments Development Milestone Payments Commercial Milestone Payments Defines Commercial Milestone Payments. Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Gross Unrealized Loss Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Fair Value, Less than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Unrealized Losses, Less than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Fair Value, Total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Unrealized Losses, Total Leasehold Improvements [Member] Leasehold improvements [Member] Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Increase Decrease In Operating Capital [Abstract] Changes in operating assets and liabilities: Payments to Acquire Marketable Securities Purchases of marketable securities Proceeds from Sale and Maturity of Marketable Securities Redemptions of marketable securities Net Cash Provided by (Used in) Investing Activities Net cash (used in) provided by investing activities Financial Instrument [Axis] Financial Instruments [Domain] Warrant [Member] Operating Leases, Future Minimum Payments Due Operating Lease Expiration Year Operating Lease Expiration Year Liabilities, Current Total current liabilities Liabilities, Noncurrent, Total Total long-term liabilities Proceeds from Stock Options Exercised Proceeds from sale of shares on exercise of underwriters’ option Class of Warrant or Right, Outstanding Collaborative Arrangement Disclosure [Text Block] Collaboration Agreement Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Deferred Revenue,Amortization Period Over Service Tenure This element represents amortisation period of deferred revenue over service tenure. Description Of Agree To Share Development Cost This element represents description of development cost agreed to share. Type of Arrangement and Non-arrangement Transactions [Axis] Allergan Pharmaceuticals International Limited [Member] Proceeds From Upfront Payment The cash inflow from upfront payment during the year. Agreed To Share Maximum Amount Development Cost This element represent the maximum amount of development cost agreed by company. Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stockholders' Transactions [Abstract] Overview [Line Items] Cost of Reimbursable Expense Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Arrangements and Non-arrangement Transactions [Domain] Collaborative Arrangement [Member] Revenue Recognition, Milestone Method, Description Stock Incentive Plan Two Thousand Seventeen [Member] 2017 Stock Incentive Plan [Member] Assets, Current Total current assets Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Statutory Federal Income Tax Rate Statutory Federal tax rate Commercial Paper [Member] US Treasury Securities [Member] U.S. Treasury Securities [Member] Deferred Revenue Non-qualified Stock Option [Member] Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Chief Financial Officer and Chief Operating Officer [Member] Share-based Compensation Arrangement by Share-based Payment Award, Description Share Based Compensation Arrangement By Share Based Payment Award Options Non Vested In Period Fair Value 1 Fair value of options non vested. Excludes equity instruments other than options. Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Scenario, Plan [Member] Document Information [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]