Entity Central Index Key Document And Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Trading Symbol Trading Symbol Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including amount of asset related to consideration paid in advance for costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer. as well as trade accounts receivable, notes and loans receivable. Statement Of Financial Position [Abstract] Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Series seed preferred stock. Series Seed Preferred Stock [Member] Series Seed Preferred Stock [Member] Series A Preferred Stock Series A Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Restricted cash Restricted Cash And Cash Equivalents At Carrying Value Short-term investments Short Term Investments Accounts receivable Accounts Receivable Net Current Prepaid expenses and other current assets Prepaid Expenses And Other Receivables Intangible asset held for sale Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangible Assets Other Than Goodwill Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Other assets Other Assets Noncurrent Total assets Assets Liabilities and shareholders’ equity Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued liabilities Accrued Liabilities Current Deferred revenue Deferred Revenue Current Convertible promissory notes and accrued interest Convertible Debt Current Total current liabilities Liabilities Current Deferred revenue, net of current portion Deferred Revenue Noncurrent Other liabilities Other Liabilities Total liabilities Liabilities Commitments and contingencies (Note 13) Commitments And Contingencies Shareholders’ equity: Stockholders Equity [Abstract] Preferred stock value Preferred Stock Value Ordinary shares: NIS 0.07 par value; 30,000 shares authorized, 10,699 issued, 10,656 outstanding and 43 held in treasury at December 31, 2017; $0.0001 par value, 2,801 issued and outstanding at December 31, 2016 Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total shareholders’ equity Stockholders Equity Total liabilities and shareholders’ equity Liabilities And Stockholders Equity Preferred stock, par value Preferred Stock Par Or Stated Value 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 value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Treasury shares Treasury Stock Common Shares Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Statement Of Income And Comprehensive Income [Abstract] Revenue in conjunction with strategic alliances and collaborations Revenues Operating expenses: Operating Expenses [Abstract] Research and development, net Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Net loss from operations Operating Income Loss Finance (expense) income, net Other Nonoperating Income Expense Net loss before taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax expense Income Tax Expense Benefit Net loss Net Income Loss Net loss per share, basic and diluted Earnings Per Share Basic And Diluted Weighted-average shares outstanding, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Comprehensive loss: Comprehensive Income Net Of Tax [Abstract] Net loss Unrealized loss on short-term investments Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Stock issued during period, value, conversion of debt securities including debt conversion expense. Stock issued during period, shares, conversion of debt securities including debt conversion expense. Stock issued during period value, warrants exercised. Stock issued during period, shares, warrants exercised. Stock issued during period, value, conversion of debt securities. Stock issued during period, shares, conversion of debt securities. Adjustments to additional paid in capital, beneficial conversion expense from notes. Stock issued during period, value, merger, net of refund for fractional shares. Stock issued during period, shares, merger net of refund for fractional shares. Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Ordinary Shares [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Accumulated Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Balance Balance (in shares) Shares Outstanding Shares issued in conjunction with share option exercise Stock Issued During Period Value Stock Options Exercised Shares issued in conjunction with share option exercise (in shares) Stock Issued During Period Shares Stock Options Exercised Share-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Stock Issued During Period Value Warrants Exercised Stock Issued During Period Shares Warrants Exercised Stock Issued During Period Value Conversion Of Debt Securities Including Debt Conversion Expense Stock Issued During Period Shares Conversion Of Debt Securities Including Debt Conversion Expense Stock Issued During Period Value Conversion Of Debt Securities Stock Issued During Period Shares Conversion Of Debt Securities Stock Issued During Period Value Conversion Of Convertible Securities Stock Issued During Period Shares Conversion Of Convertible Securities Adjustments To Additional Paid In Capital Beneficial Conversion Expense From Notes Stock Issued During Period Value Merger Net Of Refund For Fractional Shares Stock Issued During Period Shares Merger Net Of Refund For Fractional Shares Balance Balance (in shares) Issuance of preferred shares upon convertible promissory note maturity including debt conversion expense Issuance of preferred shares upon convertible promissory note maturity including debt conversion (in shares) Issuance of shares upon exercise of warrants Issuance of shares upon exercise of warrants Issuance of shares upon conversion of notes Issuance of shares upon conversion of notes (in shares) Conversion of Preferred Shares to Ordinary Shares Conversion of Preferred Shares to Ordinary Shares (in shares) Beneficial conversion expense from notes Issuance of shares in connection with merger, net Issuance of shares in connection with merger, net of refund for fractional shares (in shares) Convertible notes and accrued interest amounts reclassified to accounts payable at maturity. Statement Of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Net loss Adjustments to reconcile net loss to net cash (used in) provided by operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization Depreciation And Amortization Share-based compensation expense Share Based Compensation Gain on sale of equipment Gain Loss On Sale Of Property Plant Equipment Interest expense on convertible promissory notes Interest Expense Beneficial conversion expense from notes Induced Conversion Of Convertible Debt Expense Changes in operating assets and liabilities Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable Increase Decrease In Accounts Payable Accrued liabilities Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Deferred Revenue Net cash (used in) provided by operating activities Net Cash Provided By Used In Operating Activities Continuing Operations INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Proceeds from maturities of short-term investments Proceeds From Maturities Prepayments And Calls Of Shortterm Investments Acquisition of property and equipment Payments To Acquire Property Plant And Equipment Proceeds from sale of equipment Proceeds From Sale Of Property Plant And Equipment Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Proceeds from issuance of convertible promissory notes Proceeds From Convertible Debt Proceeds from exercise of share options Proceeds From Stock Options Exercised Proceeds from exercise of warrants Proceeds From Warrant Exercises Net cash received in the issuance of shares for the net assets of Alcobra Ltd. Proceeds From Issuance Of Common Stock Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of year Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of year Supplemental cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for taxes Income Taxes Paid Purchase of property and equipment included in accounts payable and accrued liabilities Capital Expenditures Incurred But Not Yet Paid Issuance of Series A preferred shares upon note maturity Stock Issued1 Convertible notes and accrued interest reclassified to accounts payable at maturity Convertible Notes And Accrued Interest Amounts Reclassified To Accounts Payable At Maturity Fair value of assets acquired, excluding cash, cash equivalents and restricted cash Noncash Or Part Noncash Acquisition Value Of Assets Acquired1 Less liabilities assumed Noncash Or Part Noncash Acquisition Value Of Liabilities Assumed1 Net assets acquired, excluding cash, cash equivalents and restricted cash Noncash Or Part Noncash Acquisition Net Nonmonetary Assets Acquired Liabilities Assumed1 Conversion of notes to Ordinary Shares Debt Conversion Converted Instrument Amount1 Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization Business Description And Accounting Policies [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Collaboration agreements. Collaboration Agreements [Abstract] Strategic Alliances and Collaboration Agreements Collaborative Arrangement Disclosure [Text Block] Investments Debt And Equity Securities [Abstract] Short-term Investments Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Business Combinations [Abstract] Reverse Merger with Alcobra Ltd. Business Combination Disclosure [Text Block] Balance Sheet Related Disclosures [Abstract] Balance Sheet Details Supplemental Balance Sheet Disclosures [Text Block] Property Plant And Equipment [Abstract] Property and Equipment, Net Property Plant And Equipment Disclosure [Text Block] Debt Disclosure [Abstract] Convertible Promissory Notes Debt Disclosure [Text Block] Stockholders Equity Note [Abstract] Shareholders’ Equity Stockholders Equity Note Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Share-Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Loss Contingency Information About Litigation Matters [Abstract] Litigation Schedule Of Loss Contingencies By Contingency [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Basis of Presentation and Principles of Consolidation Consolidation Policy [Text Block] Segment Information Segment Reporting Policy Policy [Text Block] Reclassifications of prior year presentation. Reclassification of Prior Year's Presentation Reclassifications Of Prior Year Presentation Policy [Text Block] Foreign Currency Translation Foreign Currency Transactions And Translations Policy [Text Block] Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy Short-term bank deposits. Short-term Bank Deposits Short Term Bank Deposits Policy Policy [Text Block] Disclosure of accounting policy for short-term investments. Short-term Investments Short Term Investments Policy [Text Block] Fair Value Measurements Fair Value Measurement Policy Policy [Text Block] Accounts Receivable Receivables Policy [Text Block] Concentration of Credit Risk and Significant Customers Concentration Risk Credit Risk Intangible asset held for sale. Intangible asset held for sale Intangible Asset Held For Sale Policy [Text Block] Property and Equipment, net Property Plant And Equipment Policy [Text Block] Comprehensive Loss Comprehensive Income Policy Policy [Text Block] Revenue Recognition Revenue Recognition Policy [Text Block] Research and Development Costs, net Research And Development Expense Policy Royalty bearing grant. Royalty Bearing Grant Royalty Bearing Grant Policy [Text Block] Share-Based Compensation Share Based Compensation Option And Incentive Plans Policy Ordinary shares valuation. Ordinary Shares Valuation Ordinary Shares Valuation Policy [Text Block] Income Tax Expense Income Tax Policy [Text Block] Net Loss per Share Earnings Per Share Policy [Text Block] Recently Issued Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of Cash and Cash Equivalents and Restricted Cash Schedule Of Cash And Cash Equivalents Table [Text Block] Schedule of revenues under strategic alliances and collaboration agreements. Summary of Revenues Under Strategic Alliances and Collaborations Schedule Of Revenues Under Strategic Alliances And Collaboration Agreements Table [Text Block] Summary of Short-term Investments Available For Sale Securities [Text Block] Schedule of Financial Assets Measured at Fair Value on a Recurring Basis Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Table [Text Block]