Entity Central Index Key Certificates of deposit fair value disclosure. Corporate debt securities fair value disclosure. Document And Entity Information [Abstract] Document And Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Document Type Document Type Trading Symbol Trading Symbol Current Fiscal Year End Date Current Fiscal Year End Date Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Amendment Flag Amendment Flag Entity Central Index Key Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus 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] 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 (Note 5) Property Plant And Equipment Net Equity method investment Equity Method Investments 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 Total current liabilities Liabilities Current Deferred revenue, net of current portion Deferred Revenue Noncurrent Other liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and Contingencies (Note 9) Commitments And Contingencies Shareholders' equity Stockholders Equity [Abstract] Ordinary shares: NIS 0.07 par value; 30,000 shares authorized, 10,761 issued, 10,718 outstanding and 43 held in treasury at September 30, 2018; NIS 0.07 par value; 30,000 shares authorized, 10,699 issued, 10,656 outstanding and 43 held in treasury at December 31, 2017 Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive gain (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 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 Loss from operations Operating Income Loss Loss related to equity method investment Income Loss From Equity Method Investments Finance (expense) income, net Other Nonoperating Income Expense 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 gain 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 Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] 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 Gain (Loss) [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Balance Balance (in shares) Shares Outstanding Share-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Shares issued in conjunction with share option exercises Stock Issued During Period Value Stock Options Exercised Shares issued in conjunction with share option exercises (in shares) Stock Issued During Period Shares Stock Options Exercised Balance Balance (in shares) Statement Of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in 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 Interest expense on convertible promissory notes Interest Expense Loss from equity method investment Changes in operating assets and liabilities Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Prepaid expense 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 operating activities Net Cash Provided By Used In Operating Activities INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities [Abstract] Proceeds from maturities of short-term investments Proceeds From Maturities Prepayments And Calls Of Shortterm Investments Purchases of short-term investments Payments To Acquire Short Term Investments Acquisition of property and equipment Payments To Acquire Property Plant And Equipment Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from issuance of convertible promissory notes, net Proceeds From Convertible Debt Proceeds from exercise of share options Proceeds From Stock Options Exercised Net cash provided by financing activities Net Cash Provided By Used In Financing Activities NET INCREASE 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 the period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of the period Sale of intangible assets for equity investment. Release of repurchase liability for restricted shares. Supplemental disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Cash paid for income taxes Income Taxes Paid Non-cash investing and financing activities Noncash Investing And Financing Items [Abstract] Sale of intangible assets for equity investment Sale Of Intangible Assets For Equity Investment Release of repurchase liability for restricted shares Release Of Repurchase Liability For Restricted Shares Purchase of property and equipment in accounts payable Capital Expenditures Incurred But Not Yet Paid Accounting Policies [Abstract] Basis of Presentation and Summary of Significant Accounting Policies Basis Of Presentation And 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] Balance Sheet Related Disclosures [Abstract] Balance Sheet Details Supplemental Balance Sheet Disclosures [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 Loss Contingency Disclosures Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Quarterly Financial Information Disclosure [Abstract] Selected Financial Data Quarterly Financial Information [Text Block] Basis of Presentation Consolidation Policy [Text Block] Organizational. Organizational Update Organizational Policy [Text Block] Reverse merger. Reverse Merger Reverse Merger Policy Policy [Text Block] Liquidity. Liquidity Liquidity Policy Policy [Text Block] Intangible Assets Held for Sale and Equity Method Investment Impairment Or Disposal Of Long Lived Assets Including Intangible Assets Policy Policy [Text Block] Segment Information Segment Reporting Policy Policy [Text Block] Revenue Recognition Revenue Recognition Policy [Text Block] Research and Development, net Research And Development Expense Policy Statement of Cash Flows Inventory Cash Flow Policy 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] 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] Schedule of prepaid expenses and other current assets. Schedule of Prepaid Expenses and Other Current Assets Schedule Of Prepaid Expenses And Other Current Assets Table [Text Block] Summary of Components of Property and Equipment Property Plant And Equipment [Text Block] Schedule of Accrued Liabilities Schedule Of Accrued Liabilities Table [Text Block] Schedule of Weighted Average Assumptions Used in Black -Scholes Valuation Model Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Share Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Schedule of Future Minimum Payments Under Leases and Lease Commitments Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Quarterly Financial Data [Abstract] Summary of Selected Financial Data Schedule Of Quarterly Financial Information Table [Text Block] Basis of presentation and summary of significant accounting policies. Basis of presentation and summary of significant accounting policies. Basis Of Presentation And Summary Of Significant Accounting Policies [Table] Basis Of Presentation And Summary Of Significant Accounting Policies [Table] Business Acquisition Business Acquisition [Axis] Business Acquisition, Acquiree Business Acquisition Acquiree [Domain] Alcobra Limited. Alocobra Limited [Member] Alcobra Limited [Member] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Term loan. Term Loan [Member] Term Loan [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Counterparty Name Counterparty Name [Axis] Counterparty Name Repurchase Agreement Counterparty Name [Domain] Western Alliance Bank. Western Alliance Bank [Member] Western Alliance Bank [Member] Type of Arrangement and Non-arrangement Transactions Type Of Arrangement [Axis] Arrangements and Non-arrangement Transactions Arrangements And Nonarrangement Transactions [Member] Loan and security agreement. Loan and Security Agreement [Member] Loan And Security Agreement [Member] Sales agreement. Sales Agreement [Member] Sales Agreement [Member] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Leerink Partners LLC. Leerink Partners LLC [Member] Leerink Partners L L C [Member] Range Range [Axis] Range Range [Member] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items] Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items] Business merger date Business Acquisition Effective Date Of Acquisition1 Stock issued during period, shares, acquisitions Stock Issued During Period Shares Acquisitions Reverse split of ordinary shares Stockholders Equity Reverse Stock Split Reverse split of ordinary shares, ratio Stockholders Equity Note Stock Split Conversion Ratio1 Business combination recognized identifiable assets acquired and liabilities assumed cash and equivalents and short-term investments. Aggregate amount of ordinary shares sold. Cash equivalents and short-term investments acquired Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents And Short Term Investments Gross proceeds from term loan agreement Proceeds From Loans Aggregate amount of ordinary shares sold Aggregate Amount Of Ordinary Shares Sold Ownership percentage Minority Interest Ownership Percentage By Noncontrolling Owners Equity method ownership percentage Equity Method Investment Ownership Percentage Restricted cash (included in other assets) Restricted Cash Noncurrent Total cash, cash equivalents and restricted cash shown in the statement of cash flows Antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Number of collaboration agreements. Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Collaboration Partner A. Collaboration Partner A [Member] Collaboration Partner A [Member]