Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Information [Table] Document Information [Line Items] Document Type Document Annual Report Document Transition Report Document Period End Date Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Central Index Key Amendment Flag Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Public Float Condensed Consolidated Balance Sheets Statement [Table] Statement [Line Items] Assets, Current [Abstract] Current Assets Cash equivalents total Cash and Cash Equivalents, at Carrying Value Cash Cash and cash equivalents Short-term Investments Short-term investments Prepaid Expense and Other Assets, Current Prepaid expenses and other assets Assets, Current Total Current Assets Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Property, Plant and Equipment, Net Property and equipment, net Property and equipment, net Restricted Cash Restricted cash Restricted cash (included in non-current assets on the consolidated balance sheets) Other Assets, Noncurrent Long-term assets Assets Total Assets Liabilities, Current [Abstract] Current Liabilities Accounts Payable, Current Accounts payable Accrued Liabilities, Current Accrued liabilities Accrued expenses Operating Lease, Liability, Current Operating lease liabilities - current Operating lease liabilities Current portion included in current liabilities Liabilities, Current Total Current Liabilities Liabilities, Noncurrent [Abstract] Non-Current Liabilities Operating Lease, Liability, Noncurrent Operating lease liabilities - noncurrent Operating lease liabilities Long-term portion included in non-current liabilities Other Liabilities, Noncurrent Other liabilities Liabilities, Noncurrent Total Non-Current Liabilities Liabilities Total Liabilities Condensed Consolidated Statements of Stockholders' Equity Stockholders' Equity Preferred Stock, Value, Issued Preferred stock, Value Common Stock, Value, Issued Common stock, $0.000041666 par value; 300,000,000 and 150,000,000 shares authorized, 126,411,808 and 123,415,576 shares issued and outstanding as of December 31, 2019 and December 31, 2018, respectively Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive loss Additional Paid in Capital Additional paid-in capital Retained Earnings (Accumulated Deficit) Accumulated deficit Stockholders' Equity Attributable to Parent Ending Balance Beginning Balance Total Stockholders' Equity Liabilities and Equity Total Liabilities and Stockholders' Equity Class of Stock [Axis] Class Of Stock [Domain] Class of Stock [Domain] Series A Preferred Stock [Member] Series A Convertible Preferred Stock Series B Preferred Stock [Member] Series B Convertible Preferred Stock Preferred Stock, Par or Stated Value Per Share Preferred stock, par or stated value per share Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Preferred Stock, Liquidation Preference, Value Common Stock, Par or Stated Value Per Share Common stock, par or stated value per share Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Common Stock, Shares, Outstanding Condensed Consolidated Statements of Operations Operating Expenses [Abstract] Costs and expenses Research and Development Expense Research and development expenses General and Administrative Expense General and administrative expenses Operating Expenses Total costs and expenses Operating Income (Loss) Loss from operations Nonoperating Income (Expense) [Abstract] Other income Investment Income, Interest Interest income, net Net loss Net loss Net Income (Loss) Attributable to Parent Net Loss Net Loss Earnings Per Share, Basic and Diluted Net loss per share, basic and diluted Net Loss Per Common Share, Basic and Diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted average share used in computing net loss per share, basic and diluted Weighted Average Common Shares Outstanding, Basic and Diluted Condensed Consolidated Statements of Comprehensive Loss Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive gain (loss): Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Unrealized loss on short-term investments Net unrealized gain (loss) on short-term investments Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive Loss Shares, Outstanding Ending Balance (in Shares) Beginning Balance (in Shares) Cumulative Effect of New Accounting Principle in Period of Adoption Adoption of ASU 2018-07 Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Stock-based compensation expense Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Vesting of restricted shares issued for services Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Vesting of restricted shares issued for services (in shares) Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Tax payments related to shares withheld for vested restricted stock awards The amount of exchange transaction inducement costs capitalized during the period. Common Stock Issued Upon Exercise Of Warrants Amount Common stock issued upon exercise of warrants Number of shares issued upon exercise of warrant. Common Stock Issued Upon Exercise Of Warrants Shares Common stock issued upon exercise of warrants (in Shares) Stock Issued During Period, Value, Stock Options Exercised Common stock issued upon exercise of stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercised Common stock issued upon exercise of stock options (in shares) Stock Issued During Period, Value, New Issues Common stock sold in public offering, net of offering costs Stock Issued During Period, Shares, New Issues Common stock sold in public offering, net of offering costs (in shares) Stock Issued During Period, Value, Conversion of Convertible Securities Conversion of convertible preferred stock into common stock Stock Issued During Period, Shares, Conversion of Convertible Securities Conversion of convertible preferred stock into common stock (in Shares) Amount of Common stock issued from preferred stock conversion. Common Stock Issued From Preferred Stock Conversion Common stock issued from preferred stock conversion Number of Common stock issued from preferred stock conversion. Common Stock Issued From Preferred Stock Conversion, Shares Common stock issued from preferred stock conversion (in Shares) The number of restricted shares cancelled during the period. Stock Cancelled During Period Restricted Shares Cancellation of restricted shares (in Shares) Amount of cancellation shares from settlement of dispute. Stock Cancelled During Period Shares Of Common Stock Cancellation of common shares from settlement of dispute Amount of cancellation shares from settlement of dispute. Cancellation of common shares from settlement of dispute (In Shares) Cancellation of common shares from settlement of dispute (In Shares) Condensed Consolidated Statements of Cash Flows Net Cash Provided by (Used in) Operating Activities [Abstract] Cash Flows from Operating Activities 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 Share-based Compensation Amount of Noncash lease expense. Non Cash Lease Expense Noncash lease expense Amortization of Debt Discount (Premium) Accretion (amortization) of discounts and premiums on investments Depreciation, Depletion and Amortization, Nonproduction Depreciation and amortization Gain (Loss) Related to Litigation Settlement Gain on settlement of dispute Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Loss on disposal of assets Increase (Decrease) in Operating Capital [Abstract] Changes in assets and liabilities: Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses, other assets, and long-term assets Amount of operating lease liabilities. Increase Decrease in operating Lease Right of Use Asset Operating lease liabilities (Right-of-use assets) Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses and other liabilities Net Cash Provided by (Used in) Operating Activities Net cash used in operating activities Net cash used in operating activities Net Cash Provided by (Used in) Investing Activities [Abstract] Cash Flows from Investing Activities Proceeds from Sale and Maturity of Debt Securities, Available-for-sale Maturities of short-term investments Payments to Acquire Available-for-sale Securities Purchase of short-term investments Payments to Acquire Property, Plant, and Equipment Purchase of property and equipment Net Cash Provided by (Used in) Investing Activities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Cash Flows from Financing Activities Payments Related to Tax Withholding for Share-based Compensation Tax payments related to shares withheld for vested restricted stock awards Proceeds from Warrant Exercises Proceeds from the issuance of common stock upon exercise of warrants Proceeds from Stock Options Exercised Proceeds from the issuance of common stock upon exercise of options Proceeds from Issuance of Common Stock Proceeds from the issuance of common stock, net The cash inflow from the additional capital contribution to the entity. Proceeds From The Issuance Of Common And Preferred Stock Proceeds from the issuance of preferred stock and common stock, net Net Cash Provided by (Used in) Financing Activities Net cash provided by financing activities Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Net (decrease) increase in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, Cash Equivalents, and Restricted Cash End of Period Cash, Cash Equivalents, and Restricted Cash Beginning of Period Total cash, cash equivalents and restricted cash Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of non-cash investing and financing activities: Amount of unrealized (loss)gain on short-term investments. Unrealized Gain Loss on Short-Term Investments Net unrealized gain (loss) on short-term investments Future cash outflow to pay for leasehold improvements that have occurred. Leasehold Improvements Paid by Landlord Acquisitions of property and equipment included in accounts payable Conversion of Stock, Amount Converted Conversion of convertible preferred stock to common stock GENERAL ORGANIZATION AND BUSINESS Business Description and Basis of Presentation [Text Block] GENERAL ORGANIZATION AND BUSINESS SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES Significant Accounting Policies [Text Block] SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES CASH AND CASH EQUIVALENTS, AND SHORT-TERM INVESTMENTS Cash, Cash Equivalents, and Short-term Investments [Text Block] CASH AND CASH EQUIVALENTS, AND SHORT-TERM INVESTMENTS BALANCE SHEET COMPONENTS Supplemental Balance Sheet Disclosures [Text Block] BALANCE SHEET COMPONENTS 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 EMPLOYEE BENEFIT PLAN Compensation and Employee Benefit Plans [Text Block] EMPLOYEE BENEFIT PLAN INCOME TAXES Income Tax Disclosure [Text Block] INCOME TAXES LICENSES AND AGREEMENTS The entire disclosure for licenses and agreements. Licenses And Agreements Disclosure [Text Block] LICENSES AND AGREEMENTS LEASES Lessee, Operating Leases [Text Block] LEASES LEGAL PROCEEDINGS Contingencies Disclosure [Text Block] LEGAL PROCEEDINGS QUARTERLY UNAUDITED RESULTS Quarterly Financial Information [Text Block] QUARTERLY UNAUDITED RESULTS RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] RELATED PARTY TRANSACTIONS Cash and Cash Equivalents, Policy [Policy Text Block] Cash, Cash Equivalents, and Short-term Investments Disclosure of accounting policy for restricted cash. Restricted Cash [Policy Text Block] Restricted Cash Property, Plant and Equipment, Policy [Policy Text Block] Property and Equipment, net Earnings Per Share, Policy [Policy Text Block] Loss per Share Fair Value Measurement, Policy [Policy Text Block] Fair Value Measurements Use of Estimates, Policy [Policy Text Block] Use of Estimates Consolidation, Policy [Policy Text Block] Principles of Consolidation Lessee, Leases [Policy Text Block] Leases Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Stock-Based Compensation Research and Development Expense, Policy [Policy Text Block] Research and Development Expenses Selling, General and Administrative Expenses, Policy [Policy Text Block] General and Administrative Expenses Income Tax, Policy [Policy Text Block] Income taxes Concentration Risk, Credit Risk, Policy [Policy Text Block] Concentrations Stockholders' Equity Note, Redeemable Preferred Stock, Issue, Policy [Policy Text Block] Preferred Stock The accounting policy for all convertible instruments issued by the entity. Convertible Instruments Policy [Text Block] Convertible Instruments New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Standards Segment Reporting, Policy [Policy Text Block] Segment reporting Subsequent Events, Policy [Policy Text Block] Subsequent Events Tabular disclosure of the components of cash, cash equivalents and Restricted Cash. Schedule of Cash and Cash Equivalents and Restricted Cash [Table Text Block] Schedule of cash and cash equivalents and restricted cash Tabular disclosure of useful lives of categories of property, plant and equipment. Schedule Of Useful Lives Of Property Plant And Equipment [Table Text Block] 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 Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of assets measured at fair value Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Schedule of stock-based compensation Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of compensation cost for share-based payment arrangements, allocation of share-based compensation costs by plan Cash, Cash Equivalents and Investments [Table Text Block] Schedule of cash, money market funds and short-term investments