Document and Entity Information [Abstract] Document Information [Table] Document Information [Line Items] Document information Document Type Document Period End Date Entity Registrant Name Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Ex Transition Period Entity Shell Company Entity Common Stock, Shares Outstanding Entity Public Float Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Central Index Key Amendment Flag CONSOLIDATED BALANCE SHEETS Statement [Table] Statement [Line Items] CONSOLIDATED BALANCE SHEETS CONSOLIDATED STATEMENTS OF CASH FLOWS Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Short-term Investments Short-term investments 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 Total property and equipment, net Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Restricted Cash, Noncurrent Restricted cash Deferred Offering Costs Deferred offering costs Deferred Income Tax Assets, Net Deferred tax assets Assets Total assets Liabilities and Equity [Abstract] Liabilities and Shareholders’ Equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Accrued Liabilities, Current Accrued expenses Accrued expenses Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to make milestone payments upon the achievement of specified clinical and regulatory milestone costs. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Accrued Milestone Liabilities, Current Accrued milestones Accrued milestone payments Operating Lease, Liability, Current Operating lease liabilities Other Liabilities, Current Other current liabilities Liabilities, Current Total current liabilities Liabilities, Noncurrent [Abstract] Noncurrent liabilities: Operating Lease, Liability, Noncurrent Noncurrent operating lease liabilities Other Liabilities, Noncurrent Other long-term liabilities Liabilities Total liabilities Commitments and Contingencies. Commitments and contingencies (Note 13) Preferred Stock, Value, Issued Balance at the end of the period Balance at the beginning of the period Convertible preferred shares (Series A, B and C), $0.000273235 par value; 0 shares and 22,885,492 shares issued and outstanding as of December 31, 2018 and December 31, 2017, respectively; aggregate liquidation preference of $0 and $120,000 as of December 31, 2018 and December 31, 2017, respectively; Stockholders' Equity Attributable to Parent [Abstract] Shareholders’ equity: Common Stock, Value, Issued Common stock value Additional Paid in Capital Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated deficit Stockholders' Equity Attributable to Parent Balance at the end of the period Balance at the beginning of the period Total shareholders’ equity Liabilities and Equity Total liabilities and shareholders’ equity Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares, Issued Common stock, shares issued (in shares) Common Stock, Shares, Outstanding Balance at the end of the period (in shares) Balance at the beginning of the period (in shares) Common stock, shares outstanding (in shares) CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS Operating Expenses [Abstract] Operating expenses: Research and Development Expense Research and development expense General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Loss from operations Investment Income, Interest Interest income Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Loss before benefit for income taxes Income Tax Expense (Benefit) Benefit for income taxes Total provision (benefit) for income taxes Net Income (Loss) Attributable to Parent Net losses Net loss Net loss Net loss attributable to common shareholders Earnings Per Share, Basic and Diluted Net loss per share attributable to common shareholders - basic and diluted Net loss per share attributable to common shareholders — basic and diluted Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted average common shares outstanding - basic and diluted Weighted average common shares outstanding — basic and diluted Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive loss: Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Unrealized gain (loss) on short-term investments and currency translation adjustments, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Total other comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total comprehensive loss CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED SHARES AND SHAREHOLDERS’ DEFICIT Increase (Decrease) in Temporary Equity [Roll Forward] Changes in temporary equity Temporary Equity, Shares Outstanding Balance at the end of the period (in shares) Balance at the beginning of the period (in shares) Temporary Equity, Stock Issued During Period, Value, New Issues Issuance of Series C convertible preferred shares, net of issuance costs Number of new stock classified as equity issued during the period. Temporary Equity, Stock Issued During Period, Shares, New Issues Issuance of Series C convertible preferred shares, net of issuance costs (in shares) The value of the stock, classified as temporary equity, that was converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. Temporary Equity, Conversion of Stock, Amount Converted Conversion of convertible preferred shares to common shares The number of shares, classified as temporary equity, converted in a noncash (or part noncash) transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. Temporary Equity, Conversion of Stock, Shares Converted Conversion of convertible preferred shares to common shares (in shares) Increase (Decrease) in Stockholders' Equity [Roll Forward] Changes in equity Stock Issued During Period, Value, Conversion of Convertible Securities Conversion of convertible preferred shares into common shares Stock Issued During Period, Shares, Conversion of Convertible Securities Conversion of convertible preferred shares into common shares (in shares) Stock Issued During Period, Value, New Issues Issuance of common shares upon completion of offering, net of underwriting discounts and commissions and offering costs Stock Issued During Period, Shares, New Issues Issuance of common shares upon completion of offering, net of underwriting discounts and commissions and offering costs (in shares) Issuance of stock (in shares) Stock Issued During Period, Value, Acquisitions Common shares issued or to be issued in connection with the acquisition of all issued and outstanding equity securities of Primatope Therapeutics, Inc. Stock Issued During Period, Shares, Acquisitions Common shares issued or to be issued in connection with the acquisition of all issued and outstanding equity securities of Primatope Therapeutics, Inc. (in shares) Value of stock issued pursuant to milestone payments during the period. Stock Issued During Period, Value, Milestone Payments Common shares issued or to be issued in connection with a milestone payment due to Primatope Therapeutics, Inc. Number of shares of stock issued during the period pursuant to milestone payments due. Stock Issued During Period, Shares, Milestone Payments Common shares issued or to be issued in connection with a milestone payment due to Primatope Therapeutics, Inc. (in shares) Stock Issued During Period, Value, Stock Options Exercised Exercise of options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercised Exercise of options (in shares) Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Share-based compensation expense Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Issuance costs CONSOLIDATED STATEMENTS OF CASH FLOWS Net Cash Provided by (Used in) Operating Activities [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: Depreciation Depreciation expense Share-based Compensation. Share-based compensation expense Fair value of stock issued as consideration in an acquisition. Issuance of Stock for Acquisition Class A common shares issued or to be issued as consideration for Primatope, including milestone payments Gain (Loss) on Disposition of Property Plant Equipment Loss on disposal of property and equipment Other Noncash Expense Other Amount of non-cash lease expense. Noncash Lease Expense Non-cash lease expense Accretion (Amortization) of Discounts and Premiums, Investments Accretion of discounts on short-term investments Deferred Income Tax Expense (Benefit) Total deferred income tax benefit Deferred income taxes Increase (Decrease) in Other Operating Assets and Liabilities, Net [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 Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expenses and other liabilities The increase (decrease) during the reporting period in the amount of milestone expenses incurred but not yet paid. Increase (Decrease) in Accrued Milestone Accrued milestones The increase (decrease) during the reporting period in lessee operating lease liabilities. Increase (Decrease) in Operating Lease Liabilities Operating lease liabilities Increase (Decrease) in Other Noncurrent Liabilities Other long-term liabilities Net Cash Provided by (Used in) Operating Activities Cash used in operations Net cash used in 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 property and equipment Payments to Acquire Short-term Investments Purchases of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-term Investments Proceeds from the maturities of short-term investments 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: Proceeds from Issuance of Convertible Preferred Stock Proceeds from issuance of convertible preferred shares, net of issuance costs Proceeds from Issuance of Common Stock Gross proceeds from offering Proceeds from issuance of common shares, net of underwriting commissions and discounts Proceeds from Issuance of Private Placement Proceeds from issuance of common shares from private placement, net of underwriting commissions and discounts Payments of Stock Issuance Costs Payments of offering costs Payment of offering expenses Proceeds from Stock Options Exercised Proceeds from exercise of options Proceeds from exercise of options and employee share purchase plan 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 increase in cash and cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Cash, cash equivalents and restricted cash at beginning of period Supplemental Cash Flow Elements [Abstract] Supplemental information: Income Taxes Paid Cash paid for income taxes Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of non-cash investing and financing activities: The amount of deferred offering costs included in accrued expenses and accounts payable. Deferred Offering Costs Included in Accrued Expenses and Accounts Payable Deferred offering costs included in accrued expenses and accounts payable Capital Expenditures Incurred but Not yet Paid Property and equipment included in accrued expenses and accounts payable Nature of the Business and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Nature of the Business and Basis of Presentation Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Summary of Significant Accounting Policies Fair Value of Financial Assets and Liabilities Fair Value Disclosures [Text Block] Fair Value of Financial Assets and Liabilities Property and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Property and Equipment, Net Leases Lessee, Operating Leases [Text Block] Leases Accrued Expenses Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Accrued Expenses Convertible Preferred Shares The entire disclosure of convertible preferred shares. Convertible Preferred Shares [Text Block] Convertible Preferred Shares Common Shares Stockholders' Equity Note Disclosure [Text Block] Common Shares Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Share-Based Compensation No definition available. License and Acquisition Agreements The entire disclosure for license and acquisition agreements. License and Acquisition Agreements Disclosure [Text Block] License and Acquisition Agreements Income Taxes Income Tax Disclosure [Text Block] Income Taxes Net Loss per Share Earnings Per Share [Text Block] Net Loss per Share Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Benefit Plans Compensation and Employee Benefit Plans [Text Block] Benefit Plans Consolidation, Policy [Policy Text Block] Principles of Consolidation Use of Estimates, Policy [Policy Text Block] Use of Estimates Foreign Currency Transactions and Translations Policy [Policy Text Block] Reporting and Functional Currency Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Investment, Policy [Policy Text Block] Short-term Investments Concentration Risk, Credit Risk, Policy [Policy Text Block] Concentrations of Credit Risk Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Property, Plant and Equipment, Policy [Policy Text Block] Property and Equipment Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Impairment of Long‑Lived Assets Disclosure of accounting policy capitalizes certain legal, professional accounting and other third party fees that are directly associated with in process preferred share or common equity financings as deferred offering costs. Deferred Offering Costs, Policy [Policy Text Block] Deferred Offering Costs Fair Value Measurement, Policy [Policy Text Block] Fair Value Measurements Separation of Lease and Nonlease Components [Policy Text Block] Leases Segment Reporting, Policy [Policy Text Block] Segment Information Research and Development Expense, Policy [Policy Text Block] Research and Development Costs Disclosure of accounting policy for costs it has incurred on research and development and accrued liabilities, that are analyses progress of the studies or clinical trials, including the phase or completion of events, invoices received and contracted costs. Research Contract Cost And Accruals, Policy [Policy Text Block] Research Contract Costs and Accruals Disclosure of accounting policy for patent costs. Patent Costs Policy [Policy Text Block] Patent Costs Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Share-Based Compensation Comprehensive Income, Policy [Policy Text Block] Comprehensive Loss Income Tax, Policy [Policy Text Block] Income Taxes Earnings Per Share, Policy [Policy Text Block] Net Loss per Share New Accounting Pronouncements, Policy [Policy Text Block] Recently Adopted and Recently Issued Accounting Pronouncements Tabular disclosure of the estimated useful lives of property, plant and equipment. Schedule of Estimated Useful Lives of Property Plant and Equipment [Table Text Block] Schedule of expected useful lives of assets Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of financial assets and liabilities measured at fair value on a recurring basis Property, Plant and Equipment [Table Text Block] Schedule of property and equipment, net Lessee, Operating Lease, Liability, Maturity [Table Text Block] Schedule of maturities of operating lease liabilities Schedule of Accrued Liabilities [Table Text Block] Schedule of accrued expenses Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based compensation Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of stock option valuation assumptions presented on weighted average basis Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of stock option activity under the Plans Nonvested Restricted Stock Shares Activity [Table Text Block] Schedule of restricted share activity