Entity Central Index Key Cover [Abstract] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Document Period End Date Document Period End Date Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation State Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, Address Line Two Entity Address Address Line2 Entity Address, City or Town Entity Address City Or Town Entity Address, State or Province Entity Address State Or Province Entity Address, Postal Zip Code Entity Address Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Title of 12(b) Security Security12b Title Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Shell Company Entity Shell Company Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Marketable securities Available For Sale Securities Debt Securities Current Accounts receivable from collaboration Accounts Receivable Net Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Operating lease right-of-use assets Operating Lease Right Of Use Asset Other assets Other Assets Noncurrent Indefinite-lived intangible asset Indefinite Lived Intangible Assets Excluding Goodwill Goodwill Goodwill Total assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities And Stockholders Equity [Abstract] Current liabilities Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Deferred revenue - short-term Contract With Customer Liability Current Operating lease liabilities - short-term Operating Lease Liability Current Total current liabilities Liabilities Current Deferred rent Deferred Rent Credit Noncurrent Deferred tax liabilities Deferred Income Tax Liabilities Net Deferred revenue - long-term Contract With Customer Liability Noncurrent Operating lease liabilities - long-term Operating Lease Liability Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments And Contingencies Stockholders' equity Stockholders Equity [Abstract] Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding Preferred Stock Value Common stock, $0.001 par value; 100,000,000 shares authorized as of September 30, 2019 and December 31, 2018; 25,872,723 and 25,495,425 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders' equity Stockholders Equity Total liabilities and stockholders' 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 Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Income Statement [Abstract] Collaboration revenue Revenue From Contract With Customer Including Assessed Tax Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Costs And Expenses Loss from operations Operating Income Loss Other income (expenses) Nonoperating Income Expense [Abstract] Interest and other income Interest Income Other Other income (expense), net Other Operating Income Expense Net Total other income Nonoperating Income Expense Loss before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax benefit Income Tax Expense Benefit Net loss Net Income Loss Other comprehensive (loss) income Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent [Abstract] Unrealized gain (loss) on marketable securities, net of tax Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Net loss per share, basic and diluted Earnings Per Share Basic And Diluted Weighted average common shares outstanding, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Amount of Accretion and Amortization of Investments in Marketable Securities. Represent non cash rent expense. Increase decrease in operating lease liabilities. Statement Of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided By Used In Operating Activities [Abstract] Net loss 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 Depletion And Amortization Stock-based compensation Share Based Compensation Net accretion and amortization of investments in marketable securities Accretion And Amortization Of Investments In Marketable Securities Non-cash rent expense Noncash Rent Expense Deferred income tax benefit Deferred Income Tax Expense Benefit Loss on disposal of fixed assets Gain Loss On Disposition Of Assets1 Other Other Noncash Income Expense Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable from collaboration Increase Decrease In Accounts Receivable Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Other assets Increase Decrease In Other Noncurrent Assets Accounts payable Increase Decrease In Accounts Payable Accrued expenses Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Contract With Customer Liability Deferred rent Increase Decrease In Prepaid Rent Operating lease liabilities Increase Decrease In Operating Lease Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Cash flows from investing activities Net Cash Provided By Used In Investing Activities [Abstract] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Purchases of marketable securities Payments To Acquire Available For Sale Securities Debt Proceeds from maturities of marketable securities Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Proceeds from sale of marketable securities Proceeds From Sale Of Available For Sale Securities Debt Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Cash flows from financing activities Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from common stock sold, net of underwriters' discount and cost Proceeds From Issuance Of Common Stock Net proceeds from the issuance of common stock through equity plans Proceeds From Issuance Initial Public Offering Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Net increase (decrease) in cash and cash equivalents Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash and cash equivalents at the beginning of the period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations Cash and cash equivalents at the end of the period Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid In Capital [Member] Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income [Member] Accumulated Deficit Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Balance Balance (in shares) Shares Outstanding Proceeds from common stock sold, net of underwriters' discount and cost Stock Issued During Period Value New Issues Proceeds from common stock sold, net of underwriters' discount and cost (in shares) Stock Issued During Period Shares New Issues Issuance of common stock upon exercise of stock options Stock Issued During Period Value Stock Options Exercised Issuance of common stock upon exercise of stock options ( in shares ) Stock Issued During Period Shares Stock Options Exercised Issuance of common stock under Employee Stock Purchase Plan (ESPP) Stock Issued During Period Value Employee Stock Ownership Plan Issuance of common stock under Employee Stock Purchase Plan (ESPP) (in shares) Stock Issued During Period Shares Employee Stock Ownership Plan Issuance of shares of common stock for settlement of restricted stock units (RSUs) Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures Issuance of shares of common stock for settlement of restricted stock units (RSUs)(in shares) Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures Reclassification of stock-based awards from equity to accrued expenses Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Balance Balance (in shares) Organization Consolidation And Presentation Of Financial Statements [Abstract] Nature of Business Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies and Recent Accounting Pronouncements Significant Accounting Policies [Text Block] Investments Debt And Equity Securities [Abstract] Investments in Marketable Securities Investments In Debt And Marketable Equity Securities And Certain Trading Assets Disclosure [Text Block] Property Plant And Equipment [Abstract] Property and Equipment, Net Property Plant And Equipment Disclosure [Text Block] Payables And Accruals [Abstract] Accrued Expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock Plans and Stock-Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Collaborative and License Arrangement Disclosure. Collaboration Agreement Collaboration Agreement [Abstract] Collaboration Agreement Collaborative And License Arrangement Disclosure [Text Block] Milestones and Research Agreements Milestones and Research Agreements Milestones And Research Agreements [Abstract] Milestones and Research Agreements Milestones And Research Agreements [Text Block] Lease Cost [Abstract] Leases Lessee Operating Leases [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] Use of Estimates Use Of Estimates Disclosure of accounting policy for Significant Accounting Policies. Significant Accounting Policies Significant Accounting Policies Policy [Text Block] Stock-Based Compensation Share Based Compensation Option And Incentive Plans Policy Leases Lessee Leases Policy [Text Block] Net Loss per Share Earnings Per Share Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Schedule of Investments in Marketable Securities Schedule Of Available For Sale Securities Reconciliation Table [Text Block] Schedule of Fair Value of Financial Assets Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Table [Text Block] Schedule of Property and Equipment Property Plant And Equipment [Text Block] Schedule of Accrued Expenses Schedule Of Accrued Liabilities Table [Text Block] Schedule of Stock Options Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Schedule of RSU's Nonvested Restricted Stock Shares Activity Table [Text Block] Assumptions for Weighted Average Fair Value of Options Granted Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Schedule of Stock-Based Compensation Expense Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Schedule of Changes in Contract Liabilities Contract With Customer Asset And Liability Table [Text Block] Schedule of Collaboration revenue recognized with the period Schedule of Collaboration Revenue Recognized with the Period Schedule Of Collaboration Revenue Recognized With Period Table [Text Block] Schedule of Quantitative Information of Operating Leases Lease Cost Table [Text Block] Schedule of Maturities Operating Lease Liabilities Lessee Operating Lease Liability Maturity Table [Text Block] Operating segments (in segments) Number Of Operating Segments Represents the number of approved products. FDA approved products (in products) Number Of Approved Products Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Warrants Warrant [Member] Options Employee Stock Option [Member] Common stock subject to purchase under employee stock purchase program. Common stock subject to purchase under ESPP Common Stock Subject To Purchase Under Employee Stock Purchase Program [Member] RSUs Restricted Stock Units R S U [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]