Entity Central Index Key Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Available-for sale investments, short-term Available For Sale Securities Debt Securities Current Prepaid expenses and other assets Prepaid Expense And Other Assets Current Total current assets Assets Current Available-for sale investments, long-term Available For Sale Securities Debt Securities Noncurrent Property and equipment, net Property Plant And Equipment Net Other assets Other Assets Noncurrent 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 Current portion of deferred rent Deferred Rent Credit Current Current portion of long-term debt Long Term Debt Current Total current liabilities Liabilities Current Deferred rent, net of current portion Deferred Rent Credit Noncurrent Long-term debt, net of current portion and issuance costs Long Term Debt Noncurrent Other long-term liabilities Other Liabilities Noncurrent Commitments and contingencies (Note 5) Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Common stock, $0.001 par value; authorized shares – 150,000,000 and 95,500,000 at December 31, 2016 and 2015, respectively; issued and outstanding shares – 23,744,832 and 23,670,079 at December 31, 2016 and 2015, 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 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] Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income Loss Interest income (expense), net Interest Income Expense Nonoperating Net Loss on extinguishment of debt Gains Losses On Extinguishment Of Debt Change in fair value of warrant liabilities Fair Value Adjustment Of Warrants Total other income (expense) Other 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 Accretion to redemption value of redeemable convertible preferred stock Temporary Equity Accretion To Redemption Value Adjustment Net loss attributable to common stockholders Net Income Loss Available To Common Stockholders Basic Net loss per share attributable to common stockholders, basic and diluted Earnings Per Share Basic And Diluted Weighted average common stock shares outstanding, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement Of Income And Comprehensive Income [Abstract] Net loss Other comprehensive gain (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Change in unrealized gain (loss) on available for sale investments, 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 Increase (decrease) to additional paid in capital changes to share repurchase liability. Changes in equity dissolution of affiliates. Temporary stock issued during period shares new issues. Adjustments to additional paid in capital and stockholder note receivable. Reclassification of convertible preferred stock warrant liability to additional paid in capital. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Redeemable Convertible Preferred Stock [Member] Redeemable Convertible Preferred Stock [Member] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Stockholder Note Receivable [Member] Receivables From Stockholder [Member] Non-Controlling Interest [Member] Noncontrolling Interest [Member] Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Redeemable Convertible Preferred Stock, Beginning balance Temporary Equity Carrying Amount Attributable To Parent Redeemable Convertible Preferred Stock, shares, Beginning balance Temporary Equity Shares Outstanding Beginning balance Beginning balance, Shares Shares Outstanding Issuance of Series E redeemable convertible preferred stock for cash Temporary Equity Stock Issued During Period Value New Issues Issuance of Series E redeemable convertible preferred stock for cash, Shares Temporary Stock Issued During Period Shares New Issues Conversion of redeemable convertible preferred stock in connection with initial public offering Stock Issued During Period Value Conversion Of Convertible Securities Conversion of redeemable convertible preferred stock in connection with IPO, Shares Stock Issued During Period Shares Conversion Of Convertible Securities Issuance of common stock through initial public offering, net Stock Issued During Period Value New Issues Issuance of common stock through initial public offering, net, Shares Stock Issued During Period Shares New Issues Repayment of stockholder note receivable Adjustments To Additional Paid In Capital And Stockholder Note Receivable Exercise of common stock options Stock Issued During Period Value Stock Options Exercised Exercise of common stock options, Shares Stock Issued During Period Shares Stock Options Exercised Reclassification of preferred stock warrant liability to additional paid-in-capital Reclassification Of Convertible Preferred Stock Warrant Liability To Additional Paid In Capital Issuance of common stock to The Scripps Research Institute Stock Issued During Period Value Issued For Services Issuance of common stock to The Scripps Research Institute, Shares Stock Issued During Period Shares Issued For Services Issuance of common stock pursuant to employee stock purchase plan Stock Issued During Period Value Employee Stock Purchase Plan Issuance of common stock pursuant to employee stock purchase plan, Shares Stock Issued During Period Shares Employee Stock Purchase Plans Issuance of warrants related to term loan Adjustments To Additional Paid In Capital Warrant Issued Changes in share repurchase liability Increase Decrease To Additional Paid In Capital Changes To Share Repurchase Liability Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Dissolution of affiliates Changes In Equity Dissolution Of Affiliates Accretion to redemption value of redeemable convertible preferred stock Adjustments To Additional Paid In Capital Increase In Carrying Amount Of Redeemable Preferred Stock Net unrealized gain (loss) on investments, net of tax Redeemable Convertible Preferred Stock, Ending balance Redeemable Convertible Preferred Stock, Ending balance, shares Ending balance Ending balance, Shares This element represents the change during the reporting period in the carrying value for deferred rent. Issuance of warrants in connection with borrowings. Statement Of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities Continuing Operations [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 Depletion And Amortization Issuance of common stock for technology Issuance Of Stock And Warrants For Services Or Claims Stock-based compensation Allocated Share Based Compensation Expense Amortization of debt discount Amortization Of Debt Discount Premium Loss on debt extinguishment Change in fair value of preferred stock warrant liability Amortization of premium of available-for-sale investment securities Accretion Amortization Of Discounts And Premiums Investments Deferred rent Increase Decrease In Deferred Rent Credit Changes in operating assets and liabilities Increase Decrease In Operating Capital [Abstract] Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable and accrued expenses Increase Decrease In Accounts Payable And Accrued Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Continuing Operations Cash flows from investing activities: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Purchase of property and equipment Payments To Acquire Property Plant And Equipment Purchases of available-for-sale investment securities Payments To Acquire Available For Sale Securities Debt Maturities of available-for-sale investment securities Proceeds From Sale And Maturity Of Available For Sale Securities Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations Cash flows from financing activities: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Issuance of preferred stock for cash, net of issuance costs Proceeds From Issuance Of Preferred Stock And Preference Stock Issuance of common stock through initial public offering, net of offering costs Proceeds From Issuance Initial Public Offering Costs paid in connection with initial public offering Payments Of Stock Issuance Costs Proceeds from issuance of common stock through option exercises Proceeds From Issuance Of Common Stock Proceeds from employee stock purchase plan Proceeds From Stock Plans Proceeds from borrowing, net Proceeds From Repayments Of Debt Repayments on notes payable to bank Repayments Of Bank Debt Repayment of convertible debt Repayments Of Convertible Debt Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Net change in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of year Cash and cash equivalents at the end of year Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid Supplemental schedule of noncash investing and financing activities: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Issuance of warrants in connection with borrowings Issuance Of Warrants In Connection With Borrowings Accounting Policies [Abstract] Organization, Business and Basis of Presentation Organization Consolidation Basis Of Presentation Business Description And Accounting Policies [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Balance sheet details. Balance Sheet Details [Abstract] Balance Sheet Details Supplemental Balance Sheet Disclosures [Text Block] Debt commitments and contingencies. Debt Instruments [Abstract] Debt, Commitments and Contingencies Debt Commitments And Contingencies [Text Block] Equity [Abstract] Stockholders' Equity Shareholders Equity And Share Based Payments [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Benefits Compensation And Employee Benefit Plans [Text Block] Quarterly Financial Data [Abstract] Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Principles of Consolidation Consolidation Policy [Text Block] Use of Estimates Use Of Estimates Segment Reporting Segment Reporting Policy Policy [Text Block] Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Investment Securities Investment Policy [Text Block] Concentration of Credit Risk Concentration Risk Credit Risk Property and Equipment Property Plant And Equipment Policy [Text Block] Impairment of Long-Lived Assets Impairment Or Disposal Of Long Lived Assets Policy [Text Block] accrued expenses. Accrued Expenses Accrued Expenses Policy [Text Block] Deferred Rent Deferred Charges Policy [Text Block] Research and Development Costs Research And Development Expense Policy Patent Costs Legal Costs Policy [Text Block] Stock-Based Compensation Compensation Related Costs Policy [Text Block] Income Taxes Income Tax 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 Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Summary of Net Loss Per Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Schedule of Available-for-sale Investments Available For Sale Securities [Text Block] Schedule of Available-for-sale Investments in Unrealized Loss Position Available For Sale Securities Continuous Unrealized Loss Position Fair Value Table [Text Block] Summary of Property and Equipment Property Plant And Equipment [Text Block] Summary of Accrued Expenses Schedule Of Accrued Liabilities Table [Text Block] Schedule of Future Principal Payments for Term Loan Including Final Payment Schedule Of Maturities Of Long Term Debt Table [Text Block] Schedule of Future Minimum Payments under Non-cancelable Operating Lease Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Employee Stock Option [Member] Employee Stock Option [Member] Performance options with market condition. Performance Options with Market Condition [Member] Performance Options With Market Condition [Member] Summary of Stock Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Assumptions Used to Determine Fair Value of Employee Stock Purchase Plan Schedule Of Share Based Payment Award Employee Stock Purchase Plan Valuation Assumptions Table [Text Block] Schedule of Restricted Stock Units Activity Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] Schedule of Allocation of Stock-Based Compensation for All Options Including Performance Options with Market Condition and Restricted Stock Units Schedule Of Compensation Cost For Share Based Payment Arrangements Allocation Of Share Based Compensation Costs By Plan Table [Text Block] Summary of Warrants Outstanding Schedule Of Stockholders Equity Note Warrants Or Rights [Text Block] Schedule of common stock reserved for future issuance. Summary of Common Stock Reserved for Future Issuance Schedule Of Common Stock Reserved For Future Issuance Table [Text Block] Schedule of Pretax Earnings (Loss) for Domestic and Foreign Operations Schedule Of Income Before Income Tax Domestic And Foreign Table [Text Block]