Entity Central Index Key Debt instrument unamortized discount and deferred financing cost. Document and entity information. 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 Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Accounts receivable prepaid expense and other current assets. Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Accounts receivable, prepaid expenses, and other current assets Accounts Receivable Prepaid Expense And Other Current Assets Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Other assets Other Assets Noncurrent Total Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Current portion of loan payable Loans Payable Current Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Current portion of deferred revenue Deferred Revenue Current Total current liabilities Liabilities Current Long-term liabilities: Liabilities Noncurrent [Abstract] Loan payable, net of current portion Long Term Loans Payable Deferred revenue Deferred Revenue Noncurrent Other long-term liabilities Other Liabilities Noncurrent Total long-term liabilities Liabilities Noncurrent Commitments (Note 11) Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Preferred stock $0.01 par value; 5,000,000 shares authorized, no shares issued or outstanding Preferred Stock Value Common stock, $0.0001 par value; 120,000,000 shares authorized, 28,937,185 and 27,346,780 shares issued and outstanding at December 31, 2016 and 2015, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity Stockholders Equity Total 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] Revenue Revenues Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Other income (expense): Nonoperating Income Expense [Abstract] Interest income Investment Income Interest Interest expense Interest Expense Loss on extinguishment of debt Gains Losses On Extinguishment Of Debt Decrease in value of preferred stock warrant liability Fair Value Adjustment Of Warrants Total other income (expense), net Nonoperating Income Expense Net loss attributable to common stockholders Net Income Loss Net loss per share attributable to common stockholders: Earnings Per Share Basic And Diluted [Abstract] Basic and diluted Earnings Per Share Basic And Diluted Weighted-average common shares outstanding: Weighted Average Number Of Shares Outstanding [Abstract] Basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Conversion of convertible notes. Conversion of convertible notes, shares. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Redeemable Convertible Preferred Stock [Member] Redeemable Convertible Preferred Stock [Member] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid In Capital [Member] Accumulated Deficit [Member] Retained Earnings [Member] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] IPO [Member] I P O [Member] Follow-on Offering. Follow-on Offering [Member] Follow On Offering [Member] Private Placement [Member] Private Placement [Member] Common stock purchase agreement. Common Stock Purchase Agreement [Member] Common Stock Purchase Agreement [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Term loan facility. Term Loan Facility [Member] Term Loan Facility [Member] Statement [Line Items] Statement [Line Items] Beginning balance Redeemable convertible preferred stock, Beginning balance Temporary Equity Value Excluding Additional Paid In Capital Beginning balance, shares Shares Outstanding Redeemable convertible preferred stock, Beginning balance, shares Temporary Equity Shares Issued Exercise of stock options Stock Issued During Period Value Stock Options Exercised Exercise of stock options, shares Stock Issued During Period Shares Stock Options Exercised Issuance of common stock from employee stock purchase plan Stock Issued During Period Value Employee Stock Purchase Plan Issuance of common stock from employee stock purchase plan, shares Stock Issued During Period Shares Employee Stock Purchase Plans Issuance of common stock for services Stock Issued During Period Value Issued For Services Issuance of common stock for services, shares Stock Issued During Period Shares Issued For Services Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Issuance of Common Stock Stock Issued During Period Value New Issues Issuance of Common Stock, shares Stock Issued During Period Shares New Issues Conversion of convertible preferred stock into common stock Stock Issued During Period Value Conversion Of Convertible Securities Conversion of convertible preferred stock into common stock, shares Stock Issued During Period Shares Conversion Of Convertible Securities Reclassification/Issuance of warrants Adjustments To Additional Paid In Capital Warrant Issued Conversion of convertible notes Conversion Of Convertible Notes Conversion of convertible notes, shares Conversion Of Convertible Notes Shares Net loss Ending balance Redeemable convertible preferred stock, Ending balance Ending balance, shares Redeemable convertible preferred stock, Ending balance, shares Stock issuance costs Adjustments To Additional Paid In Capital Stock Issued Issuance Costs Increase decrease in accounts receivable prepaid expenses and other current assets. Proceeds from issuance public offering, net. Property and equipment in accounts payable. Reclassification of warrants to additional paid in capital. Noncash warrants issued with term loan facility. 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] Stock-based compensation Share Based Compensation Noncash rent expense Straight Line Rent Adjustments Change in carrying value of preferred stock warrant liability Depreciation and amortization Depreciation Depletion And Amortization (Gain) loss on disposal of property and equipment Gain Loss On Sale Of Property Plant Equipment Loss on extinguishment of debt Amortization of debt discount and deferred financing costs Amortization Of Financing Costs And Discounts Deferred revenue Increase Decrease In Deferred Revenue Amortization of deferred revenue Recognition Of Deferred Revenue Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable, prepaid expenses and other current assets Increase Decrease In Accounts Receivable Prepaid Expenses And Other Current Assets Accounts payable Increase Decrease In Accounts Payable Accrued expenses Increase Decrease In 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] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Proceeds from sale of property and equipment Proceeds From Sale Of Property Plant And Equipment Increase (decrease) in restricted cash Increase Decrease In Restricted Cash Net cash 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] Proceeds from sale of common stock Proceeds From Issuance Of Common Stock Proceeds from public stock offering, net Proceeds From Issuance Public Offering Net Proceeds from loan payable Proceeds From Notes Payable Proceeds from issuance of convertible promissory notes Proceeds From Convertible Debt Payments on loan payable Repayments Of Notes Payable Cash paid for debt issuance costs Payments Of Debt Issuance Costs Net cash (used in) provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Net increase (decrease) in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents — Beginning of year Cash and cash equivalents — End of year Supplemental disclosures of noncash investing and financing activities: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Purchase of property and equipment in accounts payable Property And Equipment In Accounts Payable Conversion of redeemable convertible preferred stock into common stock Conversion Of Stock Amount Converted1 Conversion of convertible notes and accrued interest into common stock, net Debt Conversion Original Debt Amount1 Reclassification of warrants to additional paid-in capital Reclassification Of Warrants To Additional Paid In Capital Warrants issued with term loan facility Noncash Warrants Issued With Term Loan Facility Supplemental cash flow information — Interest paid Interest Paid Net Organization Consolidation And Presentation Of Financial Statements [Abstract] Nature of Business and Operations Nature Of Operations Accounting Policies [Abstract] Significant Accounting Policies Significant Accounting Policies [Text Block] Earnings Per Share [Abstract] Net Loss Per Share Attributable to Common Stockholders Earnings Per Share [Text Block] Property Plant And Equipment [Abstract] Property and Equipment Property Plant And Equipment Disclosure [Text Block] Payables And Accruals [Abstract] Accrued Expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Debt Disclosure [Abstract] Loan Agreements Long Term Debt [Text Block] Stockholders Equity Note [Abstract] Stockholder's Equity (Deficit) Stockholders Equity Note Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock Option Plans Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments Commitments Disclosure [Text Block] Research And Development Expense [Abstract] Licensing Agreements Collaborative Arrangement Disclosure [Text Block] Compensation And Retirement Disclosure [Abstract] Retirement Plans Pension And Other Postretirement Benefits Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Revenues [Abstract] Revenue Research And Development Arrangement Contract To Perform For Others [Text Block] Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Use of Estimates Use Of Estimates Principles of Consolidation Consolidation Policy [Text Block] Segment Information Segment Reporting Policy Policy [Text Block] Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Concentrations of Credit Risk Concentration Risk Credit Risk Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy 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] Revenue Recognition Revenue Recognition Policy [Text Block] Research and Development Costs Research And Development Expense Policy Stock-Based Compensation Share Based Compensation Option And Incentive Plans Policy Net Loss per Share Attributable to Common Stockholders Earnings Per Share Policy [Text Block] Income Taxes Income Tax Policy [Text Block] Guarantees and Indemnification Guarantees Indemnifications And Warranties Policies Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of property and equipment estimated useful life. Schedule of Property and Equipment Estimated Useful Lives Schedule Of Property And Equipment Estimated Useful Life Table [Text Block] Schedule of Basic and Diluted Net Loss Per Common Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block]