Entity Central Index Key Accrued of final payment fee. 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 Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding 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, net Accounts Receivable Net Current Inventory Inventory Net 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 Other assets Other Assets Noncurrent Total Assets Assets Liabilities, Convertible Preferred Stock and Stockholders’ Equity (Deficit) Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Deferred revenue Deferred Revenue Current Current portion of long-term debt Long Term Debt Current Total current liabilities Liabilities Current Long-term debt, net Long Term Debt Noncurrent Deferred revenue Deferred Revenue Noncurrent Deferred rent Deferred Rent Credit Noncurrent Convertible preferred stock warrant liability Warrants And Rights Outstanding Total Liabilities Liabilities Commitments and contingencies (Note 14) Commitments And Contingencies Convertible preferred stock, $0.01 par value: 308,593 shares previously authorized prior to initial public offering, issuable in series; no and 304,958 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively; no liquidation value at September 30, 2018 Temporary Equity Carrying Amount Attributable To Parent Stockholders’ Equity (Deficit): Stockholders Equity [Abstract] Preferred stock, $0.01 par value: 10,000 shares authorized; no shares issued or outstanding at September 30, 2018 and December 31, 2017 Preferred Stock Value Common stock, $0.01 par value: 200,000 shares authorized; 17,579 and 231 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Total Stockholders' Equity (Deficit) Stockholders Equity Total Liabilities, Convertible Preferred Stock and Stockholders’ Equity (Deficit) Liabilities And Stockholders Equity Convertible preferred stock, par value Temporary Equity Par Or Stated Value Per Share Convertible preferred stock, authorized Temporary Equity Shares Authorized Convertible preferred stock, issued Temporary Equity Shares Issued Convertible preferred stock, outstanding Temporary Equity Shares Outstanding Liquidation preference Temporary Equity Liquidation Preference 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] Revenues Revenues Cost of revenues Cost Of Revenue Gross Profit Gross Profit Operating expenses: Operating Expenses [Abstract] Sales and marketing Selling And Marketing Expense General and administrative General And Administrative Expense Research and development Research And Development Expense Total operating expenses Operating Expenses Loss from Operations Operating Income Loss Other (income) expense: Other Nonoperating Income Expense [Abstract] Interest expense Interest Expense Other expense (income), net Other Nonoperating Income Expense Net Loss Net Income Loss Net loss per share of common stock outstanding, 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 Adjustments to additional paid in capital, conversion of convertible preferred stock warrants into common stock warrants. 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 Deficit Retained Earnings [Member] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Convertible Preferred Stock Convertible Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Beginning balance Beginning balance, shares Shares Outstanding Beginning balance Beginning balance, shares 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 Conversion of convertible preferred stock warrants into common stock warrants Adjustments To Additional Paid In Capital Conversion Of Convertible Preferred Stock Warrants Into Common Stock Warrants Issuance of common stock in initial public offering, net of issuance costs of $3.464 Stock Issued During Period Value New Issues Issuance of common stock in initial public offering, net of issuance costs of $3.464, shares Stock Issued During Period Shares New Issues Exercises of stock options Stock Issued During Period Value Stock Options Exercised Exercises of stock options, shares Stock Issued During Period Shares Stock Options Exercised Share-based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Net loss Ending balance Ending balance, shares Ending balance Ending balance, shares Issuance of common stock in initial public offering, issuance costs Payments Of Stock Issuance Costs Cost of rental units purchased by customers. Transfer of inventory to property and equipment. Value of convertible preferred stock warrant liability converted to additional paid in capital related to conversion of convertible preferred stock warrants into common stock warrants. Statement Of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided By Used In Operating Activities [Abstract] Net loss Profit 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 Share-based compensation Share Based Compensation Non-cash interest expense Amortization Of Financing Costs And Discounts Change in fair value of convertible preferred stock warrant liability Fair Value Adjustment Of Warrants Cost of rental units purchased by customers Cost Of Rental Units Purchased By Customers Changes in certain assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable, net Increase Decrease In Accounts Receivable Inventory Increase Decrease In Inventories Prepaid expenses and other assets Increase Decrease In Prepaid Expenses Other Accounts payable Increase Decrease In Accounts Payable Accrued expenses Increase Decrease In Accrued Liabilities Deferred revenue Increase Decrease In Deferred Revenue Deferred rent Increase Decrease In Deferred Leasing Fees 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 and capitalized software Payments To Acquire Productive Assets Net Cash 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 issuance of common stock in initial public offering Proceeds From Issuance Initial Public Offering Payments of public offering costs Proceeds from exercises of stock options Proceeds From Stock Options Exercised Proceeds from issuance of Series G convertible preferred stock, net Proceeds From Issuance Of Convertible Preferred Stock Borrowings under credit facilities Proceeds From Lines Of Credit Payments of debt issuance costs Payments Of Debt Issuance Costs Net Cash Provided by Financing Activities Net Cash Provided By Used In Financing Activities Net Increase in Cash and Cash Equivalents Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect Cash and Cash Equivalents, Beginning of Period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash and Cash Equivalents, End of Period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Net Transfer of inventory to property and equipment Transfer Of Inventory To Property And Equipment Supplemental disclosure of non-cash financing activities: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Allocation of proceeds from debt financing to convertible preferred stock warrant liability Debt Issuance Costs Incurred During Noncash Or Partial Noncash Transaction Conversion of convertible preferred stock into common stock Conversion Of Stock Amount Converted1 Conversion of convertible preferred stock warrants into common stock warrants Conversion Of Convertible Preferred Stock Warrants Into Common Stock Warrant Organization Consolidation And Presentation Of Financial Statements [Abstract] Description of Business Nature Of Operations Accounting Policies [Abstract] Basis of Presentation Basis Of Accounting Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] New Accounting Pronouncements And Changes In Accounting Principles [Abstract] Recent Accounting Pronouncements New Accounting Pronouncements And Changes In Accounting Principles [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurement and Financial Instruments Fair Value Disclosures [Text Block] Receivables [Abstract] Accounts Receivable Loans Notes Trade And Other Receivables Disclosure [Text Block] Property Plant And Equipment [Abstract] Property and Equipment and Capitalized Software Property Plant And Equipment Disclosure [Text Block] Payables And Accruals [Abstract] Accrued expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Equity [Abstract] Convertible Preferred Stock and Stockholders' Deficit Stockholders Equity Note Disclosure [Text Block] Earnings Per Share [Abstract] Loss Per Share Earnings Per Share [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Share-based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Benefit Plans Compensation And Employee Benefit Plans Other Than Share Based Compensation [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Segments Geographical Areas [Abstract] Geographical Segment Information Segment Reporting Disclosure [Text Block] Interim Financial Statements Basis Of Accounting Policy Policy [Text Block] Use of Estimates Use Of Estimates Recapitalization Comparability Of Prior Year Financial Data Schedule of Carrying Amounts and Fair Values of Financial Instruments Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Summary of Fair Value Inputs and Assumptions Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques Table [Text Block] Summary of Changes in Instruments Measured on Recurring Basis Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Text Block] Composition of Accounts Receivable, Net Schedule Of Accounts Notes Loans And Financing Receivable [Text Block] Summary of Composition of Property and Equipment, Net Property Plant And Equipment [Text Block] Summary of Composition of Accrued Expenses Schedule Of Accrued Liabilities Table [Text Block] Summary of Composition of Debt Schedule Of Debt Instruments [Text Block] Summary of Future Principal Payments Schedule Of Maturities Of Long Term Debt Table [Text Block] Summary of Common Stock Issued and Reserved for Issuance Schedule Of Stock By Class [Text Block] Summary of Outstanding Common Stock Warrants Schedule Of Stockholders Equity Note Warrants Or Rights [Text Block] Schedule of Potentially Dilutive Securities Outstanding Excluded from Diluted Loss Per Share Calculation Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Summary of Share-Based Compensation Expense Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Summary of Stock Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Summary of Weighted-average Inputs and Assumptions used to Estimate Grant-date Fair Value of Stock Options Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Restricted Stock Award and Restricted Stock Unit Activity Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] Summary of Revenue Generated in Geographic Regions for Years Indicated Revenue From External Customers By Geographic Areas Table [Text Block] Initial public offering closing date. Description of business. Description of Business. Description Of Business [Table] Description Of Business [Table] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] Initial Public Offering I P O [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Thirty five million credit facility. $35.0 Million Credit Facility Thirty Five Million Credit Facility [Member] Lender Name Line Of Credit Facility [Axis] Line of Credit Facility, Lender Line Of Credit Facility Lender [Domain] Oxford Finance LLC. Oxford Finance LLC Oxford Finance Limited Liability Company [Member] Description Of Business [Line Items] Description Of Business [Line Items] IPO closing date Initial Public Offering Closing Date Common stock shares issued and sold Issuance price per share Share Price Net proceeds from initial public offering Convertible preferred stock converted into common stock Common stock, par value per share Common stock, shares authorized for issuance Preferred stock, shares authorized for issuance Preferred stock, par value per share Accumulated deficit Cash flows from operating activities Borrowings outstanding under credit facility Line Of Credit Credit facility maturity date Line Of Credit Facility Expiration Date1 Reverse stock split description Stockholders Equity Reverse Stock Split Reverse stock split, Conversion ratio Stockholders Equity Note Stock Split Conversion Ratio1 Operating leases expiration year. Aggregate future minimum lease payments Operating Leases Future Minimum Payments Due Current non-cancelable office lease, expiration date Operating Leases Expiration Year Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Hierarchy and NAV Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Quoted Prices In Active Markets (Level 1) Fair Value Inputs Level1 [Member] Significant other Observable Inputs (Level 2) Fair Value Inputs Level2 [Member] Significant Unobservable Inputs (Level 3) Fair Value Inputs Level3 [Member] Investment Type Investment Type [Axis] Investments Investment Type Categorization [Member] Money market funds Money Market Funds [Member] Measurement Basis Fair Value By Measurement Basis [Axis] Fair Value Disclosure Item Amounts [Default] Portion At Fair Value Fair Value Disclosure [Member] Fair Value Measurement Fair Value Disclosure Item Amounts [Domain] Carrying Amount Carrying Reported Amount Fair Value Disclosure [Member] Fair Value Estimate Of Fair Value Fair Value Disclosure [Member] Liability Class Fair Value By Liability Class [Axis] Fair Value by Liability Class Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Liability Class [Domain] Convertible preferred sock warrant liability Derivative Financial Instruments Liabilities [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Assets Assets Fair Value Disclosure [Abstract] Total assets Assets Fair Value Disclosure Liabilities Liabilities Fair Value Disclosure [Abstract] Total liabilities Liabilities Fair Value Disclosure Fair value measurement input remaining term. Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Table] Measurement Input Type Measurement Input Type [Axis] Measurement Input Type Measurement Input Type [Domain] Measurement input, estimated fair value of convertible preferred stock. Estimated Fair Value of Convertible Preferred Stock Measurement Input Estimated Fair Value Of Convertible Preferred Stock [Member] Exercise Price Measurement Input Exercise Price [Member] Remaining Term (in years) Measurement Input Expected Term [Member] Risk-free Interest Rate Measurement Input Risk Free Interest Rate [Member] Expected Volatility Measurement Input Price Volatility [Member] Dividend Yield Measurement Input Expected Dividend Rate [Member] Series E Series E Preferred Stock [Member] Series F Series F Preferred Stock [Member] Range Range [Axis] Range Range [Member] Minimum Minimum [Member] Maximum Maximum [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items] Fair value assumption Warrants And Rights Outstanding Measurement Input Remaining term (in years) Fair Value Measurement Input Remaining Term Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Abstract] Balance at December 31, 2017 Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value Change in fair value Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings Reclassification to additional paid in capital Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Instruments Classified In Shareholders Equity Transfers Out Of Level3 Balance at September 30, 2018 Gross accounts receivable - trade Accounts Receivable Gross Current Less: Allowances for doubtful accounts Allowance For Doubtful Accounts Receivable Current Accounts receivable, net Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Property, Plant and Equipment, Type Property Plant And Equipment By Type [Axis] Property, Plant and Equipment, Type Property Plant And Equipment Type [Domain] Laboratory Equipment Equipment [Member] Office Equipment Office Equipment [Member] Computer Equipment and Software Computer Equipment [Member] Manufacturing Equipment Manufacturing Facility [Member] Leasehold Improvements Leasehold Improvements [Member] Rental equipment. Rental Equipment Rental Equipment [Member] Property Plant And Equipment [Line Items] Property Plant And Equipment [Line Items] Property and equipment, gross Property Plant And Equipment Gross Less: Accumulated depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Property and equipment, net Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Other Assets [Member] Other Assets [Member] Depreciation and amortization expense Depreciation And Amortization Capitalized software cost, net Capitalized Computer Software Net Accrued research and development expense current. Compensation and related benefits Accrued Employee Benefits Current Consulting and professional fees Accrued Professional Fees Current Research and development expenses Accrued Research And Development Expense Current Sales and marketing expenses Accrued Marketing Costs Current Warranty Product Warranty Accrual Classified Current Sales tax payable Taxes Payable Current Interest payable Interest Payable Current Other Other Liabilities Current Accrued expenses Outstanding principal Debt Instrument Carrying Amount Accrued final payment fees Accrued Of Final Payment Fee Less debt discounts Debt Instrument Unamortized Discount Total long-term debt, net Long Term Debt Less current portion of long-term debt Debt Instrument [Table] Debt Instrument [Table] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Term A Loan. Term A Loan Term A Loan [Member] Term B Loan. Term B Loan Term B Loan [Member] Term C loan. Term C Loan Term C Loan [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] LIBOR London Interbank Offered Rate L I B O R [Member] Debt Instrument, Redemption, Period Debt Instrument Redemption Period [Axis] Debt Instrument, Redemption, Period Debt Instrument Redemption Period [Domain] Prepaid on or Before First Anniversary of Funding Debt Instrument Redemption Period One [Member] Prepaid After First and on or Before Second Anniversary of Funding Debt Instrument Redemption Period Two [Member] Prepaid After Second Anniversary of Funding Debt Instrument Redemption Period Three [Member] Twenty five million credit facility. $25.0 Million Credit Facility Twenty Five Million Credit Facility [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Cash interest expense Interest Expense Debt Non-cash interest expense Amortization Of Financing Costs The floor interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding, including current maturities, which accrues interest at a rate subject to change from time to time. Percentage of warrant issued to trance borrowed. Notification period to lenders in order to borrow loan upon achieving required revenue milestone. Trailing twelve month revenues to be achieved for borrowing additional availability under line of credit facility. Line of credit facility additional availability upon achievement of trailing twelve month revenues. Line of credit facility, maximum borrowing capacity Line Of Credit Facility Maximum Borrowing Capacity Line of credit facility, current borrowing capacity Line Of Credit Facility Current Borrowing Capacity Available borrowing achievement of trailing twelve month revenues Trailing Twelve Month Revenues To Be Achieved For Borrowing Additional Availability Under Line Of Credit Facility Notification period for lenders to borrow loan upon achieving required revenue milestone Notification Period To Lenders In Order To Borrow Loan Upon Achieving Required Revenue Milestone Line of credit facility additional borrowing capacity Debt Instrument Unused Borrowing Capacity Amount Debt instrument, interest rate Long Term Debt Percentage Bearing Variable Interest Rate Floor Debt instrument, description of variable rate basis Debt Instrument Description Of Variable Rate Basis Basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Warrants term Warrants And Rights Outstanding Term Percentage of borrowing capacity of tranche Percentage Of Warrant Issued To Tranche Borrowed Borrowing capacity of tranche Line Of Credit Facility Additional Availability Upon Achievement Of Trailing Twelve Month Revenues Line of credit facility interest-only period. Line of credit facility amortization period without interest only period extension. Line of credit facility interest only period extension period upon achievement of revenues. Line of credit facility interest only period extension upon achievement of revenues. Line of credit facility amortization period upon extension of interest-only period. Warrants expiration period. Interest-only period Line Of Credit Facility Interest Only Period Amortization period without interest-only period extension Line Of Credit Facility Amortization Period Without Interest Only Period Extension Extension of interest-only period upon achievement of revenues Line Of Credit Facility Interest Only Period Extension Period Upon Achievement Of Revenues Interest-only period upon achievement of revenues Line Of Credit Facility Interest Only Period Extension Upon Achievement Of Revenues Amortization period upon extension of interest-only period Line Of Credit Facility Amortization Period Upon Extension Of Interest Only Period Warrants to purchase shares Class Of Warrant Or Right Number Of Securities Called By Warrants Or Rights Warrants, exercise price Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 Warrants expiration period Warrants Expiration Period Line of credit facility final payment fees percentage. Line of credit facility increase in final payment fees percentage upon extension interest only periods. Line of credit facility prepayment fees percentage. Final payment fees percentage Line Of Credit Facility Final Payment Fees Percentage Increase in final payment fees percentage upon extension interest only periods Line Of Credit Facility Increase In Final Payment Fees Percentage Upon Extension Interest Only Periods Effective interest rates Line Of Credit Facility Interest Rate At Period End Prepayment fees percentage Line Of Credit Facility Prepayment Fees Percentage Line of credit facility percentage of forecasted revenue to be achieved in financial maintenance covenant. Percentage of forecasted revenue to be achieved Line Of Credit Facility Percentage Of Forecasted Revenue To Be Achieved In Financial Maintenance Covenant Term A loan and Term B loan. Term A and Term B Loans Term A Loan And Term B Loan [Member] 2018 Long Term Debt Maturities Repayments Of Principal Remainder Of Fiscal Year 2019 Long Term Debt Maturities Repayments Of Principal In Year Two 2020 Long Term Debt Maturities Repayments Of Principal In Year Three 2021 Long Term Debt Maturities Repayments Of Principal In Year Four 2022 Long Term Debt Maturities Repayments Of Principal In Year Five Total principal payments Debt instrument, accrued interest rate Debt Instrument Interest Rate Stated Percentage Debt instrument final payment fee. Debt instrument, final payment fee Debt Instrument Final Payment Fee Stockholders' deficit. Stockholders' deficit. Stockholders Deficit [Table] Stockholders Deficit [Table] Stockholders Deficit [Line Items] Stockholders Deficit [Line Items] Common stock, shares outstanding Shares of common stock reserved for issuance. Common stock shares issued and reserved for future issuance. Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Stock Options Outstanding Employee Stock Option [Member] Shares Available for Grant Under Stock Incentive Plan Stock Compensation Plan [Member] Restricted Stock Units Outstanding Restricted Stock Units R S U [Member] Shares Available for Sales Under Employee Stock Purchase Plan Employee Stock [Member] Warrants Issuable Upon Term C Loan Borrowing Warrant [Member] Class of Warrant or Right Class Of Warrant Or Right [Axis] Class of Warrant or Right Class Of Warrant Or Right [Domain] Series E convertible preferred stock warrants. Series E Convertible Preferred Stock Warrants Series E Convertible Preferred Stock Warrants [Member] Series F convertible preferred stock warrants. Series F Convertible Preferred Stock Warrants Series F Convertible Preferred Stock Warrants [Member] Common stock warrants. Common Stock Warrants Outstanding Common Stock Warrants [Member] Series A-1 convertible preferred stock. Series A-1 Convertible Preferred Stock Series A One Convertible Preferred Stock [Member] Series A-2 convertible preferred stock. Series A-2 Convertible Preferred Stock Series A Two Convertible Preferred Stock [Member] Series B convertible preferred stock. Series B Convertible Preferred Stock Series B Convertible Preferred Stock [Member] Series C convertible preferred stock. Series C Convertible Preferred Stock Series C Convertible Preferred Stock [Member] Series D convertible preferred stock. Series D Convertible Preferred Stock Series D Convertible Preferred Stock [Member] Series E convertible preferred stock. Series E Convertible Preferred Stock Series E Convertible Preferred Stock [Member] Series F convertible preferred stock. Series F Convertible Preferred Stock Series F Convertible Preferred Stock [Member] Series G convertible preferred stock. Series G Convertible Preferred Stock Series G Convertible Preferred Stock [Member] Shares of common stock issued Shares of common stock reserved for issuance for: Shares Of Common Stock Reserved For Issuance [Abstract] Shares of common stock reserved for issuance Common Stock Capital Shares Reserved For Future Issuance Total shares of common stock issued and reserved for issuance Common Stock Shares Issued And Reserved For Future Issuance Conversion of preferred stock to common stock conversion ratio. Convertible preferred stock converted to common stock, ratio Conversion Of Preferred Stock To Common Stock Conversion Ratio Class of warrants or right expiration date. Class Of Warrant Or Right [Table] Class Of Warrant Or Right [Table] Exercise price range one. Exercise Price $19.55 Exercise Price Range One [Member] Exercise price range two. Exercise Price $9.73 Exercise Price Range Two [Member] Exercise price range three. Exercise Price $9.73 Exercise Price Range Three [Member] Exercise price range four. Exercise Price $9.73 Exercise Price Range Four [Member] Exercise price range five. Exercise Price $9.73 Exercise Price Range Five [Member] Class Of Warrant Or Right [Line Items] Class Of Warrant Or Right [Line Items] Warrants Outstanding Class Of Warrant Or Right Outstanding Exercise Price Expiration Date Class Of Warrants Or Right Expiration Date Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Shares of Convertible Preferred Stock "as-converted" Convertible preferred stock warrants. Convertible Preferred Stock Warrants Convertible Preferred Stock Warrants [Member] Common Stock Warrants Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Non vested restricted stock awards. Non-vested Restricted Stock Awards Non Vested Restricted Stock Awards [Member] Non-vested Restricted Stock Units Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Potentially dilutive securities outstanding excluded from diluted loss per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Cost of Revenues Cost Of Sales [Member] Selling and Marketing Selling And Marketing Expense [Member] General and Administrative General And Administrative Expense [Member] Research and Development Research And Development Expense [Member] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Total Allocated Share Based Compensation Expense Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] 2018 Equity incentive plan. 2018 Equity Incentive Plan Two Thousand Eighteen Equity Incentive Plan [Member] Vesting Vesting [Axis] Vesting Vesting [Domain] First Anniversary of Date of Grant Share Based Compensation Award Tranche One [Member] 2003 Stock incentive plan. 2003 Stock Incentive Plan Two Thousand Three Stock Incentive Plan [Member] Restricted stock and restricted stock units RSU. Restricted Stock Awards and Restricted Stock Units Restricted Stock And Restricted Stock Units R S U [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Number of shares authorized for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized Maximum contractual term of stock options Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period Vesting percentage of stock options Sharebased Compensation Arrangement By Sharebased Payment Award Award Vesting Rights Percentage Vesting terms of stock options Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Rights Shares available for future issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Number of Shares under Option, Outstanding, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Number of Shares under Option, Granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Number of Shares under Option, Exercised Number of Shares under Option, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Number of Shares under Option, Outstanding, Ending balance Number of Shares under Option, Exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Number of Shares under Option, Vested and expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number Weighted-average Exercise Price per Option, Outstanding, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Weighted-average Exercise Price per Option, Granted Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Weighted-average Exercise Price per Option, Exercised Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Weighted-average Exercise Price per Option, Forfeited Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price Weighted-average Exercise Price per Option, Outstanding, Ending balance Weighted-average Exercise Price per Option, Exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Weighted-average Exercise Price per Option, Vested and expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price Weighted-average Remaining Contractual Life, Outstanding Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Weighted-average Remaining Contractual Life, Exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 Weighted-average Remaining Contractual Life, Vested and expected to vest Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 Aggregate Intrinsic Value, Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Aggregate Intrinsic Value, Exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Aggregate Intrinsic Value, Vested and expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value Share-based compensation expenses Unrecognized compensation cost related to non-vested stock options Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options Non-vested awards not yet recognized weighted-average period for recognition Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Weighted-average grant-date fair value of stock options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Intrinsic value of stock options exercised Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value Share based compensation arrangement by share based payment award options granted in period weighted average grant date fair value of underlying common stock. Estimated fair value of common stock Share Based Compensation Arrangement By Share Based Payment Award Options Granted In Period Weighted Average Grant Date Fair Value Of Underlying Common Stock Expected term (in years) Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 Risk-free interest rate Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Expected volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Weighted Average Volatility Rate Dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Share based compensation arrangement by share based payment award options grants in period to purchase shares of common stock. Share based compensation arrangement by share based payment award options exercise price. Share based compensation arrangement by share based payment award stock vesting period number of monthly installment. Share based compensation arrangement by share based payment award options estimated grant date fair value. Options to purchase shares Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period To Purchase Shares Of Common Stock Option exercise price Share Based Compensation Arrangement By Share Based Payment Award Options Exercise Price Stock option vesting period monthly installment Share Based Compensation Arrangement By Share Based Payment Award Stock Vesting Period Number Of Monthly Installment Estimated grant-date fair value of option awards Share Based Compensation Arrangement By Share Based Payment Award Options Estimated Grant Date Fair Value Restricted Stock Awards [Member] Restricted Stock [Member] Non-vested, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Non-vested, Ending balance Weighted-average Grant-date Fair Value, Non-vested, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Weighted-average Grant-date Fair Value, Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value Weighted-average Grant-date Fair Value, Vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value Weighted-average Grant-date Fair Value, Non-vested, Ending balance Unrecognized compensation cost related to non-vested restricted stock Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options Fair value of restricted stock vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value Schedule Of Defined Benefit Plans Disclosures [Table] Schedule Of Defined Benefit Plans Disclosures [Table] Retirement Plan Type Retirement Plan Type [Axis] Retirement Plan Type Retirement Plan Type [Domain] 401(k) Plan Supplemental Employee Retirement Plan Defined Benefit [Member] 2018 ESPP Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined contribution retirement plan, plan name Defined Contribution Plan Plan Name Defined contribution retirement plan, maximum employee contribution deferred Defined Contribution Plan Maximum Annual Contributions Per Employee Percent Share based compensation arrangement by share based payment award period of automatic annual increases in share reserve. Period of automatic annual increase in the share reserve Share Based Compensation Arrangement By Share Based Payment Award Period Of Automatic Annual Increases In Share Reserve Common stock purchase price, discount rate Share Based Compensation Arrangement By Share Based Payment Award Discount From Market Price Purchase Date Lease term Lessee Operating Lease Term Of Contract Number of operating business segment Number Of Operating Segments Schedule Of Segment Reporting Information By Segment [Table] Schedule Of Segment Reporting Information By Segment [Table] Concentration Risk Benchmark Concentration Risk By Benchmark [Axis] Concentration Risk Benchmark Concentration Risk Benchmark [Domain] Revenues Sales Revenue Net [Member] Geographical Statement Geographical [Axis] Geographical Segment Geographical [Domain] United States UNITED STATES International Non Us [Member] Concentration Risk Type Concentration Risk By Type [Axis] Concentration Risk Type Concentration Risk Type [Domain] Geographic Concentration Geographic Concentration Risk [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Percentage of Revenues Concentration Risk Percentage1