Weighted-average remaining contractual life, options vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Statistical Measurement [Domain] Statistical Measurement [Domain] Inventory, work in process, gross Inventory, Work in Process, Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Summary of Information Related to Lease Expense and Valuation of Lease Assets and Lease Liabilities Lease, Cost [Table Text Block] Cover [Abstract] Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Credit losses on investments Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Trading Symbol Trading Symbol All Trading Arrangements All Trading Arrangements [Member] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Non-NEOs Non-NEOs [Member] Schedule of Computation of Basic and Diluted Net Loss per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Performance period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Other Commitments [Line Items] Other Commitments [Line Items] Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Pay vs Performance Disclosure [Line Items] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Accounts receivable Increase (Decrease) in Accounts Receivable Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Fair Value Measurement Fair Value Disclosures [Text Block] Proceeds from the exercise of stock options Proceeds from Stock Options Exercised Award Timing Disclosures [Line Items] Other Performance Measure, Amount Other Performance Measure, Amount Common stock outstanding (in shares) Stockholders' equity, beginning of period (in shares) Stockholders' equity, end of period (in shares) Common Stock, Shares, Outstanding Operating lease expense Operating Lease, Cost Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Operating lease liabilities, net of current portion Operating Lease, Liability, Noncurrent Segments Segment Reporting, Policy [Policy Text Block] ESPP purchase rights Employee Stock Purchase Plan Shares [Member] Employee Stock Purchase Plan Shares [Member] Plan Name [Domain] Plan Name [Domain] United States UNITED STATES Construction in progress, surgical placement instrument set Construction in Progress, Surgical Placement Instrument Set [Member] Construction in Progress, Surgical Placement Instrument Set Other non-current assets Other Assets, Noncurrent Entity Tax Identification Number Entity Tax Identification Number Schedule of Outstanding Borrowings Schedule of Long-Term Debt Instruments [Table Text Block] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Money market funds Money market funds Money Market Funds [Member] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] U.S. treasury securities U.S. treasury securities US Treasury Securities [Member] Term loan Secured Debt [Member] Plan Name [Axis] Plan Name [Axis] Equity Components [Axis] Equity Components [Axis] Award Timing Method Award Timing Method [Text Block] Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Options vested and exercisable (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price Measurement Frequency [Axis] Measurement Frequency [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Insider Trading Policies and Procedures [Line Items] Use of Estimates Use of Estimates, Policy [Policy Text Block] Adjustment to Compensation, Amount Adjustment to Compensation Amount Aggregate intrinsic value, options outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Compensation Amount Outstanding Recovery Compensation Amount Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Unrealized loss on marketable securities Net unrealized loss on marketable securities Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Entity Small Business Entity Small Business Cash equivalents Cash Equivalents, at Carrying Value [Abstract] Company Selected Measure Amount Company Selected Measure Amount Geographical [Axis] Geographical [Axis] Warrants Issued 12/22/2016 Warrants Issued December Twenty-Second Twenty Sixteen [Member] Warrants Issued December Twenty-Second Twenty Sixteen [Member] Tabular List, Table Tabular List [Table Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Sales and marketing Selling and Marketing Expense [Member] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Schedule of Accounts Receivable and Allowance for Credit Losses Accounts Receivable, Allowance for Credit Loss [Table Text Block] Accrued liabilities and other Accrued liabilities and other Accrued Liabilities, Current Common stock equivalents excluded from computation of diluted net loss per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Liability associated with indemnifications Estimated Litigation Liability Class of Warrant or Right [Line Items] Class of Warrant or Right [Line Items] Credit Facility [Domain] Credit Facility [Domain] Beginning of period End of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Amortization of discount and premium on marketable securities Accretion (Amortization) of Discounts and Premiums, Investments Current assets: Assets, Current [Abstract] Balance at beginning of period Balance at end of period Accounts Receivable, Allowance for Credit Loss Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Stock options Share-Based Payment Arrangement, Option [Member] Vested (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Depreciation expense Depreciation Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Expected volatility of peer companies, minimum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Peer Companies, Minimum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Peer Companies, Minimum 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Third Amendment Term Loan Third Amendment Term Loan [Member] Third Amendment Term Loan Preferred stock outstanding (in shares) Preferred Stock, Shares Outstanding Security Exchange Name Security Exchange Name Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Award Type [Axis] Award Type [Axis] Exercised (in dollars per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Property and equipment, net Property and equipment, net Property, Plant and Equipment, Net TOTAL LIABILITIES Liabilities Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Research and development Research and Development 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] Revolving credit facility Revolving Credit Facility [Member] Expiration Date Trading Arrangement Expiration Date Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] Warrants Issued 3/1/2017 Warrants Issued March First Twenty Seventeen [Member] Warrants Issued March First Twenty Seventeen [Member] Operating lease liabilities, current portion Operating Lease, Liability, Current Total Shareholder Return Amount Total Shareholder Return Amount Common stock issued (in shares) Common Stock, Shares, Issued Prepayment fee as percentage of aggregate principal amount Debt Instrument, Fee Amount As Percentage Of Aggregate Principal Debt Instrument, Fee Amount As Percentage Of Aggregate Principal Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Revolving credit facility, aggregate principal amount Line of Credit Facility, Maximum Borrowing Capacity Instrument trays Instrument Trays [Member] Instrument Trays Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Less: Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, gross Property, Plant and Equipment, Gross Issuance of common stock upon exercise of stock options, net of shares withheld (in shares) Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Debt Instrument [Line Items] Debt Instrument [Line Items] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Research and development Research and Development Expense [Member] Weighted- Average Exercise Price Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Common stock authorized (in shares) Common Stock, Shares Authorized Class of Warrant or Right [Table] Class of Warrant or Right [Table] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Weighted-average number of common shares used to compute diluted net loss per share (in shares) Weighted-average shares used to compute diluted net loss per share (in shares) Weighted Average Number of Shares Outstanding, Diluted Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] TOTAL STOCKHOLDERS’ EQUITY Stockholders' equity, beginning of period Stockholders' equity, end of period Equity, Attributable to Parent Extended term Lessee, Operating Lease, Renewal Term Interest expense Interest Expense, Nonoperating Write-offs Accounts Receivable, Allowance for Credit Loss, Writeoff Warrants Issued 11/9/2015 Warrants Issued November Ninth Twenty Fifteen [Member] Warrants Issued November Ninth Twenty Fifteen [Member] Recurring Fair Value, Recurring [Member] Accounts receivable, net of allowance for credit losses of $591 and $588, respectively Accounts Receivable, after Allowance for Credit Loss, Current Cost of goods sold Cost of Sales [Member] Stock options granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Outstanding debt, net of debt issuance costs and unaccreted value of final payment fee Long-Term Debt Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Document Fiscal Period Focus Document Fiscal Period Focus 2029 Long-Term Debt, Maturity, Year Four All Executive Categories All Executive Categories [Member] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Weighted-average remaining contractual life, options outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term ASSETS Assets [Abstract] Dividend yield (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate Document Type Document Type Final payment fee, percentage Line of Credit Facility, Commitment Fee Percentage Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Purchases of marketable securities Payments to Acquire Marketable Securities Interest and other income (expense), net: Other Income and Expenses [Abstract] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Maximum Maximum [Member] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Furniture and fixtures Furniture and Fixtures [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] International Non-US [Member] Accounts payable Accounts Payable, Current Accounting Policies [Abstract] Accounting Policies [Abstract] Leasehold improvements Leasehold Improvements [Member] Proceeds from (repayments of) term loan Proceeds from (Repayments of) Secured Debt Current Fiscal Year End Date Current Fiscal Year End Date Less: imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total lease expense Lease, Cost Statistical Measurement [Axis] Statistical Measurement [Axis] PEO Name PEO Name Warrants outstanding, beginning balance (in shares) Warrants outstanding, ending balance (in shares) Class of Warrant or Right, Outstanding Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Equity Award [Domain] Award Type [Domain] Name Outstanding Recovery, Individual Name Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Variable lease expense Variable Lease, Cost Schedule of Anti-dilutive Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Non-PEO NEO Non-PEO NEO [Member] Marketable securities Investments, Fair Value Disclosure Additional Paid-in Capital Additional Paid-in Capital [Member] Award Timing Predetermined Award Timing Predetermined [Flag] Prepayment fee, threshold period following closing Debt Instrument, Fee, Threshold Period Following Closing Debt Instrument, Fee, Threshold Period Following Closing Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Net loss per share, diluted (in dollars per share) Earnings Per Share, Diluted First Amendment Term Loan First Amendment Term Loan [Member] First Amendment Term Loan Name Measure Name Entity Interactive Data Current Entity Interactive Data Current Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Weighted-average remaining contractual life, options vested and exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Total marketable securities, aggregate fair value Cash, Cash Equivalents, and Short-Term Investments Schedule of Warrants Issued and Outstanding Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block] Number of operating segments Number of Operating Segments Preferred stock issued (in shares) Preferred Stock, Shares Issued Schedule of Marketable Securities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Schedule of Stock-Based Compensation Share-Based Payment Arrangement, Activity [Table Text Block] Sales and marketing Selling and Marketing Expense Indemnification Agreement Indemnification Agreement [Member] Income tax provision Income Tax Expense (Benefit) Canceled and forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Revenue Revenue from Contract with Customer, Excluding Assessed Tax Carrying value Cash Equivalents, at Carrying Value Inventory reserve Inventory Write-down Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Loss from operations Operating Income (Loss) Accrued compensation and related expenses for employee payroll deductions Other Employee-related Liabilities, Current Number of reportable segments Number of Reportable Segments TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] All Adjustments to Compensation All Adjustments to Compensation [Member] Accrued compensation and related expenses Employee-related Liabilities, Current Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Additional paid-in capital Additional Paid in Capital Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Interest income Investment Income, Interest Schedule of Future Principal and Final Fee Payments Schedule of Maturities of Long-Term Debt [Table Text Block] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Individual: Individual [Axis] Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Inventory Inventory, Net U.S. agency bonds US Government Agencies Debt Securities [Member] Black-Scholes option-pricing model assumptions Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Entity Address, State or Province Entity Address, State or Province Property, Plant and Equipment [Line Items] Property and Equipment, Net Property, Plant and Equipment [Line Items] Statement [Line Items] Statement [Line Items] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Operating expenses: Operating Expenses [Abstract] Schedule of Property and Equipment, Net Property, Plant and Equipment [Table Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Financial Instruments [Domain] Financial Instruments [Domain] Outstanding, beginning of period (in dollars per share) Outstanding, end of period (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Minimum Minimum [Member] Restatement Determination Date Restatement Determination Date Options vested and expected to vest (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Adoption Date Trading Arrangement Adoption Date Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Correlation coefficient of peer companies, minimum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Correlation Coefficient Of Peer Companies, Minimum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Correlation Coefficient Of Peer Companies, Minimum Outstanding, beginning of period (in dollars per share) Outstanding, end of period (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Outstanding, beginning of period (in shares) Outstanding, end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Accounts receivable credit losses Provision Accounts Receivable, Credit Loss Expense (Reversal) Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Principal outstanding Total principal payments Long-Term Debt, Gross Exercise Price Award Exercise Price Net Loss Per Share of Common Stock Earnings Per Share [Text Block] Arrangement Duration Trading Arrangement Duration Issuance of common stock upon exercise of stock options, net of shares withheld Stock Issued During Period, Value, Stock Options Exercised STOCKHOLDERS’ EQUITY Equity, Attributable to Parent [Abstract] Granted (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Marketable Securities [Table] Marketable Securities [Table] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] All Individuals All Individuals [Member] Future principal and final fee payments Maturities of Long-Term Debt [Abstract] PEO PEO [Member] Thereafter Lessee, Operating Lease, Liability, to be Paid, After Year Four Lessee, Operating Lease, Liability, to be Paid, After Year Four Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Name Trading Arrangement, Individual Name Other income (expense) Other Nonoperating Income (Expense) Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Long-Lived Tangible Asset [Axis] Long-Lived Tangible Asset [Axis] Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Options vested and exercisable (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number Remainder of 2025 Long-Term Debt, Maturity, Remainder of Fiscal Year Maturities of marketable securities Proceeds From Maturity Of Marketable Securities Proceeds From Maturity Of Marketable Securities Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Warrants Issued 10/20/2015 Warrants Issued October Twentieth Twenty Fifteen [Member] Warrants Issued October Twentieth Twenty Fifteen [Member] Marketable securities Assets, Fair Value Disclosure [Abstract] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Local Phone Number Local Phone Number Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Total operating expenses Operating Expenses Risk-free interest rate, maximum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Schedule of Restricted Stock Unit Activity Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Weighted-Average Remaining Contractual Life and Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] PEO Total Compensation Amount PEO Total Compensation Amount Purchase price of common stock as a percent of fair market value (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Purchase Price of Common Stock, Percent SVB Term Loan SVB Term Loan [Member] SVB Term Loan Aggregate Fair Value Debt Securities, Available-for-Sale, Excluding Accrued Interest Long-Lived Tangible Asset [Domain] Long-Lived Tangible Asset [Domain] Schedule of Accrued Liabilities and Other Schedule of Accrued Liabilities [Table Text Block] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Options vested and expected to vest (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Common Stock Common Stock [Member] Measure: Measure [Axis] Employee stock purchase program offering period interval (in months) Share-Based Compensation Arrangement By Share-Based Payment Award, Offering Period Interval Share-Based Compensation Arrangement By Share-Based Payment Award, Offering Period Interval Preferred stock authorized (in shares) Preferred Stock, Shares Authorized Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Line of credit Line of Credit [Member] Entity Emerging Growth Company Entity Emerging Growth Company 2018 ESPP 2018 Employee Stock Purchase Plan [Member] A2018 Employee Stock Purchase Plan [Member] Computer and office equipment Computer And Office Equipment [Member] Computer And Office Equipment [Member] Entity Central Index Key Entity Central Index Key General and administrative General and Administrative Expense [Member] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] First-Citizens Term Loan First-Citizens Term Loan [Member] First-Citizens Term Loan Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Expected volatility of common stock, minimum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Equity Component [Domain] Equity Component [Domain] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Financial Instrument [Axis] Financial Instrument [Axis] Adjustments to reconcile net loss to net cash used in operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Entity Shell Company Entity Shell Company Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Title Trading Arrangement, Individual Title Statement [Table] Statement [Table] Fair Value, Measurement Frequency [Domain] Measurement Frequency [Domain] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] City Area Code City Area Code Current liabilities: Liabilities, Current [Abstract] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Total current assets Assets, Current Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Supplemental disclosure of non-cash information Noncash Investing and Financing Items [Abstract] Correlation coefficient of peer companies, maximum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Correlation Coefficient Of Peer Companies, Maximum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Correlation Coefficient Of Peer Companies, Maximum Total marketable securities, amortized cost Marketable Securities, Amortized Cost Total amortized cost for marketable securities included in cash equivalents and investments. Accrued liabilities and other Increase (Decrease) in Accrued Liabilities 2028 Long-Term Debt, Maturity, Year Three Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Long-term borrowings Long-Term Debt, Excluding Current Maturities Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Operating lease liabilities not commenced Unrecorded Unconditional Purchase Obligation Income Taxes Income Tax Disclosure [Text Block] 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Earnings Per Share [Abstract] Earnings Per Share [Abstract] Warrants Exercised (in shares) Class of Warrant or Right, Shares, Exercised Class of Warrant or Right, Shares, Exercised Accumulated deficit Retained Earnings (Accumulated Deficit) Canceled and forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Inventory Increase (Decrease) in Inventories General and administrative General and Administrative Expense 2027 Long-Term Debt, Maturity, Year Two Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Equity Awards Adjustments Equity Awards Adjustments [Member] Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Total operating lease liabilities Operating Lease, Liability Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Underlying Securities Award Underlying Securities Amount Performance Shares Performance Shares [Member] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Credit Facility [Axis] Credit Facility [Axis] Amendment Flag Amendment Flag Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Entity Registrant Name Entity Registrant Name Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Depreciation and amortization Depreciation, Depletion and Amortization Gross profit Gross Profit Changes in foreign currency translation Foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Machinery and equipment Machinery and Equipment [Member] Fair Value as of Grant Date Award Grant Date Fair Value Aggregate intrinsic value, options vested and expected to vest Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Less: Unamortized debt issuance costs and lender fees Debt Issuance Costs, Net Level 2 Fair Value, Inputs, Level 2 [Member] Borrowings Debt Disclosure [Text Block] Final payment fee Debt Instrument, Final Payment Fee Debt Instrument, Final Payment Fee Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Geographical [Domain] Geographical [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Aggregate principal amount Debt Instrument, Face Amount Short-term investments Debt Securities, Available-for-Sale, Excluding Accrued Interest, Current Entity Address, Postal Zip Code Entity Address, Postal Zip Code Principles of Consolidation Consolidation, Policy [Policy Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Title of 12(b) Security Title of 12(b) Security Common stock, $0.0001 par value; 100,000,000 shares authorized; 42,479,600 and 42,086,477 shares issued and outstanding, respectively Common Stock, Value, Issued Accrued interest receivable Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-Based Payment Arrangement [Abstract] Effective interest rate during the period Debt Instrument, Interest Rate During Period Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions [Table Text Block] Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Aggregate intrinsic value, options vested and exercisable Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Accrued Liabilities and Other Accrued Liabilities, Current [Abstract] Canceled and forfeited (in dollars per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Issuance of common stock upon vesting of restricted stock units (in shares) Stock Issued During Period, Shares, Restricted Stock Units Stock Issued During Period, Shares, Restricted Stock Units Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding Preferred Stock, Value, Issued Inventory, finished goods, gross Inventory, Finished Goods, Gross Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward] Net loss per share, basic (in dollars per share) Earnings Per Share, Basic Accounts payable Increase (Decrease) in Accounts Payable Cash paid for amounts included in the measurement of operating lease liabilities Operating Lease, Payments Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Unpaid purchases of property and equipment Capital Expenditures Incurred but Not yet Paid Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Total current liabilities Liabilities, Current Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Unrecognized compensation cost, stock options Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount TOTAL ASSETS Assets Cost of goods sold Cost of Goods and Services Sold Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Cash and cash equivalents at Cash and Cash Equivalents [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Other long-term liabilities Other Liabilities, Noncurrent Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Commitments and contingencies (Note 6) Commitments and Contingencies Accrued royalty Accrued Royalties, Current Risk-free interest rate, minimum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Accrued rebates Accrued Rebates, Current Accrued Rebates, Current Termination Date Trading Arrangement Termination Date Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Expected volatility of common stock, maximum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum The Company and Nature of Business Nature of Operations [Text Block] Price per Share (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights 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] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two 2026 Long-Term Debt, Maturity, Year One Stock-Based Incentive Compensation Plans Share-Based Payment Arrangement [Text Block] Accrued interest writeoff Debt Securities, Available-for-Sale, Accrued Interest Writeoff Schedule of Revenue by Geography Revenue from External Customers by Geographic Areas [Table Text Block] Entity Address, City or Town Entity Address, City or Town Prime rate adjustment Debt Instrument, Prime Rate Adjustment Debt Instrument, Prime Rate Adjustment Debt Instrument [Axis] Debt Instrument [Axis] Schedule of Stock Option Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Stock-based compensation expense Share-Based Payment Arrangement, Expense Net loss Net loss Net Income (Loss) Attributable to Parent Trading Arrangement: Trading Arrangement [Axis] Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Other Commitments [Table] Other Commitments [Table] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Common stock warrants Common Stock Warrants [Member] Common Stock Warrants [Member] Canceled and forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Short-term investments Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Entity File Number Entity File Number Aggregate Future Minimum Lease Payments Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Document Fiscal Year Focus Document Fiscal Year Focus Income Statement [Abstract] Income Statement [Abstract] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations Others Other Accrued Liabilities, Current Name Forgone Recovery, Individual Name Remainder of 2025 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Weighted average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Document Period End Date Document Period End Date Warrants Issued (in shares) Class of Warrant or Right, Shares, Issued Class of Warrant or Right, Shares, Issued Expected volatility of peer companies, maximum (percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Peer Companies, Maximum Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Peer Companies, Maximum Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Construction in progress, software costs Construction in Progress, Software Costs [Member] Construction in Progress, Software Costs Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Total operating lease payments Lessee, Operating Lease, Liability, to be Paid Outstanding, beginning of period (in shares) Outstanding, end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Insider Trading Arrangements [Line Items] Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Schedule of Performance-based Restricted Stock Unit Activity Arrangement Share-Based Payment Arrangement, Performance Shares, Activity [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Schedule of Marketable Securities Marketable Securities [Table Text Block] Adjustment to Compensation: Adjustment to Compensation [Axis] Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Document Transition Report Document Transition Report Document Quarterly Report Document Quarterly Report Purchase commitments related to inventory management and training materials Purchase Obligation Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Current Reporting Status Entity Current Reporting Status Accumulated Deficit Retained Earnings [Member] Amortization of debt issuance costs Amortization of Debt Issuance Costs Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Costs to defend lawsuits or settle claims Litigation Settlement, Fee Expense Weighted-average number of common shares used to compute basic net loss per share (in shares) Weighted-average shares used to compute basic net loss per share (in shares) Weighted Average Number of Shares Outstanding, Basic Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Marketable Securities [Line Items] Marketable Securities [Line Items] Warrants Expired (in shares) Class of Warrant or Right, Shares, Expired Class of Warrant or Right, Shares, Expired Restricted Stock Units Restricted stock units Restricted Stock Units (RSUs) [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Accrued professional services Accrued Professional Fees, Current Executive Category: Executive Category [Axis] Name Awards Close in Time to MNPI Disclosures, Individual Name Construction in progress Construction in Progress [Member] Entity Filer Category Entity Filer Category Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Company Selected Measure Name Company Selected Measure Name