Segment Reporting [Abstract] SEGMENT AND GEOGRAPHIC INFORMATION Segment Reporting Disclosure [Text Block] Accounting Policies [Abstract] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Equity [Abstract] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Private Placement Private Placement [Member] At The Market Issuance Sales Agreement (ATM) Market Issuance Sales Agreement (ATM) [Member] Market Issuance Sales Agreement (ATM) [Member] Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Common stock, shares issued (shares) Stock Issued During Period, Shares, New Issues Gross proceeds from issuance of common stock Proceeds From Issuance Of Common Stock, Gross Proceeds From Issuance Of Common Stock, Gross Issuance of common stock, net of offering costs Stock Issued During Period, Value, New Issues Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Equipment and machinery Machinery and Equipment [Member] Furniture and fixtures Furniture and Fixtures [Member] Computer equipment Computer Equipment [Member] Capitalized software costs Software and Software Development Costs [Member] Leasehold improvements Leasehold Improvements [Member] Construction in process Construction in Progress [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Estimated Useful Life (Years) Property, Plant and Equipment, Useful Life Property and equipment, gross Property, Plant and Equipment, Gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, net Property, Plant and Equipment, Net Fair Value, Option, Quantitative Disclosures [Table] Fair Value, Option, Quantitative Disclosures [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Pro Forma Pro Forma [Member] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate, Type [Domain] Change in Accounting Estimate, Type [Domain] Service period Service Life [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Second amendment to term loans Second Amendment To Term Loans [Member] Second Amendment To Term Loans [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Secured Debt Secured Debt [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09, Contra Revenue Accounting Standards Update 2014-09, Contra Revenue [Member] Accounting Standards Update 2014-09, Contra Revenue [Member] Accounting Standards Update 2014-09, Capitalization And Amortization Contract Acquisition Costs Accounting Standards Update 2014-09, Capitalization And Amortization Contract Acquisition Costs [Member] Accounting Standards Update 2014-09, Capitalization And Amortization Contract Acquisition Costs [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Product concentration risk Product Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue Sales Revenue, Net [Member] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Enlighten Enlighten Web-Based Monitoring Service [Member] Enlighten Web-Based Monitoring Service [Member] Envoy Communications Gateway Device and Enlighten Web-Based Monitoring Service Envoy Communications Gateway Device And Enlighten Web-Based Monitoring Service [Member] Envoy Communications Gateway Device And Enlighten Web-Based Monitoring Service [Member] First and Second Generation First and Second Generation [Member] First and Second Generation [Member] Third and Fourth Generation Third and Fourth Generation [Member] Third and Fourth Generation [Member] Envoy Communications Gateway Envoy Communications Gateway [Member] Envoy Communications Gateway [Member] AC Battery Storage Solution AC Battery Storage Solution [Member] AC Battery Storage Solution [Member] Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Ongoing reduction in operating expense Restructuring And Related Cost, Combined Savings Restructuring And Related Cost, Combined Savings Restructuring and other charges Restructuring Charges Percent decrease in principal payments Debt Instrument, Decrease In Principal Payments Amounts Required, Percentage Debt Instrument, Decrease In Principal Payments Amounts Required, Percentage Percent of revenue represented by product line or service, less than Concentration Risk, Percentage Revenue recognition, number of deliverables Revenue Recognition, Multiple-Deliverable Arrangements, Number Of Deliverables Revenue Recognition, Multiple-Deliverable Arrangements, Number Of Deliverables Property and equipment estimated useful life Revenue recognition period Revenue Recognition, Recognition Period Revenue Recognition, Recognition Period Increase to revenue Revenue, Net Increase to earnings Net Income (Loss) Attributable to Parent Reduction of net loss per share (in usd per share) Income (Loss) from Continuing Operations, Per Basic and Diluted Share Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Asset impairments Asset Impairment Charges Goodwill, impairment loss Goodwill, Impairment Loss Intangible assets, estimated useful life Finite-Lived Intangible Asset, Useful Life Impairment of intangible assets Impairment of Intangible Assets (Excluding Goodwill) Product warranty, term Product Warranty, Term Product Warranty Term Product installation period Product Warranty, Estimated Failure Rate, Period Between Product Sale and Installation Product Warranty, Estimated Failure Rate, Period Between Product Sale and Installation Period failure rate measurement lags product sale Product Warranty, Estimated Failure Rate, Period Between Product Sale and Start of Monitoring Product Warranty, Estimated Failure Rate, Period Between Product Sale and Start of Monitoring Number of factors considered in estimating replacement cost Product Warranty, Estimated Replacement Cost, Number Of Factors Product Warranty, Estimated Replacement Cost, Number Of Factors Research and development expense Research and Development Expense Stock-based compensation requisite service period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Increase in deferred revenue Deferred Revenue Increase in deferred costs Deferred Costs Increase in accumulated deficit Retained Earnings (Accumulated Deficit) Increase in accrued liabilities Accrued Liabilities, Current Increase in deferred costs, commissions Deferred Costs, Commissions Deferred Costs, Commissions Quarterly Financial Information Disclosure [Abstract] Net revenues Cost of revenues Cost of Revenue Gross profit Gross Profit Operating expenses: Operating Expenses [Abstract] Research and development Sales and marketing Selling and Marketing Expense General and administrative General and Administrative Expense Total operating expenses Operating Expenses Loss from operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Other income expense, net Nonoperating Income (Expense) Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax benefit (provision) Income Tax Expense (Benefit) Net loss Net loss per share, basic and diluted (usd per share) Product Warranties Disclosures [Abstract] Product Liability Contingency [Table] Product Liability Contingency [Table] Second generation Second Generation Products [Member] Second Generation Products [Member] Sixth generation Sixth Generation [Member] Sixth Generation [Member] Third generation Third Generation Products [Member] Third Generation Products [Member] Fourth generation Fourth Generation [Member] Fourth Generation [Member] IQ Series IQ Series [Member] IQ Series [Member] Warranty Variable [Axis] Warranty Variable [Axis] Warranty Variable [Axis] Warranty Variable [Domain] Warranty Variable [Domain] [Domain] for Warranty Variable [Axis] Replacement cost Replacement Cost [Member] Replacement Cost [Member] Labor reimbursement cost Labor Reimbursement Cost [Member] Labor Reimbursement Cost [Member] Failure rate Failure Rate [Member] Failure Rates [Member] Product Liability Contingency [Line Items] Product Liability Contingency [Line Items] Number of units sold Number of Units Sold Number of Units Sold Increase (decrease) in warranty expense due to changes in warranty variables estimates Product Warranty Expense, Increase (Decrease) in Warranty Expense Due to Changes in Warranty Variables Product Warranty Expense, Increase (Decrease) in Warranty Expense Due to Changes in Warranty Variables Income Tax Disclosure [Abstract] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Unrecognized tax benefits—at beginning of year Unrecognized Tax Benefits Increases in balances related to tax positions taken in prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Decreases in balances related to tax positions taken in prior years Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Increases in balances related to tax positions taken in current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Lapses in statutes of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized tax benefits—at end of year Earnings Per Share [Abstract] Schedule of Potential Common Shares Outstanding Excluded from the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Basis of Presentation and Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Cost of Revenues Cost of Sales, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Allowances for Doubtful Accounts Trade and Other Accounts Receivable, Policy [Policy Text Block] Inventory Inventory, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Capitalized Software Costs Internal Use Software, Policy [Policy Text Block] Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Goodwill and Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Warranty Obligations Standard Product Warranty, Policy [Policy Text Block] Research and Development Costs Research and Development Expense, Policy [Policy Text Block] Stock-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Comprehensive Loss Comprehensive Income, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements Not Yet Effective New Accounting Pronouncements, Policy [Policy Text Block] Inventory Disclosure [Abstract] Raw materials Inventory, Raw Materials, Gross Finished goods Inventory, Finished Goods, Gross Total inventory Inventory, Net Summary of Warranty Activity Schedule of Product Warranty Liability [Table Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] 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] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis] Income Statement Location [Axis] Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Report Line [Domain] Income Statement Location [Domain] Cost of revenues Cost of Sales [Member] Research and development Research and Development Expense [Member] Sales and marketing Selling and Marketing Expense [Member] General and administrative General and Administrative Expense [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Total stock-based compensation expense Allocated Share-based Compensation Expense Restructuring and Related Activities [Abstract] RESTRUCTURING AND OTHER Restructuring and Related Activities Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] DESCRIPTION OF BUSINESS Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Financing Receivable Financing Receivable [Member] Term Loan Agreement, July 2016 Term Loan Agreement, July 2016 [Member] Term Loan Agreement, July 2016 [Member] Financing Receivable Recorded As Debt Financing Receivable Recorded As Debt [Member] Financing Receivable Recorded As Debt [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term debt gross Long-term Debt, Gross Less unamortized discount and issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Less value of future purchase option Debt Instrument, Value Of Future Purchase Option Debt Instrument, Value Of Future Purchase Option Carrying amount of debt Long-term Debt Less current portion Long-term Debt, Current Maturities Long-term debt Long-term Debt, Excluding Current Maturities INCOME TAXES Income Tax Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] GOODWILL AND INTANGIBLE ASSETS Goodwill and Intangible Assets Disclosure [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Stock options Employee Stock Option [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] The Fair Value of Each Option Granted During the Period [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Annual risk-free rate of return Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Weighted-average fair value on grant date (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Segment, Geographical [Domain] Geographical [Domain] United States UNITED STATES International International [Member] International [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Fair Value Disclosures [Abstract] FAIR VALUE MEASUREMENTS Fair Value, Measurement Inputs, Disclosure [Text Block] Statement of Cash Flows [Abstract] Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net loss Adjustments to reconcile net loss to net cash (used in) provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Provision for doubtful accounts Provision for Doubtful Accounts Asset impairment and restructuring Restructuring Costs and Asset Impairment Charges Gain on business divestiture Gain (Loss) on Disposition of Business Amortization of debt issuance costs Amortization of Debt Issuance Costs and Discounts Stock-based compensation Share-based Compensation Revaluation of contingent consideration liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Deferred income tax (benefit) expense Increase (Decrease) in Deferred Income Taxes Changes in operating assets and liabilities (net of acquisition/divestiture): Increase (Decrease) in Operating Assets [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Inventory Increase (Decrease) in Inventories Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable, accrued and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Warranty obligations Standard and Extended Product Warranty Accrual, Period Increase (Decrease) Deferred revenues Increase (Decrease) in Deferred Revenue Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Purchases of intangible assets Payments to Acquire Intangible Assets Business divestitures Proceeds from Divestiture of Businesses, Net of Cash Divested Change in restricted cash Increase (Decrease) in Restricted Cash Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from common stock offerings, net of issuance costs Proceeds from debt, net of issuance costs Proceeds from Debt, Net of Issuance Costs Proceeds from borrowings under revolving credit facility Proceeds from Lines of Credit Payments under revolving credit facility Repayments of Lines of Credit Holdback payment related to prior acquisition Payments for Previous Acquisition Proceeds from issuance of common stock under employee stock plans Proceeds from Stock Plans Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents 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, at Carrying Value Cash and cash equivalents — End of year Supplemental cash flow disclosure: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Cash paid for income taxes Income Taxes Paid Noncash financing and investing activities: Noncash Investing and Financing Items [Abstract] Offering and loan costs included in accrued liabilities Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction Purchases of fixed and intangible assets included in accounts payable Capital Expenditures Incurred but Not yet Paid Summary of Property and Equipment Property, Plant and Equipment [Table Text Block] Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Options outstanding, beginning (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Canceled (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Options outstanding, ending (shares) Weighted- Average Exercise Price per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Options outstanding, beginning (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercised (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Canceled (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Options outstanding, ending (usd per share) Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Eligible Item or Group for Fair Value Option [Axis] Financial Instrument [Axis] Fair Value, Option, Eligible Item or Group [Domain] Financial Instruments [Domain] Warranty obligations Warranty, Rights and Obligations, Fair Value Option [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Warranty Obligations at Fair Value [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Accruals for warranties issued during period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Changes in estimates Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability, Change in Estimate Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability, Change in Estimate Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Increase due to accretion expense Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability, Accretion Expense Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability, Accretion Expense Fair value adjustments Fair Value, Measurement With Unobservable Inputs Reconciliations, Recurring Basis, Liability, Adjustments Fair Value, Measurement With Unobservable Inputs Reconciliations, Recurring Basis, Liability, Adjustments Ending balance Schedule of Weighted Average Assumptions used to Estimate Fair Value of Stock Options Granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of Total Stock Based Compensation Expense Components Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Summary of Stock Based Compensation Expense Associated with Each Type of Award Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Summary of Stock Option Activity Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of Stock Options Outstanding Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] Summary of Restricted Stock Unit Activity Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Summary of ESPP Activity Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity [Table Text Block] Number of business activities Number Of Business Activities Number Of Business Activities Number of operating segments Number of Operating Segments Number of reportable segments Number of Reportable Segments Summary of Net Revenues and Long-Lived Assets by Geographic Region Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Payables and Accruals [Abstract] Accrued Liabilities [Abstract] Accrued Liabilities [Abstract] Salaries, commissions, incentive compensation and benefits Employee-related Liabilities, Current Customer rebates and sales incentives Accrued Marketing Costs, Current Freight Accrued Freight Costs Accrued Freight Costs Other Other Accrued Liabilities, Current Total Schedule of Product Information [Table] Schedule of Product Information [Table] Microinverter Microinverter [Member] Microinverter [Member] Residential and Commercial Systems Residential And Commercial Systems [Member] Residential And Commercial Systems [Member] Product Information [Line Items] Product Information [Line Items] Number of product shipped, more than Number Of Product Shipped Number Of Product Shipped Gigawatts, over Number Of Watts Number Of Watts Number of product deployed, more than Number Of Product Deployed Number Of Product Deployed Number of countries in which product is deployed, over Number Of Countries In Which Product Is Deployed Number Of Countries In Which Product Is Deployed Document and Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-Known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Commitments and Contingencies Disclosure [Abstract] Schedule of Minimum Lease Payments Under Noncancelable Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Summary of Inventory Schedule of Inventory, Current [Table Text Block] Risks and Uncertainties [Abstract] CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS Concentration Risk Disclosure [Text Block] ACCRUED LIABILITIES Accounts Payable and Accrued Liabilities Disclosure [Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Deficit Retained Earnings [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] BALANCE, Beginning Stockholders' Equity Attributable to Parent BALANCE, Beginning (shares) Shares, Outstanding Issuance of common stock under employee stock plans Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Issuance of common stock under employee stock plans (shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Issuance of common stock, net of offering costs (shares) Issuance of warrants Adjustments to Additional Paid in Capital, Warrant Issued Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax BALANCE, Ending BALANCE, Ending (shares) QUARTERLY FINANCIAL INFORMATION (UNAUDITED) Quarterly Financial Information [Text Block] Rent expense Operating Leases, Rent Expense, Net Purchase obligation Purchase Obligation Line of Credit Facility [Table] Line of Credit Facility [Table] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Proceeds from term loan, net of issuance costs Proceeds from Issuance of Long-term Debt Value of future purchase option Liability, Purchase Option For Receivables, Fair Value Liability, Purchase Option For Receivables, Fair Value Line of Credit Line of Credit [Member] Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Wells Fargo Bank Wells Fargo Bank [Member] Wells Fargo Bank. Revolving Credit Facility Revolving Credit Facility [Member] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Accordion feature Line Of Credit Facility, Accordion Feature Line Of Credit Facility, Accordion Feature Revolving credit facility Line of Credit, Current Repayments of lines of credit STOCK-BASED COMPENSATION Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Subsequent Events [Abstract] SUBSEQUENT EVENTS Subsequent Events [Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock options to purchase common stock Unvested restricted stock units Restricted Stock Units (RSUs) [Member] Warrants to purchase common stock Warrant [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Total (shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Shareholders' Equity Class [Axis] Shareholders' Equity Class [Axis] Fair Value by Shareholders' Equity Class [Domain] Fair Value by Shareholders' Equity Class [Domain] Warrants Not Settleable in Cash Warrants Not Settleable in Cash [Member] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Debt Covenant Terms [Domain] Debt Covenant Terms [Domain] [Domain] for Debt Covenant Terms [Axis] Closing date to March 31, 2018 Closing Date to March 31, 2018 [Member] Closing Date to March 31, 2018 [Member] April 1, 2019 and thereafter April 1, 2019 and Thereafter [Member] April 1, 2019 and Thereafter [Member] Amended Term Loan Agreement Amended Tennenbaum Capital Partners LLC Agreement [Member] Amended Tennenbaum Capital Partners LLC Agreement [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Tennenbaum Capital Partners, LLC Tennenbaum Capital Partners, LLC [Member] Tennenbaum Capital Partners, LLC [Member] Debt instrument principal amount Debt Instrument, Face Amount Line of credit facility, interest rate during period Line of Credit Facility, Interest Rate During Period Reduction of interest rate during period, percent Line of Credit Facility, Reduction of Interest Rate During Period, Percent Line of Credit Facility, Reduction of Interest Rate During Period, Percent Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Closing fee, percentage Line of Credit Facility, Closing Fee, Percentage Line of Credit Facility, Closing Fee, Percentage Prepayment fee, percent Line of Credit Facility, Prepayment Fee, Percent Line of Credit Facility, Prepayment Fee, Percent Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Unrestricted cash requirement, minimum Debt Instrument, Covenant, Unrestricted Cash Requirement, Minimum Debt Instrument, Covenant, Unrestricted Cash Requirement, Minimum Liquidity ratio required Debt Instrument, Covenant, Liquidity Ratio Required, Minimum Debt Instrument, Covenant, Liquidity Ratio Required, Minimum Number of securities called by warrants (shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Warrant to purchase common stock, price per share (usd per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Class of warrant term year Class Of Warrant Or Right, Term Class Of Warrant Or Right, Term Common stock issued, price per share (usd per share) Share Price Expected volatility rate Fair Value Assumptions, Expected Volatility Rate Risk free interest rate Fair Value Assumptions, Risk Free Interest Rate Expected dividend rate Fair Value Assumptions, Expected Dividend Rate Expected term Fair Value Assumptions, Expected Term Warrants not settleable in cash Warrants Not Settleable in Cash, Fair Value Disclosure Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2006 Plan Two Thousand Six Equity Incentive Plan [Member] Two thousand six equity incentive plan. 2011 Plan Two Thousand and Eleven Equity Incentive Plan [Member] Two thousand and eleven equity incentive plan. 2011 Employee Stock Purchase Plan (ESPP) Employee Stock Purchase Plan (ESPP) [Member] Employee Stock Purchase Plan (ESPP) Tender Offer, Exchange Out Of The Money Stock Options For Restricted Stock Units [Member] Tender Offer, Exchange Out Of The Money Stock Options For Restricted Stock Units [Member] Tender Offer, Exchange Out Of The Money Stock Options For Restricted Stock Units [Member] Award Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] Before August 1, 2012 Before August 1, 2012 [Member] Before August 1, 2012 After August 1, 2012 After August 1, 2012 [Member] After August 1, 2012 Restricted stock units Equity awards granted period, vest over Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Equity awards granted contractual term Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Options outstanding (shares) Number of shares available for issuance (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Issue of common stock (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Expiration term of ESPP Share Based Compensation Arrangement by Share Based Payment Award Expiration in Years Share based compensation arrangement by share based payment award expiration in years. Increase on each January 1 in number of shares of common stock reserved for issuance under the stock incentive plan Increase in Common Stock Shares Reserved for Future Issuance Percentage Increase in common stock shares reserved for future issuance percentage. Increase in shares authorized for issuance under plan (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Annual share increase in reserved shares on each January 1 (shares) Share Based Compensation Arrangement by Share Based Payment Award Evergreen Shares Share based compensation arrangement by share based payment award evergreen shares. Increase in shares authorized as a percentage of the total number of shares of common stock outstanding Share-based Compensation Arrangement by Share-based Payment Award, Increase in Number of Shares Authorized, Ratio Share-based Compensation Arrangement by Share-based Payment Award, Increase in Number of Shares Authorized, Ratio Number of interim purchase periods, up to Employee Stock Purchase Plan, Number of Interim Purchase Periods Employee Stock Purchase Plan, Number of Interim Purchase Periods General duration (months) of employee stock purchase plan General Duration of Employee Stock Purchase Plan General duration of employee stock purchase plan. Payroll deductions Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Fair market value Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Look-back feature in ESPP Share Based Compensation Arrangement by Share Based Payment Award Look Back Feature Period Share based compensation arrangement by share based payment award look back feature period. Recognition period for additional expense triggered by the reset feature Employee Stock Purchase Plan, Additional Expense Trigged by Reset Feature, Period for Recognition Employee Stock Purchase Plan, Additional Expense Trigged by Reset Feature, Period for Recognition Purchase of common stock limit IRS Limitation for Employees Right to Acquire Class Common Stock Under ESPP IRS Limitation for an employee's right to acquire class common stock under ESPP. Total unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted-average period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Income tax benefit recognized relating to stock-based compensation expense Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Income tax benefit realized from exercised stock options Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Number of options outstanding that were vested and expected to vest (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number Weighted-average fair value, vested (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price Weighted-average remaining contractual term, vested Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term Aggregate intrinsic value, exercisable shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Number of shares exercisable (shares) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options Common stock fair value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Basis for Determining Aggregate Intrinsic Value, Company's Share Price, Per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Basis for Determining Aggregate Intrinsic Value, Company's Share Price, Per Share Common stock to be purchased in exchange for options (in shares) Replacement awards of restricted stock units (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Intrinsic value of units vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested Weighted average remaining contractual term Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms Intrinsic value of restricted stock units outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Value Changes in the Company's product warranty liability Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward] Balance, at beginning of year Standard and Extended Product Warranty Accrual Accruals for warranties issued during the year Standard and Extended Product Warranty Accrual, Increase for Warranties Issued Changes in estimates Standard and Extended Product Warranty Accrual, Increase (Decrease) for Preexisting Warranties Settlements Standard and Extended Product Warranty Accrual, Decrease for Payments Increase due to accretion expense Product Warranty Accrual, Accretion Expense Product Warranty Accrual, Accretion Expense Fair value adjustments Product Warranty Accrual, Fair Value Adjustment Product Warranty Accrual, Fair Value Adjustment Balance, at end of year Less current portion Product Warranty Accrual, Current Long-term portion Product Warranty Accrual, Noncurrent Derivative [Table] Derivative [Table] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Discounted cash flows Income Approach Valuation Technique [Member] Derivative [Line Items] Derivative [Line Items] Decrease to fair value measurement as a result of 100 basis point increase Warranty Obligations at Fair Value, Decrease in Fair Value Resulting from One Percentage Point Increase in Discount Rate Warranty Obligations at Fair Value, Decrease in Fair Value Resulting from One Percentage Point Increase in Discount Rate Increase to fair value measurement as a result of 100 basis point decrease Warranty Obligations At Fair Value, Increase In Fair Value Resulting From One Percentage Point Decrease In Discount Rate Warranty Obligations At Fair Value, Increase In Fair Value Resulting From One Percentage Point Decrease In Discount Rate Employee severance and benefit arrangements Severance Costs Asset impairments Restructuring Charges, Asset Impairment Charges Restructuring Charges, Asset Impairment Charges Consultants engaged in restructuring activities Restructuring Charges, Consultant Activity Restructuring Charges, Consultant Activity Lease loss and other Other Restructuring Costs Total restructuring and other Restructuring Costs, Asset Impairment Charges And (Gain) Loss On Disposition Of Business Restructuring Costs, Asset Impairment Charges And (Gain) Loss On Disposition Of Business WARRANTY OBLIGATIONS Product Warranty Disclosure [Text Block] Summary of Goodwill and Purchased Intangible Assets Schedule of Intangible Assets and Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Patents and licensed technology Patents And Licensed Technology [Member] Patents And Licensed Technology [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Goodwill, gross Goodwill, Gross Goodwill Goodwill Other indefinite-lived intangibles Indefinite-Lived Intangible Assets (Excluding Goodwill) Intangibles assets with finite lives: Finite-Lived Intangible Assets, Net [Abstract] Gross Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Total Finite-Lived Intangible Assets, Net Total purchased intangibles, gross Intangible Assets, Gross (Excluding Goodwill) Total purchased intangibles, accumulated amortization Intangible Assets, Accumulated Amortization Intangible Assets, Accumulated Amortization Total purchased intangibles, net Intangible Assets, Net (Excluding Goodwill) Schedule of Domestic and Foreign Components of Loss before Provision for Income Taxes Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Provision for Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Reconciliation of Total Amounts of Unrecognized Tax Benefits Summary of Income Tax Contingencies [Table Text Block] Components of Deferred Tax Assets and Liabilities [Abstract] Deferred tax assets: Deferred Tax Assets, Net of Valuation Allowance, Current Classification [Abstract] Allowances and reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Current Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Current Net operating loss and tax credit carryforwards Deferred Tax Assets, Operating Loss Carryforwards, Noncurrent Deferred Tax Assets, Operating Loss Carryforwards, Noncurrent Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost, Noncurrent Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost, Noncurrent Deferred revenue Deferred Tax Assets, Deferred Income, Noncurrent Deferred Tax Assets, Deferred Income, Noncurrent Fixed assets and intangibles Deferred Tax Liabilities, Property, Plant and Equipment and Intangible Assets, Noncurrent Deferred Tax Liabilities, Property, Plant and Equipment and Intangible Assets, noncurrent Other Deferred Tax Assets, Deferred Expense Other, Noncurrent Deferred Tax Assets Tax Deferred Expense Other Current Subtotal Deferred Tax Assets, Gross Less valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets, net of valuation allowance Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Net [Abstract] Goodwill Deferred Tax Liabilities, Goodwill Unremitted foreign earnings Undistributed Earnings of Foreign Subsidiaries Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax asset Deferred Tax Assets, Net Net deferred tax liability Deferred Tax Liabilities, Net NET LOSS PER SHARE Earnings Per Share [Text Block] Income Statement [Abstract] Other income (expense): Other Nonoperating Income (Expense) [Abstract] Interest expense Interest Expense Other income (expense), net Other Nonoperating Income (Expense) Total other expense, net Benefit (provision) for income taxes Shares used in computing net loss per share, basic and diluted (shares) Weighted Average Number of Shares Outstanding, Basic and Diluted 2018 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three Total Restructuring and Related Costs Restructuring and Related Costs [Table Text Block] Schedule of Restructuring Reserve by Type of Cost Schedule of Restructuring Reserve by Type of Cost [Table Text Block] DEBT Long-term Debt [Text Block] Schedule of Accrued Liabilities Schedule of Accrued Liabilities [Table Text Block] SALE OF COMMON STOCK Stockholders' Equity Note Disclosure [Text Block] Schedule of Quarterly Financial Information Quarterly Financial Information [Table Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] 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] Schedule of Financial Instruments Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Reconciliation of Beginning and Ending Balances of Warranty Obligations/Contingent Consideration Measured at Fair Value Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Summary of Significant Unobservable Inputs used in the Fair Value Measurements of the Company's Liabilities Designated as Level 3 Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2018 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total minimum lease payments Operating Leases, Future Minimum Payments Due PROPERTY AND EQUIPMENT, NET Property, Plant and Equipment Disclosure [Text Block] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance and Benefits Employee Severance [Member] Asset Impairments Asset Impairments [Member] Asset Impairments [Member] Lease Loss Reserves and Contractual Obligations Contract Termination [Member] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] Restructuring Plan 2016 Restructuring Plan 2016 [Member] Restructuring Plan 2016 [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring reserve, beginning Restructuring Reserve Charges Cash payments Payments for Restructuring Non-cash settlement Restructuring Reserve, Settled without Cash Restructuring reserve, ending Depreciation expense Depreciation Unamortized capitalized software costs Capitalized Computer Software, Net Consideration Disposal Group, Including Discontinued Operation, Consideration Identifiable assets Disposal Group, Including Discontinued Operation, Assets, Net Disposal Group, Including Discontinued Operation, Assets, Net Contingent Consideration Disposal Group, Including Discontinued Operation, Contingent Consideration Asset Disposal Group, Including Discontinued Operation, Contingent Consideration Asset Gain on business divestiture Proceeds from common stock issued under ESPP Proceeds from Issuance of Common Stock, Employee Stock Purchase Plan Proceeds from Issuance of Common Stock, Employee Stock Purchase Plan Shares of common stock issued (shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Weighted-average price per share (usd per share) Employee Stock Purchase Plan, Weighted Average Purchase Price of Shares Purchased Employee Stock Purchase Plan, Weighted Average Purchase Price of Shares Purchased Statement of Financial Position [Abstract] Allowances, accounts receivable Warrant obligations at fair value, current Standard Product Warranty Accrual, Current, Fair Value Disclosure Standard Product Warranty Accrual, Current, Fair Value Disclosure Warrant obligations at fair value, noncurrent Standard Product Warranty Accrual, Noncurrent, Fair Value Disclosure Standard Product Warranty Accrual, Noncurrent, Fair Value Disclosure Preferred stock, par value (usd per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (shares) Preferred Stock, Shares Outstanding Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, shares issued (shares) Common Stock, Shares, Issued Common stock, shares outstanding (shares) Common Stock, Shares, Outstanding Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Warranty obligations for microinverters sold since January 1, 2014 Third party option to purchase receivables at a discount Third Party Option To Purchase Receivables At Discount [Member] Third Party Option To Purchase Receivables At Discount [Member] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Profit element and risk premium Fair Value Inputs, Profit Element and Risk Premium Fair Value Inputs, Profit Element and Risk Premium Credit-adjusted risk-free rate Fair Value Inputs, Entity Credit Risk Counter party credit-adjusted risk-free rate Fair Value Inputs, Counterparty Credit Risk Schedule of Revenue by Major Customers, by Reporting Segments [Table] Schedule of Revenue by Major Customers, by Reporting Segments [Table] Major Customers [Axis] Customer [Axis] Name of Major Customer [Domain] Customer [Domain] Customer Accounting for the largest concentration of accounts payable Customer Accounting For The Largest Concentration Of Accounts Payable [Member] Customer Accounting For The Largest Concentration Of Accounts Payable [Member] Customer accounting for the largest concentration of revenue Largest Customer Accounting for Most Revenue [Member] Largest Customer Accounting for Most Revenue [Member] Customer accounting for second largest concentration of revenue Second Largest Customer Accounting for Most Revenue [Member] Second Largest Customer Accounting for Most Revenue [Member] Accounts receivable Accounts Receivable [Member] Net revenue Net Revenue [Member] Net Revenue [Member] Credit concentration risk Credit Concentration Risk [Member] Customer concentration risk Customer Concentration Risk [Member] Revenue, Major Customer [Line Items] Revenue, Major Customer [Line Items] Percentage of concentration risk Stock options and restricted stock units Employee Stock Options and Restricted Stock Units [Member] Employee Stock Options and Restricted Stock Units [Member] ESPP Employee Stock [Member] Total stock-based compensation expense Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] $0.27 – $1.63 Range One [Member] Range One [Member] $1.88 - $6.90 Range Two [Member] Range Two [Member] $6.98 – $8.57 Range Three [Member] Range Three [Member] $8.58 - $15.15 Range Four [Member] Range Four [Member] $16.01 - $16.01 Range Five [Member] Range Five [Member] Exercise Price Range of Options Outstanding and Options Exercisable [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Range of Exercise Prices - Lower Range Limit (usd per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit Range of Exercise Prices - Upper Range Limit (usd per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Options Outstanding - Number of Shares (shares) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Options Outstanding - Weighted- Average Remaining Life Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term Options Outstanding - Weighted- Average Exercise Price (usd per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price Options Exercisable - Number of Shares Exercisable (shares) Options Exercisable - Weighted- Average Exercise Price (usd per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price Schedule of Activity in Allowance for Doubtful Accounts Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] INVENTORY Inventory Disclosure [Text Block] United States Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Total Current Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Total Deferred Income Tax Expense (Benefit) (Benefit) provision for income taxes Restricted Stock Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding units, beginning (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (shares) Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Canceled (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding units, ending (shares) Weighted Average Fair Value per Share at Grant Date Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding units, beginning (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (usd 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 Vested (usd 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 Canceled (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Outstanding units, ending (usd per share) ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Accounts receivable, net of allowances of $2,378 and $2,921 at December 31, 2017 and 2016, respectively Accounts Receivable, Net, Current Inventory Prepaid expenses and other Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net Intangibles, net Other assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Deferred revenues Deferred Revenue, Current Warranty obligations, current portion (includes $2,240 and $3,296 measured at fair value at December 31, 2017 and 2016, respectively) Debt, current Loans Payable, Current Total current liabilities Liabilities, Current Deferred revenues, non-current Deferred Revenue, Noncurrent Warranty obligations, non-current (includes $7,551 and $7,036 measured at fair value at December 31, 2017 and 2016, respectively) Other non-current liabilities Other Liabilities, Noncurrent Debt, less current portion Loans Payable, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Stockholders’ (deficit) equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.00001 par value, 10,000 shares authorized; none issued and outstanding Preferred Stock, Value, Issued Common stock, $0.00001 par value, 125,000 and 100,000 shares authorized and 85,914 and 62,269 shares issued and outstanding at December 31, 2017 and 2016, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ (deficit) equity Total liabilities and stockholders’ (deficit) equity Liabilities and Equity United States China CHINA Other Other Country [Member] Other country. Total Long-Lived Assets Effective Income Tax Rate Reconciliation, Percent [Abstract] Income tax benefit at statutory federal rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Foreign tax rate and tax law differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Amount Stock-based compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Other permanent items Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Other nondeductible/nontaxable items Income Tax Reconciliation, Nondeductible and Nontaxable Expense Other Income Tax Reconciliation Nondeductible and Nontaxable Expense Other Uncertain tax positions Effective Income Tax Rate Reconciliation, Tax Contingency, Foreign, Amount Tax law changes Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Amount Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Amount Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Federal Domestic Tax Authority [Member] State State and Local Jurisdiction [Member] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Research tax credit carryforward Research Tax Credit Carryforward [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Federal statutory income tax rate percent Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Valuation allowance on its U.S. and state deferred tax assets Decrease in valuation allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Reduction in deferred tax assets Tax Cuts And Jobs Act, Change In Tax Rate, Deferred Tax Asset, Income Tax Expense Tax Cuts And Jobs Act, Change In Tax Rate, Deferred Tax Asset, Income Tax Expense Operating loss carryforwards Operating Loss Carryforwards Research tax credit carryforwards Tax Credit Carryforward, Amount Increase to unrecognized tax benefits Unrecognized Tax Benefits, Period Increase (Decrease) Liabilities: Liabilities, Fair Value Disclosure [Abstract] Warranty obligations/ Third party option to purchase receivables at a discount Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Debt Schedule of Debt [Table Text Block] Statement of Comprehensive Income [Abstract] Other comprehensive loss: Other Comprehensive Income (Loss), Net of Tax [Abstract] Foreign currency translation adjustments Other comprehensive loss: Other Comprehensive Income (Loss), Net of Tax Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Allowance for Doubtful Accounts Receivable [Roll Forward] Allowance for Doubtful Accounts Receivable [Roll Forward] Balance, at beginning of year Net charges to expenses Allowance for Doubtful Accounts Receivable, Period Increase (Decrease) Write-offs, net of recoveries Allowance for Doubtful Accounts Receivable, Write-offs Balance, at end of year COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Patents Patents [Member] ASIC Application Specific Integrated Circuits [Member] Application Specific Integrated Circuits [Member] Licensed technology term Licensed Technology, Term Licensed Technology, Term Aggregate amortization expense Amortization of Intangible Assets Patents and licensed technology amortized in 2018 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Subsequent Event [Table] Subsequent Event [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Number of shares issued (in shares) Sale of Stock, Number of Shares Issued in Transaction Price per share issued (in USD per share) Sale of Stock, Price Per Share