Income Tax Disclosure [Abstract] U.S. federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent State income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Foreign income at other than U.S. rates Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent Stock-based compensation expense Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Percent Meals and entertainment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Percent Goodwill impairment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent Research and development tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent Other permanent items Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Percent Debt cancellation Effective Income Tax Rate Reconciliation, Intercompany Financing Charges Effective Income Tax Rate Reconciliation, Intercompany Financing Charges Worthless stock Effective Income Tax Rate Reconciliation, Stock With No Value Effective Income Tax Rate Reconciliation, Stock With No Value Change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Tax rate change; U.S. tax reform Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Finite-lived Intangible Assets Acquired as Part of Business Combination Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Intent Marketing Solution Intent Marketing Solution [Member] Intent Marketing Solution [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue Revenues Payment terms Revenue, Payment Terms Revenue, Payment Terms Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States UNITED STATES International Non-US [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Purchased software Computer Software, Intangible Asset [Member] Computer equipment and network hardware Computer Equipment [Member] Furniture, fixtures and office equipment Furniture and Fixtures [Member] Leasehold improvements Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Gross property and equipment Property, Plant and Equipment, Gross Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, net Property, Plant and Equipment, Net Debt Disclosure [Abstract] Debt Debt and Capital Leases Disclosures [Text Block] Investments, Fair Value Disclosure [Abstract] Weighted remaining contractual maturity Available-for-sale Securities, Weighted-average Remaining Contractual Maturity Available-for-sale Securities, Weighted-average Remaining Contractual Maturity Sales of available-for-sale securities Proceeds from Sale of Available-for-sale Securities Unrealized gain (loss) Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax Realized gain (loss) Available-for-sale Securities, Gross Realized Gain (Loss) Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2014 Employee Stock Purchase Plan 2014 Employee Stock Purchase Plan [Member] 2014 Employee Stock Purchase Plan [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Employee Stock Employee Stock [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Maximum employee subscription rate Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Purchase price of common stock, percent Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent Number of shares available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Number of shares reserved Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Evergreen Annual % Increase Evergreen Annual % Increase Evergreen Annual % Increase Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] nToggle nToggle [Member] nToggle [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Payments to Acquire Businesses, Net of Cash Acquired Payments to Acquire Businesses, Net of Cash Acquired Business Combination, Consideration Transferred Business Combination, Consideration Transferred Cash Acquired from Acquisition Cash Acquired from Acquisition Business Combination, In-The-Money Options Assumed Business Combination, In-The-Money Options Assumed Business Combination, In-The-Money Options Assumed Business Combination, Restricted Stock Assumed Business Combination, Restricted Stock Assumed Business Combination, Restricted Stock Assumed Equity interest issued, number of shares Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Business Combination, Acquisition Related Costs Business Combination, Acquisition Related Costs Business Combination, Net Operating Loss Acquired Business Combination, Net Operating Loss Acquired Business Combination, Net Operating Loss Acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Impairment of goodwill Goodwill, Impairment Loss Investments in Marketable Securities Marketable Securities [Table Text Block] Equity [Abstract] Accumulated Other Comprehensive Loss Comprehensive Income (Loss) Note [Text Block] 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 provision 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 benefit Deferred Income Tax Expense (Benefit) Total provision (benefit) for income taxes Income Tax Expense (Benefit) Restructuring and Related Activities [Abstract] 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] Non-cash stock-based compensation Noncash Stock Based Compensation [Member] Noncash Stock Based Compensation [Member] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] The 2018 Restructuring Events The 2018 Restructuring Events [Member] The 2018 Restructuring Events [Member] The 2017 Restructuring Events The 2017 Restructuring Events [Member] The 2017 Restructuring Events [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Accrued restructuring and other exit costs at December 31, 2017 Restructuring Reserve Restructuring and other exit costs Restructuring Charges Cash paid for restructuring and other exit costs Payments for Restructuring Accrued restructuring and other exit costs at December 31, 2018 Severance costs Severance Costs Business exit costs Business Exit Costs Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Canceled Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Ending balance 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] Beginning balance (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 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 Canceled (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 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 Ending balance (in dollars per share) Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Cash equivalents Money Market Funds [Member] Corporate debt securities Corporate Debt Securities [Member] U.S. Treasury, government and agency debt securities US Treasury and Government [Member] 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] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Available-for-sale Securities Available-for-sale Securities Provision (benefit) for income taxes Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Foreign Tax Authority Foreign Tax Authority [Member] Domestic Tax Authority Domestic Tax Authority [Member] State and Local Jurisdiction State and Local Jurisdiction [Member] Tax Credit Carryforward [Line Items] Tax Credit Carryforward [Line Items] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] 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] Change in valuation allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Operating loss carryforwards Operating Loss Carryforwards Tax credit carryforwards Tax Credit Carryforward, Amount Unremitted earnings of the subsidiaries outside of the United States Undistributed Earnings of Foreign Subsidiaries Statement of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net loss Net Income (Loss) Attributable to Parent Adjustments to reconcile net loss to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock-based compensation Share-based Compensation Impairment of intangible assets and internal use software Impairment of Intangible Assets, Finite-lived Impairment of goodwill Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Provision for doubtful accounts Provision for Doubtful Accounts Accretion of available for sale securities Accretion Of Available-For-Sale Securities Accretion Of Available-For-Sale Securities Unrealized foreign currency gains, net Foreign Currency Transaction Gain (Loss), Unrealized Deferred income taxes Deferred Income Taxes and Tax Credits Changes in operating assets and liabilities, net of effect of business acquisitions: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Capitalized internal use software development costs Payments to Develop Software Acquisitions, net of cash acquired Investments in available-for-sale securities Payments to Acquire Available-for-sale Securities Maturities of available-for-sale securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from issuance of common stock under employee stock purchase plan Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Taxes paid related to net share settlement Payments Related to Tax Withholding for Share-based Compensation Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities EFFECT OF EXCHANGE RATE CHANGES ON CASH, CASH EQUIVALENTS AND RESTRICTED CASH Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Cash paid for income taxes Income Taxes Paid, Net Cash paid for interest Interest Paid Capitalized assets financed by accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Capitalized stock-based compensation Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain (loss) on investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Document and Entity Information [Abstract] Document and Entity Information [Abstract] 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 Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Public Float Entity Public Float Pro forma revenues Business Acquisition, Pro Forma Revenue Pro forma net loss Business Acquisition, Pro Forma Net Income (Loss) Pro forma net loss per share, basic (in usd per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Pro forma net loss per share, diluted (in usd per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Prepaid and other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets Fixed assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Other non-current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Goodwill Goodwill Total assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Accounts payable and accrued expenses Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable Deferred revenue Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue Deferred tax liability, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent Total liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Total net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Restricted Stock Awards Restricted Stock [Member] Schedule of Income before Income Tax, Domestic and Foreign Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) 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 Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns Roll Forward Schedule of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns Roll Forward [Table Text Block] Income Tax Expense (Benefit) Related To Worthless Stock Income Tax Expense (Benefit) Related To Worthless Stock Income Tax Expense (Benefit) Related To Worthless Stock Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Transition Tax For Accumulated Foreign Earnings Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Transition Tax For Accumulated Foreign Earnings Provisional Income Tax Expense Amount of reasonable estimate for income tax expense from transition tax on accumulated earnings of controlled foreign corporation deemed repatriated pursuant to Tax Cuts and Jobs Act for which accounting for tax effect is incomplete. Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Change In Tax Rate Deferred Tax Asset Provisional Income Tax Expense Tax Cuts And Jobs Act Of 2017 Incomplete Accounting Change In Tax Rate Deferred Tax Asset Provisional Income Tax Expense Amount of reasonable estimate for income tax expense for remeasurement of deferred tax asset from change in tax rate pursuant to Tax Cuts and Jobs Act for which accounting for tax effect is incomplete. Provisional GILTI inclusion for ASC Topic 740 Global Intangible Low-Taxed Income (GILTI) Provisional Inclusion Global Intangible Low-Taxed Income (GILTI) Provisional Inclusion Schedule of Restructuring and Other Exit Costs Restructuring and Related Costs [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Accounting Policies [Abstract] Basis of Presentation and Summary of Significant Accounting Policies Basis of Accounting, Policy [Policy Text Block] Segments Segment Reporting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Cost of Revenue Cost of Sales, Policy [Policy Text Block] Sales and Marketing Sales and Marketing [Policy Text Block] Sales and Marketing [Policy Text Block] Technology and Development Research, Development, and Computer Software, Policy [Policy Text Block] General and Administrative Selling, General and Administrative Expenses, Policy [Policy Text Block] Restructuring and Other Exit Costs Costs Associated with Exit or Disposal Activities or Restructurings, Policy [Policy Text Block] Impairment of Intangible Assets and Internal Use Software Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Impairment of Goodwill Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Stock-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Capital Stock Stockholders' Equity, Policy [Policy Text Block] Net Income (Loss) Per Share Attributable to Common Stockholders Earnings Per Share, Policy [Policy Text Block] Comprehensive Income (Loss) Comprehensive Income, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Accounts Receivable Allowance for Doubtful Accounts Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Property and Equipment, Net Property, Plant and Equipment, Policy [Policy Text Block] Internal Use Software Development Costs Internal Use Software, Policy [Policy Text Block] Intangible Assets Intangible Assets, Finite-Lived, Policy [Policy Text Block] Impairment of Long-Lived Assets and including Internal Use Capitalized Software Costs Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Business Combinations Business Combinations Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Operating and Capital Leases Lessee, Leases [Policy Text Block] Fair Value of Financial Instruments Fair Value Measurement, Policy [Policy Text Block] Concentration of Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Foreign Currency Transactions and Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock Option Employee Stock Option [Member] Intrinsic values of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Unrecognized employee stock-based compensation Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options Unrecognized employee stock-based compensation, period for recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Fair value of options vested in period Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value 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 Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Accumulated Deficit Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance (in shares) Common Stock, Shares, Outstanding Beginning Balance Stockholders' Equity Attributable to Parent Exercise of common stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of common stock options Stock Issued During Period, Value, Stock Options Exercised Restricted stock awards, net (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock awards, net Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Issuance of common stock related to employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Issuance of common stock related to employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Issuance of common stock related to RSU vesting (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Issuance of common stock related to RSU vesting Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Shares withheld related to net share settlement (in shares) Shares Paid for Tax Withholding for Share Based Compensation Shares withheld related to net share settlement Adjustments Related to Tax Withholding for Share-based Compensation Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Other comprehensive loss Ending Balance (in shares) Ending Balance Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Deferred Tax Assets: Deferred Tax Assets, Net of Valuation Allowance [Abstract] Accrued liabilities Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Net operating loss carryovers Deferred Tax Assets, Operating Loss Carryforwards Research tax credit carryovers Deferred Tax Assets, Tax Credit Carryforwards, Research Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross Less valuation allowance Deferred Tax Assets, Valuation Allowance Deferred tax assets, net of valuation allowance Deferred Tax Assets, Net of Valuation Allowance Deferred Tax Liabilities: Deferred Tax Liabilities, Gross [Abstract] Fixed assets Deferred Tax Liabilities, Property, Plant and Equipment Intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax assets (liability) Deferred Tax Assets, Net Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Finite-Lived Intangible Assets [Member] Finite-Lived Intangible Assets [Member] Software Development [Member] Software Development [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Income Approach Valuation Technique [Member] Income Approach Valuation Technique [Member] Market Approach Valuation Technique [Member] Market Approach Valuation Technique [Member] Fair Value Inputs, Discount Rate Fair Value Inputs, Discount Rate Fair Value Inputs, Control Premium Fair Value Inputs, Control Premium EBITDA multiple used for fair value Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple Impairment of intangible assets and internal use software Asset Impairment Charges Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Gross Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Gross Expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Beginning balance (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 Expired (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Forfeited (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value Ending balance (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Outstanding, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Exercisable (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Exercisable, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Statement of Financial Position [Abstract] Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, par or stated value per share (usd per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par or stated value per share Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares, issued Common Stock, Shares, Issued Common stock, shares, outstanding Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Finite-lived Intangible Assets Amortization Finite-lived Intangible Assets Amortization Expense [Table Text Block] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Two Year RSUs [Member] Two Year RSUs [Member] Two Year RSUs [Member] Unvested restricted stock units Equity plans other than ESPP Other Than ESPP [Member] Other Than ESPP [Member] Restricted awards Restricted awards [Member] Restricted awards including RSAs and RSUs Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award vesting rights, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage RSUs granted Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted Earnings Per Share [Abstract] 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] Options to purchase common stock Equity Option [Member] Unvested restricted stock awards ESPP Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [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 excluded from net income (loss) per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Available-for-sale—short-term Short-term Investments [Member] Available-for-sale — long-term Other Long-term Investments [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. Treasury, government and agency debt securities Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Debt Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Available-for-sale Securities, Debt Securities International Other International [Member] Other International [Member] Research and Development [Abstract] Schedule Of Internal Use Software Costs Schedule Of Internal Use Software Costs [Table Text Block] Schedule of Internal Use Software Costs [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, Beginning balance Goodwill, Acquired During Period Goodwill, Acquired During Period Impairment of goodwill Goodwill, Ending balance Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Quarterly Financial Information Disclosure [Abstract] Cost of revenue Cost of Revenue Sales and marketing Selling and Marketing Expense Technology and development Research and Development Expense General and administrative General and Administrative Expense Restructuring and other exit costs Total expenses Costs and Expenses Loss from operations Operating Income (Loss) Total other income, net Nonoperating Income (Expense) Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Net loss Basic and Diluted (usd per share) Earnings Per Share, Basic and Diluted Basic and Diluted (in shares) Weighted Average Number Of Shares Outstanding Used To Compute Earnings Per Share, Basic and Diluted Weighted Average Number Of Shares Outstanding Used To Compute Earnings Per Share, Basic and Diluted Payables and Accruals [Abstract] Accounts payable—seller Accounts Payable, Seller, Current Description of balance sheet netting of assets and liabilities per ASC 210-20. Accounts payable—trade Accounts Payable, Trade, Current Accrued employee-related payables Employee-related Liabilities, Current Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current Net Income (Loss) Per Share Earnings Per Share [Text Block] Internal use software development costs, gross Capitalized Computer Software, Gross Accumulated amortization Capitalized Computer Software, Accumulated Amortization Internal use software development costs, net Capitalized Computer Software, Net ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities Accounts receivable, net Accounts Receivable, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current TOTAL CURRENT ASSETS Assets, Current Property and equipment, net Internal use software development costs, net Internal Use Software Development Costs, Net The carrying amount of internal use software development costs net of accumulated amortization as of the balance sheet date. Other assets, non-current Other Assets, Noncurrent Intangible assets, net Intangible Assets, Net (Excluding Goodwill) TOTAL ASSETS Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] LIABILITIES Liabilities [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable and accrued expenses Other current liabilities Other Liabilities, Current TOTAL CURRENT LIABILITIES Liabilities, Current Other liabilities, non-current Other Liabilities, Noncurrent TOTAL LIABILITIES Liabilities Commitments and contingencies (Note 16) Commitments and Contingencies STOCKHOLDERS' EQUITY Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.00001 par value, 10,000 shares authorized at December 31, 2018 and 2017; 0 shares issued and outstanding at December 31, 2018 and 2017 Preferred Stock, Value, Issued Common stock, $0.00001 par value; 500,000 shares authorized at December 31, 2018 and 2017; 51,159 and 50,239 shares issued and outstanding at December 31, 2018 and 2017, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated deficit Retained Earnings (Accumulated Deficit) TOTAL STOCKHOLDERS' EQUITY TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity Other Commitments [Table] Other Commitments [Table] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] Data Centers For Cloud-Based Services Data Centers For Cloud-Based Services [Member] Data Centers For Cloud-Based Services [Member] Office Lease Office Lease [Member] Office Lease [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Financial Standby Letter of Credit Financial Standby Letter of Credit [Member] Other Commitments [Line Items] Other Commitments [Line Items] Rental expense Operating Leases, Rent Expense Letters of credit outstanding, amount Letters of Credit Outstanding, Amount Operating lease expense Operating Expenses [Abstract] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years Total Operating Leases, Future Minimum Payments Due Operating sublease income Lessee, Operating Sublease, Description [Abstract] 2019 OperatingLeasesRentExpenseSubleaseRentalsDueinNextTwelveMonths OperatingLeasesRentExpenseSubleaseRentalsDueinNextTwelveMonths 2020 Operating Leases Rent Expense Sublease Rentals Due in Two Years Operating Leases Rent Expense Sublease Rentals Due in Two Years 2021 Operating Leases Rent Expense Sublease Rentals Due in Three Years Operating Leases Rent Expense Sublease Rentals Due in Three Years 2022 Operating Leases Rent Expense Sublease Rentals Due in Four Years Operating Leases Rent Expense Sublease Rentals Due in Four Years 2023 Operating Leases Rent Expense Sublease Rentals Due in Five Years Operating Leases Rent Expense Sublease Rentals Due in Five Years Total Operating Leases, Rent Expense, Sublease Rentals Due Operating Leases, Rent Expense, Sublease Rentals Due Total lease obligations and sublease income Operating Lease Liabilities, Payments Due [Abstract] 2019 OperatingLeasesRentExpenseNetinNextTwelveMonths OperatingLeasesRentExpenseNetinNextTwelveMonths 2020 Operating Leases Rent Expense Net, in Two Years Operating Leases Rent Expense Net, in Two Years 2021 Operating Leases Rent Expense Net, in Three Years Operating Leases Rent Expense Net, in Three Years 2022 Operating Leases Rent Expense Net, in Four Years Operating Leases Rent Expense Net, in Four Years 2023 Operating Leases Rent Expense Net, in Five Years Operating Leases Rent Expense Net, in Five Years Total Operating Leases, Rent Expense, Net Due Operating Leases, Rent Expense, Net Due Internal Use Software Development Costs Research, Development, and Computer Software Disclosure [Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic International Income (Loss) from Continuing Operations before Income Taxes, Foreign Loss before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Investments Investment Holdings, Schedule of Investments [Text Block] Fair value of restricted stock Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Unrecognized employee stock-based compensation Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Intrinsic value of nonvested unit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Basic and Diluted EPS: Earnings Per Share, Basic [Abstract] Net loss Weighted-average common shares outstanding Weighted Average Number Of Shares Outstanding Including Unvested Restricted Shares, Basic and Diluted Weighted Average Number Of Shares Outstanding Including Unvested Restricted Shares, Basic and Diluted Weighted-average unvested restricted shares Weighted Average Number of Shares, Restricted Stock Weighted-average common shares outstanding used to compute net loss per share Basic and diluted net loss per share Line of Credit Facility [Table] Line of Credit Facility [Table] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Axis] Debt Instrument Covenant Compliance Period [Domain] Debt Instrument Covenant Compliance Period [Domain] [Domain] for Debt Instrument Covenant Compliance Period [Axis] Covenant Compliance Period Two Covenant Compliance Period Two [Member] Covenant Compliance Period Two [Member] Covenant Compliance Period Three Covenant Compliance Period Three [Member] Covenant Compliance Period Three [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] Covenant Term, Scenario One Covenant Term, Scenario One [Member] Covenant Term, Scenario One [Member] Covenant Term, Scenario Two Covenant Term, Scenario Two [Member] Covenant Term, Scenario Two [Member] Streamline Period [Axis] DebtInstrumentCovenantComplianceStreamlinePeriodAxis [Axis] DebtInstrumentCovenantComplianceStreamlinePeriod [Axis] Streamline Period [Domain] DebtInstrumentCovenantComplianceStreamlinePeriodAxis [Domain] [Domain] for DebtInstrumentCovenantComplianceStreamlinePeriod [Axis] Streamline Period Applies Streamline Period Applies [Member] Streamline Period Applies [Member] Streamline Period Does Not Apply Streamline Period Does Not Apply [Member] Streamline Period Does Not Apply [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 2011 Loan Agreement 2011 Loan Agreement [Member] 2011 Loan Agreement [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Prime Rate Prime Rate [Member] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Line Of Credit Facility Borrowing Capacity Reserve Line Of Credit Facility Borrowing Capacity Reserve Line Of Credit Facility Borrowing Capacity Reserve Debt instrument, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Line of credit facility, unused capacity, commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of credit facility, remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Debt Issuance Costs, Net Debt Issuance Costs, Net Debt Instrument Adjusted Quick Ratio Requirement In Streamline Period Debt Instrument Adjusted Quick Ratio Requirement In Streamline Period Debt Instrument Adjusted Quick Ratio Requirement In Streamline Period Debt Instrument Adjusted Quick Ratio Requirement Debt Instrument Adjusted Quick Ratio Requirement Debt Instrument Adjusted Quick Ratio Requirement Debt Instrument Covenant Compliance Adjusted Earnings Before Interest Taxes Depreciation And Amortization Maximum Debt Instrument Covenant Compliance Adjusted Earnings Before Interest Taxes Depreciation And Amortization Maximum Debt Instrument Covenant Compliance Adjusted Earnings Before Interest Taxes Depreciation And Amortization Maximum Debt Instrument, Covenant Compliance, Adjusted Earnings Before Interest Taxes Depreciation And Amortization Minimum Debt Instrument, Covenant Compliance, Adjusted Earnings Before Interest Taxes Depreciation And Amortization Minimum Debt Instrument, Covenant Compliance, Adjusted Earnings Before Interest Taxes Depreciation And Amortization Minimum Debt Instrument Adjusted Quick Ratio Debt Instrument Adjusted Quick Ratio Debt Instrument Adjusted Quick Ratio Adjusted EBITDA Threshold Adjusted EBITDA Threshold Adjusted EBITDA Threshold Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Property, Plant and Equipment, Useful Life Property, Plant and Equipment, Useful Life Restructuring and Other Exit Costs Restructuring and Related Activities Disclosure [Text Block] Schedule of Share-based Compensation, Stock Options, Activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Nonvested Restricted Stock Shares Activity Nonvested Restricted Stock Shares Activity [Table Text Block] Schedule of Nonvested Restricted Stock Units Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs for all Plans Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Organization and Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Goodwill and Intangible Assets Intangible Assets Disclosure [Text Block] Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Business Combinations Business Combination Disclosure [Text Block] Depreciation expense on property and equipment Depreciation Impairment of long-lived assets Impairment of Long-Lived Assets Held-for-use Property and equipment under capital leases Capital Leased Assets, Gross Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Operations Nature of Operations [Text Block] Concentration Risk [Table] Concentration Risk [Table] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Customer One Customer One [Member] Customer One [Member] Customer Two Customer Two [Member] Customer Two [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer concentration risk, accounts receivable Customer Concentration Risk [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk, percentage Concentration Risk, Percentage Number of Operating Segments Number of Operating Segments Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Fair Value Assumptions, Expected Dividend Rate Fair Value Assumptions, Expected Dividend Rate Common Stock, Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Allowance for Doubtful Accounts Receivable Allowance for Doubtful Accounts Receivable Allowance for Doubtful Accounts Receivable, Write-offs Allowance for Doubtful Accounts Receivable, Write-offs Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Domain] Contract with Customer, Sales Channel [Domain] Desktop Desktop [Member] Desktop [Member] Mobile Mobile [Member] Mobile [Member] Revenues Revenues, percent Revenues, Percent Revenues, Percent Quarterly Financial Data (Unaudited) Quarterly Financial Information [Table Text Block] Schedule of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Revenues Revenue from Contract with Customer [Text Block] 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Total Finite-Lived Intangible Assets, Net Income Statement [Abstract] Expenses: Costs and Expenses [Abstract] Other (income) expense: Nonoperating Income (Expense) [Abstract] Interest income, net Interest Income (Expense), Net Other income Other Operating Income Foreign exchange (gain) loss, net Foreign Currency Transaction Gain (Loss), before Tax Net loss per share: Weighted average shares used to compute net loss per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Accounts Payable and Accrued Expense Accounts Payable and Accrued Liabilities Disclosure [Text Block] Accrued restructuring costs Property and Equipment Property, Plant and Equipment Disclosure [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] Developed technology Developed Technology Rights [Member] Non-compete agreements Noncompete Agreements [Member] Trademarks Trademarks [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Amortizable intangible assets, gross Finite-Lived Intangible Assets, Gross Total accumulated amortization—intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Net Asset Carrying Value Prior to Impairment Net Asset Carrying Value Prior to Impairment Net Asset Carrying Value Prior to Impairment Amortization expense of intangible assets Amortization of Intangible Assets Impairment of intangible assets Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Unrealized Gain (Loss) on Investments, net of tax Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Foreign Currency Translation Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Other comprehensive income (loss) Beginning balance Unrecognized Tax Benefits Increases related to 2017 tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Decreases related to prior year tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Increases related to current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Decreases related to current year tax positions Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions Ending balance Capitalized computer software, additions Capitalized Computer Software, Additions Capitalized computer software, amortization Capitalized Computer Software, Amortization Internal use software development costs, write-offs Internal Use Software Development Costs, Write-offs Internal Use Software Development Costs, Write-offs Estimated amortization expense, 2019 Capitalized Computer Software, Amortization Expense, Next Twelve Months Capitalized Computer Software, Amortization Expense, Next Twelve Months Estimated amortization expense, 2020 Capitalized Computer Software, Amortization Expense, Year Two Capitalized Computer Software, Amortization Expense, Year Two Estimated amortization expense, 2021 Capitalized Computer Software, Amortization Expense, Year Three Capitalized Computer Software, Amortization Expense, Year Three Capitalized computer software, impairments Capitalized Computer Software, Impairments Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Developed technology Trademark & trade name Trademarks and Trade Names [Member] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Finite-lived Intangible Assets Acquired Finite-lived Intangible Assets Acquired Estimated Useful Life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Client relationships Customer Relationships [Member] Other intangible assets Other Intangible Assets [Member] Finite-Lived Intangible Asset, Useful Life Finite-Lived Intangible Asset, Useful Life Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of revenue Cost of Sales [Member] Sales and marketing Selling and Marketing Expense [Member] Technology and development Research and Development Expense [Member] General and administrative General and Administrative Expense [Member] Restructuring and other exit costs Restructuring Charges [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] Stock-based compensation expense Allocated Share-based Compensation Expense