Business Combinations [Abstract] 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] 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 and Liabilities Assumed, Net Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] 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] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Unvested restricted stock awards Restricted Stock [Member] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Weighted Average Grant Date Value Per Share Share-based Compensation Award, Tranche Three [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Unrecognized employee stock-based compensation Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Unrecognized employee stock-based compensation, period for recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Fair value of restricted stock unit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Intrinsic value of nonvested unit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition Employee Service Share-Based Compensation, Non-Vested Restricted Stock Units, Compensation Cost Not Yet Recognized, Period for Recognition Balance Sheet Related Disclosures [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 Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Vesting, Requisite Service Conditions [Member] Vesting, Requisite Service Conditions [Member] Vesting, Requisite Service Conditions [Member] Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Granted (in dollars per share) Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Stock-based compensation expense Allocated Share-based Compensation Expense 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 Canceled (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 Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] General and administrative General and Administrative Expense [Member] Goodwill, Impairment Loss Cash consideration paid Business Combination, Consideration Transferred Outstanding unvested in-the-money options assumed Business Combination, In-The-Money Options Assumed Business Combination, In-The-Money Options Assumed 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 Acquisition-related costs Business Combination, Acquisition Related Costs Net operating loss acquired Business Combination, Net Operating Loss Acquired Business Combination, Net Operating Loss Acquired Impairment of goodwill Asset Impairment Charges Deferred tax liabilities related to acquired intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Deferred tax assets related to net operating loss carryforwards Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Investments in Marketable Securities Marketable Securities [Table Text Block] Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Schedule of Restricted Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Stock Option Employee Stock Option [Member] Employee Stock Employee Stock [Member] 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 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 Award vesting rights, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Earnings Per Share [Abstract] 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] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Accounting Policies [Abstract] Organization and Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Fair Value Disclosures [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Cash equivalents Money Market Funds [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring Fair Value, Measurements, Recurring [Member] Class of Stock [Line Items] Class of Stock [Line Items] Available-for-sale Securities Available-for-sale Securities 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 Statement of Financial Position [Abstract] Preferred stock, par or stated value per share Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred Stock, Shares Issued Preferred Stock, Shares Issued Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding Common stock, par 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 Common Stock, Shares, Outstanding Weighted remaining contractual maturity Available-for-sale Securities, Weighted-average Remaining Contractual Maturity Available-for-sale Securities, Weighted-average Remaining Contractual Maturity Realized gains (losses) on available-for-sale securities Available-for-sale Securities, Gross Realized Gain (Loss) Unrealized holding gains (losses) reclassified out of AOCI into the statements of operations for the sale of AFS investments Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax Beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 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 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) Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Available-for-sale—short-term: Short-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 US Treasury and Government [Member] Corporate debt securities Corporate Debt Securities [Member] 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 Business Combinations Business Combination Disclosure [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] Options to purchase common stock Equity Option [Member] Unvested restricted stock units 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 Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] Business Acquisition, Pro Forma Information, Nonrecurring Adjustments [Table] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items] Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Beginning balance Additions from the acquisition of nToggle Goodwill, Acquired During Period Ending balance Risk-free interest rate (in percentage) Expected volatility (in percentage) Dividend yield (in percentage) Pro forma revenues Business Acquisition, Pro Forma Revenue Pro forma net income (loss) Business Acquisition, Pro Forma Net Income (Loss) Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Income Approach Valuation Technique Income Approach Valuation Technique [Member] Market Approach Valuation Technique Market Approach Valuation Technique [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Rate used for discounted cash flow method Fair Value Inputs, Discount Rate Rate used for control premium Fair Value Inputs, Control Premium Multiple for EBITDA Fair Value Inputs, Earnings before Interest, Taxes, Depreciation, and Amortization Multiple Nets assets carrying value prior to impairment Net Asset Carrying Value Prior to Impairment Net Asset Carrying Value Prior to Impairment Intangible asset impairment Amortization expense of intangible assets Amortization of Intangible Assets 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] 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 Restructuring and Related Activities [Abstract] Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Accrued restructuring and other exit costs at December 31, 2016 Restructuring Reserve Restructuring and other exit costs Restructuring Charges Cash paid for restructuring and other exit costs Payments for Restructuring Non-cash stock-based compensation for restructuring and other exit costs Restructuring Reserve, Settled without Cash Accrued restructuring and other exit costs at September 30, 2017 Restructuring and other exit costs Restructuring Charges [Abstract] Employee termination costs Severance Costs Facility closing costs Business Exit Costs Basic EPS: Earnings Per Share, Basic [Abstract] Net income (loss) attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Weighted-average common shares outstanding (in shares) Weighted Average Number of Shares Issued, Basic Weighted-average unvested restricted shares (in shares) Weighted Average Number of Shares, Restricted Stock Weighted-average escrow shares (in shares) Weighted Average Number of Shares, Contingently Issuable Weighted-average shares used to compute net income (loss) per share (in shares) Weighted Average Number of Shares Outstanding, Basic Basic net income (loss) per share (usd per share) Earnings Per Share, Basic Diluted EPS: Earnings Per Share, Diluted [Abstract] Net income (loss) attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Diluted Weighted-average common shares used in basic EPS (in shares) Restricted Stock Awards ESPP Dilutive effect of share-based payments Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Dilutive effect of weighted-average escrow shares Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Weighted-average shares used to compute diluted net income (loss) per share (in shares) Weighted Average Number of Shares Outstanding, Diluted Diluted net income (loss) per share (usd per share) Earnings Per Share, Diluted Schedule of Restructuring and Other Exit Costs Restructuring and Related Costs [Table Text Block] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash (included in prepaid expenses and other current assets) Restricted Cash Total cash, cash equivalents, and restricted cash Cash, Cash Equivalents and Restricted Cash, Ending Balance Cash, Cash Equivalents and Restricted Cash, Ending Balance 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] AOCI Attributable to Parent [Member] 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) 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 Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Shares Paid for Tax Withholding for Share Based Compensation Shares Paid for Tax Withholding for Share Based Compensation Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Issuance of common stock related to RSU vesting (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Stock Issued During Period, Value, Employee Stock Purchase Plan Stock Issued During Period, Value, Employee Stock Purchase Plan Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit) Additional Paid in Capital Additional Paid in Capital Net income (loss) Net Income (Loss) Attributable to Parent Ending Balance (in shares) Ending Balance Other Balance Sheet Amounts Supplemental Balance Sheet Disclosures [Text Block] Statement of Cash Flows [Abstract] OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income (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 Loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Provision for doubtful accounts Provision for Doubtful Accounts 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 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 Payments to Acquire Businesses, 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 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 provided by (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 and Restricted Cash Effect of Exchange Rate on Cash, Cash Equivalents and Restricted Cash CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Change in Cash, Cash Equivalent and Restricted Cash Change in Cash, Cash Equivalent and Restricted Cash CASH, CASH EQUIVALENTS AND RESTRICTED CASH — Beginning of period Cash, Cash Equivalents and Restricted Cash, Beginning Balance Cash, Cash Equivalents and Restricted Cash, Beginning Balance CASH, CASH EQUIVALENTS AND RESTRICTED CASH — End of period SUPPLEMENTAL DISCLOSURES OF OTHER CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] 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 Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] U.S. Treasury, government and agency debt securities Fair Value, Measurements, Recurring 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] 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] Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain (loss) on investments, net of tax of $0 for the nine months ended September 30, 2017 and 2016 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 Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Finite-Lived Intangible Assets Acquired as Part of Business Combination [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] Trademark & trade name Trademarks and Trade Names [Member] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Intangible Assets Finite-lived Intangible Assets Acquired Estimated Useful Life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Customer relationships Customer Relationships [Member] Trademarks Trademarks [Member] Amortizable intangible assets, gross Finite-Lived Intangible Assets, Gross Total accumulated amortization—intangible assets Finite-Lived Intangible Assets, Accumulated Amortization Total Finite-Lived Intangible Assets, Net Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value 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 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 Options outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Unrealized gain (loss) on investments, net of tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax 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] Net Income (Loss) Per Share Earnings Per Share [Text Block] Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Income Statement [Abstract] Revenue Revenues Expenses: Costs and Expenses [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 Total expenses Costs and Expenses Loss from operations Operating Income (Loss) 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 Total other income, net Nonoperating Income (Expense) Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Benefit for income taxes Income Tax Expense (Benefit) Net income (loss) Net income (loss) attributable to common stockholders Net income (loss) per share: Basic (usd per share) Diluted (usd per share) Weighted-average shares used to compute net income (loss) per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Restructuring and Other Exit Costs Restructuring and Related Activities Disclosure [Text Block] Basis of Presentation and Summary of Significant Accounting Policies Basis of Accounting, Policy [Policy Text Block] Consolidation Consolidation, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Rental expense Operating Leases, Rent Expense Rent expense for sublease rentals Operating Leases, Rent Expense, Sublease Rentals Purchase obligations Purchase Obligation Other Commitments [Table] Other Commitments [Table] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Axis] Lease Arrangement, Type [Domain] Lease Arrangement, Type [Domain] 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] Letters of credit outstanding, amount Letters of Credit Outstanding, Amount Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] 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] Cost of revenue Cost of Sales [Member] Sales and marketing Selling and Marketing Expense [Member] Technology and development Research and Development 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] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] 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 Property, Plant 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 Deferred tax liability, net Deferred Income Tax Liabilities, Net Other liabilities, non-current Other Liabilities, Noncurrent TOTAL LIABILITIES Liabilities Commitments and contingencies (Note 9) Commitments and Contingencies STOCKHOLDERS' EQUITY Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.00001 par value, 10,000 shares authorized at March 31, 2017 and December 31, 2016; 0 shares issued and outstanding at March 31, 2017 and December 31, 2016 Preferred Stock, Value, Issued Common stock, $0.00001 par value; 500,000 shares authorized at March 31, 2017 and December 31, 2016; 49,547 and 49,378 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively Common Stock, Value, Issued Additional paid-in capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated deficit TOTAL STOCKHOLDERS' EQUITY TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity Remaining 2017 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2022 and thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five