Business Combinations [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum Maximum [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Intralinks Holdings, Inc. Intralinks Holdings, Inc. [Member] Intralinks Holdings, Inc. [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Impala Impala [Member] Impala [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Divestiture of SpeechCycle Divestiture of SpeechCycle [Member] Divestiture of SpeechCycle [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Decrease in noncontrolling interest Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Increase to Additional Paid in Capital Noncontrolling Interest, Increase to Additional Paid in Capital Noncontrolling Interest, Increase to Additional Paid in Capital Consideration transferred, equity interests issued and issuable Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Contingent interest derivative Business Combination, Contingent Consideration, Liability Total preliminary consideration transferred Business Combination, Consideration Transferred Total preliminary cash consideration transferred Payments to Acquire Businesses, Gross Potential cash proceeds Business Combination, Potential Cash Proceeds Business Combination, Potential Cash Proceeds Payment of reimbursement fees Business Combination, Payment of Reimbursement Fees Business Combination, Payment of Reimbursement Fees Divestiture consideration Disposal Group, Including Discontinued Operation, Consideration Period of transition services agreement Disposal Group, Including Discontinued Operation, Period of Transition Services Agreement Disposal Group, Including Discontinued Operation, Period of Transition Services Agreement Gain on divestiture Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Document and Entity Information Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Organization, Consolidation and Presentation of Financial Statements [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Contract with Customer, Asset and Liability Contract with Customer, Asset and Liability [Table Text Block] Schedule of New Accounting Pronouncements and Changes in Accounting Principles Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Stockholders' Equity Note [Abstract] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2016 Share Repurchase Program Share Repurchase Program2016 [Member] Information pertaining to February 2016 share repurchase program. Treasury Stock Equity, Class of Treasury Stock [Line Items] Treasury Stock Treasury Stock, Number of Shares and Restriction Disclosures [Abstract] Number of shares repurchased under program (shares) Treasury Stock, Shares, Acquired Shares retired Treasury Stock, Shares, Retired Convertible Senior Notes Long-term Debt, Gross Unamortized debt issuance cost Debt Issuance Costs, Net Total long-term debt, carrying value Long-term Debt Total short-term debt, carrying value Long-term Debt, Current Maturities Total long-term debt, carrying value Long-term Debt, Excluding Current Maturities Fair Value Disclosures [Abstract] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Redeemable Noncontrolling Interests Redeemable Noncontrolling Interest [Member] Represents the portion of liability or temporary equity in a subsidiary not attributable, directly or indirectly, to the parent. Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Changes in fair value of the Company’s Level 3 redeemable noncontrolling interests Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward] Beginning Balance Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Fair value adjustment Temporary Equity, Accretion to Redemption Value Net loss attributable to redeemable noncontrolling interests Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Ending Balance Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Foreign Currency Translation Adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Unrealized (Loss) Income on Intra-Entity Foreign Currency Transactions Accumulated Net Gain Loss On Intra Entity Foreign Currency Transactions [Member] Changes to accumulated comprehensive income resulting from net gain (loss) on intra-entity foreign currency transactions. Unrealized Holding Gains (Losses) on Available-for-Sale Securities Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accumulated Other Comprehensive Income Accumulated Other Comprehensive Income (Loss) [Line Items] Changes in accumulated other comprehensive income (loss) AOCI Attributable to Parent, Net of Tax [Roll Forward] Beginning Balance Stockholders' Equity Attributable to Parent Other comprehensive income Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Tax effect Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Total comprehensive income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Ending Balance Other Income and Expenses [Abstract] Additional Financial Information Other Nonoperating Income and Expense [Text Block] Statement [Table] Statement [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Open Exchange Open Exchange Settlement [Member] Open Exchange Settlement [Member] F-Secure Settlement F-Secure Settlement [Member] F-Secure Settlement [Member] Statement [Line Items] Statement [Line Items] FX gains Foreign Currency Transaction Gain (Loss), before Tax PIK Note impairment Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Litigation settlement Gain (Loss) Related to Litigation Settlement Remeasurement gain on financial instrument Fair Value Adjustment of Warrants Divestiture: SpeechCycle Income from Investment Cost-method Investments, Realized Gain (Loss) Royalty income Royalty Income, Nonoperating Others Other Sundry Nonoperating Income (Expense), Net Other Sundry Nonoperating Income (Expense), Net Total Other Nonoperating Income (Expense) Restructuring and Related Activities [Abstract] Restructuring Restructuring and Related Activities Disclosure [Text Block] Equity Method Investments and Joint Ventures [Abstract] Investments in Affiliates and Related Transactions Equity Method Investments and Joint Ventures Disclosure [Text Block] Contract Asset, balance Contract with Customer, Asset, Net Contract Liabilities, beginning balance Contract with Customer, Liability Revenue recognized in the period Contract with Customer, Liability, Revenue Recognized Amounts billed but not recognized as revenue Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Contract Liabilities, ending balance Statement of Financial Position [Abstract] Accounts receivable, allowance for doubtful accounts (in dollars) Allowance for Doubtful Accounts Receivable, Current Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (shares) Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, shares issued (shares) Common Stock, Shares, Issued Common stock, shares outstanding (shares) Common Stock, Shares, Outstanding Treasury stock, shares (shares) Treasury Stock, Shares Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Restricted stock awards Restricted Stock [Member] Convertible Debt Securities Convertible Debt Securities [Member] Employee Stock Option Employee Stock Option [Member] Series A Preferred Stock Series A Preferred Stock [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 2019 Notes Convertible Senior Notes Due2019 [Member] Represents activity related to 0.75% Convertible Senior Notes due 2019 (the "2019 Notes"). Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share Reconciliation [Abstract] Earnings Per Share Reconciliation [Abstract] Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Net loss from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net (income) loss attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Preferred stock dividend Preferred Stock Dividends and Other Adjustments Net (loss) income from continuing operations attributable to Synchronoss Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income from discontinued operations, net of taxes Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income effect for interest on convertible debt, net of tax Interest on Convertible Debt, Net of Tax Net loss from continuing operations adjusted for the convertible debt Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted Net loss attributable to Synchronoss Net Income (Loss) Attributable to Parent Weighted-average common shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average common shares outstanding - basic (shares) Weighted Average Number of Shares Outstanding, Basic Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Shares from assumed conversion of convertible debt (shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Shares from assumed conversion of preferred stock (shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock Options and unvested restricted shares (shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average common shares outstanding - diluted (shares) Weighted Average Number of Shares Outstanding, Diluted Basic: Earnings Per Share, Basic [Abstract] Continuing operations (usd per share) Income (Loss) from Continuing Operations, Per Basic Share Discontinued operations (usd per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Basic (usd per share) Earnings Per Share, Basic Diluted: Earnings Per Share, Diluted [Abstract] Continuing operations (usd per share) Income (Loss) from Continuing Operations, Per Diluted Share Discontinued operations (usd per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Diluted (usd per share) Earnings Per Share, Diluted Anti-dilutive stock options excluded (shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Conversion ratio Debt Instrument, Convertible, Conversion Ratio Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Selling, general and administrative Selling, General and Administrative Expenses [Member] Lender Name [Axis] Lender Name [Axis] Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Goldman Sachs Bank USA Goldman Sachs Bank USA [Member] Goldman Sachs Bank USA [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] 2017 Term Facility Secured Debt [Member] Honeybee Software Honeybee Software [Member] Honeybee Software [Member] Acquisition Business Acquisition [Line Items] Transaction costs Business Combination, Acquisition Related Costs Additional consideration transferred Business Combination, Additional Consideration Transferred Business Combination, Additional Consideration Transferred Additional consideration transferred, period (in years) Business Combination, Additional Consideration Transferred, Period Business Combination, Additional Consideration Transferred, Period Intangible assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Net working capital Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Working Capital Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Working Capital Borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Proceeds from credit agreement Proceeds from Long-term Lines of Credit Stockholders' Equity Shareholders' Equity and Share-based Payments [Text Block] Remaining performance obligation Revenue, Remaining Performance Obligation, Amount Remaining performance obligation, expected timing of satisfaction, percent Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Percent Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Percent Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Amortized Cost Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Due after 1 year through 5 years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Due after 5 years through 10 years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Due after 10 years Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Total available-for-sale debt securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due after 1 year through 5 years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Due after 5 years through 10 years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Due after 10 years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Total available-for-sale debt securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Equity Method Investments Equity Method Investments [Table Text Block] Summary of the restructuring accrual and changes Restructuring and Related Costs [Table Text Block] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Cloud Technology and Support Cloud Technology and Support [Member] Cloud Technology and Support [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued Operations, Disposed of by Sale Discontinued Operations, Disposed of by Sale [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] STIH STIH [Member] STIH [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Sequential Technology International, LLC Sequential Technology International, LLC [Member] Sequential Technology International, LLC [Member] BPO Divestiture BPO Divestiture [Member] BPO Divestiture [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Equity method investment Equity Method Investments Equity method investment, ownership interest Equity Method Investment, Ownership Percentage Duration of services agreement Duration of Customer Contract Duration of Customer Contract Discontinued operation after disposal, revenue Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Revenue Earnings per Common Share (EPS) Earnings Per Share [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Stockholder's Equity Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of Awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Non-vested at the beginning of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested at the end of the period (in shares) Weighted-Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Non-vested at the beginning of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value 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 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 Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Non-vested at the end of the period (in dollars per share) Statement of Comprehensive Income [Abstract] Net loss Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other comprehensive income, net of tax: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Unrealized loss on available for sale securities Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Net (loss) income on intra-entity foreign currency transactions Other Comprehensive Income, Net Gain (Loss) on Intra Entity Foreign Currency Transactions Arising During Period, Net of Tax Represents the amount after tax, changes to accumulated comprehensive income resulting from net gain (loss) on intra-entity foreign currency transactions. Comprehensive loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive (income) loss attributable to redeemable noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive loss attributable to Synchronoss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Legal Matters and Contingencies [Text Block] Securities in unrealized loss position (as of September 30, 2018, less than $14.8 million) Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Schedule of reconciliation of the numerator and denominator used in computing basic and diluted net income attributable to common stockholders per common share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Basis of Presentation and Consolidation Basis of Presentation and Significant Accounting Policies [Text Block] Statement of Cash Flows [Abstract] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Revolving Facility Revolving Credit Facility [Member] Amendment Amended And Restated Credit Agreement [Member] Information pertaining to Amended and Restated Credit Agreement (the "Credit Agreement"). Long-term Debt Long-term Debt [Member] Operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile Net Loss to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization expense Depreciation, Depletion and Amortization, Net of Impairment Depreciation, Depletion and Amortization, Net of Impairment Change in fair value of financial instruments Amortization of debt issuance costs Amortization of Debt Issuance Costs Accrued PIK interest Paid-in-Kind Interest Income Paid-in-Kind Interest Income Allowance for loan losses Provision for Loan, Lease, and Other Losses Loss (earnings) from equity method investments Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Loss (Gain) on disposals Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Discontinued operations non-cash and working capital adjustments Discontinued Operations, Non-cash, and Working Capital Adjustments Discontinued Operations, Non-cash, and Working Capital Adjustments Amortization of bond premium Amortization of Debt Discount (Premium) Deferred income taxes Deferred Income Tax Expense (Benefit) Stock-based compensation Share-based Compensation Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable, net of allowance for doubtful accounts Increase (Decrease) in Accounts Receivable Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other assets Increase (Decrease) in Other Operating Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued expenses Increase (Decrease) in Accrued Liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Deferred revenues Increase (Decrease) in Contract with Customer, Liability Net cash 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 fixed assets Payments to Acquire Property, Plant, and Equipment Purchases of intangible assets and capitalized software Payments for Software Proceeds from the sale of SpeechCycle Proceeds from Divestiture of Businesses Purchases of marketable securities available for sale Payments to Acquire Available-for-sale Securities Maturity of marketable securities available for sale Proceeds from Sale and Maturity of Debt Securities, Available-for-sale Equity investment distributions Proceeds from Sale of Equity Method Investments Investing in discontinued operations Payments to Acquire Interest in Subsidiaries and Affiliates Investment in note receivable Payments to Acquire Loans Receivable Business acquired, net of cash Payments to Acquire Businesses, Net of Cash Acquired 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] Share-based compensation-related proceeds, net of taxes paid on withholding shares Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Taxes paid on withholding shares Payments Related to Tax Withholding for Share-based Compensation Payments of debt issuance costs Payments of Debt Issuance Costs Proceeds from issuance of long term debt Proceeds from Issuance of Long-term Debt Repayment of long term debt Repayments of Long-term Debt Repayment of revolving line of credit Repayments of Lines of Credit Proceeds from the sale of treasury stock in connection with an employee stock purchase plan Proceeds from Sale of Treasury Stock Proceeds from issuance of preferred stock Proceeds from Issuance of Redeemable Preferred Stock Payments on capital obligations Repayments of Long-term Capital Lease Obligations Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Net decrease in cash, restricted cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, restricted cash and cash equivalents, beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, restricted cash and cash equivalents, end of period Supplemental disclosures of non-cash investing and financing activities: Supplemental Cash Flow Information [Abstract] Issuance of common stock in connection with Intralinks acquisition Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Issued Total cash, cash equivalents and restricted cash Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash Total cash, cash equivalents and restricted cash Subsequent Events [Abstract] Subsequent Events Review Subsequent Events [Text Block] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Equity Incentive Plan 2015 Equity Incentive Plan 2015 [Member] Definition: Information pertaining to the 2015 Equity Incentive Plan (the "2015 Plan"). New Hire Equity Incentive Plan 2017 New Hire Equity Incentive Plan 2017 [Member] New Hire Equity Incentive Plan 2017 [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Chief Executive Officer Chief Executive Officer [Member] Board of Directors Chairman Board of Directors Chairman [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Silver Private Holdings I, LLC Silver Private Holdings I, LLC [Member] Silver Private Holdings I, LLC [Member] Minimum Minimum [Member] Ownership Percentage [Axis] Ownership Percentage [Axis] Ownership Percentage [Axis] Ownership Percentage [Domain] Ownership Percentage [Domain] [Domain] for Ownership Percentage [Axis] Ten Percent or Greater Ownership Ten Percent or Greater Ownership [Member] Ten Percent or Greater Ownership [Member] Greater than Five and Less than Ten Percent Ownership Greater than Five and Less than Ten Percent Ownership [Member] Greater than Five and Less than Ten Percent Ownership [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock Common Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Number of votes per share (vote) Number of Votes Per Share Represents the number of votes available for each share held. Dividends Dividends Preferred stock, liquidation preference (dollars per share) Preferred Stock, Liquidation Preference Per Share Consideration received on transaction Sale of Stock, Consideration Received on Transaction Preferred stock, dividends (shares) Preferred Stock Dividends, Shares Dividend rate, percentage Preferred Stock, Dividend Rate, Percentage Convertible preferred stock, conversion price per share Convertible Preferred Stock, Conversion Price Per Share Convertible Preferred Stock, Conversion Price Per Share Preferred stock, liquidation preference Preferred Stock, Liquidation Preference, Value Preferred stock, redemption amount Preferred Stock, Redemption Amount Number of elected directors Number of Elected Directors Number of Elected Directors Preferred stock, ownership percentage Preferred Stock, Ownership Percentage Preferred Stock, Ownership Percentage Fair value, approval threshold Long-term Debt, Fair Value, Approval Threshold Under EBITDA Non-Compliance Long-term Debt, Fair Value, Approval Threshold Under EBITDA Non-Compliance Fair market value of transaction, individual Fair Market Value of Individual Transaction, Approval Threshold Under EBITDA Non-Compliance Fair Market Value of Individual Transaction, Approval Threshold Under EBITDA Non-Compliance Fair market value of transaction, aggregate Fair Market Value of Aggregate Transactions, Approval Threshold Under EBITDA Non-Compliance Fair Market Value of Aggregate Transactions, Approval Threshold Under EBITDA Non-Compliance Capital expenditure threshold Capital Expenditures, Approval Threshold Under EBITDA Non-Compliance Capital Expenditures, Approval Threshold Under EBITDA Non-Compliance Percentage ownership after conversion Conversion of Stock, Percentage Ownership after Conversion Conversion of Stock, Percentage Ownership after Conversion Voting percentage threshold of ownership Conversion of Stock, Voting Percentage Threshold of Ownership Conversion of Stock, Voting Percentage Threshold of Ownership Number of board of director members Number Of Board Of Director Members Number Of Board Of Director Members Number of board of director members elected by preferred stock holders Number Of Board Of Director Members Elected By Preferred Stock Holders Number Of Board Of Director Members Elected By Preferred Stock Holders Number of board of directors agreed upon to be elected meeting independence criteria Number Of Board Of Directors Agreed Upon To Be Elected Meeting Independence Criteria Number Of Board Of Directors Agreed Upon To Be Elected Meeting Independence Criteria Number of board of directors elected meeting independence criteria Number Of Board Of Directors Elected Meeting Independence Criteria Number Of Board Of Directors Elected Meeting Independence Criteria Minimum number of board of director members that preferred stock holders can appoint pursuant to certification Minimum Number Of Board Of Director Members That Preferred Stock Holders Can Appoint Pursuant To Certification Minimum Number Of Board Of Director Members That Preferred Stock Holders Can Appoint Pursuant To Certification Maximum ownership threshold allowed for director election rights, percent Maximum Ownership Threshold Allowed For Director Election Rights, Percent Maximum Ownership Threshold Allowed For Director Election Rights, Percent Demand registrations allowed under agreement Equity Agreement, Demand Registrations Allowed Under Agreement Equity Agreement, Demand Registrations Allowed Under Agreement Demand registrations allowed under agreement annually Equity Agreement, Demand Registrations Allowed Under Agreement Annually Equity Agreement, Demand Registrations Allowed Under Agreement Annually Demand registration, minimum percentage of shares Equity Agreement, Demand Registration, Minimum Percentage Of Shares Equity Agreement, Demand Registration, Minimum Percentage Of Shares Shares available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Liability, accrued expenses, non-vested Deferred Compensation Share-based Arrangements, Liability, Current STI STI [Member] STI [Member] Income Statement Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] Revenues Equity Method Investment, Summarized Financial Information, Revenue Expenses Equity Method Investment, Summarized Financial Information, Cost of Sales Net(loss) income Equity Method Investment, Summarized Financial Information, Net Income (Loss) Balance Sheet Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract] Equity Method Investment, Summarized Financial Information, Balance Sheet [Abstract] Restricted cash Equity Method Investment, Summarized Financial Information, Restricted Cash and Cash Equivalents, Current Equity Method Investment, Summarized Financial Information, Restricted Cash and Cash Equivalents, Current Accounts receivable Equity Method Investment, Summarized Financial Information, Accounts Receivable, Net, Current Equity Method Investment, Summarized Financial Information, Accounts Receivable, Net, Current Total assets Equity Method Investment, Summarized Financial Information, Assets Accrued expenses Equity Method Investment, Summarized Financial Information, Current Liabilities Total liabilities Equity Method Investment, Summarized Financial Information, Liabilities Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Restatement [Axis] Restatement [Axis] Restatement [Domain] Restatement [Domain] Restatement Adjustment Restatement Adjustment [Member] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Cost of revenues Cost of Services, Excluding Depreciation, Depletion, and Amortization Stock options Employee And Directors Stock Options [Member] An arrangement whereby an employee or member of the Board of Directors is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement. Weighted-average assumptions Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] Expected stock price volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected life of options (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Weighted-average fair value (grant date) of the options (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Restricted cash Restricted Cash and Cash Equivalents, Current Marketable securities, current Available-for-sale Securities, Current Accounts receivable, net of allowances of $3,492 and $3,107 at September 30, 2018 and December 31, 2017, respectively Accounts Receivable, Net, Current Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total current assets Assets, Current Marketable securities, non-current Available-for-sale Securities, Noncurrent Property and equipment, net Property, Plant and Equipment, Net Goodwill Goodwill Intangible assets, net Finite-Lived Intangible Assets, Net Other assets Other Assets, Noncurrent Note receivable from related party Due from Related Parties, Noncurrent Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses Accrued Liabilities, Current Deferred revenues, current Contract with Customer, Liability, Current Short-term debt Short-term Debt Mandatorily redeemable financial instrument Derivative Liability, Current Total current liabilities Liabilities, Current Lease financing obligation Capital Lease Obligations, Noncurrent Convertible debt, net of debt issuance costs Convertible Notes Payable, Noncurrent Deferred tax liabilities Deferred Tax Liabilities, Net Deferred revenues, non-current Contract with Customer, Liability, Noncurrent Other liabilities Other Liabilities, Noncurrent Commitments and contingencies Commitments and Contingencies Redeemable noncontrolling interest Redeemable Noncontrolling Interest, Equity, Carrying Amount Series A Convertible Participating Perpetual Preferred Stock, $0.0001 par value; 10,000 shares authorized; 195 shares issued and outstanding at September 30, 2018 Preferred Stock, Value, Issued Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $0.0001 par value; 100,000 shares authorized, 49,817 and 52,024 shares issued; 42,655 and 46,965 outstanding at September 30, 2018 and December 31, 2017, respectively Common Stock, Value, Issued Treasury stock, at cost (7,162 and 5,059 shares at September 30, 2018 and December 31, 2017, respectively) Treasury Stock, Value Additional paid-in capital Additional Paid in Capital, Common Stock 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 Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Amended Credit Facility Credit Facility Line of Credit [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Commitment fees Debt Instrument, Unused Borrowing Capacity, Fee Interest expense on borrowings Interest Expense, Debt Contingent Interest Derivative Debt Instrument, Convertible, Associated Derivative, Interest Expense Debt Instrument, Convertible, Associated Derivative, Interest Expense Amendment fees paid to third parties Interest Expense, Debt, Amendment Fees Interest Expense, Debt, Amendment Fees Additional interest on default Additional Interest Expense on Default Additional Interest Expense on Default Non-cash interest on leased facility Interest Expense, Lessee, Assets under Capital Lease Other Interest Expense, Other Interest Expense Interest Expense Cost of revenues Cost of Sales [Member] Research and development Research and Development Expense [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Employee Stock Purchase Plan Employee Stock [Member] Share-based compensation expense Employee Service Share-based Compensation, Aggregate Disclosures [Abstract] Total stock-based compensation expense Allocated Share-based Compensation Expense Total stock-based compensation before taxes Allocated Share-based Compensation Expense, Including Discontinued Operations Allocated Share-based Compensation Expense, Including Discontinued Operations Tax benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Stock-based compensation cost related to non-vested equity awards not yet recognized as an expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted-average period over which stock-based compensation cost related to non-vested equity awards is expected to be recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Accumulated Other Comprehensive Income/ (Loss) Comprehensive Income (Loss) Note [Text Block] Schedule of Debt Schedule of Debt [Table Text Block] Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table Text Block] Sequential Technology International Holdings, LLC Sequential Technology International Holdings, LLC [Member] Sequential Technology International Holdings, LLC [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Indirect Guarantee of Indebtedness Indirect Guarantee of Indebtedness [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Reduction in equity investment Restricted Cash, Current Modification to liquidation preference Financing Receivable, Modifications, Liquidation Preference, Increase Financing Receivable, Modifications, Liquidation Preference, Increase Movement in Financing Receivable [Roll Forward] Movement in Financing Receivable [Roll Forward] Movement in Financing Receivable [Roll Forward] Seller Note, beginning balance Financing Receivable, Gross Impairment, beginning balance Financing Receivable, Allowance for Credit Losses Unamortized Discount, beginning balance Financing Receivable, Unamortized Discount (Premium) Financing Receivable, Unamortized Discount (Premium) Loan Accrued Interest, beginning balance Accrued Investment Income Receivable Distribution Note, beginning balance Escrow Deposit Distribution interest, beginning balance Interest on Escrow Deposit Interest on Escrow Deposit Total, beginning balance Financing Receivable, Net Seller Note, activity Financing Receivable, Gross, Increase (Decrease), Net Financing Receivable, Gross, Increase (Decrease), Net Impairment, activity Unamortized Discount, activity Financing Receivable, Amortization Of Discount Financing Receivable, Amortization Of Discount Loan Accrued Interest, activity Impaired Financing Receivable, Interest Income, Accrual Method Distribution Note, activity Increase (Decrease) in Deposits Outstanding Distribution interest, activity Escrow Deposit, Interest Income Escrow Deposit, Interest Income Total, activity Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease) Seller Note, ending balance Impairment, ending balance Unamortized Discount, ending balance Loan Accrued Interest, ending balance Distribution Note, ending balance Distribution interest, ending balance Total, ending balance Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Certificates of deposit Certificates of Deposit [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Corporate bonds Corporate Debt Securities [Member] Municipal bonds Municipal Bonds [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Amortized Cost to Fair Value Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Available-for-sale Securities Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Impacts of the New Revenue Standard Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Adjusted amounts under prior GAAP Calculated under Revenue Guidance in Effect before Topic 606 [Member] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Accounts receivable, net Common stock, $0.0001 par value; 100,000 shares authorized, 49,817 and 52,024 shares issued; 42,655 and 46,965 outstanding at September 30, 2018 and December 31, 2017, respectively Accumulated other comprehensive loss Acquisitions and Divestitures Business Combination Disclosure [Text Block] Fair Value Measurements of Assets and Liabilities Fair Value Disclosures [Text Block] Components of other (expense) income, net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Number of Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Options outstanding at the beginning of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Options Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options Cancelled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Options outstanding at the end of the period (in shares) Vested or expected to vest (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted-Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Balance at the beginning of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Options Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Options Cancelled (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Balance at the end of the period (in dollars per share) Vested or expected to vest (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Remaining Contractual Term (Years) Share Based Compensation Arrangement by Share Based Payment Award, Options Weighted Average Remaining Contractual Term [Abstract] Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Vested or expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Share Based Compensation Arrangement by Share Based Payment Award, Aggregate Intrinsic Value [Abstract] Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Vested or expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Additional disclosures related to stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Total intrinsic value for stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Summary of assets and liabilities held by the Company and their related classifications under the fair value hierarchy Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets Assets, Fair Value Disclosure [Abstract] Cash, cash equivalents and restricted cash Cash and Cash Equivalents, Fair Value Disclosure Marketable securities-short term Marketable securities-long term Total assets Assets, Fair Value Disclosure Liabilities Liabilities, Fair Value Disclosure [Abstract] Mandatorily redeemable financial instrument Convertible Debt Interest Derivative Convertible Debt Interest Derivative Total liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Temporary equity Equity, Fair Value Disclosure [Abstract] Redeemable noncontrolling interests Redeemable Noncontrolling Interest, Equity, Other, Fair Value Total temporary equity Equity, Fair Value Disclosure Transfers between Levels Fair Value, Transfers Between Level 1 and Level 2, Description and Policy [Abstract] Fair value of asset transfers between Levels 1, 2, and 3 Fair Value, Assets, Transfers between Levels 1, 2, and 3, Amount Amount of transfers of assets measured on a recurring basis between Levels 1, 2, and 3 of the fair value hierarchy. Schedule of stock-based compensation Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of fair value assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of information about stock options outstanding Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of unvested restricted stock Schedule of Nonvested Share Activity [Table Text Block] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employment termination costs Employee Severance [Member] Facilities consolidation Facility Closing [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accrued expenses Accrued Liabilities [Member] Restructuring accrual and changes Restructuring Cost and Reserve [Line Items] Restructuring accrual and changes Restructuring Reserve [Roll Forward] Balance at December 31, 2017 Restructuring Reserve Charges Restructuring Charges Payments Payments for Restructuring Other adjustments Restructuring Reserve, Period Increase (Decrease) Balance at September 30, 2018 Net revenues Revenue from Contract with Customer, Excluding Assessed Tax Costs and expenses: Costs and Expenses [Abstract] Research and development Research and Development Expense Selling, general and administrative Selling, General and Administrative Expense Restructuring charges Depreciation and amortization Depreciation, Depletion and Amortization Total costs and expenses Costs and Expenses Loss from continuing operations Operating Income (Loss) Interest income Investment Income, Interest Interest expense Equity method investment income Equity method investment income Income (Loss) from Equity Method Investments Loss from continuing operations, before taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Benefit for income taxes Income Tax Expense (Benefit) Net loss Preferred stock dividend Preferred Stock Dividends, Income Statement Impact Net loss from continued operations Weighted Average Number of Shares Outstanding, Basic [Abstract] Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Income Statement [Abstract] Total costs and expenses Interest expense Other (expense) income, net Loss from continuing operations, before taxes Benefit for income taxes Net loss from continuing operations Net loss from discontinued operations, net of tax Basic (usd per share) Diluted (usd per share) Basic (in shares) Diluted (in shares) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value Measurements of Assets and Liabilities Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Schedule of assets and liabilities held and their related classifications under the fair value hierarchy Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of estimated fair value of investments classified as available for sale Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Expected maturities Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of changes in fair value of Level 3 Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Decrease in restricted cash Decrease in Restricted Cash New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Reduction to retained earnings Net revenues Revenues Capitalized contract cost Capitalized Contract Cost, Net Cumulative catch up Topic 606 adjustment as of January 1, 2018 Cumulative Effect on Retained Earnings, Net of Tax Retained Earnings at September 30, 2018 Provision (benefit) for income taxes Effective income tax rate, percent Effective Income Tax Rate Reconciliation, Percent Change in valuation allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Convertible senior notes Debt Instrument, Face Amount Interest rate, as a percent Debt Instrument, Interest Rate, Stated Percentage Principal amount Debt issuance costs Debt Issuance Costs, Noncurrent, Net Conversion price Debt Instrument, Convertible, Conversion Price Repurchase price, expressed as a percentage of principal of debt repurchased Debt Instrument, Repurchase Price as a Percentage of Principal Amount Repurchased Represents the purchase price of debt to be repurchased expressed as a percentage of the principal amount of the repurchased debt. Interest rate, effective percentage Debt Instrument, Interest Rate, Effective Percentage Total debt, carrying value Long-term Debt, Fair Value Additional interest for non-compliance, percent Convertible Debt, Additional Interest for Non-compliance, Percent Convertible Debt, Additional Interest for Non-compliance, Percent Second additional interest for non-compliance, percent Convertible Debt, Second Additional Interest for Non-compliance, Percent Convertible Debt, Second Additional Interest for Non-compliance, Percent Debt default, percent of holders Debt Instrument, Debt Default, Percent of Holders Debt Instrument, Debt Default, Percent of Holders Liability at fair value Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value Notice of holders of 2019 Notes threshold for acceleration of notes due (percent) Debt Instrument, Subjective Acceleration Clause, Outstanding Principle Amount Of Debt Threshold Debt Instrument, Subjective Acceleration Clause, Outstanding Principle Amount Of Debt Threshold Debt retired as part of settlement agreement Extinguishment of Debt, Amount Schedule of changes in accumulated other comprehensive income (loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Cloud Cloud [Member] Cloud [Member] Digital Digital [Member] Digital [Member] Messaging Messaging [Member] Messaging [Member] Professional Services Professional Services [Member] Professional Services [Member] Transaction Services Transaction Services [Member] Transaction Services [Member] Subscription Services Subscription Services [Member] Subscription Services [Member] License License [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Americas Americas [Member] APAC Asia Pacific [Member] EMEA EMEA [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Description of Business Description of Business Nature of Operations [Text Block] Basis of Presentation and Consolidation Consolidation, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Fair Value Measurement Fair Value Measurement, Policy [Policy Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation Pending Litigation [Member] The Securities Law Actions The Securities Law Actions [Member] The Securities Law Actions [Member] Legal Matters Loss Contingencies [Line Items] Number of complaints filed Loss Contingency, New Claims Filed, Number Subsequent Event [Table] Subsequent Event [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Proceeds from previous disposition Proceeds From Previous Disposition Proceeds From Previous Disposition