Business Combinations [Abstract] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2014 Repurchase Program [Domain] 2014 Repurchase Program [Domain] 2014 Repurchase Program [Domain] [Domain] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Proceeds from Issuance of Warrants Proceeds from Issuance of Warrants CASH DIVIDENDS DECLARED PER COMMON SHARE (in usd per share) Common Stock, Dividends, Per Share, Declared Dividends, Common Stock, Cash Dividends, Common Stock, Cash Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Stock Repurchased During Period, Shares Stock Repurchased During Period, Shares Stock Repurchased During Period, Value Stock Repurchased During Period, Value Equity component of the 2020 Notes, net of tax Equity Component of the Notes, Net of Tax [2] equity component of the notes, net of tax [2] Deferred financing costs allocated to equity Payments of Financing Costs Stockholders' Equity Attributable to Parent Stockholders' Equity Attributable to Parent Adjustments Related to Tax Withholding for Share-based Compensation Adjustments Related to Tax Withholding for Share-based Compensation Tax benefit from share-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Unrealized (loss) gain on investments, net of tax Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Cash dividends declared Dividends Repurchase of common stock Payments for Repurchase of Common Stock Proceeds from Stock Options Exercised Proceeds from Stock Options Exercised Convertible note hedge transactions, net of tax Payments for (Proceeds from) Hedge, Financing Activities Share-based compensation Share-based Compensation Noncontrolling Interest, Increase from Business Combination Noncontrolling Interest, Increase from Business Combination Distribution preference Distribution preference Distribution preference Net loss attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Noncontrolling interest Noncontrolling Interest in Variable Interest Entity Proceeds from noncontrolling interests Proceeds from Noncontrolling Interests Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Organization, Consolidation and Presentation of Financial Statements [Abstract] Revenue, Initial Application Period Cumulative Effect Transition [Table] Revenue, Initial Application Period Cumulative Effect Transition [Table] 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] Static Fixed Fee Agreements [Domain] Static Fixed Fee Agreements [Domain] Static Fixed Fee Agreements [Domain] Static Prepayments [Domain] Static Prepayments [Domain] Static Prepayments [Domain] Quarter Lag Reporting [Domain] Quarter Lag Reporting [Domain] Quarter Lag Reporting [Domain] Significant Financing Component [Domain] Significant Financing Component [Domain] Significant Financing Component [Domain] Related Tax Effect and Other Balance Sheet Impact [Domain] Related Tax Effect and Other Balance Sheet Impact [Domain] Related Tax Effect and Other Balance Sheet Impact [Domain] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accounts Receivable [Member] Accounts Receivable [Member] Deferred Tax Asset [Domain] Deferred Tax Asset [Domain] Taxes Payable [Domain] Taxes Payable [Domain] Taxes Payable [Domain] Deferred Revenue [Domain] Deferred Revenue [Domain] Retained Earnings, Unappropriated [Member] Retained Earnings [Member] Other Noncurrent Assets [Member] Other Noncurrent Assets [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Revenue, Initial Application Period Cumulative Effect Transition [Line Items] Contract with Customer, Asset, Net Contract with Customer, Asset, Net Accounts Receivable 606 Accounts Receivable, Net Deferred Tax Assets Deferred Tax Assets, Net Taxes Payable 606 Taxes Payable Deferred Revenue Deferred Revenue Retained Earnings Retained Earnings (Accumulated Deficit) Retained earnings Retained Earnings, Unappropriated DEFERRED TAX ASSETS Deferred Tax Assets, Net of Valuation Allowance, Noncurrent 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] Business Acquisition [Line Items] Business Acquisition [Line Items] Actual revenue Revenue from Contract with Customer, Including Assessed Tax Supplemental pro forma revenue Business Acquisition, Pro Forma Revenue Actual earnings Supplemental pro forma earnings Business Acquisition, Pro Forma Net Income (Loss) Actual diluted earnings per share (in usd per share) Earnings Per Share, Diluted Supplemental pro forma diluted earnings per share (in usd per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Significant Agreements [Abstract] Significant Agreements [Abstract] Prepaid Expenses and Other Current Assets [Member] Prepaid Expenses and Other Current Assets [Member] Technicolor Technicolor [Member] Technicolor [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed Cash Payments to Acquire Businesses, Gross Contingent consideration liability Business Combination, Contingent Consideration, Liability Consideration transferred Business Combination, Consideration Transferred Less: Transaction-related receivable Business Combination, Acquired Receivable, Fair Value Net fair value of consideration transferred Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Other non-current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Long-term debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Other long-term liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities Total net tangible assets and liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Patents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Goodwill Goodwill Total identified intangible assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Intangible Assets, Including Goodwill Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Intangible Assets, Including Goodwill Total fair value of consideration transferred Estimated useful lives Finite-Lived Intangible Asset, Useful Life Additional annualized amortization expense EstimatedAdditionalAmortizationExpenseFromAcquiredIntangibles EstimatedAdditionalAmortizationExpenseFromAcquiredIntangibles CONCENTRATION OF CREDIT RISK AND FAIR VALUE OF FINANCIAL ASSETS AND FINANCIAL LIABILITIES: [Abstract] CONCENTRATION OF CREDIT RISK AND FAIR VALUE OF FINANCIAL ASSETS AND FINANCIAL LIABILITIES: [Abstract] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Convertible Notes 2016 [Member] Convertible Notes 2016 [Member] Convertible Notes 2016 [Member] Convertible Notes 2020 [Member] Convertible Notes 2020 [Member] Convertible Notes 2020 [Member] [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Money Market Funds and Demand Deposits [Member] Accounts that may or may not bear interest and that depositor is entitled to withdraw at anytime without prior notice. Checking and negotiable order of withdrawal (NOW) accounts are the most common forms of demand deposits. Additionally, includes a fund that has underlying investments in short-term money-market instruments, such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and other highly liquid and safe securities and pays money market rates of interest. Commercial Paper [Member] Commercial Paper [Member] US Government and Government Agencies and Authorities [Member] US Treasury and Government [Member] Corporate Bonds and Asset Backed Securities [Domain] Corporate Bonds and Asset Backed Securities [Domain] Corporate Bonds-This category includes information about long-term debt securities that are issued by either a domestic or foreign corporate business entity with a date certain promise of repayment and a return to the holder for the time value of money (for example, variable or fixed interest, original issue discount). Asset Backed Securities-This category includes information about securities that are primarily serviced by the cash flows of a discrete pool of receivables or other financial assets (such as mortgage loans or credit-card receivables). 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] Business Combination, Contingent Consideration, Liability, Measurement Input Business Combination, Contingent Consideration, Liability, Measurement Input Assets, Fair Value Disclosure Assets, Fair Value Disclosure Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Senior Notes Senior Notes Commercial Paper Commercial Paper LONG-TERM DEBT Long-term Debt, Excluding Current Maturities Long-term Debt, Fair Value Long-term Debt, Fair Value Debt Instrument, Face Amount Debt Instrument, Face Amount Other Liabilities, Fair Value Disclosure Other Liabilities, Fair Value Disclosure NET INCOME PER SHARE: [Abstract] NET INCOME PER SHARE: [Abstract] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Equity [Member] Equity [Member] Convertible Debt [Member] Convertible Debt [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Convertible Debt Securities [Member] Convertible Debt Securities [Member] Warrant [Member] Warrant [Member] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Earnings Per Share, Basic & Dilutive, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Debt Instrument, Convertible, Conversion Price Debt Instrument, Convertible, Conversion Price Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Weighted Average Number of Shares Outstanding, Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Weighted Average Number Diluted Shares Outstanding Adjustment Weighted Average Number Diluted Shares Outstanding Adjustment Weighted Average Number of Shares Outstanding, Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Dilutive Securities, Efffect on Basic Earnings Per Share [2] Dilutive Securities, Effect on Basic Earnings Per Share Net Income Per Common Share, Basic (in usd per share) Earnings Per Share, Basic NET INCOME PER COMMON SHARE — DILUTED (in usd per share) Class of Warrant or Right, Outstanding Class of Warrant or Right, Outstanding Warrant Option Strike Price Warrant Option Strike Price Warrant Option Strike Price VIE [Abstract] VIE [Abstract] Statement [Table] Statement [Table] Cash and Cash Equivalents [Member] Cash and Cash Equivalents [Member] Patents [Member] Patents [Member] Statement [Line Items] Statement [Line Items] Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities INCOME TAXES: [Abstract] INCOME TAXES: [Abstract] Income Tax Contingency [Table] Income Tax Contingency [Table] Scenario, Unspecified [Domain] Scenario, Forecast [Member] Scenario, Forecast [Member] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Uncertain tax position [Member] Uncertain Tax Position [Member] Uncertain Tax Position [Member] Foreign Country [Member] Foreign Tax Authority [Member] Internal Revenue Service (IRS) [Member] Internal Revenue Service (IRS) [Member] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Effective Income Tax Rate, Continuing Operations Effective Income Tax Rate Reconciliation, Percent Estimated Annual Effective Tax Rate Estimated Annual Effective Tax Rate Estimated Annual Effective Tax Rate INCOME TAX BENEFIT (PROVISION) Income Tax Expense (Benefit) Income taxes paid, including foreign withholding taxes Income Taxes Paid Taxes payable Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority Tax Adjustments, Settlements, and Unusual Provisions Tax Adjustments, Settlements, and Unusual Provisions Estimated Tax Refund Estimated Tax Refund Estimated Tax Refund 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] Deferred Revenue, Revenue Recognized Deferred Revenue, Revenue Recognized Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Basis of Presentation Basis of Presentation and Significant Accounting Policies [Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Variable Patent Royalty Revenue [Domain] Variable Patent Royalty Revenue [Domain] Variable Patent Royalty Revenue [Domain] Fixed-Fee Royalty Revenue [Domain] Fixed-Fee Royalty Revenue [Domain] Fixed-Fee Royalty Revenue [Domain] Current Patent Royalties [Domain] Current Patent Royalties [Domain] Current Patent Royalties [Domain] Non Current Patent Royalties [Domain] Non Current Patent Royalties [Domain] Non Current Patent Royalties [Domain] Total Patent Royalties [Member] Total Patent Royalties [Member] Total Patent Royalties [Member] Technology solutions Current Technology Solutions [Domain] Current Technology Solutions [Domain] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Duration [Axis] Contract with Customer, Duration [Axis] Contract with Customer, Duration [Domain] Contract with Customer, Duration [Domain] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Domain] Contract with Customer, Sales Channel [Domain] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from Contract with Customer, Including Assessed Tax Increase/(Decrease) in Disaggregated Revenue Increase/(Decrease) in Disaggregated Revenue Increase/(Decrease) in Disaggregated Revenue Revenues, Net of Interest Expense Revenues, Net of Interest Expense Percentage Increase/(Decrease) in Disaggregated Revenue Percentage Increase/(Decrease) in Disaggregated Revenue Percentage Increase/(Decrease) in Disaggregated Revenue Commitments and Contingencies Disclosure [Abstract] Litigation and Legal Proceedings Legal Matters and Contingencies [Text Block] Schedule of Long Lived Assets Held-for-sale [Table] Schedule of Long Lived Assets Held-for-sale [Table] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] King of Prussia [Domain] King of Prussia [Domain] King of Prussia [Domain] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale, Name [Domain] Long Lived Assets Held-for-sale, Name [Domain] Long Lived Assets Held-for-sale [Line Items] Long Lived Assets Held-for-sale [Line Items] Sale Leaseback Transaction, Net Proceeds, Investing Activities Sale Leaseback Transaction, Net Proceeds, Investing Activities Gain (Loss) on Disposition of Assets Gain (Loss) on Disposition of Assets EQUITY TRANSACTIONS: [Abstract] EQUITY TRANSACTIONS: [Abstract] Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Repurchases related to 2020 Notes [Member] Repurchases related to 2020 Notes [Member] Repurchases related to 2020 Notes [Member] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Note Warrant2 [Member] Note Warrant2 [Member] Note Warrant2 [Member] Balance Sheet by Location [Domain] Balance Sheet by Location [Domain] Balance Sheet by Location [Domain] Cumulative Effect on Retained Earnings, Net of Tax Cumulative Effect on Retained Earnings, Net of Tax Payments of Financing Costs Treasury Stock Acquired, Repurchase Authorization Treasury Stock Acquired, Repurchase Authorization Accelerated Share Repurchases, Initial Price Paid Per Share Accelerated Share Repurchases, Initial Price Paid Per Share Noncontrolling Interest, Increase from Business Combination Equity Transactions [Roll Forward] Equity Transactions [Roll Forward] Balance as of December 31, 2011 NET INCOME Adjustments Related to Tax Withholding for Share-based Compensation Balance as of September 30, 2012 Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities Excess Tax Benefit from Share-based Compensation, Financing Activities Long-term Debt, Unclassified [Abstract] Long-term Debt [Text Block] Long-term Debt [Text Block] Business Combination Disclosure [Text Block] Business Combination Disclosure [Text Block] Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Note Disclosure [Text Block] Legal Gain (Loss) Contingencies [Table] Loss Contingencies [Table] Huawei China [Member] Huawei China [Member] Huawei China [Member] Legal Gain (Loss) Contingencies [Line Items] Loss Contingencies [Line Items] Deferred revenue Deferred Revenue, Current Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Equity Component [Domain] Equity Component [Domain] Other Noncurrent Liabilities [Member] Convertible Note Overallotment [Member] Convertible Note 2 [Member] Convertible Debt 1 [Member] Convertible Debt 1 [Member] Convertible Note Hedge 2 [Member] convertible note hedge 2 [Member] Convertible Note Hedge [Member] Convertible Hedge [Member] Convertible Note Hedge 1 [Member] convertible note hedge 1 [Member] Convertible Note/ Hedge Warrant, net [Member] Convertible Note Hedge Warrant, net [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Interest Expense, Debt, Excluding Amortization Interest Expense, Debt, Excluding Amortization Accretion of Discount Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves, Accretion of Discount Amortization of Financing Costs Amortization of Debt Issuance Costs Payments for (Proceeds from) Hedge, Financing Activities Debt Instrument, Unamortized Discount Debt Instrument, Unamortized Discount Deferred financing costs Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Accumulated Amortization Senior Convertible Notes [Equity net of tax] Senior Convertible Notes [Equity net of tax] Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. Convertible notes can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder. Debt Conversion, Converted Instrument, Amount Debt Conversion, Converted Instrument, Amount Debt Instrument, Convertible, Stock Price Trigger Debt Instrument, Convertible, Stock Price Trigger Shares, Issued Shares, Issued Proceeds from (Payments for) Other Financing Activities Proceeds from (Payments for) Other Financing Activities Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Interest Rate, Effective Percentage Payments of Debt Issuance Costs Payments of Debt Issuance Costs Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Convertible, Conversion Ratio Debt Instrument, Convertible, Conversion Ratio Interest Expense Interest Expense Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Long-term Debt Instruments [Table Text Block] Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Non-cash interest expense Amortization of Debt Issuance Costs and Discounts Change in deferred revenue Increase (Decrease) in Deferred Revenue Deferred income taxes Deferred Income Tax Expense (Benefit) Loss on disposal of assets Other Other Operating Activities, Cash Flow Statement (Increase) decrease in assets: Increase (Decrease) in Operating Assets [Abstract] Receivables Increase (Decrease) in Receivables Deferred charges and other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in liabilities: Increase (Decrease) in Operating Liabilities [Abstract] Accounts payable Increase (Decrease) in Accounts Payable Accrued compensation and other expenses Increase (Decrease) in Other Accrued Liabilities Accrued taxes payable and other tax contingencies Increase (Decrease) in Accrued Taxes Payable Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of short-term investments Payments to Acquire Short-term Investments Sales of short-term investments Proceeds from Sale of Short-term Investments Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Capitalized patent costs Capitalized patent costs Capitalized costs inccured and are direclty related to the defense and generation of Patents. Acquisition of patents Payments to Acquire Intangible Assets Acquisition of business, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Long-term investments Payments to Acquire Long-term Investments Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Net proceeds from exercise of stock options Dividends paid Payments of Dividends Taxes withheld upon restricted stock unit vestings Payments Related to Tax Withholding for Share-based Compensation Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash and Cash Equivalents, Period Increase (Decrease) CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents CASH, CASH EQUIVALENTS AND RESTRICTED CASH, END OF PERIOD Interest paid Interest Paid, Including Capitalized Interest, Operating and Investing Activities Dividends payable Dividends Payable Non-cash acquisition of patents Noncash or Part Noncash Acquisition, Intangible Assets Acquired Accrued capitalized patent costs, property and equipment, and acquisition of patents Accrued Capitalized Patent Costs Accrued Capitalized Patent Costs Revenue Recognition, Multiple-deliverable Arrangements [Table] Revenue Recognition, Multiple-deliverable Arrangements [Table] Revenue Classification [Axis] Revenue Classification [Axis] Revenue Classification [Axis] Revenue Classification [Domain] Revenue Classification [Domain] [Domain] for Revenue Classification [Axis] Past Patent Royalties [Domain] Past Patent Royalties [Domain] Past Patent Royalties [Domain] Related to Cash Receipts [Domain] Related to Cash Receipts [Domain] Related to Cash Receipts [Domain] Related to Patents Transferred [Domain] Related to Patents Transferred [Domain] Related to Patents Transferred [Domain] Revenue Recognition, Multiple-deliverable Arrangements [Line Items] Revenue Recognition, Multiple-deliverable Arrangements [Line Items] Revenues 606 Revenues Significant Agreements [Text Block] Significant Agreements [Text Block] Significant Agreements- Disclosure of significant agreements during interim period. [Text Block] Significant Agreements [Text Block] Disclosure of Long Lived Assets Held-for-sale [Table Text Block] Income Statement [Abstract] Patent licensing royalties Patent Licensing Royalties [Domain] Patent Licensing Royalties [Domain] REVENUES OPERATING EXPENSES: Operating Expenses [Abstract] Patent administration and licensing Patent administration and licensing Patent administration and licensing expenses. Expenses (ie. legal, filings, etc.) incurred and are directly related to generating license revenue. Development Research and Development Expense Selling, general and administrative Selling, General and Administrative Expense Total Operating Expenses Costs and Expenses Income from operations Operating Income (Loss) OTHER EXPENSE (NET) Other Operating Income (Expense), Net Income (loss) before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest NET INCOME NET INCOME ATTRIBUTABLE TO INTERDIGITAL, INC. NET INCOME PER COMMON SHARE — BASIC (in usd per share) WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING — BASIC (in shares) WEIGHTED AVERAGE NUMBER OF COMMON SHARES OUTSTANDING — DILUTED (in shares) Reclassifications Reclassification, Policy [Policy Text Block] New Accounting Guidance New Accounting Pronouncements, Policy [Policy Text Block] Equity Method Investments Equity Method Investments New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Guidance [Axis] Accounting Guidance [Axis] Accounting Guidance [Axis] Accounting Guidance [Domain] Accounting Guidance [Domain] ASU 2018-02 [Domain] ASU 2018-02 [Domain] ASU 2018-02 [Domain] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Cumulative Effect of New Accounting Principle in Period of Adoption Cumulative Effect of New Accounting Principle in Period of Adoption Fair Value, Measurement Inputs, Disclosure [Table Text Block] Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block] Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Equity Method Investments and Joint Ventures Disclosure [Text Block] Variable Interest Entity Disclosure [Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill balance as of December 31, 2017 Technicolor Acquisition Goodwill, Acquired During Period Goodwill balance as of September 30, 2018 Statement of Financial Position [Abstract] Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Common stock, par value (in usd 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 Preferred stock, par value (in usd 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 Treasury stock, shares Treasury Stock, Common, Shares Patent Sale [Table] Supply Commitment [Table] Supply Commitment [Axis] Supply Commitment [Axis] Supply Commitment Arrangement [Domain] Supply Commitment Arrangement [Domain] Supply Commitment [Line Items] Supply Commitment [Line Items] Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Restricted Cash [Abstract] Restrictions on Cash and Cash Equivalents [Table] Restrictions on Cash and Cash Equivalents [Table] Restricted Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Restricted Cash and Cash Equivalents Items [Line Items] Restricted Cash and Cash Equivalents Items [Line Items] Cash and Cash Equivalents, at Carrying Value Cash and Cash Equivalents, at Carrying Value Restricted Cash Restricted Cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Concentration Risk [Table] Concentration Risk [Table] Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration Risk, Percentage Concentration Risk, Percentage Concentration Risk, Customer Concentration Risk, Customer ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Short-term investments Short-term Investments Accounts receivable, less allowances of $456 Prepaid and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current NON-CURRENT ASSETS: Assets, Noncurrent [Abstract] PROPERTY AND EQUIPMENT, NET Property, Plant and Equipment, Net PATENTS, NET Finite-Lived Patents, Net Finite-Lived Patents, Net DEFERRED TAX ASSETS OTHER NON-CURRENT ASSETS Other Assets, Noncurrent Total non-current assets Assets, Noncurrent TOTAL ASSETS Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] CURRENT LIABILITIES: Liabilities, Current [Abstract] Accounts payable Accounts Payable Accrued compensation and related expenses Employee-related Liabilities, Current Other accrued expenses Other Accrued Liabilities Total current liabilities Liabilities, Current NON-CURRENT LIABILITIES Liabilities, Noncurrent [Abstract] LONG-TERM DEFERRED REVENUE Deferred Revenue, Noncurrent OTHER LONG-TERM LIABILITIES Other Liabilities, Noncurrent TOTAL LIABILITIES Liabilities COMMITMENTS AND CONTINGENCIES Commitments and Contingencies SHAREHOLDERS’ EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Preferred Stock, $0.10 par value, 14,399 shares authorized, 0 shares issued and outstanding Preferred Stock, Value, Outstanding Common Stock, $0.01 par value, 100,000 shares authorized, 71,117 and 70,749 shares issued and 34,442 and 34,622 shares outstanding Common Stock, Value, Outstanding Additional paid-in capital Additional Paid in Capital Retained earnings Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax TOTAL SHAREHOLDERS’ EQUITY Stockholders' Equity before Treasury Stock Treasury stock, 36,675 and 36,127 shares of common held at cost Treasury Stock, Value Total InterDigital, Inc. shareholders’ equity Total equity TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity Calculated under Revenue Guidance in Effect before Topic 606 [Member] Calculated under Revenue Guidance in Effect before Topic 606 [Member] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Retained Earnings, Unappropriated [Member] Retained Earnings, Unappropriated [Member] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] ASC 605 [Domain] ASC 605 [Domain] ASC 605 [Domain] Costs and Expenses Operating Income (Loss) Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Taxes Payable 606 Deferred Revenue Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Payments of Debt Issuance Costs Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Business Combination, Acquired Receivable, Fair Value Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Schedule of Stockholders Equity [Table Text Block] Schedule of Stockholders Equity [Table Text Block] Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Revenue Volatility [Member] Revenue Volatility [Member] Revenue Volatility [Member] Discount Rate for Revenue [Member] Discount Rate for Revenue [Member] Discount Rate for Revenue [Member] Credit Risk Discount Rate [Member] Credit Risk Discount Rate [Member] Credit Risk Discount Rate [Member] RiskAdjustedDiscountRateForRevenue [Member] RiskAdjustedDiscountRateForRevenue [Member] RiskAdjustedDiscountRateForRevenue [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Axis] Other Comprehensive Income Location [Domain] Other Comprehensive Income Location [Domain] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Debt Instrument, Measurement Input Debt Instrument, Measurement Input Statement of Comprehensive Income [Abstract] Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to noncontrolling interest Total comprehensive income attributable to InterDigital, Inc. Comprehensive Income (Loss), Net of Tax, Attributable to Parent