v2.4.1.9

Geographic Concentration (Details) (USD $) | 3 Months Ended | 12 Months Ended
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Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries | $ 86,121,000 us-gaap_Revenues | $ 77,622,000 us-gaap_Revenues | $ 194,234,000 us-gaap_Revenues | $ 57,844,000 us-gaap_Revenues | $ 99,683,000 us-gaap_Revenues | $ 110,623,000 us-gaap_Revenues | $ 67,692,000 us-gaap_Revenues | $ 47,363,000 us-gaap_Revenues | $ 415,821,000 us-gaap_Revenues | $ 325,361,000 us-gaap_Revenues | $ 663,063,000 us-gaap_Revenues
Pegatron [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Entity-Wide Revenues, Major Customer, Percentage |  |  |  |  |  |  |  |  | 0.18 | 0.3 | < 10%
Intel Corporation [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Entity-Wide Revenues, Major Customer, Percentage |  |  |  |  |  |  |  |  | 0 | 0 | 0.57
Intel Mobile Communications GmbH [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Entity-Wide Revenues, Major Customer, Percentage |  |  |  |  |  |  |  |  | < 10% | 0.18 | < 10%
Samsung Electronics, Ltd. [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 138,000,000 us-gaap_Revenues / us-gaap_MajorCustomersAxis = idcc_SamsungElectronicsLtdMember |  |
Entity-Wide Revenues, Major Customer, Percentage |  |  |  |  |  |  |  |  | 0.33 | 0 | 0.15
Sony Corporation of America [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Entity-Wide Revenues, Major Customer, Percentage |  |  |  |  |  |  |  |  | < 10% | 0.12 | < 10%
KOREA |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 144,398,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_KR | 15,334,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_KR | 118,078,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_KR
JAPAN |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 52,194,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_JP | 27,494,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_JP | 39,558,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_JP
SWEDEN |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 24,530,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_SE | 0 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_SE | 0 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_SE
CANADA |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 15,422,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CA | 36,148,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CA | 40,667,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CA
Canada, UK, and South Korea [Domain] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Long-Lived Assets in Entity's Country of Domicile | 100,000 us-gaap_NoncurrentAssets / us-gaap_StatementGeographicalAxis = idcc_CanadaUKandSouthKoreaDomain |  |  |  | 100,000 us-gaap_NoncurrentAssets / us-gaap_StatementGeographicalAxis = idcc_CanadaUKandSouthKoreaDomain |  |  |  | 100,000 us-gaap_NoncurrentAssets / us-gaap_StatementGeographicalAxis = idcc_CanadaUKandSouthKoreaDomain | 100,000 us-gaap_NoncurrentAssets / us-gaap_StatementGeographicalAxis = idcc_CanadaUKandSouthKoreaDomain | 100,000 us-gaap_NoncurrentAssets / us-gaap_StatementGeographicalAxis = idcc_CanadaUKandSouthKoreaDomain
TAIWAN |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 115,955,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_TW | 128,551,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_TW | 40,394,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_TW
UNITED STATES |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 53,163,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_US | 108,728,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_US | 406,950,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_US
UNITED STATES | Property and Equipment [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Long-Lived Assets in Entity's Country of Domicile | 278,100,000 us-gaap_NoncurrentAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = idcc_PropertyPlantAndEquipmentAndPatentsNetMember / us-gaap_StatementGeographicalAxis = country_US |  |  |  | 215,900,000 us-gaap_NoncurrentAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = idcc_PropertyPlantAndEquipmentAndPatentsNetMember / us-gaap_StatementGeographicalAxis = country_US |  |  |  | 278,100,000 us-gaap_NoncurrentAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = idcc_PropertyPlantAndEquipmentAndPatentsNetMember / us-gaap_StatementGeographicalAxis = country_US | 215,900,000 us-gaap_NoncurrentAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = idcc_PropertyPlantAndEquipmentAndPatentsNetMember / us-gaap_StatementGeographicalAxis = country_US | 185,400,000 us-gaap_NoncurrentAssets / us-gaap_PropertyPlantAndEquipmentByTypeAxis = idcc_PropertyPlantAndEquipmentAndPatentsNetMember / us-gaap_StatementGeographicalAxis = country_US
GERMANY |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 5,293,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_DE | 4,539,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_DE | 3,470,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_DE
CHINA |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 800,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CN | 1,563,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CN | 9,246,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = country_CN
Other Europe [Domain] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 4,064,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherEuropeDomain | 3,004,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherEuropeDomain | 4,700,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherEuropeDomain
Other Asia [Domain] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | 2,000 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherAsiaDomain | 0 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherAsiaDomain | 0 us-gaap_Revenues / us-gaap_StatementGeographicalAxis = idcc_OtherAsiaDomain
Past Infringement [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Amount |  |  |  |  | 36,400,000 us-gaap_LitigationSettlementAmount / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |  |  |  |  |  |
Past Infringement [Member] | Pegatron [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Amount |  |  |  |  |  |  | 23,500,000 us-gaap_LitigationSettlementAmount / us-gaap_MajorCustomersAxis = idcc_PegatronMember / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |  |  | 71,400,000 us-gaap_LitigationSettlementAmount / us-gaap_MajorCustomersAxis = idcc_PegatronMember / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |
Past Infringement [Member] | Technology Solutions Customer [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Amount |  |  |  |  |  | 51,600,000 us-gaap_LitigationSettlementAmount / us-gaap_MajorCustomersAxis = idcc_TechnologySolutionsCustomerMember / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |  |  |  | 53,300,000 us-gaap_LitigationSettlementAmount / us-gaap_MajorCustomersAxis = idcc_TechnologySolutionsCustomerMember / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |
Past Infringement [Member] | Samsung Electronics, Ltd. [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries |  |  |  |  |  |  |  |  | $ 86,200,000 us-gaap_Revenues / us-gaap_MajorCustomersAxis = idcc_SamsungElectronicsLtdMember / idcc_RoyaltyRevenueAxis = idcc_PastInfringementMember |  |

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