Variable Interest Entities Variable Interest Entities (Notes)	6 Months Ended
Jun. 30, 2015
Variable Interest Entities [Abstract]
Equity Method Investments and Joint Ventures Disclosure [Text Block]	VARIABLE INTEREST ENTITIES: As further discussed below, we are the primary beneficiary of two variable interest entities. As of June 30, 2015, the combined book values of the assets and liabilities associated with these variable interest entities included in our Consolidated Balance Sheet were $16.6 million and $0.6 million, respectively. Assets include $12.1 million of cash and cash equivalents and $4.4 million of patents, net. The impact of consolidating these variable interest entities on our Consolidated Statements of Income was not significant. Convida Wireless On December 21, 2012, we formed a joint venture with Sony Corporation of America to combine Sony's consumer electronics expertise with our wireless machine-to-machine ("M2M") and bandwidth management research. The joint venture, called Convida Wireless, focuses on driving new research in M2M wireless communications and other connectivity areas. Based on the terms of the agreement, the parties contributed funding and resources for additional M2M research and platform development, which we perform. Stephens Capital Partners LLC ("Stephens"), the principal investing affiliate of Stephens Inc., is a minority investor in Convida Wireless. Our agreement with Sony is a multiple-element arrangement that also includes a three-year license to our patents for Sony's sale of 3G and 4G products, effective January 1, 2013, and an amount for past sales. Convida Wireless is a variable interest entity. Based on our provision of M2M research and platform development services to Convida Wireless, we have determined that we are the primary beneficiary for accounting purposes and must consolidate Convida Wireless. For the three months ended June 30, 2015 and 2014, we have allocated approximately $0.6 million and $0.8 million, respectively, of Convida Wireless' net loss to noncontrolling interests held by other parties. For the six months ended June 30, 2015 and 2014, we have allocated approximately $1.4 million and $1.5 million, respectively, of Convida Wireless' net loss to noncontrolling interests held by other parties. Signal Trust for Wireless Innovation On October 17, 2013, we announced the establishment of the Signal Trust for Wireless Innovation, which seeks to monetize a large InterDigital patent portfolio related to cellular infrastructure. The more than 500 patents and patent applications transferred to the Signal Trust focus primarily on 3G and LTE technologies, and were developed by InterDigital's engineers and researchers over more than a decade, with a number of the innovations contributed to the worldwide standards process. InterDigital has committed funding to the Signal Trust to help ensure its successful launch. The distributions from the Signal Trust will support continued research related to cellular wireless technologies. A small portion of the proceeds from the Signal Trust will be used to fund, through the Signal Foundation for Wireless Innovation, scholarly analysis of intellectual property rights and the technological, commercial and creative innovations they facilitate. The Signal Trust is a variable interest entity. Based on the terms of the Trust Agreement, we have determined that we are the primary beneficiary for accounting purposes and must consolidate the Signal Trust.

VARIABLE INTEREST ENTITIES:

As further discussed below, we are the primary beneficiary of two variable interest entities. As of June 30, 2015, the combined book values of the assets and liabilities associated with these variable interest entities included in our Consolidated Balance Sheet were $16.6 million and $0.6 million, respectively. Assets include $12.1 million of cash and cash equivalents and $4.4 million of patents, net. The impact of consolidating these variable interest entities on our Consolidated Statements of Income was not significant.

Convida Wireless

On December 21, 2012, we formed a joint venture with Sony Corporation of America to combine Sony's consumer electronics expertise with our wireless machine-to-machine ("M2M") and bandwidth management research. The joint venture, called Convida Wireless, focuses on driving new research in M2M wireless communications and other connectivity areas. Based on the terms of the agreement, the parties contributed funding and resources for additional M2M research and platform development, which we perform. Stephens Capital Partners LLC ("Stephens"), the principal investing affiliate of Stephens Inc., is a minority investor in Convida Wireless.

Our agreement with Sony is a multiple-element arrangement that also includes a three-year license to our patents for Sony's sale of 3G and 4G products, effective January 1, 2013, and an amount for past sales.

Convida Wireless is a variable interest entity. Based on our provision of M2M research and platform development services to Convida Wireless, we have determined that we are the primary beneficiary for accounting purposes and must consolidate Convida Wireless. For the three months ended June 30, 2015 and 2014, we have allocated approximately $0.6 million and $0.8 million, respectively, of Convida Wireless' net loss to noncontrolling interests held by other parties. For the six months ended June 30, 2015 and 2014, we have allocated approximately $1.4 million and $1.5 million, respectively, of Convida Wireless' net loss to noncontrolling interests held by other parties.

Signal Trust for Wireless Innovation

On October 17, 2013, we announced the establishment of the Signal Trust for Wireless Innovation, which seeks to monetize a large InterDigital patent portfolio related to cellular infrastructure.

The more than 500 patents and patent applications transferred to the Signal Trust focus primarily on 3G and LTE technologies, and were developed by InterDigital's engineers and researchers over more than a decade, with a number of the innovations contributed to the worldwide standards process.

InterDigital has committed funding to the Signal Trust to help ensure its successful launch. The distributions from the Signal Trust will support continued research related to cellular wireless technologies. A small portion of the proceeds from the Signal Trust will be used to fund, through the Signal Foundation for Wireless Innovation, scholarly analysis of intellectual property rights and the technological, commercial and creative innovations they facilitate.

The Signal Trust is a variable interest entity. Based on the terms of the Trust Agreement, we have determined that we are the primary beneficiary for accounting purposes and must consolidate the Signal Trust.