Patent Assets, Net (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			78 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization of patent assets	$ 1,500	$ 1,500	$ 1,500
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization of patent assets	$ 119,700	$ 105,500	$ 80,400
Minimum | Patents
Finite-Lived Intangible Assets [Line Items]
Patent assets, useful life	24 months
Maximum | Patents
Finite-Lived Intangible Assets [Line Items]
Patent assets, useful life	60 months
Weighted Average | Patents
Finite-Lived Intangible Assets [Line Items]
Patent assets, useful life	39 months			45 months