Patents (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Patents, accumulated amortization	$ 152,838,000		$ 112,323,000
Weighted average useful life of patents and patent rights	6 years
Investments in patents/ patent rights	24,518,000	10,416,000
Patent acquisition costs included in accrued expenses	2,000,000	9,750,000
Accelerated amortization expense - up-front payments	1,186,000	593,000
Accelerated amortization expense (termination)	2,702,000	1,631,000
Proceeds from patent sale	3,500,000
Accelerated amortization expense - impairment	$ 2,565,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of patents and patent rights	1 year
Finite lived intangible asset acquired during the year, useful life	4 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life of patents and patent rights	10 years
Finite lived intangible asset acquired during the year, useful life	10 years