Patents (Details) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Patents, accumulated amortization	$ 192,831,000		$ 166,565,000
Weighted average useful life of patents and patent rights	6 years
Investments in patents/ patent rights	$ 18,667,000	$ 22,096,000
Patent acquisition costs included in accrued expenses	$ 0	3,000,000
Accelerated amortization expense (termination)		2,702,000
Proceeds from patent sale		3,500,000
Gain on Patent Sale		833,000
Impairment of Intangible Assets (Excluding Goodwill)		$ 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	9 years
Finite lived intangible asset acquired during the year, useful life	10 years