Identifiable Intangible Assets - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 79,448		$ 79,448
Finite-Lived Intangible Assets, Accumulated Amortization	67,450		66,855
Intangible Assets, Net (Excluding Goodwill)	11,998		12,593
Amortization of Intangible Assets	595	$ 515
Future Amortization Expense, Remainder of Fiscal Year	1,726
Future Amortization Expense, Year One	1,933
Future Amortization Expense, Year Two	1,496
Future Amortization Expense, Year Three	1,496
Future Amortization Expense, Year Four	1,294
Future Amortization Expense, Year Five	546
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	65,527		65,527
Finite-Lived Intangible Assets, Accumulated Amortization	55,592		55,110
Intangible Assets, Net (Excluding Goodwill)	9,935		10,417
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	9,560		9,560
Finite-Lived Intangible Assets, Accumulated Amortization	8,258		8,170
Intangible Assets, Net (Excluding Goodwill)	1,302		1,390
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,361		4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,600		3,575
Intangible Assets, Net (Excluding Goodwill)	$ 761		$ 786