Identifiable Intangible Assets - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 79,448		$ 79,448		$ 79,448
Finite-Lived Intangible Assets, Accumulated Amortization	70,185		70,185		69,175
Intangible Assets, Net (Excluding Goodwill)	9,263		9,263		10,273
Amortization of Intangible Assets	505	$ 595	1,010	$ 1,190
Future Amortization Expense, Remainder of Fiscal Year	923		923
Future Amortization Expense, Year One	1,496		1,496
Future Amortization Expense, Year Two	1,496		1,496
Future Amortization Expense, Year Three	1,294		1,294
Future Amortization Expense, Year Four	546		546
Future Amortization Expense, Year Five	480		480
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	65,527		65,527		65,527
Finite-Lived Intangible Assets, Accumulated Amortization	57,790		57,790		56,986
Intangible Assets, Net (Excluding Goodwill)	7,737		7,737		8,541
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	9,560		9,560		9,560
Finite-Lived Intangible Assets, Accumulated Amortization	8,670		8,670		8,514
Intangible Assets, Net (Excluding Goodwill)	890		890		1,046
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,361		4,361		4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,725		3,725		3,675
Intangible Assets, Net (Excluding Goodwill)	$ 636		$ 636		$ 686