Identifiable Intangible Assets - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets and Goodwill [Line Items]
Goodwill	$ 24,934		$ 24,934		$ 16,845
Business Acquisition, Purchase Price Allocation, Goodwill Amount	7,939		7,939
Business Acquisition Purchase Price Allocation Goodwill Amount 2	150		150
Finite-Lived Intangible Assets, Gross	73,689		73,689		72,034
Finite-Lived Intangible Assets, Accumulated Amortization	61,617		61,617		59,676
Intangible Assets, Net (Excluding Goodwill)	12,072		12,072		12,358
Amortization of Intangible Assets	666	523	1,930	1,355
Future Amortization Expense, Remainder of Fiscal Year	674		674
Future Amortization Expense, Year One	2,411		2,411
Future Amortization Expense, Year Two	2,039		2,039
Future Amortization Expense, Year Three	1,931		1,931
Future Amortization Expense, Year Four	1,543		1,543
Future Amortization Expense, Year Five	1,106		1,106
Developed Technology Rights [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	59,794		59,794		58,961
Finite-Lived Intangible Assets, Accumulated Amortization	50,959		50,959		49,358
Intangible Assets, Net (Excluding Goodwill)	8,835		8,835		9,603
Customer Relationships [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	9,534		9,534		8,712
Finite-Lived Intangible Assets, Accumulated Amortization	7,353		7,353		7,102
Intangible Assets, Net (Excluding Goodwill)	2,181		2,181		1,610
Trade Names [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	4,361		4,361		4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,305		3,305		3,216
Intangible Assets, Net (Excluding Goodwill)	$ 1,056		$ 1,056		$ 1,145