Identifiable Intangible Assets - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	$ 71,955		$ 72,034
Finite-Lived Intangible Assets, Accumulated Amortization	60,284		59,676
Intangible Assets, Net (Excluding Goodwill)	11,671		12,358
Amortization of Intangible Assets	616	416
Future Amortization Expense, Remainder of Fiscal Year	1,839
Future Amortization Expense, Year One	2,196
Future Amortization Expense, Year Two	1,824
Future Amortization Expense, Year Three	1,715
Future Amortization Expense, Year Four	1,327
Future Amortization Expense, Year Five	891
Goodwill	11,252		11,371
Business Acquisition, Purchase Price Allocation, Goodwill Amount	(125)
Business Acquisition Purchase Price Allocation Goodwill Amount 2	6
Developed Technology Rights [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	58,916		58,961
Finite-Lived Intangible Assets, Accumulated Amortization	49,889		49,358
Intangible Assets, Net (Excluding Goodwill)	9,027		9,603
Customer Relationships [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	8,678		8,712
Finite-Lived Intangible Assets, Accumulated Amortization	7,167		7,102
Intangible Assets, Net (Excluding Goodwill)	1,511		1,610
Trade Names [Member]
Finite-Lived Intangible Assets and Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	4,361		4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,228		3,216
Intangible Assets, Net (Excluding Goodwill)	$ 1,133		$ 1,145