Goodwill and Purchased Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 11,371	$ 4,492
Business Combination, Goodwill Recognized, Description	4154
Business Combination Goodwill Recognized Description2	2725
Finite-Lived Intangible Assets, Gross	72,034	65,633
Finite-Lived Intangible Assets, Accumulated Amortization	59,676	57,819
Intangible Assets, Net (Excluding Goodwill)	12,358	7,814
Amortization of Intangible Assets	1,853	1,757	1,715
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	2,464
Finite-Lived Intangible Assets, Amortization Expense, Year Two	2,205
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,833
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,725
Finite-Lived Intangible Assets, Amortization Expense, Year Five	1,337
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	58,961	53,826
Finite-Lived Intangible Assets, Accumulated Amortization	49,358	47,879
Intangible Assets, Net (Excluding Goodwill)	9,603	5,947
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	8,712	7,446
Finite-Lived Intangible Assets, Accumulated Amortization	7,102	6,905
Intangible Assets, Net (Excluding Goodwill)	1,610	541
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,361	4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,216	3,035
Intangible Assets, Net (Excluding Goodwill)	$ 1,145	$ 1,326