Goodwill and Purchased Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 25, 2015
Finite-Lived Intangible Assets [Line Items]
Document Period End Date	Dec. 31, 2015
Goodwill	$ 22,495	$ 22,495	$ 22,553
Business Combination, Goodwill Recognized, Description	0	-58
Finite-Lived Intangible Assets, Gross	$ 79,448	$ 73,752
Finite-Lived Intangible Assets, Accumulated Amortization	66,855	64,710
Intangible Assets, Net (Excluding Goodwill)	12,593	9,042
Amortization of Intangible Assets	2,145	2,422	$ 2,592
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	2,321
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,933
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,496
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,496
Finite-Lived Intangible Assets, Amortization Expense, Year Five	1,294
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	65,527	59,831		$ 5,696
Finite-Lived Intangible Assets, Accumulated Amortization	55,110	53,417
Intangible Assets, Net (Excluding Goodwill)	10,417	6,414
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	9,560	9,560
Finite-Lived Intangible Assets, Accumulated Amortization	8,170	7,818
Intangible Assets, Net (Excluding Goodwill)	1,390	1,742
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,361	4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,575	3,475
Intangible Assets, Net (Excluding Goodwill)	$ 786	$ 886