Goodwill and Purchased Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 25, 2015
Finite-Lived Intangible Assets [Line Items]
Document Period End Date	Dec. 31, 2016
Goodwill	$ 22,495	$ 22,495
Finite-Lived Intangible Assets, Gross	79,448	79,448
Finite-Lived Intangible Assets, Accumulated Amortization	69,175	66,855
Intangible Assets, Net (Excluding Goodwill)	10,273	12,593
Amortization of Intangible Assets	2,320	2,145	$ 2,422
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,933
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,496
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,496
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,294
Finite-Lived Intangible Assets, Amortization Expense, Year Five	546
Developed Technology Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	65,527	65,527		$ 5,696
Finite-Lived Intangible Assets, Accumulated Amortization	56,986	55,110
Intangible Assets, Net (Excluding Goodwill)	8,541	10,417
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	9,560	9,560
Finite-Lived Intangible Assets, Accumulated Amortization	8,514	8,170
Intangible Assets, Net (Excluding Goodwill)	1,046	1,390
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	4,361	4,361
Finite-Lived Intangible Assets, Accumulated Amortization	3,675	3,575
Intangible Assets, Net (Excluding Goodwill)	$ 686	$ 786