Investments in Cash Equivalents and Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 150,831		$ 25,904
Available For Sale Securities Net Unrealized Gains	0		0
Available For Sale Securities Net Unrealized Losses	(22)		0
Available-for-sale Securities	150,809		25,904
Maximum Term Of Available For Sale Securities	1 year		1 year
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount	0	0
Cash Equivalents [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	8,998
Available For Sale Securities Net Unrealized Gains	0
Available For Sale Securities Net Unrealized Losses	0
Available-for-sale Securities	8,998
Cash Equivalents [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	117,481		25,904
Available For Sale Securities Net Unrealized Gains	0		0
Available For Sale Securities Net Unrealized Losses	0		0
Available-for-sale Securities	117,481		25,904
Short-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	24,352
Available For Sale Securities Net Unrealized Gains	0
Available For Sale Securities Net Unrealized Losses	(22)
Available-for-sale Securities	$ 24,330