Cash Equivalents and Investments - Company's Available-for-Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012
Long-term investments in equity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, Amortized Cost	$ 669	$ 669
Available-for-sale Equity Securities, Gross Unrealized Gain	2,018	1,020
Available-for-sale Equity Securities, Gross Unrealized Loss
Available-for-sale Securities, Equity Securities	2,687	1,689
Asset-backed and mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost	140,718	125,563
Available-for-sale Debt Securities Gross Unrealized Gain	4,617	6,390
Available-for-sale Debt Securities, Gross Unrealized Loss	(2,257)	(1,097)
Available-for-sale Securities, Debt Securities	143,078	130,856
Government and agency securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost	95,481	65,904
Available-for-sale Debt Securities Gross Unrealized Gain	430	802
Available-for-sale Debt Securities, Gross Unrealized Loss	(305)	(6)
Available-for-sale Securities, Debt Securities	95,606	66,700
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost	18,926	5,864
Available-for-sale Debt Securities Gross Unrealized Gain	87	137
Available-for-sale Debt Securities, Gross Unrealized Loss	(46)
Available-for-sale Securities, Debt Securities	18,967	6,001
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost	10,731	900
Available-for-sale Debt Securities Gross Unrealized Gain
Available-for-sale Debt Securities, Gross Unrealized Loss
Available-for-sale Securities, Debt Securities	10,731	900
Total short-term debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost	265,856	198,231
Available-for-sale Debt Securities Gross Unrealized Gain	5,134	7,329
Available-for-sale Debt Securities, Gross Unrealized Loss	(2,608)	(1,103)
Available-for-sale Securities, Debt Securities	$ 268,382	$ 204,457