Cash, Cash Equivalents, and Investments - Components of Cash, Cash Equivalents, and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 29, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 38,814	$ 40,124
Money market instruments	1,358	520
Cash and cash equivalents	40,172	40,644	47,874	45,160
Short-term investments	83,677	184,822
Limited partnership interest	1,956	1,956
Long-term investments	343,725	229,655
Total	467,574	455,121
Asset-Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	33,733	53,559
Long-term investments	36,959	21,820
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	28,013	109,040
Long-term investments	207,767	109,909
Treasury Bills
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	12,996	0
Long-term investments	74,971	73,666
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	5,707	9,276
Long-term investments	4,885	5,919
Sovereign Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	3,228	11,448
Long-term investments	15,687	16,385
Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
Short-term investments	0	1,499
Long-term investments	$ 1,500	$ 0