Cash, Cash Equivalents and Short-Term Investments and Long-Term Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 85,674	$ 92,094
Unrealized Holdings Gains	53	86
Unrealized Holdings Losses	7	11
Fair Value	85,720	92,169
Cash
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,158	5,939
Fair Value	6,158	5,939
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,468	18,322
Fair Value	10,468	18,322
Cash and Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,626	24,261
Fair Value	16,626	24,261
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	48,399	40,558
Unrealized Holdings Gains	38	37
Unrealized Holdings Losses	4	4
Fair Value	48,433	40,591
Short-term Investments | Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	997	2,495
Fair Value	997	2,495
Short-term Investments | Corporate bonds and medium-term notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,930	19,539
Unrealized Holdings Gains	23	13
Unrealized Holdings Losses	3	4
Fair Value	21,950	19,548
Short-term Investments | Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,113	1,203
Unrealized Holdings Gains	2	1
Unrealized Holdings Losses	1
Fair Value	6,114	1,204
Short-term Investments | US Government Agencies Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,199	16,976
Unrealized Holdings Gains	13	23
Fair Value	19,212	16,999
Short-term Investments | Variable rate demand notes ("VRDNs")
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	160	345
Fair Value	160	345
Other Long-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,649	27,275
Unrealized Holdings Gains	15	49
Unrealized Holdings Losses	3	7
Fair Value	20,661	27,317
Other Long-term Investments | Corporate bonds and medium-term notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,576	16,776
Unrealized Holdings Gains	9	33
Unrealized Holdings Losses	3	7
Fair Value	15,582	16,802
Other Long-term Investments | Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,065	1,000
Unrealized Holdings Gains	2	2
Fair Value	1,067	1,002
Other Long-term Investments | US Government Agencies Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,008	9,499
Unrealized Holdings Gains	4	14
Fair Value	$ 4,012	$ 9,513