Cash Equivalents and Investments (Details 3) (USD $) In Thousands	Oct. 02, 2011	Dec. 31, 2010
Gross unrealized losses and fair values of the Company's short-term investments
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 13,305	$ 32,303
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(216)	(378)
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Fair Value	575	2,469
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Unrealized Losses	(47)	(172)
Asset-backed and mortgage-backed securities [Member]
Gross unrealized losses and fair values of the Company's short-term investments
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	7,654	11,807
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(170)	(179)
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Fair Value	575	2,469
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Unrealized Losses	(47)	(172)
U.S. government and agency securities [Member]
Gross unrealized losses and fair values of the Company's short-term investments
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	1,037	13,969
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	0	(127)
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Unrealized Losses	0	0
Corporate debt securities [Member]
Gross unrealized losses and fair values of the Company's short-term investments
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	4,614	6,527
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(46)	(72)
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Greater than 12 Months, Unrealized Losses	$ 0	$ 0