Convertible Senior Notes (Details) (0.625% Convertible senior notes due 2014 [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 29, 2013	Sep. 29, 2013
Extinguishment of Debt [Line Items]
Cash paid for principal of notes converted	$ 1,505	$ 10,505
Conversion value over principal amount paid in shares of common stock	4,071	21,053
Number of shares of common stock issued upon conversion	50	315
Loss on extinguishment of debt	$ 44	$ 555
Minimum [Member]
Extinguishment of Debt [Line Items]
Effective interest rates used to measure fair value of converted notes upon conversion	0.60%	0.60%
Maximum [Member]
Extinguishment of Debt [Line Items]
Effective interest rates used to measure fair value of converted notes upon conversion	0.60%	0.80%