Convertible Notes (Details 1) (Convertible Senior Notes Due 2015 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011
Convertible Senior Notes Due 2015 [Member]
Effective interest rate and components of interest expense of 2015 notes
Effective interest rate	8.10%	8.10%
Contractual interest expense	$ 9,157	$ 5,005
Amortization of debt discount	$ 13,665	$ 7,035