Debt (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2013 Convertible Senior Notes Due 2013 [Member]	Dec. 29, 2012 Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2011 Convertible Senior Notes Due 2011 and 2013 [Member]
Effective interest rate and components of interest expense
Effective interest rate	6.40%	6.40%	6.30%
Contractual interest expense	$ 2,082	$ 2,159	$ 4,119
Amortization of debt discount	6,447	6,272	12,654
Total Interest Expense	$ 8,529	$ 8,431	$ 16,773