Net Loss per Share (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Numerator [Abstract]
Net loss used in computing basic and diluted net loss per share	$ (277)	$ (10,714)	$ (17,314)	$ (38,894)
Denominator [Abstract]
Weighted-average shares used in computing basic net loss per share	56,297	54,437	55,720	54,070
Add potentially dilutive securities	0	0	0	0
Weighted-average shares used in computing basic and diluted net loss per share	56,297	54,437	55,720	54,070