Net Loss per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Numerator:
Net loss	$ (5,964)	$ (448)	$ (15,957)	$ (1,656)
Denominator:
Weighted average common shares outstanding	33,274	32,171	33,105	32,051
Less: weighted average unvested shares of common stock subject to repurchase	0	0	0	3
Weighted average common shares used in computing basic and diluted net loss per share	33,274	32,171	33,105	32,048
Basic and diluted net loss per share, in dollars per share	$ (0.18)	$ (0.01)	$ (0.48)	$ (0.05)
Historical outstanding anti-dilutive securities not included in diluted net loss per share calculation:
Common stock options and awards	8,477	8,552	8,477	8,552
Common stock options and awards
Historical outstanding anti-dilutive securities not included in diluted net loss per share calculation:
Common stock options and awards	8,475	8,550	8,475	8,550
Common stock warrants
Historical outstanding anti-dilutive securities not included in diluted net loss per share calculation:
Common stock options and awards	2	2	2	2