Net Income (Loss) Per Share - Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 26, 2014
Numerator:
Net income (loss)	$ 10,051	$ (10,732)	$ 11,357
Shares used in computation — basic:
Weighted average common shares outstanding	32,632	31,564	29,301
Shares used in computation — diluted:
Weighted average common shares outstanding	32,632	31,564	29,301
Dilutive effect of common shares outstanding subject to repurchase	485		396
Dilutive effect of options outstanding	33		239
Shares used in computing diluted net income (loss) per share	33,150	31,564	29,936
Net income (loss) per share — basic	$ 0.31	$ (0.34)	$ 0.39
Net income (loss) per share — diluted	$ 0.30	$ (0.34)	$ 0.38