Net Income Per Share - Basic and Diluted Net Income (loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 25, 2016
Numerator:
Net income (loss)	$ 14,341	$ (3,239)
Shares used in computation — basic:
Weighted average common shares outstanding	33,061	32,309
Shares used in computation — diluted:
Shares used in computing basic net income (loss) per share	33,061	32,309
Dilutive effect of common shares outstanding subject to repurchase	793
Dilutive effect of options outstanding	11
Weighted average shares used in computing diluted net income (loss) per share	33,865	32,309
Net income (loss) per share — basic	$ 0.43	$ (0.10)
Net income (loss) per share — diluted	$ 0.42	$ (0.10)