Net Income Per Share - Computation of Basic and Diluted Net Income per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2015	Jun. 25, 2014	Jul. 01, 2015	Jun. 25, 2014
Numerator:
Net income	$ 7,230	$ 6,569	$ 14,021	$ 12,039
Denominator:
Weighted-average shares outstanding—basic	37,812,767	28,715,485	37,618,756	28,714,053
Weighted-average shares outstanding—diluted	39,085,206	30,372,281	39,002,974	30,595,565
Net income per share—basic	$ 0.19	$ 0.23	$ 0.37	$ 0.42
Net income per share—diluted	$ 0.18	$ 0.22	$ 0.36	$ 0.39
Anti-dilutive securities not considered in diluted EPS calculation		123,106		123,106