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
	Jun. 29, 2016	Jul. 01, 2015	Jun. 29, 2016	Jul. 01, 2015
Numerator:
Net income	$ 7,267	$ 7,230	$ 12,710	$ 14,021
Denominator:
Weighted-average shares outstanding—basic	38,294,575	37,812,767	38,289,505	37,618,756
Weighted-average shares outstanding—diluted	38,962,802	39,085,206	38,981,610	39,002,974
Net income per share—basic	$ 0.19	$ 0.19	$ 0.33	$ 0.37
Net income per share—diluted	$ 0.19	$ 0.18	$ 0.33	$ 0.36
Anti-dilutive securities not considered in diluted EPS calculation	473,836		473,836