Net Income Per Share - Computation of Basic and Diluted Net Income per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2017	Sep. 28, 2016	Sep. 27, 2017	Sep. 28, 2016
Numerator:
Net income	$ (4,039)	$ 5,211	$ 8,657	$ 17,921
Denominator:
Weighted-average shares outstanding—basic (shares)	38,462,100	38,415,189	38,449,453	38,331,400
Weighted-average shares outstanding—diluted (shares)	38,462,100	39,083,577	39,101,214	39,020,127
Net income per share—basic (usd per share)	$ (0.11)	$ 0.14	$ 0.23	$ 0.47
Net income per share—diluted (usd per share)	$ (0.11)	$ 0.13	$ 0.22	$ 0.46
Anti-dilutive securities not considered in diluted EPS calculation (shares)	2,490,029	451,325	749,421	451,325