Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2018	Sep. 27, 2017	Sep. 26, 2018	Sep. 27, 2017
Numerator:
Net income (loss)	$ 6,835	$ (4,039)	$ 14,416	$ 8,657
Denominator:
Weighted-average shares outstanding—basic (shares)	38,602,658	38,462,100	38,516,792	38,449,453
Weighted-average shares outstanding—diluted (shares)	39,205,090	38,462,100	39,102,130	39,101,214
Net income (loss) per share—basic (usd per share)	$ 0.18	$ (0.11)	$ 0.37	$ 0.23
Net income (loss) per share—diluted (usd per share)	$ 0.17	$ (0.11)	$ 0.37	$ 0.22
Anti-dilutive securities not considered in diluted EPS calculation (shares)	557,300	2,490,029	671,565	749,421