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. 25, 2019	Sep. 26, 2018	Sep. 25, 2019	Sep. 26, 2018
Numerator:
Net income	$ 6,402	$ 6,835	$ 21,402	$ 14,416
Denominator:
Weighted-average shares outstanding—basic (shares)	35,859,502	38,602,658	37,484,372	38,516,792
Weighted-average shares outstanding—diluted (shares)	36,397,368	39,205,090	38,173,097	39,102,130
Net income (loss) per share—basic (usd per share)	$ 0.18	$ 0.18	$ 0.57	$ 0.37
Net income (loss) per share—diluted (usd per share)	$ 0.18	$ 0.17	$ 0.56	$ 0.37
Anti-dilutive securities not considered in diluted EPS calculation (shares)	882,253	557,300	636,099	671,565