Net Income (Loss) Per Share - Computation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 27, 2019	Mar. 28, 2018
Numerator:
Net income	$ 913	$ 2,529
Denominator:
Weighted-average shares outstanding—basic (shares)	38,653,702	38,465,208
Weighted-average shares outstanding—diluted (shares)	39,496,436	38,987,351
Net income (loss) per share—basic (usd per share)	$ 0.02	$ 0.07
Net income (loss) per share—diluted (usd per share)	$ 0.02	$ 0.06
Anti-dilutive securities not considered in diluted EPS calculation (shares)	56,016	652,871