Earnings Per Share - Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 27, 2017	Sep. 27, 2017	Jun. 28, 2017	Mar. 29, 2017	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Numerator:
Net (loss) income	$ (23,410)	$ 6,835	$ 5,052	$ 2,529	$ (38)	$ (4,039)	$ 7,819	$ 4,877	$ (8,994)	$ 8,619	$ 18,339
Denominator:
Weighted-average shares outstanding—Basic (shares)	38,751,522	38,602,658	38,482,074	38,465,208	38,465,208	38,462,100	38,449,240	38,437,020	38,574,553	38,453,347	38,357,805
Weighted-average shares outstanding—Diluted (shares)	38,751,522	39,205,090	39,043,434	38,987,351	38,465,208	38,462,100	39,123,961	39,079,007	38,574,553	39,086,676	39,026,950
Net (loss) income per share—Basic (usd per share)	$ (0.60)	$ 0.18	$ 0.13	$ 0.07	$ 0.00	$ (0.11)	$ 0.20	$ 0.13	$ (0.23)	$ 0.22	$ 0.48
Net (loss) income per share—Diluted (usd per share)	$ (0.60)	$ 0.17	$ 0.13	$ 0.06	$ 0.00	$ (0.11)	$ 0.20	$ 0.12	$ (0.23)	$ 0.22	$ 0.47
Anti-dilutive securities not considered in diluted EPS calculation (shares)	0					0			2,593,104	747,985	468,705