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. 25, 2019	Sep. 25, 2019	Jun. 26, 2019	Mar. 27, 2019	Dec. 26, 2018	Sep. 26, 2018	Jun. 27, 2018	Mar. 28, 2018	Dec. 25, 2019	Dec. 26, 2018	Dec. 27, 2017
Numerator:
Net income (loss)	$ 3,498	$ 6,402	$ 14,087	$ 913	$ (23,410)	$ 6,835	$ 5,052	$ 2,529	$ 24,900	$ (8,994)	$ 8,619
Denominator:
Weighted-average shares outstanding—Basic (shares)	34,503,722	35,859,502	37,939,912	38,633,702	38,751,522	38,602,658	38,482,074	38,465,208	36,739,209	38,574,553	38,453,347
Weighted-average shares outstanding—Diluted (shares)	35,242,122	36,397,368	38,580,722	39,496,436	38,751,522	39,205,090	39,043,434	38,987,351	37,441,503	38,574,553	39,086,676
Net (loss) income per share—Basic (usd per share)	$ 0.10	$ 0.18	$ 0.37	$ 0.02	$ (0.60)	$ 0.18	$ 0.13	$ 0.07	$ 0.68	$ (0.23)	$ 0.22
Net (loss) income per share—Diluted (usd per share)	$ 0.10	$ 0.18	$ 0.37	$ 0.02	$ (0.60)	$ 0.17	$ 0.13	$ 0.06	$ 0.67	$ (0.23)	$ 0.22
Anti-dilutive securities not considered in diluted EPS calculation (shares)					0	0			526,295.47	2,593,104	747,985