Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2016	Sep. 30, 2015	Sep. 28, 2016	Sep. 30, 2015
Revenue
Company-operated restaurant revenue	$ 89,738	$ 82,986	$ 268,984	$ 251,295
Franchise revenue	6,078	5,884	18,660	17,456
Total revenue	95,816	88,870	287,644	268,751
Cost of operations
Food and paper cost	26,960	26,371	80,760	80,549
Labor and related expenses	24,455	20,822	73,323	63,493
Occupancy and other operating expenses	20,071	18,207	58,401	52,732
Gain on recovery of insurance proceeds, lost profit	(502)		(502)
Company restaurant expenses	70,984	65,400	211,982	196,774
General and administrative expenses	8,252	6,316	25,776	20,206
Franchise expenses	797	925	2,960	2,620
Depreciation and amortization	4,074	3,278	11,796	9,624
Loss on disposal of assets	58	261	524	427
Expenses related to fire loss			48
Loss (gain) on recovery of insurance proceeds	148		(741)
Asset impairment and closed-store reserves	2,490	163	2,624	24
Total expenses	86,803	76,343	254,969	229,675
(Loss) gain on disposition of restaurants	(5)		28
Income from operations	9,008	12,527	32,703	39,076
Interest expense-net of interest income	785	810	2,441	3,035
Expenses related to selling shareholders				50
Income tax receivable agreement expense	182	546	411	1,022
Income before provision for income taxes	8,041	11,171	29,851	34,969
Provision for income taxes	2,830	6,505	11,930	16,281
Net income	$ 5,211	$ 4,666	$ 17,921	$ 18,688
Net income per share
Basic	$ 0.14	$ 0.12	$ 0.47	$ 0.49
Diluted	$ 0.13	$ 0.12	$ 0.46	$ 0.48
Weighted-average shares used in computing net income per share
Basic	38,415,189	38,275,317	38,331,400	37,837,610
Diluted	39,083,577	39,107,241	39,020,127	39,044,388