Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 24, 2014	Sep. 30, 2015	Sep. 24, 2014
Revenue
Company-operated restaurant revenue	$ 82,986	$ 80,861	$ 251,295	$ 238,432
Franchise revenue	5,884	5,696	17,456	16,456
Total revenue	88,870	86,557	268,751	254,888
Cost of operations
Food and paper cost	26,371	25,881	80,549	75,834
Labor and related expenses	20,822	20,137	63,493	59,552
Occupancy and other operating expenses	18,207	18,102	52,732	51,091
Company restaurant expenses	65,400	64,120	196,774	186,477
General and administrative expenses	6,316	7,509	20,206	20,974
Franchise expenses	925	901	2,620	2,827
Depreciation and amortization	3,278	2,924	9,624	8,271
Loss on disposal of assets	261	118	427	609
Asset impairment and closed-store reserves	163	22	24	415
Total expenses	76,343	75,594	229,675	219,573
Gain on sale of restaurants		2,658		2,658
Income from operations	12,527	13,621	39,076	37,973
Interest expense, net	810	3,960	3,035	15,286
Early extinguishment of debt		5,082		5,082
Expenses related to selling shareholders			50
Income tax receivable agreement expense	546	40,119	1,022	40,119
Income (loss) before provision (benefit) for income taxes	11,171	(35,540)	34,969	(22,514)
Provision (benefit) for income taxes	6,505	(61,389)	16,281	(60,402)
Net income	$ 4,666	$ 25,849	$ 18,688	$ 37,888
Net income per share
Basic	$ 0.12	$ 0.76	$ 0.49	$ 1.24
Diluted	$ 0.12	$ 0.70	$ 0.48	$ 1.17
Weighted-average shares used in computing net income per share
Basic	38,275,317	34,221,829	37,837,610	30,549,979
Diluted	39,107,241	36,821,095	39,044,388	32,450,231