Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2017	Jun. 28, 2016	Jul. 04, 2017	Jun. 28, 2016
Revenue:
Restaurant revenue	$ 111,628	$ 120,204	$ 227,155	$ 233,069
Franchising royalties and fees	1,164	1,203	2,352	2,324
Total revenue	112,792	121,407	229,507	235,393
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Cost of sales	29,598	32,164	61,685	62,353
Labor	36,430	39,316	76,024	76,750
Occupancy	12,630	13,688	26,631	27,002
Other restaurant operating costs	16,194	18,596	33,341	35,488
General and administrative	9,393	9,840	20,059	19,877
Depreciation and amortization	6,279	7,071	12,546	13,977
Pre-opening	246	796	791	1,833
Restaurant impairments, closure costs and asset disposals	2,830	11,248	24,884	12,264
Total costs and expenses	113,600	132,719	255,961	249,544
Loss from operations	(808)	(11,312)	(26,454)	(14,151)
Interest expense, net	927	598	1,935	1,226
Loss before income taxes	(1,735)	(11,910)	(28,389)	(15,377)
Provision (benefit) for income taxes	80	2,177	271	1,083
Net loss	(1,815)	(14,087)	(28,660)	(16,460)
Accretion of preferred stock to redemption value	(7,001)	0	(7,967)	0
Net loss attributable to common stockholders	$ (8,816)	$ (14,087)	$ (36,627)	$ (16,460)
Loss per share of Class A and Class B common stock, combined:
Basic (USD per share)	$ (0.22)	$ (0.51)	$ (1.06)	$ (0.59)
Diluted (USD per share)	$ (0.22)	$ (0.51)	$ (1.06)	$ (0.59)
Weighted average shares of Class A and Class B common stock outstanding, combined:
Basic (in shares)	40,779,277	27,776,094	34,404,222	27,754,615
Diluted (in shares)	40,779,277	27,776,094	34,404,222	27,754,615