Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2019	Jul. 03, 2018	Jul. 02, 2019	Jul. 03, 2018
Revenue:
Total revenue	$ 120,190	$ 117,395	$ 230,236	$ 227,921
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Other restaurant operating costs	16,858	16,875	33,314	33,773
General and administrative	11,848	14,813	21,988	25,081
Depreciation and amortization	5,661	5,797	11,168	11,617
Pre-opening	65	3	65	50
Restaurant impairments, closure costs and asset disposals	2,884	2,580	3,304	4,160
Total costs and expenses	118,952	121,557	230,088	234,761
Income (loss) from operations	1,238	(4,162)	148	(6,840)
Loss on extinguishment of debt	0	626	0	626
Interest expense, net	800	1,154	1,561	2,292
Income (loss) before income taxes	438	(5,942)	(1,413)	(9,758)
Provision (benefit) for income taxes	0	(7)	0	(248)
Net income (loss) and comprehensive income (loss)	438	(5,935)	(1,413)	(9,510)
Net income (loss) attributable to common stockholders	$ 438	$ (5,935)	$ (1,413)	$ (9,510)
Earnings (loss) per share of Class A and Class B common stock, combined:
Basic (USD per share)	$ 0.01	$ (0.14)	$ (0.03)	$ (0.23)
Diluted (USD per share)	$ 0.01	$ (0.14)	$ (0.03)	$ (0.23)
Weighted average shares of Class A and Class B common stock outstanding, combined:
Basic (in shares)	43,964,175	41,172,924	43,955,580	41,150,698
Diluted (in shares)	45,075,888	41,172,924	43,955,580	41,150,698
Restaurant revenue
Revenue:
Total revenue	$ 118,858	$ 116,451	$ 227,623	$ 226,064
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Cost of goods and services sold	30,448	31,089	59,539	60,345
Labor
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Cost of goods and services sold	38,877	38,043	75,969	74,615
Franchising royalties and fees, and other
Revenue:
Total revenue	1,332	944	2,613	1,857
Occupancy
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Cost of goods and services sold	$ 12,311	$ 12,357	$ 24,741	$ 25,120