Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Jan. 02, 2018
Revenue:
Total revenue	$ 462,411	$ 457,841	$ 456,492
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Cost of sales	117,179	121,102	121,473
Labor	150,565	149,746	150,161
Occupancy	48,863	49,020	51,877
Other restaurant operating costs	66,684	65,575	64,091
General and administrative	43,446	46,092	39,746
Depreciation and amortization	22,086	22,872	24,613
Pre-opening	402	50	935
Restaurant impairments, closure costs and asset disposals	7,747	7,142	37,446
Total costs and expenses	456,972	461,599	490,342
Income (loss) from operations	5,439	(3,758)	(33,850)
Loss on extinguishment of debt	746	626	0
Interest expense, net	2,942	4,305	3,839
Income (loss) before income taxes	1,751	(8,689)	(37,689)
Provision (benefit) for income taxes	104	(248)	(207)
Net income (loss)	1,647	(8,441)	(37,482)
Accretion of preferred stock to redemption value	0	0	(7,967)
Net income (loss) attributable to common stockholders	$ 1,647	$ (8,441)	$ (45,449)
Earnings per share of Class A and Class B common stock, combined:
Basic (USD per share)	$ 0.04	$ (0.20)	$ (1.20)
Diluted (USD per share)	$ 0.04	$ (0.20)	$ (1.20)
Weighted average shares of Class A and Class B common stock outstanding, combined:
Basic (in shares)	44,036,947	42,329,556	37,759,497
Diluted (in shares)	44,976,436	42,329,556	37,759,497
Restaurant revenue
Revenue:
Total revenue	$ 456,671	$ 453,671	$ 451,599
Franchising royalties and fees, and other
Revenue:
Total revenue	$ 5,740	$ 4,170	$ 4,893