Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2022	Jun. 29, 2021	Jun. 28, 2022	Jun. 29, 2021
Revenue:
Total revenue	$ 131,067	$ 125,649	$ 243,629	$ 235,226
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Other restaurant operating costs	22,792	21,082	44,658	41,287
General and administrative	12,744	12,978	24,584	23,907
Depreciation and amortization	5,763	5,576	11,484	11,163
Pre-opening	353	163	761	221
Restaurant impairments, closure costs and asset disposals	1,971	390	3,360	1,621
Total costs and expenses	129,189	119,439	247,826	230,381
Income (loss) from operations	1,878	6,210	(4,197)	4,845
Interest expense, net	489	498	926	1,120
Income (loss) before taxes	1,389	5,712	(5,123)	3,725
Provision for (benefit from) income taxes	44	29	(39)	19
Net income (loss)	$ 1,345	$ 5,683	$ (5,084)	$ 3,706
Earnings (loss) per Class A and Class B common stock, combined
Basic (USD per share)	$ 0.03	$ 0.12	$ (0.11)	$ 0.08
Diluted (USD per share)	$ 0.03	$ 0.12	$ (0.11)	$ 0.08
Weighted average shares of Class A and Class B common stock outstanding, combined:
Basic (in shares)	45,881,354	45,506,476	45,803,927	45,303,160
Diluted (in shares)	46,108,720	46,246,169	45,803,927	45,992,119
Restaurant revenue
Revenue:
Total revenue	$ 128,274	$ 123,715	$ 238,235	$ 231,459
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	35,664	30,805	66,435	57,782
Franchising royalties and fees, and other
Revenue:
Total revenue	2,793	1,934	5,394	3,767
Labor
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	38,828	36,926	74,321	71,232
Occupancy
Restaurant operating costs (exclusive of depreciation and amortization shown separately below):
Restaurant operating costs	$ 11,074	$ 11,519	$ 22,223	$ 23,168