Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2021	Sep. 23, 2020	Sep. 29, 2021	Sep. 23, 2020
Revenue
Total revenue	$ 115,700	$ 110,979	$ 345,406	$ 315,746
Cost of operations
Food and paper cost	26,698	24,922	78,971	73,357
Labor and related expenses	27,802	28,756	90,060	83,208
Occupancy and other operating expenses	25,108	23,836	74,288	67,867
Gain on recovery of insurance proceeds, lost profits		(2,000)		(2,000)
Company restaurant expenses	79,608	75,514	243,319	222,432
General and administrative expenses	9,357	9,803	30,354	29,599
Franchise expenses	8,545	7,572	24,457	21,110
Depreciation and amortization	3,685	4,092	11,540	12,629
Loss on disposal of assets	83	29	194	156
Recovery of securities lawsuits related legal expenses and other insurance claims				(123)
Impairment and closed-store reserves	167	1,776	1,091	4,615
Loss on disposition of restaurants	10		1,534
Total expenses	101,455	98,786	312,489	290,418
Income from operations	14,245	12,193	32,917	25,328
Interest expense, net	449	770	1,399	2,583
Income tax receivable agreement (income) expense	(19)	(144)	(69)	26
Income before provision for income taxes	13,815	11,567	31,587	22,719
Provision for income taxes	3,654	1,647	8,644	3,700
Net income	$ 10,161	$ 9,920	$ 22,943	$ 19,019
Net income per share
Basic (usd per share)	$ 0.28	$ 0.28	$ 0.64	$ 0.54
Diluted (usd per share)	$ 0.28	$ 0.28	$ 0.63	$ 0.53
Weighted-average shares used in computing net income per share
Basic (shares)	36,067,754	35,471,452	35,930,246	34,989,007
Diluted (shares)	36,525,424	36,064,559	36,457,110	35,609,320
Company-operated restaurant revenue
Revenue
Total revenue	$ 99,986	$ 97,276	$ 301,117	$ 277,617
Franchise revenue
Revenue
Total revenue	8,918	7,781	24,919	21,562
Franchise advertising fee revenue
Revenue
Total revenue	$ 6,796	$ 5,922	$ 19,370	$ 16,567