Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 03, 2018	Jul. 02, 2019	Jul. 03, 2018	Jan. 02, 2019	Jan. 01, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected unredeemed percent		9.00%
Estimated redemption period		24 months
Gift card liability		$ 1,647			$ 3,284
Revenue recognized		$ 3,200	$ 3,400
Gift card breakage	$ 1,800		$ 300
Period in which initial fees received from franchisees will be recognized as revenue		20 years
Retained earnings		$ (118,540)		$ (117,127)	(111,135)
Accrued Expenses and Other Current Liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability		1,600			3,300
Other Long-term Liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability, non-current		$ 700			$ 400