Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 02, 2018	Oct. 03, 2017	Jan. 02, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected unredeemed percent	8.00%
Estimated redemption period	18 months
Gift card liability	$ 2,520		$ 4,078
Revenue recognized	4,400	$ 4,100
Gift card breakage	$ 300
Period in which initial fees received from franchisees will be recognized as revenue	20 years
Retained earnings	$ (111,154)		(101,188)
Accrued Expenses and Other Current Liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability	2,500		4,100
Other Long-term Liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability, non-current	300		400
Calculated under Revenue Guidance in Effect on Adoption of Topic 606 | Accounting Standards Update 2014-09
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized	$ 100
Retained earnings			$ 1,500