Selected Quarterly Financial Data (Details) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Jan. 02, 2018 USD ($) restaurant $ / shares	Oct. 03, 2017 USD ($) restaurant $ / shares	Jul. 04, 2017 USD ($) restaurant $ / shares	Apr. 04, 2017 USD ($) restaurant $ / shares	Jan. 03, 2017 USD ($) restaurant $ / shares	Sep. 27, 2016 USD ($) $ / shares	Jun. 28, 2016 USD ($) restaurant $ / shares	Mar. 29, 2016 USD ($) restaurant $ / shares	Dec. 29, 2015 restaurant	Jan. 02, 2018 USD ($) restaurant $ / shares	Jan. 03, 2017 USD ($) restaurant $ / shares	Dec. 29, 2015 USD ($) restaurant $ / shares
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 112,774	$ 114,211	$ 112,792	$ 116,715	$ 129,400	$ 122,681	$ 121,407	$ 113,986		$ 456,492	$ 487,474	$ 455,451
Operating income	87	(7,483)	(808)	(25,646)	(44,315)	(9,062)	(11,312)	(2,839)		(33,850)	(67,528)	(21,067)
Net loss	(487)	(8,335)	(1,815)	(26,845)	$ (45,376)	$ (9,841)	$ (14,087)	$ (2,373)		(37,482)	(71,677)	(13,765)
Net loss attributable to common stockholders	$ (487)	$ (8,335)	$ (8,816)	$ (27,810)						$ (45,449)	$ (71,677)	$ (13,765)
Basic EPS (USD per share) | $ / shares	$ (0.01)	$ (0.20)	$ (0.22)	$ (0.99)	$ (1.63)	$ (0.35)	$ (0.51)	$ (0.09)		$ (1.20)	$ (2.58)	$ (0.48)
Diluted EPS (USD per share) | $ / shares	$ (0.01)	$ (0.20)	$ (0.22)	$ (0.99)	$ (1.63)	$ (0.35)	$ (0.51)	$ (0.09)		$ (1.20)	$ (2.58)	$ (0.48)
Closure costs				$ 19,900				$ 200		$ 20,052	$ 2,251	$ 3,076
Impairment costs related to closure of restaurants		$ 9,100
Number of restaurants closed | restaurant				55					16
Number of restaurants impaired | restaurant	3	18	9	4	42		11	1		34	54	39
Impairment costs of restaurants	$ 1,100		$ 4,000	$ 1,900	$ 31,100		$ 10,300
Estimated losses resulting from claims and anticipated claims by payment card companies						$ 10,600
Severance expenses						2,500
Litigation settlement, expense						$ 3,000