Business Summary and Basis of Presentation - New Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jul. 02, 2019	Apr. 02, 2019	Jan. 02, 2019	Jan. 01, 2019	Jul. 03, 2018	Apr. 03, 2018	Jan. 02, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 3,338		$ 4,655	$ 4,655	$ 3,640		$ 3,361
Accounts receivable	2,544		2,616	2,391
Inventories	9,860		9,646	9,646
Prepaid expenses and other assets	4,797		3,231	6,474
Income tax receivable	191		185	185
Total current assets	20,730		20,333	23,351
Property and equipment, net	134,692		139,618	138,774
Operating lease assets, net	215,347		219,883	0
Goodwill	7,154		6,400	6,400
Goodwill	1,057		1,224	1,291
Other assets, net	2,376		2,216	2,216
Total long-term assets	360,626		369,341	148,681
Total assets	381,356		389,674	172,032
Accounts payable	7,567		7,854	7,854
Accrued payroll and benefits	13,027		13,391	13,391
Accrued expenses and other current liabilities	8,530		10,630	11,183
Current operating lease liabilities	21,781		0	0
Current portion of long-term debt	938		719	719
Total current liabilities	51,843		32,594	33,147
Long-term debt, net	43,714		44,183	44,183
Long-term operating lease liabilities, net	233,902		260,931	0
Deferred rent	0		148	37,334
Deferred tax liabilities, net	133		133	133
Other long-term liabilities	4,861		4,996	4,554
Total liabilities	334,453		342,985	119,351
Preferred stock—$0.01 par value, 1,000,000 shares authorized and undesignated as of January 1, 2019; no shares issued or outstanding	0		0	0
Common stock—$0.01 par value, 180,000,000 shares authorized as of January 1, 2019; 46,353,309 issued and 43,929,438 outstanding as of January 1, 2019	465		464	464
Treasury stock, at cost, 2,423,871 shares as of January 1, 2019	(35,000)		(35,000)	(35,000)
Additional paid-in capital	199,978		198,352	198,352
Accumulated deficit	(118,540)		(117,127)	(111,135)
Total stockholders’ equity	46,903	$ 45,596	46,689	52,681	$ 26,169	$ 31,407	$ 35,861
Total liabilities and stockholders’ equity	$ 381,356		389,674	$ 172,032
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents			0
Accounts receivable			225
Inventories			0
Prepaid expenses and other assets			(3,243)
Income tax receivable			0
Total current assets			(3,018)
Property and equipment, net			844
Operating lease assets, net			219,883
Goodwill			0
Goodwill			(67)
Other assets, net			0
Total long-term assets			220,660
Total assets			217,642
Accounts payable			0
Accrued payroll and benefits			0
Accrued expenses and other current liabilities			(553)
Current operating lease liabilities			0
Current portion of long-term debt			0
Total current liabilities			(553)
Long-term debt, net			0
Long-term operating lease liabilities, net			260,931
Deferred rent			(37,186)
Deferred tax liabilities, net			0
Other long-term liabilities			442
Total liabilities			223,634
Preferred stock—$0.01 par value, 1,000,000 shares authorized and undesignated as of January 1, 2019; no shares issued or outstanding			0
Common stock—$0.01 par value, 180,000,000 shares authorized as of January 1, 2019; 46,353,309 issued and 43,929,438 outstanding as of January 1, 2019			0
Treasury stock, at cost, 2,423,871 shares as of January 1, 2019			0
Additional paid-in capital			0
Accumulated deficit			(5,992)
Total stockholders’ equity			(5,992)
Total liabilities and stockholders’ equity			$ 217,642