Business Summary and Basis of Presentation - New Accounting Pronouncements (Details) - USD ($) $ in Thousands	Apr. 02, 2019	Jan. 02, 2019	Jan. 01, 2019	Apr. 03, 2018	Jan. 02, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 1,800	$ 4,655	$ 4,655	$ 2,624	$ 3,361
Accounts receivable	2,254	2,616	2,391
Inventories	9,870	9,646	9,646
Prepaid expenses and other assets	3,066	3,231	6,474
Income tax receivable	191	185	185
Total current assets	17,181	20,333	23,351
Property and equipment, net	138,381	139,618	138,774
Operating lease assets, net	218,311	219,883	0
Goodwill	7,154	6,400	6,400
Goodwill	1,179	1,224	1,291
Other assets, net	2,360	2,216	2,216
Total long-term assets	367,385	369,341	148,681
Total assets	384,566	389,674	172,032
Accounts payable	10,563	7,854	7,854
Accrued payroll and benefits	7,833	13,391	13,391
Accrued expenses and other current liabilities	8,524	10,630	11,183
Current operating lease liabilities	21,528	0	0
Current portion of long-term debt	750	719	719
Total current liabilities	49,198	32,594	33,147
Long-term debt, net	47,035	44,183	44,183
Long-term operating lease liabilities, net	237,341	260,931	0
Deferred rent	0	148	37,334
Deferred tax liabilities, net	133	133	133
Other long-term liabilities	5,263	4,996	4,554
Total liabilities	338,970	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	464	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	199,110	198,352	198,352
Accumulated deficit	(118,978)	(117,127)	(111,135)
Total stockholders’ equity	45,596	46,689	52,681	$ 31,407	$ 35,861
Total liabilities and stockholders’ equity	$ 384,566	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