Business and Summary of Significant Accounting Policies - Adoption of New Lease Standard (Details) - USD ($) $ in Thousands	Dec. 29, 2020	Dec. 31, 2019	Jan. 02, 2019	Jan. 01, 2019	Jan. 02, 2018
Assets
Cash and cash equivalents	$ 7,840	$ 10,459		$ 4,655
Accounts receivable	3,428	3,503		2,391
Inventories	9,643	9,871		9,646
Prepaid expenses and other assets	2,759	5,386		6,474
Income tax receivable	44	103		185
Total current assets	23,714	29,322		23,351
Property and equipment, net	122,917	128,867		138,774
Operating lease assets, net	195,618	209,717		0
Goodwill	7,154	7,154		6,400
Intangibles, net	757	883		1,291
Other assets, net	3,471	2,576		2,216
Total long-term assets	329,917	349,197		148,681
Total assets	353,631	378,519		172,032
Liabilities and Stockholders’ Equity
Accounts payable	6,402	9,351		7,854
Accrued payroll and benefits	12,876	13,479		13,391
Accrued expenses and other current liabilities	11,632	11,679		11,183
Current operating lease liabilities	26,094	22,775		0
Current portion of long-term debt	1,125	750		719
Total current liabilities	58,129	58,034		33,147
Long-term debt, net	40,949	40,497		44,183
Long-term operating lease liabilities, net	210,454	225,014		0
Deferred rent				37,334
Deferred tax liabilities, net	240	200		133
Other long-term liabilities	14,160	4,203		4,554
Total liabilities	323,932	327,948		119,351
Preferred stock—$0.01 par value, 1,000,000 shares authorized and undesignated as of December 29, 2020 and December 31, 2019; no shares issued or outstanding	0	0		0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 29, 2020 and December 31, 2019; 46,807,587 issued and 44,383,716 outstanding as of December 29, 2020; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019	468	466		464
Treasury stock, at cost, 2,423,871 shares as of December 29, 2020 and December 31, 2019, respectively	(35,000)	(35,000)		(35,000)
Additional paid-in capital	202,970	200,585		198,352
Accumulated deficit	(138,739)	(115,480)		(111,135)
Total stockholders’ equity	29,699	50,571		52,681	$ 35,861
Total liabilities and stockholders’ equity	$ 353,631	$ 378,519		$ 172,032
ASU No. 2016-02
Assets
Cash and cash equivalents			$ 4,655
Accounts receivable			2,616
Inventories			9,646
Prepaid expenses and other assets			3,231
Income tax receivable			185
Total current assets			20,333
Property and equipment, net			139,618
Operating lease assets, net			219,883
Goodwill			6,400
Intangibles, net			1,224
Other assets, net			2,216
Total long-term assets			369,341
Total assets			389,674
Liabilities and Stockholders’ Equity
Accounts payable			7,854
Accrued payroll and benefits			13,391
Accrued expenses and other current liabilities			10,630
Current operating lease liabilities			0
Current portion of long-term debt			719
Total current liabilities			32,594
Long-term debt, net			44,183
Long-term operating lease liabilities, net			260,931
Deferred rent			148
Deferred tax liabilities, net			133
Other long-term liabilities			4,996
Total liabilities			342,985
Preferred stock—$0.01 par value, 1,000,000 shares authorized and undesignated as of December 29, 2020 and December 31, 2019; no shares issued or outstanding			0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 29, 2020 and December 31, 2019; 46,807,587 issued and 44,383,716 outstanding as of December 29, 2020; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019			464
Treasury stock, at cost, 2,423,871 shares as of December 29, 2020 and December 31, 2019, respectively			(35,000)
Additional paid-in capital			198,352
Accumulated deficit			(117,127)
Total stockholders’ equity			46,689
Total liabilities and stockholders’ equity			389,674
ASU No. 2016-02 | Adjustments Due to the Adoption of Topic 842
Assets
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
Intangibles, net			(67)
Other assets, net			0
Total long-term assets			220,660
Total assets			217,642
Liabilities and Stockholders’ Equity
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 December 29, 2020 and December 31, 2019; no shares issued or outstanding			0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 29, 2020 and December 31, 2019; 46,807,587 issued and 44,383,716 outstanding as of December 29, 2020; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019			0
Treasury stock, at cost, 2,423,871 shares as of December 29, 2020 and December 31, 2019, respectively			0
Additional paid-in capital			0
Accumulated deficit			(5,992)
Total stockholders’ equity			(5,992)
Total liabilities and stockholders’ equity			$ 217,642