Business and Summary of Significant Accounting Policies (Adoption of New Lease Standard) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 02, 2019	Jan. 01, 2019	Jan. 02, 2018	Jan. 03, 2017
Assets
Cash and cash equivalents	$ 10,459		$ 4,655
Accounts receivable	3,503		2,391
Inventories	9,871		9,646
Prepaid expenses and other assets	5,386		6,474
Income tax receivable	103		185
Total current assets	29,322		23,351
Property and equipment, net	128,867		138,774
Operating lease assets, net	209,717		0
Goodwill	7,154		6,400	$ 6,400
Intangibles, net	883		1,291
Other assets, net	2,576		2,216
Total long-term assets	349,197		148,681
Total assets	378,519		172,032
Liabilities and Stockholders’ Equity
Accounts payable	9,351		7,854
Accrued payroll and benefits	13,479		13,391
Accrued expenses and other current liabilities	11,679		11,183
Current operating lease liabilities	22,775		0
Current portion of long-term debt	750		719
Total current liabilities	58,034		33,147
Long-term debt, net	40,497		44,183
Long-term operating lease liabilities, net	225,014		0
Deferred rent	0		37,334
Deferred tax liabilities, net	200		133
Other long-term liabilities	4,203		4,554
Total liabilities	327,948		119,351
Preferred stock—$0.01 par value, 1,000,000 shares authorized and undesignated as of December 31, 2019 and January 1, 2019; no shares issued or outstanding	0		0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 31, 2019 and January 1, 2019; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019 and 46,353,309 issued and 43,929,438 outstanding as of January 1, 2019	466		464
Treasury stock, at cost, 2,423,871 shares as of December 31, 2019 and January 1, 2019, respectively	(35,000)		(35,000)
Additional paid-in capital	200,585		198,352
Accumulated deficit	(115,480)		(111,135)
Total stockholders’ equity	50,571		52,681	$ 35,861	$ 25,818
Total liabilities and stockholders’ equity	$ 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 31, 2019 and January 1, 2019; no shares issued or outstanding		0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 31, 2019 and January 1, 2019; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019 and 46,353,309 issued and 43,929,438 outstanding as of January 1, 2019		464
Treasury stock, at cost, 2,423,871 shares as of December 31, 2019 and January 1, 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 31, 2019 and January 1, 2019; no shares issued or outstanding		0
Common stock—$0.01 par value, 180,000,000 shares authorized as of December 31, 2019 and January 1, 2019; 46,557,934 issued and 44,134,063 outstanding as of December 31, 2019 and 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 December 31, 2019 and January 1, 2019, respectively		0
Additional paid-in capital		0
Accumulated deficit		(5,992)
Total stockholders’ equity		(5,992)
Total liabilities and stockholders’ equity		$ 217,642