Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal		$ (513,000)	$ (972,000)
State	$ (4,000)	(155,000)	(378,000)
Current income tax (expense) benefit	(4,000)	(668,000)	(1,350,000)
Deferred:
Federal	(495,000)	34,000	423,000
State	38,000	2,000	85,000
Deferred income tax (expense) benefit	(457,000)	36,000	508,000
Total
Total income tax expense	$ (461,000)	$ (632,000)	$ (842,000)
Reconciliation of the effective income tax rate with the applicable statutory federal income tax rate
Federal tax at statutory rate (as a percent)	34.00%	34.00%	34.00%
State taxes, net of federal benefit (as a percent)	5.40%	6.00%	6.00%
Non-deductible stock based compensation (as a percent)	(11.80%)	8.40%	6.30%
Federal tax credit for payroll tax on employee tips	6.70%	(4.70%)	(14.60%)
Tax Cuts and Jobs Act (as a percent)	(109.20%)
Other (as a percent)	(1.00%)	0.90%	(0.70%)
Effective income tax rate (as a percent)	(75.90%)	44.60%	31.00%
Deferred income tax assets:
Point loyalty program	$ 474,000	$ 656,000
Accrued expenses	2,827,000	4,077,000
Federal tax credits	131,000	96,000
Other	129,000	236,000
Total deferred income tax assets	3,561,000	5,065,000
Deferred income tax liabilities:
Depreciation - property and equipment	(1,931,000)	(3,045,000)
Total deferred income tax liabilities	(1,931,000)	(3,045,000)
Net deferred income tax assets	1,630,000	2,020,000
Amounts recognized in the consolidated balance sheet:
Noncurrent deferred income tax assets	$ 1,630,000	$ 2,020,000