Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
Deferred tax assets, valuation allowance	$ 2,542		$ 2,542	$ 3,867
Effective income tax rate reconciliation, at statutory federal income tax rate, percent	21.00%	35.00%
Reduction in net deferred tax assets due to change in corporate tax rate	$ 1,100
Deferred tax assets offset by change in valuation allowance	1,100
Operating losses expiration period			beginning in 2035
Federal [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
Operating loss carryforwards	3,800		$ 3,800
State [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
Operating loss carryforwards	$ 3,900		$ 3,900