Accrued Expenses (Schedule of Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accrued Expenses [Abstract]
Accrued payroll and bonus	$ 1,711	$ 2,627
Property and franchise taxes accrual	340	424
Accrued other miscellaneous liabilities	882	1,033
Total accrued expenses	$ 2,933	$ 4,084