Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Prepaid Expenses and Other Current Assets [Abstract]
Inventory	$ 139	$ 755
Income tax receivable	310	418
Prepaid expenses	556	549
Other current assets	795	1,073
Total prepaid expenses and other current assets	$ 1,800	$ 2,795