Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid insurance	$ 100	$ 115
Prepaid expenses	94	91
Prepaid rent	4	4
Short-term deposits	825	386
Debt acquisition costs - short-term	71	0
Total prepaid and other current assets	1,094	$ 596
Annual facility fee	$ 50
Facility fee, amortization period	1 year
Debt acquisition costs, amortization period	3 years