Other Assets and Liabilities - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Valued-added tax recoverable	$ 1,051	$ 1,378
Prepaid and other expenses	2,116	2,145
Guarantee from Armistice (see Note 17)	454	534
Income tax receivable	536	921
Short-term deposit	0	3,350
Other	107	225
Total	$ 4,264	$ 8,553