Other Assets and Liabilities - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Prepaid Expenses and Other Current Assets:
Valued-added tax recoverable	$ 258	$ 341
Prepaid and other expenses	4,990	1,018
Short-term deposit	1,477	1,477
Guarantee from Armistice	272	318
Income tax receivable	18,835	18,615
Receivable from Exela (see Note 3)	8,250	16,500
Other	149	457
Total	$ 34,231	$ 38,726