Other Assets and Liabilities - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Prepaid Expenses and Other Current Assets:
Value-added tax recoverable	$ 306	$ 341
Prepaid and other expenses	3,983	1,018
Short-term deposit	1,418	1,477
Guarantee from Armistice	274	318
Income tax receivable	18,835	18,615
Receivable from Exela (see Note 3)	0	16,500
Other	492	457
Total	$ 25,308	$ 38,726