Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Expenses
Employee compensation expenses	$ 2,184	$ 4,389
Research and development expenses	1,824	1,278
Litigation settlements (see Note 16)		2,650
Other	1,679	1,734
Total accrued expenses	$ 5,687	$ 10,051