Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Expenses
Employee compensation expenses	$ 1,694	$ 3,910
Research and development expenses	1,232	6,661
Licensing expenses	794	5,478
Restructuring expenses (Note 12)	2,588	3,112
Other expenses	257	285
Total accrued expenses	$ 6,565	$ 19,446