Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accrued Expenses
Employee related expenses	$ 9,388	$ 10,159
External research and development expenses	7,176	5,614
Intellectual property and patent related fees	1,304	1,408
Professional service expenses	1,098	2,345
Other expenses	293	666
Total accrued expenses	$ 19,259	$ 20,192