Stock-Based Compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Stock-Based Compensation
Total compensation expense	$ 1,800	$ 2,709	$ 3,591	$ 4,738
Research and development expense
Stock-Based Compensation
Total compensation expense	549	637	1,122	1,233
General and administrative expense
Stock-Based Compensation
Total compensation expense	$ 1,251	$ 2,072	$ 2,469	$ 3,505