Stock-Based Compensation - Stock based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock based compensation expense
Total stock-based compensation expense	$ 2,001	$ 2,312	$ 6,204	$ 7,182
Research and development
Stock based compensation expense
Total stock-based compensation expense	721	779	2,184	2,274
General and administrative
Stock based compensation expense
Total stock-based compensation expense	$ 1,280	$ 1,533	$ 4,020	$ 4,908