Stock-Based Compensation - Expense Allocation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock-based compensation
Stock-based compensation expense	$ 2,692	$ 4,232	$ 5,747
Research and development
Stock-based compensation
Stock-based compensation expense	1,039	2,161	2,791
General and administrative
Stock-based compensation
Stock-based compensation expense	$ 1,653	$ 2,071	$ 2,956