Liabilities, Convertible Preferred Stock and Stockholders' (Deficit) Equity - 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
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 4,785	$ 1,565	$ 8,405	$ 5,684
Stock-based compensation			8,405	5,684
Parapyre Option Obligation
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	2,700	0	2,900	0
Research and Development Expense
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,965	639	4,136	2,031
General and administrative
Employee Service Share Based Compensation Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,820	$ 926	$ 4,269	$ 3,653