Income Tax - Components of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
United States	$ (231,790)	$ (185,612)	$ (165,160)
Foreign	1,215	730	591
Loss before income tax expense	$ (230,575)	$ (184,882)	$ (164,569)