Segment Reporting -Summary of Significant Segment Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment, Reconciliation of Other Items from Segments to Consolidated [Line Items]
Revenue	$ 0	$ 886	$ 2,329
Less:
Share-based compensation	44,833	25,675	7,111
Net loss	208,018	338,790	83,815
Reconciliation of net loss
Adjustments and reconciling items	208,018	338,790	83,815
Net loss	208,018	338,790	83,815
Related Party
Less:
Share-based compensation	15,600	11,400	0
Research and development, excluding compensation and share-based compensation	25,500	37,100	0
Reportable Segment
Less:
Net loss	208,018	338,790	83,815
Reconciliation of net loss
Adjustments and reconciling items	208,018	338,790	83,815
Net loss	208,018	338,790	83,815
Reportable Segment | Operating Segments
Segment, Reconciliation of Other Items from Segments to Consolidated [Line Items]
Revenue	0	886	2,329
Less:
Compensation	21,780	22,590	25,776
Share-based compensation	44,833	25,675	7,111
Research and development, excluding compensation and share-based compensation	127,491	65,282	40,700
Other segment items	13,914	226,129	12,557
Net loss	208,018	338,790	83,815
Reconciliation of net loss
Adjustments and reconciling items	208,018	338,790	83,815
Net loss	208,018	338,790	83,815
Reportable Segment | Adjustments and reconciling items
Less:
Net loss	0	0	0
Reconciliation of net loss
Adjustments and reconciling items	0	0	0
Net loss	$ 0	$ 0	$ 0