Segment Information - Research and development costs and an allocation of indirect research and development costs to each program (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Information
Research and Development Expense	$ 52,614	$ 31,661
Single reportable segment
Segment Information
Research and Development Expense	52,614	31,661
Single reportable segment | Barzolvolimab/Anti-KIT Program
Segment Information
Research and Development Expense	39,703	23,778
Single reportable segment | CDX-622
Segment Information
Research and Development Expense	5,451	3,421
Single reportable segment | Other Programs
Segment Information
Research and Development Expense	$ 7,460	$ 4,462