Segment Disclosure - Summary of Net Loss Related To Segment Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenue			$ 9,434
Direct external research and development costs	$ 210,394	$ 167,512	105,767
Personnel-related expenses	68,340	47,739	36,088
stock-based compensation	50,717	32,372	20,376
Other research and development costs	11,232	9,560	7,274
Other general and administrative costs	20,657	14,376	9,996
Interest income	(41,943)	(27,620)	(8,713)
Other segment items	(3,025)	(4,041)	4,943
Net loss	(234,330)	(182,393)	(125,373)
Azetukalner
Segment Reporting Information [Line Items]
Direct external research and development costs	106,806	89,303	37,367
XEN496
Segment Reporting Information [Line Items]
Direct external research and development costs		5,152	14,765
Pre-clinical, discovery and other programs
Segment Reporting Information [Line Items]
Direct external research and development costs	$ 21,546	$ 15,552	$ 12,711