Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Statement [Abstract]
Collaboration revenue (note 10)	$ 7,500	$ 0	$ 0
Operating expenses:
Research and development	300,938	210,394	167,512
General and administrative	79,632	68,904	46,542
Total operating expenses	380,570	279,298	214,054
Loss from operations	(373,070)	(279,298)	(214,054)
Other income (expense):
Interest income	26,828	41,943	27,620
Unrealized fair value gain on trading securities	(0)	(0)	3,550
Foreign exchange gain (loss)	1,348	(1,064)	199
Total other income	28,176	40,879	31,369
Loss before income taxes	(344,894)	(238,419)	(182,685)
Income tax recovery (expense) (note 14)	(1,016)	4,089	292
Net loss	(345,910)	(234,330)	(182,393)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities (note 5)	1,947	(1,535)	2,923
Comprehensive loss	$ (343,963)	$ (235,865)	$ (179,470)
Net loss per common share (note 11):
Basic	$ (4.36)	$ (3.01)	$ (2.73)
Diluted	$ (4.36)	$ (3.01)	$ (2.73)
Weighted average common shares outstanding (note 11):
Basic	79,253,751	77,894,643	66,889,005
Diluted	79,253,751	77,894,643	66,889,005