Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue (note 10)			$ 9,434
Operating expenses:
Research and development	$ 210,394	$ 167,512	105,767
General and administrative	68,904	46,542	32,810
Total operating expenses	279,298	214,054	138,577
Loss from operations	(279,298)	(214,054)	(129,143)
Other income (expense):
Interest income	41,943	27,620	8,713
Unrealized fair value gain (loss) on trading securities		3,550	(2,934)
Foreign exchange gain (loss)	(1,064)	199	(1,891)
Other income (expense)	40,879	31,369	3,888
Loss before income taxes	(238,419)	(182,685)	(125,255)
Income tax recovery (expense) (note 13)	4,089	292	(118)
Net loss	(234,330)	(182,393)	(125,373)
Net loss attributable to preferred shareholders			(437)
Net loss attributable to common shareholders	(234,330)	(182,393)	(124,936)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities (note 5)	(1,535)	2,923	(2,010)
Comprehensive loss	$ (235,865)	$ (179,470)	$ (127,383)
Net loss per common share (note 11):
Basic	$ (3.01)	$ (2.73)	$ (2.06)
Diluted	$ (3.01)	$ (2.73)	$ (2.06)
Weighted-average common shares outstanding (note 4):
Basic	77,894,643	66,889,005	60,542,142
Diluted	77,894,643	66,889,005	60,542,142