Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue (note 11)		$ 9,434	$ 18,437
Operating expenses:
Research and development	$ 167,512	105,767	75,463
General and administrative	46,542	32,810	21,967
Total operating expenses	214,054	138,577	97,430
Loss from operations	(214,054)	(129,143)	(78,993)
Other income (expense):
Interest income	27,620	8,713	466
Unrealized fair value gain (loss) on trading securities	3,550	(2,934)	(719)
Foreign exchange gain (loss)	199	(1,891)	358
Other income (expense)	31,369	3,888	105
Loss before income taxes	(182,685)	(125,255)	(78,888)
Income tax recovery (expense) (note 13)	292	(118)	6
Net loss	(182,393)	(125,373)	(78,882)
Net loss attributable to preferred shareholders		(437)	(1,795)
Net loss attributable to common shareholders	(182,393)	(124,936)	(77,087)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities (note 6)	2,923	(2,010)
Comprehensive loss	$ (179,470)	$ (127,383)	$ (78,882)
Net loss per common share (note 4):
Basic	$ (2.73)	$ (2.06)	$ (1.77)
Diluted	$ (2.73)	$ (2.06)	$ (1.77)
Weighted-average common shares outstanding (note 4):
Basic	66,889,005	60,542,142	43,627,452
Diluted	66,889,005	60,542,142	43,627,452