Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue (note 11)	$ 6,554	$ 3,500	$ 27,016	$ 3,500
Operating expenses:
Research and development	13,045	9,751	35,556	27,093
General and administrative	3,208	2,700	9,838	7,628
Total operating expenses	16,253	12,451	45,394	34,721
Loss from operations	(9,699)	(8,951)	(18,378)	(31,221)
Other income (expense):
Interest income	166	528	2,194	1,916
Interest expense		(363)	(484)	(1,086)
Foreign exchange gain (loss)	475	(80)	899	185
Loss on repayment of term loan (note 9)			(988)
Loss before income taxes	(9,058)	(8,866)	(16,757)	(30,206)
Income tax (expense) recovery (note 12)	203	(5)	243	(13)
Net loss and comprehensive loss	(8,855)	(8,871)	(16,514)	(30,219)
Net loss attributable to preferred shareholders	(250)	(336)	(474)	(1,146)
Net loss attributable to common shareholders	$ (8,605)	$ (8,535)	$ (16,040)	$ (29,073)
Net loss per common share (note 5):
Basic and diluted	$ (0.25)	$ (0.33)	$ (0.47)	$ (1.13)
Weighted-average common shares outstanding (note 5):
Basic and diluted	34,994,944	25,793,482	34,387,986	25,773,732