Consolidated Statements of Changes in Shareholders’ Equity - USD ($) $ in Thousands	Total	Common shares	Accumulated deficit	Accumulated other comprehensive loss	Additional paid-in capital
Beginning balance (in shares) at Dec. 31, 2018		31,977,668
Beginning balance at Dec. 31, 2018	$ 180,490	$ 320,074	$ (145,272)	$ (6,659)	$ 12,347
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares on exercise of stock options (in shares)		529,661
Issuance of common shares on exercise of stock options (note 10e)	9,303	$ 11,432			(2,129)
Issuance of common shares through employee share purchase plan (note 10f)		43,308
Issuance of common shares through employee stock purchase plan (note 10f)	763	$ 763
Fair value adjustments upon reclassification of stock options to liabilities	(119)				(119)
Stock-based compensation	12,676				12,676
Issuance of common shares and pre-funded warrants in connection with public offering, net of offering costs (notes 10a and 10d)		7,013,892
Issuance of common shares and pre-funded warrants in connection with public offering, net of offering costs (notes 10a and 10d)	188,005	$ 117,941			70,064
Net loss	(145,437)		(145,437)
Ending balance (in shares) at Dec. 31, 2019		39,564,529
Ending balance at Dec. 31, 2019	245,681	$ 450,210	(290,709)	(6,659)	92,839
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares on exercise of stock options (in shares)		602,158
Issuance of common shares on exercise of stock options (note 10e)	15,430	$ 18,373			(2,943)
Issuance of common shares through employee share purchase plan (note 10f)		43,973
Issuance of common shares through employee stock purchase plan (note 10f)	1,618	$ 1,618
Fair value adjustments upon reclassification of stock options to liabilities	(110)				(110)
Stock-based compensation	26,945				26,945
Issuance of common shares and pre-funded warrants in connection with public offering, net of offering costs (notes 10a and 10d)		5,824,729
Issuance of common shares and pre-funded warrants in connection with public offering, net of offering costs (notes 10a and 10d)	300,910	$ 254,018			46,892
Net loss	(180,552)		(180,552)
Ending balance (in shares) at Dec. 31, 2020		46,035,389
Ending balance at Dec. 31, 2020	409,922	$ 724,219	(471,261)	(6,659)	163,623
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common shares on exercise of stock options (in shares)		502,019
Issuance of common shares on exercise of stock options (note 10e)	9,660	$ 12,878			(3,218)
Issuance of common shares through employee share purchase plan (note 10f)		68,964
Issuance of common shares through employee stock purchase plan (note 10f)	3,080	$ 3,080
Issuance of common shares upon vesting of restricted stock units ("RSUs")		27,563
Issuance of common shares upon vesting of restricted stock units ("RSUs")	0	$ 970			(970)
Stock-based compensation	38,275				38,275
Net loss	(211,843)		(211,843)
Ending balance (in shares) at Dec. 31, 2021		46,633,935
Ending balance at Dec. 31, 2021	$ 249,094	$ 741,147	$ (683,104)	$ (6,659)	$ 197,710