Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Collaboration revenue		$ 15		$ 31
Operating expenses:
Research and development	$ 5,408	6,109	$ 10,988	12,012
General and administrative	2,178	1,799	4,416	3,899
Total operating expenses	7,586	7,908	15,404	15,911
Loss from operations	(7,586)	(7,893)	(15,404)	(15,880)
Other income (expense):
Interest income	125	109	233	258
Interest expense	(200)		(359)
Foreign exchange gain (loss)	(140)	404	(424)	725
Gain on termination of collaboration agreement (note 9c)			4,398
Net loss and comprehensive loss	(7,801)	(7,380)	(11,556)	(14,897)
Net loss attributable to preferred shareholders	(1,303)		(996)
Net loss attributable to common shareholders	$ (6,498)	$ (7,380)	$ (10,560)	$ (14,897)
Net loss per common share (note 5):
Basic	$ (0.45)	$ (0.41)	$ (0.66)	$ (0.83)
Diluted	$ (0.45)	$ (0.41)	$ (0.66)	$ (0.84)
Weighted-average common shares outstanding (note 5):
Basic	14,306,491	17,997,194	16,055,456	17,971,702
Diluted	14,306,491	18,015,748	16,055,456	17,995,109