Income Taxes - Schedule of Income tax Recovery (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Computed taxes at combined Canadian and U.S. tax rates	(27.30%)	(27.90%)	(27.30%)
Change in tax rate	(0.10%)	(3.60%)
Non-deductible expenses	3.30%	2.20%	1.80%
Research and development credits	(1.60%)	(0.90%)	(3.50%)
Change in valuation allowance	24.80%	25.40%	28.40%
Effect of the U.S. Tax Cuts and Jobs Act		4.60%
Other	0.90%	0.20%	0.60%
Income tax recovery	0.00%	0.00%	0.00%