Income taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income tax recovery varies from the amounts that would be computed by applying the expected Canadian income tax rate (26%) and U.S. income tax rates (40.75%). The combined Canadian and U.S. income tax rates of 27.89% (2016 – 27.28%; 2015 –27.4%) was applied to loss before income taxes as shown in the following table:


	YEARS ENDED DECEMBER 31,
	2017			2016			2015
Computed taxes at combined Canadian and U.S. tax rates		(27.9	)%		(27.3	)%		(27.4	)%
Change in tax rate		(3.6	)		—			0.1
Non-deductible expenses		2.2			1.8			2.0
Research and development credits		(0.9	)		(3.5	)		—
Change in valuation allowance		25.4			28.4			25.3
Effect of the U.S. Tax Cuts and Jobs Act		4.6			—			—
Other		0.2			0.6			—

Income tax recovery		—			—			—

Schedule of Net (Loss) Income Before Taxes


(in thousands)	YEARS ENDED DECEMBER 31,
Net loss before taxes:		2017			2016			2015

Canada	$	(43,758	)	$	(31,737	)	$	(18,382	)
U.S.		(6,425	)		(5,265	)		(3,478	)

Total	$	(50,183	)	$	(37,002	)	$	(21,860	)

Components of Deferred Income Tax Assets

Deferred income tax assets and liabilities result from the temporary differences between the amount of assets and liabilities recognized for financial statement and income tax purposes. The significant components of the deferred income tax assets are as follows:


(in thousands)	DECEMBER 31, 2017			DECEMBER 31, 2016
Canadian net operating losses	$	35,605		$	24,049
U.S. net operating losses		3,749			3,889
Research and development deductions and credits		8,234			7,331
Other		1,810			1,389
Less: valuation allowance		(49,398	)		(36,658	)

Net deferred income tax assets	$	—		$	—