Income taxes (Tables)

12 Months Ended

Dec. 31, 2014

Schedule of Income Tax Expense (Recovery)

Income tax expense (recovery) varies from the amounts that would be computed by applying the expected Canadian and provincial statutory income tax rate of 26% (2013 – 25.75%, 2012- 25%) to loss before income taxes as shown in the following table:

	2014			2013			2012
Computed taxes (recoveries) at Canadian federal and provincial tax rates	$	3,385		$	3,098		$	(1,075	)
Change in valuation allowance		(2,364	)		(2,029	)		2,710
Investment tax credits earned		(1,283	)		(529	)		(1,418	)
Tax attributes expired/utilized		2,011			198			(356	)
Financing fees in equity		(1,945	)		—			—
Changes in tax rates		—			(1,019	)		—
Non-deductible expenditures		(1,053	)		(374	)		107
Other		1,249			655			32
Income tax expense	$	—		$	—		$	—

Schedule of Net Deferred Income Tax Assets and Liabilities

The significant components of the net deferred income tax assets and liabilities are as follows:

	2014			2013
Deferred income tax assets
Investment tax credits	$	20,108		$	19,833
Scientific research and experimental development pool		19,648			18,592
Deferred revenues		3,063			7,230
Non-capital losses		1,390			2,755
Property, plant and equipment		2,651			2,386
Deferred financing fees		1,318			(176	)
Other		858			780
Less - valuation allowance		(49,036	)		(51,400	)
Net deferred income tax assets	$	—		$	—

Schedule of Activity Related to Unrecognized Tax Benefits

The following table summarizes the activity related to our unrecognized tax benefits:

	2014		2013
Balance as of January 1	$	6,350	$	6,350
Increases related to current year positions		—		—
Balance as of December 31	$	6,350	$	6,350