Income taxes: (Tables)

12 Months Ended

Dec. 31, 2012

Income taxes:

Schedule of reconciliation of income tax provision

	Year  ended December 31, 2012			Nine months ended December 31, 2011			Year  ended March 31,  2011
Loss before income taxes	$	(97,036	)	$	(46,954	)	$	(41,721	)
Expected income tax recovery	$	24,259		$	12,443		$	11,682
Reduction (increase) in income taxes resulting from:
Non-deductible stock-based compensation	(3,019		)	(1,642		)	(1,379		)
Other permanent differences	2,158			(87		)	(600		)
Withholding taxes	(1,187		)	(500		)	(303		)
Change in enacted rates	(62		)	(189		)	24
Foreign tax rate differences, foreign exchange and other adjustments	382			552			(710		)
Non-taxable income from equity investment	3,308			3,974			1,888
Change in valuation allowance	(27,577		)	(13,391		)	(11,023		)
Income tax recovery (expense)	$	(1,738	)	$	1,160		$	(421	)

Schedule of significant components of net deferred income tax assets and liabilities

	December 31, 2012			December 31, 2011
Deferred income tax assets:
Net operating loss carry forwards	$	76,496		$	51,240
Intangible assets	1,557			873
Property, plant and equipment	5,703			3,109
Financing and share issuance costs	3,248			5,212
Warranty liability	2,013			1,073
Deferred revenue	1,601			861
Inventory	2,300			1,972
Unrealized foreign exchange	595			1,324
Research and development	2,132			2,086
Other	3,917			1,782
Total gross deferred income tax assets	99,562			69,532
Valuation allowance	(89,033		)	(61,456		)
Total deferred income tax assets	10,529			8,076
Deferred income tax liabilities:
Intangible assets	8,784			6,696
Property, plant and equipment	3,297			3,878
Other	575			—
Total deferred income tax liabilities	12,656			10,574
Total net deferred income tax liabilities	$	2,127		$	2,498
Allocated as follows (Restated — note 2(a)):
Current deferred income tax assets	$	7,183		$	5,654
Current deferred income tax liabilities	(65		)	—
Long-term deferred income tax liabilities	(9,245		)	(8,152		)
Total net deferred income tax liabilities	$	(2,127	)	$	(2,498	)

Summary of changes in deferred income tax asset valuation allowance

	Year			Nine months
	ended			ended
	December 31,			December 31,
	2012			2011
Beginning balance	$	61,456		$	48,065
Additions	27,639			13,391
Reductions	(62		)	—
Ending valuation allowance	$	89,033		$	61,456

Schedule of components of income tax recovery (expense)

	Net income (loss) before income			Income tax recovery (expense)
	taxes			Current			Deferred			Total
Year ended December 31, 2012:
Canada	$	(93,688	)	$	(1,339	)	$	(53	)	$	(1,392	)
United States	(1,589		)	62			—			62
Italy	(318		)	(775		)	(25		)	(800		)
Other	(1,441		)	(95		)	487			392
	$	(97,036	)	$	(2,147	)	$	409		$	(1,738	)
Nine months ended December 31, 2011:
Canada	$	(45,899	)	$	(500	)	$	—		$	(500	)
United States	(1,862		)	(95		)	—			(95		)
Italy	(1,342		)	(388		)	2,205			1,817
Other	2,149			(45		)	(17		)	(62		)
	$	(46,954	)	$	(1,028	)	$	2,188		$	1,160
Year ended March 31, 2011:
Canada	$	(39,219	)	$	(304	)	$	(32	)	$	(336	)
United States	(2,121		)	—			—			—
Italy	1,015			372			(457		)	(85		)
Other	(1,396		)	—			—			—
	$	(41,721	)	$	68		$	(489	)	$	(421	)

Schedule of loss carry forwards in various jurisdictions available to offset future taxable income

Expiring in:	2013		2014		2015		2016		2017		2025 and later		Total
Canada	$	2,717	$	2,521	$	—	$	—	$	—	$	283,624	$	288,862
Italy	—		—		—		—		—		4,247		4,247
United States	—		—		—		—		—		3,433		3,433
Sweden	—		—		—		—		—		4,752		4,752
Other	63		522		215		303		1,821		44		2,968
Total	$	2,780	$	3,043	215		$	303	1,821		$	296,100	$	304,262