Research and development expenses: (Tables)

12 Months Ended

Dec. 31, 2012

Research and development expenses:

Schedule of research and development expenses

	Year  ended December 31, 2012			Nine months ended December 31, 2011			Year  ended March 31,  2011
Research and development expenses	$	74,040		$	37,178		$	25,602
Program funding (note 16)	(842		)	(604		)	(982		)
Research and development	$	73,198		$	36,574		$	24,620