Subsequent events - Additional Information (Detail)	1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended		194 Months Ended	1 Months Ended
	Jun. 06, 2011 USD ($)	Oct. 26, 2010 CAD	Jun. 16, 2010 CAD	Jun. 30, 2012 CAD	Jun. 30, 2011 CAD	Jun. 30, 2012 CAD	Jun. 30, 2011 CAD	Dec. 31, 2003 CAD	Dec. 31, 2002 CAD	Jun. 30, 2012 CAD	Jul. 06, 2012 Subsequent Event Issuance of Equity USD ($)
Subsequent Event [Line Items]
Shares issued, shares			11,078,666								12,261,562
Shares issued, par value	$ 1.60		0.60								$ 1.28
Warrant exercise price		0.40									$ 1.85
Warrants exercise period											18 months
Proceeds from units issued			6,647,199								$ 15,694,799
Proceeds from warrants			1,504,997					73,625	246,839		1,969,112
Proceeds from Common stock issued, net of issue costs			5,142,202	989,774	12,109,739	1,115,518	16,420,564		1,171,286	88,936,912	$ 13,725,687