Share capital - Additional Information (Detail)	1 Months Ended								3 Months Ended		6 Months Ended		12 Months Ended												194 Months Ended	12 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			6 Months Ended			6 Months Ended		12 Months Ended				1 Months Ended							12 Months Ended	1 Months Ended																12 Months Ended						8 Months Ended		1 Months Ended			12 Months Ended
	Jun. 30, 2012 CAD	Dec. 31, 2011	Jun. 06, 2011 USD ($)	Jun. 06, 2011 CAD	Sep. 30, 2010 CAD	Jun. 16, 2010 CAD	Mar. 31, 2008 CAD	Jan. 31, 2006 CAD	Jun. 30, 2012 CAD	Jun. 30, 2011 CAD	Jun. 30, 2012 CAD	Jun. 30, 2011 CAD	Dec. 31, 2011 CAD	Dec. 31, 2010 CAD	Dec. 31, 2009 CAD	Dec. 31, 2008 CAD	Dec. 31, 2007 CAD	Dec. 31, 2006 CAD	Dec. 31, 2005 CAD	Dec. 31, 2004 CAD	Dec. 31, 2003 CAD	Dec. 31, 2002 CAD	Dec. 31, 1998 CAD	Dec. 31, 1997 CAD	Jun. 30, 2012 CAD	Dec. 31, 1998 Warrant 1 CAD	Dec. 31, 2002 Warrant 2 CAD	Dec. 31, 2002 Warrant 3 CAD	Dec. 31, 2002 Warrant 4 CAD	Jun. 30, 2012 Salaries and labor CAD	Jun. 30, 2011 Salaries and labor CAD	Jun. 30, 2012 Salaries and labor CAD	Jun. 30, 2011 Salaries and labor CAD	Jun. 30, 2012 Salary And Benefit CAD	Jun. 30, 2011 Salary And Benefit CAD	Jun. 30, 2012 Salary And Benefit CAD	Jun. 30, 2011 Salary And Benefit CAD	Jun. 30, 2012 Consulting Services CAD	Jun. 30, 2011 Consulting Services CAD	Jun. 30, 2012 Consulting Services CAD	Jun. 30, 2011 Consulting Services CAD	Jun. 30, 2012 Minimum CAD	Jun. 30, 2012 Maximum	Jun. 30, 2012 Employee Maximum	Jun. 30, 2012 Consultant Maximum	Jun. 30, 2012 At The Market CAD	Sep. 23, 2011 At The Market Maximum	Dec. 31, 1998 Gemstone	Dec. 31, 1997 Gemstone USD ($)	Dec. 31, 1997 Gemstone CAD	Dec. 31, 2002 Rex	Dec. 31, 2008 Pan-Nevada Gold Corporation	Oct. 11, 2008 Pan-Nevada Gold Corporation	Dec. 31, 2007 Pan-Nevada Gold Corporation	Apr. 16, 2007 Pan-Nevada Gold Corporation CAD	Feb. 09, 2011 Public offering	Nov. 30, 2010 Public offering USD ($)	Nov. 30, 2010 Public offering CAD	Dec. 31, 1997 Initial public offering CAD	Apr. 09, 2010 Private placement CAD	Nov. 12, 2008 Private placement CAD	Aug. 01, 2008 Private placement USD ($)	Aug. 01, 2008 Private placement CAD	Jun. 12, 2008 Private placement CAD	Nov. 10, 2007 Private placement	Aug. 24, 2007 Private placement CAD	May 16, 2007 Private placement	Nov. 30, 2006 Private placement CAD	May 31, 2006 Private placement CAD	Aug. 31, 2005 Private placement CAD	Jul. 31, 2005 Private placement CAD	Feb. 28, 2005 Private placement CAD	Dec. 31, 2004 Private placement CAD	Aug. 31, 2004 Private placement CAD	Jan. 31, 2004 Private placement CAD	Dec. 31, 2009 Private placement CAD	Dec. 31, 2005 Private placement	Dec. 31, 2004 Private placement	Dec. 31, 2003 Private placement CAD	Dec. 31, 1998 Private placement	Dec. 31, 1997 Private placement CAD	Dec. 31, 1996 Private placement First Issuance CAD	Dec. 31, 1996 Private placement Second Issuance CAD	Apr. 09, 2010 Private placement Period 1 CAD	Apr. 09, 2010 Private placement Period 2 CAD	Apr. 09, 2010 Private placement Period 3 CAD	Dec. 31, 2001 Principal shares	Dec. 31, 2000 Principal shares	Dec. 31, 1999 Principal shares	Dec. 31, 1998 Principal shares	Dec. 31, 1997 Principal shares CAD	Dec. 31, 2002 Short form offering CAD	Dec. 31, 2002 Short form offering Warrant 1 CAD
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Shares issued						11,078,666																																								69,110											6,660,000	6,660,000	2,000,000	1,333,000	12,500,000	600,000	600,000	1,421,500		2,000,000		2,000,000	3,725,000	500,000	1,000,000	2,500,000	700,000	1,020,000	400,000				700,000		1,000,000	420,000	280,000								750,000	3,500,000
Common shares, per share			$ 1.60			0.60																																																			$ 0.60		0.35	0.60	0.22	$ 2.50		2.00		2.70		2.50	1.80	1.40	1.15	0.85	0.85	0.75	2.00				1.20		2.50	0.25	0.25									0.25
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																																	3,151,855	590,570	514,365	1,793,491	$ 1,500,000	1,537,950	2,843,000		5,400,000		1,761,509	5,998,846	608,015	995,193	1,598,457			624,593				638,838			98,722	70,000								7,500
Commission on sale of shares, percentage																						10.00%																																					10.00%																						7.50%
Commission on sale of shares, per share																																																											0.035																						0.1875
Shares issued as a finance fee																						40,000																																					25,000																																	150,000
Proceeds from units issued						6,647,199																																																				4,070,725		800,000	2,750,000							2,000,000	6,705,000	700,000	1,150,000	2,125,000	595,000	765,000	800,000				840,000		2,253,793											875,000
Purchase of additional Common shares, per share						0.80																1.55																											$ 2.00								$ 0.90				0.28							3.00	2.70	1.45	1.15	1.00	1.00	0.80	2.35				1.50		3.00			0.70	0.80	0.90						0.25
Proceeds from units issued, gross																																																																				5,000,000													2,500,000
Proceeds from issuance of common stock, gross			12,000,000	11,742,000																																																																													2,178,761
Proceeds from issuance of warrants, gross																																																																																	321,239
Exercise of share purchase warrants					12,500	658,840															294,500					100,000	1,134,500	170,175	4,028,000																							108,500		761,823	870,323	2,650,000									908,782		1,725,000									12,500,000	23,000	161,000		100,000													875,000
Stock warrants expired											24,000																																										70,000			680,000									91,218		137,500											539,000		900,000
Finance fee						395,304																																																														88,750				69,700									15,000
Percentage of shares released from Escrow																																																																																							25.00%	25.00%	25.00%	25.00%
Shares issued to acquire an interest, shares							30,000	40,000																																								200,000	1,000,000	1,000,000	4,500,000				7,764,109
Shares issued to acquire an interest, value							88,500	88,000								88,500	27,028,505	88,000				3,600,000	246,000	2,065,500																									1,500,000	2,065,500					25,000,431
Proceeds from exercise of share warrants					10,000						1,226,921											1,418,125				300,000																							2,000,000	2,803,205																										3,500,000
Issue of shares as a finders' fee																																																	150,000	150,000																						75,800	18,750	55,650	40,000
Share purchase warrants exercisable price per share						0.80																					1.25	1.55																																																																	0.25
Proceeds from warrants						1,504,997															73,625	246,839							1,007,000																													918,870		285,635	956,509							238,491	706,154	91,985	154,807	526,543			175,407				201,162
Commission on sale of shares			600,000	587,100																		113,450																																				244,244
Exercise of stock options											108,333				33,333	395,000						32,000																														84,000		154,000	308,000
Proceeds from stock options exercised											65,319				21,651	613,250						12,800
Shares issued to a director as additional consideration																						31,250
Loan from a director																						780,000			12,010,075
Loan from a director, interest per annum																						12.00%
Share issuance cost						307,553	1,489						990,900	1,218,918		139,705	28,000	248,512		183,512	19,932	544,260																																				176,288		95,529	23,395		39,450	75,371		28,000		94,546	65,216	8,261	15,560	26,709							19,932
Issue of shares as a finders' fee																							224,250	309,825																																																64,430
Exercise of stock options, value											65,319		452,749		21,651	733,250	790,900	214,200	92,400	130,000		12,800																																	608,020
Exercise of share purchase warrants, value						212,109					1,226,921		9,271,320	10,000	3,500,000	154,999	8,696,523	3,414,500	1,539,000	254,625	73,625	1,007,000	300,000	2,803,205																															1,420,054
Risk free interest rate	1.60%	0.91%				1.82%
Volatility rate	151.00%	68.00%				131.00%
Expected life	3 months 18 days	9 months 26 days				2 years
Dividend						0
Fair value per warrant						0.32
Bought deal offering			7,500,000	7,500,000
Issuance cost				151,839
Common Stock Issuable Shares, Authorized																																															6,000,000
Common stock issued	115,560,568	113,849,475							115,560,568		115,560,568		113,849,475												115,560,568																					637,736
Proceeds from stock issued																																														1,554,957
Exercise of share purchase warrants											1,533,650
Exercise price of stock options																																										0.10
Percentage of aggregate number of shares that may be reserved for issuance pursuant to stock options																																											10.00%	5.00%	2.00%
Stock options term																																											10 years
Stock options term, upon termination of optionee's employment											90 days
Stock options term, upon death or disability											1 year
Stock-based compensation expense, net of forfeitures									450,717	210,522	1,145,824	739,479													11,747,237					62,596	51,888	104,615	75,622	378,026	130,464	1,058,745	635,687	10,095	28,170	(17,536)	28,170
Estimated unrecognized compensation cost from unvested options	1,045,824								1,045,824		1,045,824														1,045,824
Estimated unrecognized compensation cost from unvested options remaining vesting period											1 year 4 months 24 days
Weighted-average grant date fair value of options granted											1.24	0.69
Outstanding warrants	0	1,577,650							0		0		1,577,650												0