Share capital (Narrative) (Details)	3 Months Ended				6 Months Ended		12 Months Ended	49 Months Ended
	May. 31, 2015 USD ($) $ / shares shares	May. 31, 2015 USD ($) $ / shares CAD / shares shares	Feb. 28, 2015	May. 31, 2014 USD ($) shares	May. 31, 2015 USD ($) $ / shares shares	May. 31, 2014 USD ($)	Nov. 30, 2013 shares	May. 31, 2015 USD ($) $ / shares shares	Nov. 30, 2014 USD ($) $ / shares shares	Apr. 30, 2012 USD ($) shares
Contributed surplus	$ 124,000	$ 124,000			$ 124,000			$ 124,000	$ 124,000
Common Stock, Shares Authorized | shares
Stock options granted | shares					1,620,000
Stock-based compensation					$ 371,000	$ 251,000
Non-vested stock options outstanding | shares	3,161,666	3,161,666			3,161,666			3,161,666	1,741,666
Weighted average exercise price options outstanding | $ / shares	$ 0.75	$ 0.75			$ 0.75			$ 0.75	$ 1.11
Stock option expense	$ 0			$ 0	$ 0	0		$ 316,000
Aggregate intrinsic value, vested options	0	$ 0		10,000	0	10,000		0
Vesting of deferred share units | shares							154,373
Proceeds from private placement, net	$ 0			0	$ 0	17,000		$ 7,231,000
Non-Vested Options [Member]
Non-vested stock options outstanding | shares	1,245,008	1,245,008			1,245,008			1,245,008
Weighted average exercise price options outstanding | $ / shares	$ 0.75	$ 0.75			$ 0.75			$ 0.75
Number of RSU's [Member]
Granted | shares					0
Plan of Arrangement [Member]
Common stock committed for issuance | shares										6,181,352
Contributed surplus										$ 12,200,000
Number of DSU's [Member]
Common stock committed for issuance | shares	20,685	20,685			20,685			20,685
Granted | shares					74,067
Stock-based Compensation [Member]
Stock-based compensation					$ 30,000	200,000
NovaGold Arrangement Options [Member]
Stock based compensation, recovery					$ 0
Non-vested stock options outstanding | shares	546,771	546,771			546,771			546,771	721,415
Weighted average exercise price options outstanding | $ / shares	$ 5.10	$ 5.10			$ 5.10			$ 5.10	$ 5.06
Stock-based Compensation for NovaGold Arrangement Options						10,000
Aggregate intrinsic value, vested options	$ 0	$ 0		$ 0	$ 0	0		$ 0
Approximations [Member] | Non-Vested Options [Member]
Stock option expense	$ 200,000
Maximum [Member]
Vesting terms			2 years
Non-executive directors [Member]
Percentage of annual retainer in DSUs to be distributed	50.00%
New Employees [Member]
Stock options granted | shares				0	1,620,000
Stock options granted, weighted average exercise price | (per share)		$ 0.62			$ 0.21
Directors, Employees and Services Providers [Member]
Stock-based compensation					$ 340,000	$ 20,000