Share capital (Narrative) (Details)		1 Months Ended	6 Months Ended
	Dec. 15, 2016 shares	Dec. 23, 2016 USD ($) shares	May 31, 2017 USD ($) $ / shares shares	May 31, 2017 USD ($) $ / shares CAD / shares shares	May 31, 2016 USD ($) shares	May 31, 2016 USD ($) CAD / shares	Nov. 30, 2016 $ / shares shares
Stock options granted, weighted average exericse price | CAD / shares				CAD 0.72		CAD 0.44
Stock-based compensation | $			$ 499,000		$ 398,000
Non-vested stock options outstanding			7,419,326	7,419,326
Weighted average exercise price options outstanding | $ / shares			$ 0.51	CAD 0.51
Units vested		399,999
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		209,198
Aggregate intrinsic value, vested options | $			$ 1,200,000	CAD 1,200,000	780,000	CAD 780,000
Aggregate intrinsic value, options exercised | $			$ 30,000		30,000
Cash paid upon vesting | $		$ 90,000
Maximum [Member]
Vesting terms			2 years
Minimum [Member]
Vesting terms			0 years
Non-Vested Options [Member]
Non-vested stock options outstanding			1,405,843	1,405,843
Weighted average exercise price options outstanding | $ / shares			$ 0.45	CAD 0.45
Number of RSU's [Member]
Granted	600,000		600,000
Number of DSU's [Member]
Common stock committed for issuance			20,685	20,685
Granted			72,241
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			3,447	3,447
Stock-based Compensation [Member]
Stock-based compensation | $			$ 300,000		$ 150,000
NovaGold Arrangement Options [Member]
Non-vested stock options outstanding			0	0			312,195
Weighted average exercise price options outstanding | $ / shares			$ 0	CAD 0			$ 4.26
Approximationss [Member] | Non-Vested Options [Member]
Stock option expense | $			$ 100,000
New Employees [Member]
Stock options granted			1,695,000		1,785,000
Stock options granted, weighted average exercise price | $ / shares			$ 0.22
Directors, Employees and Services Providers [Member]
Stock-based compensation | $			$ 270,000		$ 250,000