CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance at Dec. 31, 2011	$ 219,304	$ 613,831	$ (1,289)	$ (393,238)
Balance (in shares) at Dec. 31, 2011		139,753,000
Increase (Decrease) in Shareholders' Equity
Stock-based compensation	1,573	1,573
Issuance of exchangeable shares to acquire Minera Andes Inc.	664,671	664,671
Issuance of exchangeable shares to acquire Minera Andes Inc. (in shares)		127,331,000
Assumption of stock options in connection with the acquisition of Minera Andes Inc.	3,175	3,175
Exercise of stock options	15	15
Exercise of stock options (in shares)		17,000
Exercise of stock options assumed from Minera Andes Inc. acquisition	2,500	2,500
Exercise of stock options assumed from Minera Andes Inc. acquisition (in shares)		747,000
Shares issued for Mexico mining concessions	226	226
Shares issued for Mexico mining concessions (in shares)		42,000
Unrealized loss on marketable equity securities, net of taxes	(376)		(376)
Net loss (As adjusted - note 5)	(17,351)			(17,351)
Balance at Mar. 31, 2012	873,737	1,285,991	(1,665)	(410,589)
Balance (in shares) at Mar. 31, 2012		267,890,000
Balance at Dec. 31, 2012	889,591	1,349,777	(294)	(459,892)
Balance (in shares) at Dec. 31, 2012		296,025,000
Increase (Decrease) in Shareholders' Equity
Stock-based compensation	378	378
Exercise of stock options	34	34
Exercise of stock options (in shares)	20,000	20,000
Shares issued for litigation settlement	3,270	3,270
Shares issued for litigation settlement (in shares)		1,000,000
Shares issued for Mexico mining concessions	96	96
Shares issued for Mexico mining concessions (in shares)	41,500	41,000
Net loss (As adjusted - note 5)	(10,982)			(10,982)
Balance at Mar. 31, 2013	$ 882,387	$ 1,353,555	$ (294)	$ (470,874)
Balance (in shares) at Mar. 31, 2013		297,086,000