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	2,135	2,135
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	594	594
Exercise of stock options (in shares)		317,000
Exercise of stock options assumed from Minera Andes Inc. acquisition	2,710	2,710
Exercise of stock options assumed from Minera Andes Inc. acquisition (in shares)		852,000
Shares issued for Mexico mining concessions	227	227
Shares issued for Mexico mining concessions (in shares)		42,000
Realized loss on marketable securities	(994)		(994)
Other-than-temporary impairment on marketable equity securities	1,993		1,993
Net loss (adjusted - note 6)	(37,715)			(37,715)
Balance at Jun. 30, 2012	856,100	1,287,343	(290)	(430,953)
Balance (in shares) at Jun. 30, 2012		268,295,000
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	686	686
Exercise of stock options	95	95
Exercise of stock options (in shares)	48,000	48,000
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 (adjusted - note 6)	(139,663)			(139,663)
Balance at Jun. 30, 2013	$ 754,075	$ 1,353,924	$ (294)	$ (599,555)
Balance (in shares) at Jun. 30, 2013		297,114,000