CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance at Dec. 31, 2009	$ 203,226	$ 501,786	$ (285)	$ (298,275)
Balance (in shares) at Dec. 31, 2009		121,893
Increase (Decrease) in Shareholders' Equity
Stock-based compensation	643	643
Exercise of stock options	89	89
Exercise of stock options (in shares)		72
Net loss	(17,581)			(17,581)
Balance at Jun. 30, 2010	186,377	502,518	(285)	(315,856)
Balance (in shares) at Jun. 30, 2010		121,965
Balance at Dec. 31, 2010	173,280	504,389	257	(331,366)
Balance (in shares) at Dec. 31, 2010		122,186
Increase (Decrease) in Shareholders' Equity
Stock-based compensation	1,222	1,222
Sale of shares for cash, net of issuance costs	105,415	105,415
Sale of shares for cash, net of issuance costs (in shares)		17,250
Exercise of stock options	412	412
Exercise of stock options (in shares)		163
Exercise of stock options from 2007 acquisition	361	361
Exercise of stock options from 2007 acquisition (in shares)		70
Shares issued for Mexican mining concessions	325	325
Shares issued for Mexican mining concessions (in shares)		42
Unrealized loss on marketable equity securities	(866)		(866)
Net loss	(21,888)			(21,888)
Balance at Jun. 30, 2011	$ 258,261	$ 612,124	$ (609)	$ (353,254)
Balance (in shares) at Jun. 30, 2011		139,711