XML 22 R47.htm IDEA: XBRL DOCUMENT v2.4.0.6
STOCK-BASED COMPENSATION (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended
Jan. 19, 2012
Sep. 30, 2012
Stock Options
Sep. 30, 2011
Stock Options
Sep. 30, 2012
Stock Options
Oz
Sep. 30, 2011
Stock Options
Oz
Sep. 30, 2012
Minera Andes
Stock Options
Sep. 30, 2012
Minera Andes
Stock Options
Sep. 30, 2012
Chief Operating Officer
Sep. 30, 2011
Certain employees, directors and consultants
STOCK-BASED COMPENSATION                  
Number of shares of common stock reserved for issuance before amendment 9                
Number of shares of common stock reserved for issuance 13.5                
Stock options granted (in shares)               0.3 0.9
Exercise price of options granted (in dollars per share)               $ 5.80 $ 7.10
Vesting period of options                 3 years
Exercise period of options                 10 years
Stock option expense   $ 0.7 $ 0.7 $ 2.8 $ 1.9 $ 0.1 $ 1.1    
Principal assumptions used in applying the Black-Scholes option pricing model for the awards                  
Risk-free interest rate (as a percent)       0.97%          
Risk-free interest rate, low end of range (as a percent)         1.82%        
Risk-free interest rate, high end of range (as a percent)         2.33%        
Volatility factor of the expected market price of common stock (as a percent)       75.00%          
Volatility factor of the expected market price of common stock, low end of range (as a percent)         90.00%        
Volatility factor of the expected market price of common stock, high end of range (as a percent)         100.00%        
Weighted-average expected life of option       6 years 6 years 7 months 6 days        
Weighted-average grant date fair value (in dollars per share)       3.80 4.97