| 
           CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) 
         | 
        
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
      
|---|---|---|
| Stockholders' equity: | ||
| Common stock, par value (in dollars per share) | $ 0.0075 | $ 0.0075 | 
| Common shares, shares authorized (in shares) | 138,666,666 | 138,666,666 | 
| Common shares, shares outstanding (in shares) | 105,386,216 | 82,447,274 | 
| X | ||||||||||
| 
             
- Definition 
          Face amount or stated value per share of common stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Definition 
          Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
        
| X | ||||||||||
| 
             
- Details 
          
  |