v2.4.0.8
Consolidated Balance Sheets (Parenthetical) (USD $)
Sep. 30, 2014
Dec. 31, 2013
Stockholders' equity    
Common stock, par value (in dollars per share) $ 0.001  
Common stock, shares authorized (in shares) 200,000,000  
Common stock, shares issued (in shares) 61,357,390 58,673,215
Common stock, shares outstanding (in shares) 58,666,797 55,319,239
Treasury stock, at cost (in shares) 2,690,593 3,353,976