Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation (Details 2)

v2.4.0.8
Stock-based Compensation (Details 2) (Employee Stock Option Plans, USD $)
In Millions, except Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2014
item
Mar. 31, 2013
Stock award plans    
Number of homogenous groups for purposes of determining fair values of options 3  
Contractual term of the option 10 years  
Weighted-average assumptions relating to options granted    
Risk-free interest rate (as a percent) 2.20% 0.80%
Expected term (in years) 6 years 6 months 5 years 6 months
Dividend yield (as a percent) 0.00% 0.00%
Expected volatility (as a percent) 75.20% 73.40%
Additional disclosures    
Options granted (in shares) 3,188,150 2,018,691
Grant-date weighted-average fair value (in dollars per share) $ 2.36 $ 4.02
Unrecognized compensation cost, net of estimated forfeitures related to unvested stock-based award $ 12.0  
Shares of common stock available for future grant 6,290,247  
Options exercised during the period (in shares) 6,968  
Consultants
    
Stock award plans    
Contractual term of the option 10 years  
Recipients of performance shares
    
Additional disclosures    
Options granted (in shares) 950,000