Quarterly report pursuant to Section 13 or 15(d)

Stock Plans (Tables)

v2.4.0.6
Stock Plans (Tables)
3 Months Ended
Mar. 31, 2013
Stock Plans [Abstract]  
Summary of stock-based compensation expense recorded for awards under the stock option plans
                 
    Three Months Ended
March 31,
 

(in thousands, except per share amounts)

    2013         2012    

Research and development

  $ 304     $ 616  

General and administrative

    201       936  
   

 

 

   

 

 

 

Total share-based compensation expenses

  $ 505     $ 1,552  
   

 

 

   

 

 

 
Schedule of assumptions used to estimate the stock-based compensation expense
                 
    Three Months Ended
March 31,
 
      2013         2012    

Weighted-average risk-free interest rate

    0.64     0.94

Expected dividend payments

           

Expected holding period (years) 1

    4.4       5.1  

Weighted-average volatility factor 2

    1.83       1.74  

Estimated forfeiture rates for options granted to management 3

    23     23

Estimated forfeiture rates for options granted to non-management 3

    41     41

 

(1) Expected holding periods are based on historical data.
(2) Weighted average volatility is based on the historical volatility of our common stock.
(3) Estimated forfeiture rates are based on historical data.
Summary of option activity
                                 

(in thousands, except per share amounts)

  Options     Weighted
Average
Exercise
Price
    Weighted
Average
Remaining
Option
Term
    Aggregate
Intrinsic
Value
 

Outstanding at January 1, 2013

    6,842     $ 1.33       6.65     $ 722  

Granted

    —         —                    

Exercised

    (75     1.50                  

Expired or canceled

    —         —                    

Forfeited

    —         —                    
   

 

 

   

 

 

                 

Outstanding at March 31, 2013

    6,767     $ 1.32       6.47     $ 3,386  
   

 

 

   

 

 

   

 

 

   

 

 

 

Exercisable at March 31, 2013

    6,639     $  1.32       6.47     $  3,323