Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

v2.4.0.8
Stock Based Compensation (Tables)
 9 Months Ended
Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Stock-Based Compensation Expense

Stock-based compensation expense, which consists of the compensation cost for employee stock options and ESPP, and the value of options issued to non-employees for services rendered, was allocated to research and development and general and administrative in the unaudited condensed consolidated statements of operations as follows (in thousands):

 

     Three Months  Ended
September 30, 		     Nine months Ended
September 30, 		 
     2013      2012      2013      2012  

Amortization of stock-based compensation:

            

Research and development

    $ 622       $ 471       $ 1,818       $ 1,082   

General and administrative

      609         473         1,738         1,005   
  

 

 

     

 

 

     

 

 

     

 

 

  
   $ 1,231       $ 944       $ 3,556       $ 2,087   
  

 

 

     

 

 

     

 

 

     

 

 

  
Weighted-Average Fair Value Valuation Assumptions

The fair value of employee stock options and employee purchase rights under the Company’s ESPP was estimated using the following weighted-average assumptions for the three and nine months ended September 30, 2013 and 2012:

 

     Three Months Ended
September 30,		     Nine months Ended
September 30,		  
     2013     2012     2013     2012  

Employee Stock Options

         

Risk-free interest rate

      1.79 %      1.03 %      1.14 %      1.13 % 

Expected term (in years)

      6.08        6.08        5.97        5.99   

Dividend yield

      —          —          —          —     

Volatility

      100 %      98 %      101 %      106 % 

Weighted-average fair value of stock options granted

    $ 4.21      $ 5.87      $ 4.04      $ 5.12   

 

     Three Months Ended
September 30,		     Nine months Ended
September 30,		  
     2013     2012     2013     2012  

Employee Stock Purchase Plan (ESPP):

         

Risk-free interest rate

      0.19 %      0.21 %      0.19 %      0.21 % 

Expected term (in years)

      1.25        1.25        1.25        1.25   

Dividend yield

      —          —          —          —     

Volatility

      72 %      111 %      77 %      111 % 

Weighted-average fair value of ESPP purchase rights

    $ 2.22      $ 4.62      $ 2.27      $ 3.46   
Stock Option Activity Under Equity Incentive Plan

The following table summarizes stock option activity under the Company’s 2004 Equity Incentive Plan:

 

Options

    Number of
Shares		     Weighted-
Average
Exercise
Price		      Weighted-
Average
Remaining
Contractual
Term		      Aggregate
Intrinsic
Value		  

Outstanding at December 31, 2012

      5,098,972     $ 3.18        —          —    

Granted

      1,653,500     $ 5.10        —          —    

Exercised

      (127,153 )   $ 1.59        —          —    

Forfeitures

      (65,303 )   $ 7.15        —          —    
  

 

 

          

Outstanding at September 30, 2013

      6,560,016     $ 3.66        7.83      $ 10,534,778  
  

 

 

          

Vested and expected to vest September 30, 2013

      6,504,707     $ 3.64        7.82      $ 10,518,742  

Exercisable at September 30, 2013

      3,361,581     $ 2.67        7.01      $ 8,034,963