Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

v2.4.0.8
Stock Based Compensation (Tables)
 3 Months Ended
Mar. 31, 2014
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 the Company’s 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
March 31,		  
     2014      2013  

Research and development

    $ 671       $ 534   

General and administrative

      595         519   
  

 

 

     

 

 

  
   $ 1,266       $ 1,053   
  

 

 

     

 

 

  
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 months ended March 31, 2014 and 2013:

 

     Three Months Ended
March 31,		  
     2014     2013  

Employee Stock Options:

     

Risk-free interest rate

      1.90 %     1.15 %

Expected term (in years)

      6.04        6.02   

Dividend yield

      —          —     

Volatility

      96 %     101 %

Weighted-average fair value of stock options granted

    $ 3.84      $ 4.01   

 

     Three Months Ended
March 31,		  
     2014     2013  

Employee Stock Purchase Plan (ESPP):

     

Risk-free interest rate

      0.18 %     0.20 %

Expected term (in years)

      1.23        1.25   

Dividend yield

      —          —     

Volatility

      53 %     92 %

Weighted-average fair value of stock options granted

    $ 1.79      $ 2.44   
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, 2013

      6,526,506      $ 3.66         —          —    

Granted

      175,000      $ 4.97         —          —    

Exercised

      (39,352 )   $ 1.40         —          —    

Forfeitures

      (5,937 )   $ 6.18         —          —    
  

 

 

          

Outstanding at March 31, 2014

      6,656,217      $ 3.71         7.43       $ 10,708,746   
  

 

 

          

Vested and expected to vest March 31, 2014

      6,617,299      $ 3.70         7.42       $ 10,701,253   

Exercisable at March 31, 2014

      4,077,685      $ 2.93         6.78       $ 9,204,627