Share-Based Compensation (Tables)
12 Months Ended
Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Total Stock-Based Compensation Expense

Total stock-based compensation expense, related to all of the Company’s share-based awards to employees, directors and non-employees recognized during the years ended 2013 and 2012, was comprised of the following:

 

     Years Ended December 31,  
         2013              2012      

Research and development

   $ 132,543       $ 111,206   

General and administrative

     258,850         183,900   
  

 

 

    

 

 

 

Total share-based compensation expense

   $ 391,393       $ 295,106   
  

 

 

    

 

 

 
Weighted-Average Assumptions Used for Calculating Value of Options Granted

The following table describes the weighted-average assumptions used for calculating the value of options granted for the years ended December 31:

 

     2013      2012  

Dividend yield

     0.0%         0.0

Expected volatility

     80.0%         79.7

Weighted-average risk-free interest rate

     2.2%         1.2

Expected term

     6.2 years            6.3 years   
Stock Option Activity

Information regarding the stock options activity including employees, directors and non-employees as of December 31, 2013, and changes during the year then ended, are summarized as follows:

 

    Number of
Shares
    Weighted-
Average
Exercise
Price
    Weighted-
Average
Contractual
Life
 

Outstanding at December 31, 2012

    1,707,114      $ 1.3802        4.4 years   

Options granted

    247,600        3.2600        6.2 years   

Options exercised

    (514,466     0.6472        2.3 years   

Options canceled or expired

    (40,123     0.8479        8.8 years   
 

 

 

   

 

 

   

Outstanding at December 31, 2013

    1,400,125      $ 1.9825        5.3 years   
 

 

 

   

 

 

   

Vested or expected to vest at December 31, 2013

    1,400,125      $ 1.9825     
 

 

 

   

 

 

   

Exercisable at December 31, 2013

    1,182,140      $ 1.7461        4.6 years