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, 2014
Stock-based Compensation [Abstract]  
Weighted average assumptions
The fair value of the stock options granted was estimated based on the following weighted average assumptions for the three and nine months ended September 30, 2014 and 2013:

 
  
Three months ended September 30,
    
Nine months ended September 30,
  
   
2014
    
2013
    
2014
    
2013
  
Dividend yield
    
0
%
    
0
%
    
0
%
    
0
%
Expected volatility
    
88
%
    
92
%
    
93
%
    
92
%
Risk-free interest rate
    
1.79
%
    
1.43
%
    
1.72
%
    
0.87
%
Expected term
  
5.6 years
    
5.6 years
    
5.6 years
    
5.6 years
  
Stock option activity
Stock option activity for the nine months ended September 30, 2014 was as follows:

 
  
Options
    
Weighted Average Exercise Price Per Share
    
Weighted Average Remaining Contractual Life (in years)
    
Aggregate Intrinsic Value (in thousands)
  
Options outstanding at December 31, 2013
    
7,218,241
    
$
8.42
      
6.75
    
$
18,213
  
Granted
    
1,846,089
      
6.75
                  
Exercised
    
(862,622
)
    
4.02
                  
Forfeited, expired or cancelled
    
(417,567
)
    
15.45
                  
Options outstanding at September 30, 2014
    
7,784,141
    
$
8.13
      
6.97
    
$
5,609
  
Options exercisable at September 30, 2014
    
4,729,821
    
$
10.24
      
5.78
    
$
3,511
  
Unvested RSU activity
Unvested RSU activity for the nine months ended September 30, 2014 is summarized below:

 
  
Number of
Shares
    
Weighted-
Average Grant-
Date Fair Value
  
Unvested balance at December 31, 2013
    
1,738,037
    
$
2.73
  
Granted
    
1,493,594
      
6.51
  
Vested
    
(693,566
)
    
3.96
  
Forfeited
    
(178,416
)
    
4.12
  
Unvested balance at September 30, 2014
    
2,359,649
    
$
5.00
  
Stock-based compensation expense
The following table shows total stock-based compensation expense included in the condensed consolidated statements of comprehensive loss for the three and nine months ended September 30, 2014 and 2013 (in thousands):

   
Three months ended September 30,
    
Nine months ended September 30,
  
   
2014
    
2013
    
2014
    
2013
  
Research and development
  
$
1,765
    
$
474
    
$
5,124
    
$
1,904
  
Selling, general and administrative
    
1,772
      
753
      
4,761
      
2,042
  
Total stock-based compensation expense
  
$
3,537
    
$
1,227
    
$
9,885
    
$
3,946