Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation Plans and Awards (Schedule of Fair Value Calculation Assumptions) (Details)

v3.2.0.727
Stock-based Compensation Plans and Awards (Schedule of Fair Value Calculation Assumptions) (Details)
3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Assumptions used for calculation of fair value per share        
Dividend yield        
Risk-free interest rate, minimum 1.44% 1.90% 1.41% 1.74%
Risk-free interest rate, maximum 2.34% 2.61% 2.34% 2.67%
Volatility   66.00%   66.00%
Volatility, minimum 73.00%   73.00%  
Volatility, maximum 74.00%   74.00%  
Minimum [Member]        
Assumptions used for calculation of fair value per share        
Expected term 6 years 6 years 6 years 6 years
Maximum [Member]        
Assumptions used for calculation of fair value per share        
Expected term 10 years 8 years 10 years 10 years