3. StockBased Compensation (Details) 
3 Months Ended  6 Months Ended  

Jun. 30, 2016 
Jun. 30, 2015 
Jun. 30, 2016 
Jun. 30, 2015 

Stockbased Compensation Details  
Risk free interest rate, minimum  0.70%  1.61%  0.70%  1.61% 
Risk free interest rate, maximum  1.73%  1.97%  1.73%  1.97% 
Dividend yield  0.00%  0.00%  0.00%  0.00% 
Expected term, minimum  2 years  5 years  2 years  5 years 
Expected term, maximum  10 years  10 years  10 years  10 years 
Expected volatility, minimum  35.90%  41.20%  34.90%  41.20% 
Expected volatility, maximum  50.40%  54.20%  50.40%  54.20% 
X  
 References No definition available.

X  
 References No definition available.

X  
 References No definition available.

X  
 Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef

X  
 Definition The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probabilityweighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.

X  
 Definition The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probabilityweighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. No definition available.

X  
 Definition The maximum riskfree interest rate assumption that is used in valuing an option on its own shares. No definition available.

X  
 Definition The minimum riskfree interest rate assumption that is used in valuing an option on its own shares. No definition available.
