XML 63 R39.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock Compensation (Tables)
12 Months Ended
Dec. 31, 2019
Stock Compensation  
Schedule of valuation assumptions used for valuation of fair value of stock compensation granted

Employee Stock Options

Employee Stock Purchase Plan

For the year ended December 31,

For the year ended December 31,

 

2019

  

2018

  

2017

  

2019

  

2018

  

2017

Average risk-free interest rates

2.27

%  

2.61

%  

1.80

%  

1.82

%  

2.62

%  

1.53

%

Average expected life (in years)

5.27

5.26

5.25

0.50

0.50

0.50

Volatility

45

%  

45

%  

49

%  

31

%  

46

%  

38

%

Weighted-average fair value (in dollars)

32.38

34.20

53.41

14.04

15.80

19.42