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Stock-Based Compensation (Tables)
6 Months Ended
Jun. 30, 2020
Share-based Payment Arrangement [Abstract]  
Schedule of Weighted Average Assumptions
The weighted average assumptions used in the Black-Scholes model for option grants to employees and directors are presented below:
 
Three Months Ended June 30,
 
Six Months Ended June 30,
 
2020
 
2019
 
2020
 
2019
Risk-free interest rate
0.40%
 
2.31%
 
0.67%
 
2.43%
Expected volatility
80%
 
70%
 
77%
 
70%
Expected life in years
5.9
 
6.2
 
5.9
 
6.2
Dividend yield