Annual report pursuant to Section 13 and 15(d)

Stock Option Plans - Schedule of Options Outstanding and Exercisable (Details)

v3.20.1
Stock Option Plans - Schedule of Options Outstanding and Exercisable (Details) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
2015 Equity Incentive Plan [Member]        
Number of options outstanding 5,795,395 5,525,405 5,112,967 4,443,000
Weighted-average Remaining life in years 10 years      
Weighted-average Exercise price $ 7.96 $ 8.08 $ 9.07 $ 4.94
Number of options exercisable 3,452,689      
2015 Equity Incentive Plan [Member] | Range One [Member]        
Range of exercise price, lower limit $ 2.26      
Range of exercise price, upper limit $ 5.44      
Number of options outstanding 1,989,150      
Weighted-average Remaining life in years 7 years      
Weighted-average Exercise price $ 3.66      
Number of options exercisable 1,462,346      
Weighted-average Remaining life in years, exercisable 6 years 6 months      
Weighted-average Exercise price, exercisable $ 3.46      
2015 Equity Incentive Plan [Member] | Range Two [Member]        
Range of exercise price, lower limit 5.90      
Range of exercise price, upper limit $ 9.23      
Number of options outstanding 2,425,240      
Weighted-average Remaining life in years 7 years 7 months 6 days      
Weighted-average Exercise price $ 7.35      
Number of options exercisable 1,253,189      
Weighted-average Remaining life in years, exercisable 6 years 2 months 12 days      
Weighted-average Exercise price, exercisable $ 7.32      
2015 Equity Incentive Plan [Member] | Range Three [Member]        
Range of exercise price, lower limit 11.43      
Range of exercise price, upper limit $ 14.45      
Number of options outstanding 456,619      
Weighted-average Remaining life in years 8 years 6 months      
Weighted-average Exercise price $ 13.49      
Number of options exercisable 204,025      
Weighted-average Remaining life in years, exercisable 8 years 4 months 24 days      
Weighted-average Exercise price, exercisable $ 13.56      
2015 Equity Incentive Plan [Member] | Range Four [Member]        
Range of exercise price, lower limit 15.25      
Range of exercise price, upper limit $ 17.30      
Number of options outstanding 924,386      
Weighted-average Remaining life in years 8 years      
Weighted-average Exercise price $ 16.09      
Number of options exercisable 533,129      
Weighted-average Remaining life in years, exercisable 8 years      
Weighted-average Exercise price, exercisable $ 16.07      
2005 Equity Incentive Plan [Member]        
Number of options outstanding 260,000 316,400 316,760 328,560
Weighted-average Exercise price $ 12.94 $ 14.15 $ 14.31 $ 14.57
Number of options exercisable 260,000      
2005 Equity Incentive Plan [Member] | Range One [Member]        
Range of exercise price, lower limit $ 3.25      
Range of exercise price, upper limit $ 3.25      
Number of options outstanding 120,000      
Weighted-average Remaining life in years 1 month 6 days      
Weighted-average Exercise price $ 3.25      
Number of options exercisable 120,000      
Weighted-average Remaining life in years, exercisable 1 month 6 days      
Weighted-average Exercise price, exercisable $ 3.25      
2005 Equity Incentive Plan [Member] | Range Two [Member]        
Range of exercise price, lower limit 11.50      
Range of exercise price, upper limit $ 30.50      
Number of options outstanding 136,100      
Weighted-average Remaining life in years 4 years 1 month 6 days      
Weighted-average Exercise price $ 18.48      
Number of options exercisable 136,100      
Weighted-average Remaining life in years, exercisable 4 years 1 month 6 days      
Weighted-average Exercise price, exercisable $ 18.48      
2005 Equity Incentive Plan [Member] | Range Three [Member]        
Range of exercise price, lower limit 113.50      
Range of exercise price, upper limit $ 122.50      
Number of options outstanding 3,900      
Weighted-average Remaining life in years 10 months 25 days      
Weighted-average Exercise price $ 117.65      
Number of options exercisable 3,900      
Weighted-average Remaining life in years, exercisable 10 months 25 days      
Weighted-average Exercise price, exercisable $ 117.65