Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Stock Option Activity (Details)

v3.19.1
Stock-Based Compensation - Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Number of Options Outstanding      
Options exercised (shares) 547,820 464,600  
Stock options      
Number of Options Outstanding      
Outstanding, beginning (shares) 2,341,340 1,607,346  
Options granted (shares) 376,667 898,334  
Options exercised (shares) 224,400 141,840  
Options forfeited (shares) 6,961 22,500  
Outstanding, ending (shares) 2,486,646 2,341,340 1,607,346
Outstanding, Exercisable (shares) 1,450,458    
Weighted Average Exercise Price      
Beginning balance (in dollars per share) $ 1.77 $ 0.83  
Options granted (in dollars per share) 2.41 2.13  
Options exercised (in dollars per share) 1.59 1.60  
Options forfeited (in dollars per share) 1.42 1.78  
Ending balance (in dollars per share) 1.89 $ 1.77 $ 0.83
Exercisable (in dollars per share) $ 1.66    
Average Remaining Contractual Life (in years) 7 years 4 days 5 years 9 months 10 days 7 years 25 days
Average Remaining Contractual Life, Exercisable (in years) 5 years 8 months 12 days    
Aggregate Intrinsic Value, Outstanding $ 1,550 $ 1,087 $ 0
Aggregate Intrinsic Value, Exercisable $ 1,235