Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation - 2009 Stock Option Plan (Details)

v3.19.1
Stock-based Compensation - 2009 Stock Option Plan (Details) - 2009 Stock Option Plan
12 Months Ended
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expiration period of options 10 years
Minimum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Percentage of exercise price 100.00%
Vesting period of options 3 years
Maximum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Percentage of exercise price 110.00%
Vesting period of options 4 years