Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments - Stock Options (Details)

v3.10.0.1
Stock-Based Payments - Stock Options (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2018
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Shares        
Outstanding at beginning of year (in shares)   2,846,668    
Granted (in shares)   1,358,552    
Exercised (in shares)   (103,153)    
Cancelled (in shares)   (390,917)    
Outstanding at end of period (in shares) 3,711,150 3,711,150   2,846,668
Exercisable (in shares) 1,354,815 1,354,815    
Weighted Average Exercise Price        
Outstanding at beginning of year (in dollars per share)   $ 9.25    
Granted (in dollars per share)   10.90    
Exercised (in dollars per share)   4.73    
Cancelled (in dollars per share)   10.95    
Outstanding at end of period (in dollars per share) $ 9.80 9.80   $ 9.25
Exercisable (in dollars per share) $ 7.50 $ 7.50    
Remaining Contractual Life        
Outstanding   8 years 1 month 6 days   8 years 2 months 12 days
Exercisable   6 years 8 months 12 days    
Aggregate Intrinsic Value        
Outstanding $ 9,358 $ 9,358   $ 5,713
Exercisable 6,505 6,505    
Intrinsic value of options exercised   800 $ 4,100  
Performance-based stock options        
Stock-based payments        
Additional stock-based compensation expense recorded related to achievement of certain performance-based milestones 0 200    
Unrecognized compensation costs 1,100 $ 1,100    
Period in which compensation costs will be recognized   4 years 4 days    
Performance-based stock options | Advisor        
Stock-based payments        
Unrecognized compensation costs $ 700 $ 700    
Period in which compensation costs will be recognized   7 years 11 months 12 days    
Shares        
Outstanding at end of period (in shares) 75,000 75,000