Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments - Summary of Status of Stock Options and Changes During the Period (Details)

v3.19.2
Stock-Based Payments - Summary of Status of Stock Options and Changes During the Period (Details)
$ / shares in Units, $ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Outstanding at beginning of year (in shares) | shares 3,732,643  
Granted and outstanding (in shares) | shares 1,096,500  
Exercised (in shares) | shares (2,300)  
Cancelled (in shares) | shares (85,843)  
Outstanding at end of period (in shares) | shares 4,741,000 3,732,643
Exercisable (in shares) | shares 1,919,931  
Outstanding at beginning of year (in dollars per share) | $ / shares $ 9.88  
Granted (in dollars per share) | $ / shares 6.73  
Exercised (in dollars per share) | $ / shares 2.93  
Cancelled (in dollars per share) | $ / shares 11.38  
Outstanding at end of period (in dollars per share) | $ / shares 9.12 $ 9.88
Exercisable (in dollars per share) | $ / shares $ 8.97  
Remaining Contractual Life, Outstanding 8 years 7 years 10 months 24 days
Remaining Contractual Life, Exercisable 6 years 10 months 24 days  
Aggregate Intrinsic Value, Outstanding | $ $ 6,966 $ 1,694
Aggregate Intrinsic Value, Options Exercisable | $ $ 3,601