Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of Activity under Stock Option Plan and Related Information (Details)

v3.19.1
Stock-Based Compensation - Summary of Activity under Stock Option Plan and Related Information (Details)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Number of options outstanding, Outstanding, Beginning balance | shares 2,181,466  
Number of options outstanding, Options granted | shares 578,000  
Number of options outstanding, Options exercised | shares (4,000)  
Number of options outstanding, Outstanding, Ending balance | shares 2,755,466 2,181,466
Number of options outstanding, options vested and exercisable | shares 1,104,476  
Weighted average exercise price, Outstanding, Beginning balance | $ / shares $ 3.80  
Weighted average exercise price, Options granted | $ / shares 22.50  
Weighted average exercise price, Options exercised | $ / shares 0.90  
Weighted average exercise price, Outstanding, Ending balance | $ / shares 7.73 $ 3.80
Weighted average exercise price, options vested and exercisable | $ / shares $ 2.93  
Weighted average remaining contractual term, Outstanding, Beginning balance 8 years 8 months 12 days 8 years 8 months 12 days
Weighted average remaining contractual term,options vested and exercisable 7 years 10 months 24 days  
Aggregate intrinsic value, Outstanding, Beginning balance | $ $ 43,189  
Aggregate intrinsic value, Options exercised | $ 78  
Aggregate intrinsic value, Outstanding, Ending balance | $ 30,395 $ 43,189
Aggregate intrinsic value, options vested and exercisable | $ $ 16,468