Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details)

v3.19.1
Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Compensation Related Costs [Abstract]      
Number of Shares, Options outstanding Beginning Balance 248,128 49,330  
Number of Shares, Granted 479,986 198,798  
Number of Shares, Exercised (2,008)    
Number of Shares, Forfeited (60,887)    
Number of Shares, Options outstanding Ending Balance 665,219 248,128 49,330
Number of Shares, Exercisable at December 31, 2018 98,406    
Weighted Average Exercise Price, Options outstanding Beginning Balance $ 3.31 $ 3.14  
Weighted Average Exercise Price, Granted 12.60 3.36  
Weighted Average Exercise Price, Options outstanding Ending Balance 9.31 $ 3.31 $ 3.14
Weighted Average Exercise Price, Exercised 3.30    
Weighted Average Exercise Price, Forfeited 10.99    
Weighted Average Exercise Price, Exercisable at December 31, 2018 $ 3.71    
Weighted Average Remaining Contractual Life in Years, Options outstanding 8 years 11 months 4 days 9 years 5 months 8 days 8 years 6 months 3 days
Weighted Average Remaining Contractual Life in Years, Granted 9 years 5 months 12 days 9 years 8 months 1 day  
Weighted Average Remaining Contractual Life in Years, Exercisable at December 31, 2018 7 years 2 months 12 days    
Aggregate Intrinsic Value, Options outstanding $ 395    
Aggregate Intrinsic Value, Exercised 8    
Aggregate Intrinsic Value, Exercisable at December 31, 2018 $ 162