Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details) - USD ($)
$ / shares in Units, $ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Compensation Related Costs [Abstract]    
Number of Shares, Options outstanding Beginning Balance 665,219  
Number of Shares, Granted 512,178  
Number of Shares, Exercised (18,232)  
Number of Shares, Forfeited (1,086)  
Number of Shares, Options outstanding Ending Balance 1,158,079 665,219
Number of Shares, Exercisable at June 30, 2019 (unaudited) 232,530  
Weighted Average Exercise Price, Options outstanding Beginning Balance $ 9.31  
Weighted Average Exercise Price, Granted 5.94  
Weighted Average Exercise Price, Exercised 3.29  
Weighted Average Exercise Price, Forfeited 9.44  
Weighted Average Exercise Price, Options outstanding Ending Balance 7.92 $ 9.31
Weighted Average Exercise Price, Exercisable at June 30, 2019 (unaudited) $ 8.66  
Weighted Average Remaining Contractual Life in Years, Options outstanding 9 years 1 month 6 days 8 years 11 months 4 days
Weighted Average Remaining Contractual Life in Years, Exercisable at June 30,2019 (unaudited) 8 years 5 months 23 days  
Aggregate Intrinsic Value, Options outstanding $ 395  
Aggregate Intrinsic Value, Options outstanding 1,245 $ 395
Aggregate Intrinsic Value, Exercisable at June 30,2019 (unaudited) $ 372