Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Share-Based Compensation - Summary of Number of Options Outstanding and Weighted-average Exercise Price (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Compensation Related Costs [Abstract]    
Number of Shares, Options outstanding Beginning Balance 665,219  
Number of Shares, Granted 442,500  
Number of Shares, Exercised (15,395)  
Number of Shares, Forfeited (1,086)  
Number of Shares, Options outstanding Ending Balance 1,091,238 665,219
Number of Shares, Exercisable at March 31, 2019 (unaudited) 106,325  
Weighted Average Exercise Price, Options outstanding Beginning Balance $ 9.31  
Weighted Average Exercise Price, Granted 5.82  
Weighted Average Exercise Price, Exercised 3.16  
Weighted Average Exercise Price, Forfeited 9.44  
Weighted Average Exercise Price, Options outstanding Ending Balance 7.98 $ 9.31
Weighted Average Exercise Price, Exercisable at March 31, 2019 (unaudited) $ 4.59  
Weighted Average Remaining Contractual Life in Years, Options outstanding 9 years 3 months 7 days 8 years 11 months 4 days
Weighted Average Remaining Contractual Life in Years, Exercisable at March 31, 2019 (unaudited) 8 years 3 months  
Aggregate Intrinsic Value, Options outstanding $ 395  
Aggregate Intrinsic Value, Options outstanding 1,956 $ 395
Aggregate Intrinsic Value, Exercisable at March 31, 2019 (unaudited) $ 425