Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Details) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Numerator: | |||
| Net loss attributable to ordinary shareholders | $ (50,384,176) | $ (37,512,212) | $ (18,021,737) |
| Denominator: | |||
| Weighted average number of ordinary shares- basic and diluted | 21,752,757 | 9,439,028 | 8,693,655 |
| Net loss per share-basic and diluted | $ (2.32) | $ (3.97) | $ (2.07) |