Net Loss per Share - Schedule of Basic and Diluted Net Loss per Share (Detail) - USD ($)		12 Months Ended
	Jun. 07, 2018	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net loss-basic and diluted		$ (82,865,874)	$ (31,044,535)
Accretion of Preferred Shares financing costs	$ (664,718)	(1,806,512)	(191,963)
Accretion of warrant			(615,000)
Adjusted net loss-basic and diluted		$ (84,672,386)	$ (31,851,498)
Weighted-average ordinary shares outstanding:
Basic and Diluted		18,948,520	8,572,315
Net loss per share:
Basic and Diluted		$ (4.47)	$ (3.72)