Net Loss per Share - Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share, amount	3,915,539	6,978,078
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share, amount		5,005,934
Restricted Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share, amount	653,174	105,913
Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share, amount	3,262,365	938,637
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earning per share, amount		927,594