Subsequent Events - Additional Information (Detail) - $ / shares	Jan. 16, 2019	Apr. 01, 2019	Dec. 31, 2018	Dec. 16, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Common stock, shares outstanding			3,530,150	3,530,150	0
Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock, shares outstanding		3,530,250
IPO | Subsequent Event [Member]
Subsequent Event [Line Items]
Initial public offering/conversion, shares	100
Common stock, per share	$ 10.00