Preferred Stock - Additional Information (Detail) - $ / shares	Mar. 31, 2019	Dec. 31, 2018	Mar. 09, 2017
Temporary Equity Disclosure [Abstract]
Preferred stock, shares authorized	10,000,000	10,000,000	10,000,000
Preferred stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0