UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	45,000,000	45,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Warrants issued	2,173,913	2,173,913
Warrants outstanding	2,173,913	2,173,913
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	22,305,256	22,181,881
Common stock, shares outstanding	22,305,256	22,181,881