Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts payable to related parties	$ 37	$ 32
Preferred stock, shares authorized		20,320,667
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	30,000,000
Common stock, shares issued	28,048,315	5,659,089
Common stock, shares outstanding	28,048,315	5,659,089
Common stock, shares vested	28,046,815	4,562,640
Series A Redeemable Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	15,527,951
Preferred stock, shares issued	0	15,527,951
Preferred stock, shares outstanding	0	15,527,951
Series B Redeemable Convertible Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	4,792,716
Preferred stock, shares issued	0	4,792,716
Preferred stock, shares outstanding	0	4,792,716