Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	25,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	175,000,000	95,000,000
Common stock, shares issued	22,734,333	1,294,352
Common stock, shares outstanding	22,734,333	1,294,352
Series A-1 convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	0	25,085,153
Convertible preferred stock, shares issued	0	25,085,153
Convertible preferred stock, shares outstanding	0	25,085,153
Series B-1 convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	0	32,936,919
Convertible preferred stock, shares issued	0	32,936,919
Convertible preferred stock, shares outstanding	0	32,936,919
Series C-1 convertible preferred stock
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	0	14,674,062
Convertible preferred stock, shares issued	0	14,674,062
Convertible preferred stock, shares outstanding	0	14,674,062