Condensed consolidated balance sheets (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Common stock, par value	$ 0.000001	$ 0.000001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	28,140,243	23,537,368
Common stock, shares outstanding	28,140,243	23,537,368
Preferred stock, par value	$ 0.000001
Preferred stock, shares authorized	5,000,000
Preferred stock, shares issued	101,927	0
Preferred stock, shares outstanding	101,927	0
Non-voting convertible preferred stock [Member]
Preferred stock, par value	$ 0.000001	$ 0.000001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	101,927	0
Preferred stock, shares outstanding	101,927	0