Nature of Operations (Details) - USD ($)			9 Months Ended
	Apr. 21, 2017	Oct. 06, 2015	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Issuance of Common Stock [Abstract]
Common stock, par value (in dollars per share)			$ 0.00033		$ 0.00033
Common Stock issued upon conversion of preferred stock (in shares)		18,566,856
Proceeds from issuance of common stock, net of issuance costs			$ 17,382,943	$ 0
IPO [Member]
Issuance of Common Stock [Abstract]
Shares of common stock sold (in shares)		8,412,423
Common stock, par value (in dollars per share)		$ 0.00033
Sales price per share (in dollars per share)		$ 11.00
Gross proceeds from issuance of common stock		$ 92,500,000
Proceeds from issuance of common stock, net of issuance costs		$ 82,800,000
Subscription Agreement [Member]
Issuance of Common Stock [Abstract]
Shares of common stock sold (in shares)	1,800,000
Sales price per share (in dollars per share)	$ 10.00
Proceeds from issuance of common stock, net of issuance costs	$ 17,382,943