Business and Nature of Operations - Additional Information (Details) - USD ($)		1 Months Ended	9 Months Ended	12 Months Ended
	Sep. 21, 2016	Apr. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Business And Nature Of Operations [Line Items]
Common stock, par value			$ 0.001	$ 0.001
Common shares sold pursuant to exercise of employee stock option			370,084	163,968
IPO
Business And Nature Of Operations [Line Items]
Issuance of common stock, public offering, net of issuance costs, shares	6,250,000
Common stock, par value	$ 12.00
Proceeds from issuance of initial public offering gross	$ 66,100,000
Follow-On Public Offering [Member]
Business And Nature Of Operations [Line Items]
Issuance of common stock, public offering, net of issuance costs, shares		553,825
Common stock, par value		$ 19.85
Proceeds from issuance of common stock		$ 9,900,000
Underwriter Purchase Option [Member]
Business And Nature Of Operations [Line Items]
Issuance of common stock, public offering, net of issuance costs, shares		26,825
Selling Stockholders [Member]
Business And Nature Of Operations [Line Items]
Issuance of common stock, public offering, net of issuance costs, shares		3,162,164
Common shares sold pursuant to exercise of employee stock option		73,000
Proceeds from issuance of common stock		$ 0