Stockholders' Equity (Details)			3 Months Ended	9 Months Ended
	Aug. 10, 2017 USD ($) $ / shares shares	Aug. 08, 2017 USD ($)	Sep. 30, 2017 $ / shares shares	Sep. 30, 2017 USD ($) Vote $ / shares shares	Dec. 31, 2016 $ / shares shares
Class of Stock [Line Items]
Preferred stock, shares authorized | shares			10,000,000	10,000,000	10,000,000
Preferred stock, shares outstanding | shares			0	0	0
Common stock shares authorized | shares			100,000,000	100,000,000	100,000,000
Common stock par value (in dollars per share) | $ / shares			$ 0.00001	$ 0.00001	$ 0.00001
Number of votes per share | Vote				1
Dividends declared				$ 0
Common stock, shares outstanding | shares			30,834,679	30,834,679	26,059,181
Proceeds from issuance of common stock in connection with private placement, gross				$ 20,003,000
Proceeds from initial public offering, gross	$ 86,270,000	$ 86,270,000
Proceeds from issuance of common stock in connection with public offering, net of issuance costs		80,918,000		80,918,000
Exercise of over-allotment option
Class of Stock [Line Items]
Payments of Stock Issuance Costs		5,176,000
IPO
Class of Stock [Line Items]
Number of shares issued | shares	3,747,602
Issuance of common stock				80,918,000
Share Price | $ / shares	$ 23.02
Payments of Stock Issuance Costs		$ 176,000
Private Placement
Class of Stock [Line Items]
Number of shares issued | shares			0
Issuance of common stock				$ 19,311,000
Common stock, shares outstanding | shares			635,000	635,000
Share Price | $ / shares			$ 31.50	$ 31.50
Payments of Stock Issuance Costs				$ 691,000