Organization and Operations (Details) $ / shares in Units, $ in Thousands			1 Months Ended		12 Months Ended
	Oct. 07, 2016 $ / shares shares	Oct. 07, 2016 USD ($) $ / shares shares	Feb. 28, 2018 USD ($)	Sep. 30, 2016	Dec. 31, 2016 USD ($) shares
Organization And Operations
Reverse stock split ratio				0.038
Net proceeds from initial public offering					$ 33,864
Net proceeds from issuance of common stock in private placement					4,650
Convertible promissory notes payable
Organization And Operations
Conversion of convertible promissory notes to common stock (in shares) | shares	1,361,009
Initial Public Offering
Organization And Operations
Issuance of Series B redeemable convertible stock (in shares) | shares		5,000,000
Initial public offering price per share | $ / shares	$ 8.00	$ 8.00
Net proceeds from initial public offering		$ 33,900
Proceeds, net of underwriting discounts and commissions, but before offering costs					33,864
Private Placement
Organization And Operations
Issuance of Series B redeemable convertible stock (in shares) | shares		625,000
Net proceeds from issuance of common stock in private placement		$ 4,700
Proceeds, net of underwriting discounts and commissions, but before offering costs					$ 4,650
Follow-on offering
Organization And Operations
Proceeds, net of underwriting discounts and commissions, but before offering costs			$ 24,800
Redeemable Convertible Preferred Stock
Organization And Operations
Conversion of redeemable convertible preferred stock to common stock (in shares) | shares	2,486,199				(2,486,199)