Organization and Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				3 Months Ended		9 Months Ended
	Nov. 03, 2017	Sep. 20, 2018	May 21, 2017	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jun. 13, 2017	Dec. 31, 2016
Organization and Nature of Operations [Line Items]
Cash						$ 2,286	$ 4,623	$ 2,286	$ 4,623	$ 5,965		$ 9,375
Stock issued during period, shares, new issues				588,235
Proceeds from issuance initial public offering				$ 9,300
Proceeds from Warrant Exercises			$ 1,500
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				25,000
Class of Warrant or Right, Exercisable, Number			441,176
Class of Warrant or Right, Exercised, Number			11,176
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings								400
Gain (Loss) on Extinguishment of Debt						$ 0	$ 0	0	$ 440
Reclassified to equity								200
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings								$ 1,000
Stockholders' Equity, Reverse Stock Split								1-for-10
Reduced Exercise Price [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Exercised, Number			430,000
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 3.80
New Warrants [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 6.00
Class of Warrant or Right, Terms			5 years
Warrants 2016 [Member]
Organization and Nature of Operations [Line Items]
Proceeds from issuance initial public offering		$ 1,200
Class of Warrant or Right, Number of Securities Called by Warrants or Rights											127,941
Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues				294,118
Stock issued during period, value, new issues				$ 10,000	$ 25,000
Proceeds from issuance initial public offering	$ 3,600
2016 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Proceeds from issuance initial public offering				$ 300
2017 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues	1,333,333
Stock issued during period, value, new issues	$ 4,000
2017 Registered Direct Offering | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues	666,667
2018 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		1,969,077
Stock issued during period, value, new issues		$ 1,500
2018 Registered Direct Offering | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		292,461
Private Placement [Member] | Series A warrants [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		2,261,538
Roth Capital Partners, Llc [Member] | 2017 Registered Direct Offering | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues	16,000
HC Wainwright Co [Member] | 2018 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		135,692