Organization and Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended				12 Months Ended
	Feb. 08, 2018	Nov. 03, 2017	May 21, 2017	Jul. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Jun. 13, 2017	Dec. 31, 2015
Organization and Nature of Operations [Line Items]
Cash							$ 5,965	$ 9,375		$ 8,854
Stock issued during period, shares, new issues				588,235	588,235
Stock issued during period, value, new issues							3,567	$ 4,388
Proceeds from issuance initial public offering					$ 9,300
Proceeds from Warrant Exercises			$ 1,500
Class Of Warrant Or Right Exercisable Number			441,176
Stockholders' Equity, Reverse Stock Split	1-for-10
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements							(175)
Class Of Warrant Or Right Exercised Number			11,176
New Warrants [Member]
Organization and Nature of Operations [Line Items]
Proceeds from Warrant Exercises			$ 1,500
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 6.00
Warrants 2016 [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights									127,941
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements							200
Extinguishment of Debt, Amount							400
Warrants2014 [Member]
Organization and Nature of Operations [Line Items]
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings							$ 1,000
Reduced Exercise Price [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right			3.80
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 3.80
Class Of Warrant Or Right Exercised Number			430,000
Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues				294,118	294,118
Stock issued during period, value, new issues					$ 10,000	$ 25,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			250,000
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 23.00
2016 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Debt Issuance Costs, Net					$ 300
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					25,000
Registered Direct Offering 2017 [Member]
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
Proceeds from issuance initial public offering		$ 3,600
Registered Direct Offering 2017 [Member] | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		666,667
Roth Capital Partners, Llc [Member] | Registered Direct Offering 2017 [Member] | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		16,000