Organization and Business - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands			1 Months Ended			3 Months Ended
	Feb. 08, 2018	Nov. 03, 2017	May 21, 2017	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2018	Dec. 31, 2017	Jun. 13, 2017	Mar. 31, 2017	Dec. 31, 2016
Organization and Nature of Operations [Line Items]
Cash						$ 4,284	$ 5,965		$ 7,111	$ 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, 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						400
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]
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]
Debt Issuance Costs, Net				$ 300
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				25,000
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
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