Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				12 Months Ended
	Nov. 03, 2017	May 21, 2017	Jul. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Shareholders Equity [Line Items]
Common stock and warrants issued, Value			$ 10,000
Common Stock, shares issued						11,339	9,564
Stock Issued During Period Shares New Issues			588,235	588,235
Stock Issued During Period, Value, New Issues						$ 3,567	$ 4,388
Stockholders Equity						$ 8,067	$ 8,240	$ 9,818
Proceeds from Issuance Initial Public Offering				$ 9,300
ClassOfWarrantOrRightExercisableNumber		441,176
Class Of Warrant Or Right Exercised Number		11,176
Proceeds from Warrant Exercises		$ 1,500
New Warrants [Member]
Shareholders Equity [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 6.00
Proceeds from Warrant Exercises		$ 1,500
Reduced Exercise Price [Member]
Shareholders Equity [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 3.80
Class Of Warrant Or Right Exercised Number		430,000
Registered Direct Offering 2017 [Member]
Shareholders Equity [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
Warrant
Shareholders Equity [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 23.00
Stock Issued During Period Shares New Issues			294,118	294,118
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		250,000
Stock Issued During Period, Value, New Issues				$ 10,000	$ 25,000
Warrant | Registered Direct Offering 2017 [Member]
Shareholders Equity [Line Items]
Stock Issued During Period Shares New Issues	666,667
Roth Capital Partners, Llc [Member] | Warrant | Registered Direct Offering 2017 [Member]
Shareholders Equity [Line Items]
Stock Issued During Period Shares New Issues	16,000
Placement Agent
Shareholders Equity [Line Items]
Common stock and warrant issued, shares			25,000