Organization and Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended									12 Months Ended
	Mar. 12, 2019	Jan. 14, 2019	Nov. 03, 2017	Jan. 31, 2019	Jan. 18, 2019	Jan. 17, 2019	Sep. 20, 2018	Nov. 30, 2017	May 31, 2017	May 21, 2017	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2017
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues											29,412
Stock issued during period, value, new issues													$ 1,180	$ 3,567
Proceeds from Issuance of Common Stock	$ 17,000												$ 1,180	3,567
Class Of Warrant Or Right Exercisable Number									22,059	22,059
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements														$ (175)
Class Of Warrant Or Right Exercised Number									559	559
Common Stock, Shares, Issued													680	567
Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues					648,233
Stock issued during period, value, new issues					$ 1,700
Proceeds from Issuance of Common Stock	$ 17,000	$ 900		$ 900	$ 1,500
Stockholders' Equity, Reverse Stock Split					1-for-20	common stock at a ratio of 1-for-20, and our common stock began trading on the split-adjusted basis on the Nasdaq Capital Market at the commencement of trading on January 18, 2019. All common stock share and per share amounts in our consolidated financial statements have been adjusted to give effect to the 1-for-20 reverse stock split.
New Warrants [Member]
Organization and Nature of Operations [Line Items]
Proceeds from Issuance of Common Stock									$ 1,500
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 120.00	$ 120.00
Class Of Warrant Or Right Terms									5 years
Warrants 2016 [Member]
Organization and Nature of Operations [Line Items]
Proceeds from Issuance of Common Stock							$ 1,200
Class of Warrant or Right, Number of Securities Called by Warrants or Rights															6,398
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, Exercise Price of Warrants or Rights									$ 76.00	$ 76.00
Class Of Warrant Or Right Exercised Number									21,500	21,500
Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues											14,706
Stock issued during period, value, new issues											$ 10,000	$ 25,000
Proceeds from Issuance of Common Stock							$ 1,200
Class of Warrant or Right, Number of Securities Called by Warrants or Rights										12,500
Warrant | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues	712,910
Stock issued during period, value, new issues	$ 18,500
Warrants issued	42,775
Series A Warrants [Member] | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights					324,117
HC Wainwright LLC [Member] | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Shares Issued, Price Per Share		$ 2.418
Common Stock [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues													113,000	67,000
Stock issued during period, value, new issues													$ 0	$ 1
Common Stock [Member] | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues					38,894
2016 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights											1,250
Registered Direct Offering 2017 [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues			66,667					66,667
Stock issued during period, value, new issues			$ 4,000					$ 4,000
Proceeds from Issuance of Common Stock								$ 3,600
Registered Direct Offering 2017 [Member] | Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues			33,334					33,334
2018 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues							98,454
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							14,624
Private Placement [Member] | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Common Stock, Shares, Issued		25,777
Private Placement [Member] | Series A Warrants [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues							113,077
IPO [Member] | Subsequent Event [Member]
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues	712,910	429,616
Stock issued during period, value, new issues	$ 18,500
Proceeds from Issuance of Common Stock		$ 1,100
Shares Issued, Price Per Share		$ 2.60
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			800					800
HC Wainwright Co [Member] | 2018 Registered Direct Offering
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues							6,785