Organization and Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended
	May 21, 2017	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 13, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization and Nature of Operations [Line Items]
Cash				$ 4,623	$ 11,299	$ 4,623	$ 11,299		$ 9,375	$ 8,854
Stock issued during period, shares, new issues		5,882,352
Proceeds from issuance initial public offering		$ 9,300
Proceeds from Warrant Exercises						1,518	0
Class of Warrant or Right, Exercisable, Number	4,411,764
Class of Warrant or Right, Exercised, Number	111,764
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings						(357)
Gain (Loss) on Extinguishment of Debt				$ 0	$ 0	(440)	$ 0
Reclassified to equity						(175)
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, Exercised, Number	4,300,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.38
New Warrants [Member]
Organization and Nature of Operations [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.60
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								1,279,412
Warrant
Organization and Nature of Operations [Line Items]
Stock issued during period, shares, new issues		2,941,176
Stock issued during period, value, new issues		$ 10,000	$ 25,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	2,500,000
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		250,000