Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($)		12 Months Ended
	Jan. 11, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Accumulated deficit		$ 191,338,054	$ 178,478,801
Cash and cash equivalents		4,043,681	$ 3,949,135	$ 12,462,872
2017 Offerings
Organization And Basis Of Presentation [Line Items]
Gross proceeds from issuance of equity		14,000,000
Net proceed from offering common stock and warrants		$ 12,900,000
Subsequent Event | Market Technology, Patents, and Related Assets
Organization And Basis Of Presentation [Line Items]
Proceeds from asset purchase agreement	$ 5,000,000
Contingent payments (up to)	$ 21,500,000