Description of Business and Basis of Presentation - Additional Information (Detail) - USD ($)	12 Months Ended		24 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Organization And Basis Of Presentation [Line Items]
Substantial Doubt about Going Concern, within One Year [true false]	true
Net proceed from offering common stock and warrants	$ 15,106	$ 18,618
Accumulated deficit	194,789,605	191,016,591	$ 194,789,605
Cash and cash equivalents	3,126,206	$ 6,780,429	3,126,206
Attainment Of Development Milestone [Member]
Organization And Basis Of Presentation [Line Items]
Proceeds from Collaborators			20.5
Attainment of Commercialization Milestone [Member]
Organization And Basis Of Presentation [Line Items]
Potential Proceeds From Collaborators	$ 4.5		$ 4.5