Summarized Quarterly Data (Unaudited) - Summarized Quarterly Data (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Research and development expense	$ 641,541	$ 822,444	$ 1,205,599	$ 746,882	$ 695,360	$ 625,497	$ 1,388,791	$ 1,385,366	$ 3,416,466	$ 4,095,014
General and administrative expense	782,617	814,218	918,139	1,223,013	1,073,061	897,060	917,305	1,032,245	3,737,987	3,919,671
Gain from change in fair value of warrant liability								433,392		433,392
Net loss	$ (1,418,228)	$ (1,628,065)	$ (2,114,096)	$ (1,965,266)	$ (1,760,633)	$ (1,519,468)	$ (2,303,193)	$ (1,982,786)	$ (7,125,655)	$ (7,566,080)
Net loss per share of common stock, basic and diluted	$ (0.06)	$ (0.07)	$ (0.09)	$ (0.11)	$ (0.10)	$ (0.09)	$ (0.14)	$ (0.13)	$ (0.32)	$ (0.46)
Weighted average shares outstanding, basic and diluted	24,313,411	24,128,060	23,258,567	17,484,318	17,427,533	17,129,649	16,425,468	15,427,037	22,296,089	16,602,422