Stockholders' Equity - Summary of Recognized Non-Cash Stock-Based Compensation Expense (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 362,955	$ 344,841	$ 673,117	$ 723,800
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	134,400	202,117	254,962	354,291
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 228,555	$ 142,724	$ 418,155	$ 369,509