Equity - Summary of Stock-Based Compensation Expense (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense at December 31, 2019	$ 119,000
Weighted average remaining years to vest	6 months 7 days
Research and Development Expenses [Member] | Stock Based Compensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	$ 59,000
General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	293,000	$ 88,000
General and Administrative Expenses [Member] | Common Stock Issued for Services [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	80,000	60,000
General and Administrative Expenses [Member] | Stock Based Compensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	$ 154,000	$ 28,000