Stockholders' Equity - Summary of Stock Based Compensation Expense (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock compensation expense	$ 825,000	$ 1,300,000
Continuing Operations [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock compensation expense	825,000	1,187,000
Research and Development [Member] | Continuing Operations [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock compensation expense	158,000	205,000
General and Administrative [Member] | Continuing Operations [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock compensation expense	$ 667,000	$ 982,000