Prepaid Expenses and Other (Detail) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Prepaid Expenses and Other
Unamortized commercial insurance	$ 1,311,000	$ 502,000
Deposits	453,000	1,162,000
Other	183,000	54,000
Total prepaid expenses and other	$ 1,947,000	$ 1,718,000