Prepaid Expenses and Other (Detail) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Prepaid Expenses and Other
Unamortized commercial insurance premiums	$ 856,000	$ 465,000
Deposits	365,000	884,000
Professional fees	83,000	235,000
Clinical trial inventory		72,000
Other	70,000	84,000
Total prepaid expenses and other	$ 1,374,000	$ 1,740,000