Prepaid Expenses and Other Assets (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Prepaid Expenses and Other Assets
Prepaid insurance	$ 453,000	$ 488,000
Current portion of deferred offering costs		45,000
Recoupable deposits and other	581,000	609,000
Prepaid expenses and other assets	1,034,000	1,142,000
Receivables for reimbursement of costs	$ 50,000	$ 74,000