SUPPLEMENTAL FINANCIAL INFORMATION - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Supplemental Financial Information [Abstract]
Research and development service agreements, current	$ 4,024	$ 4,841
Research and development service agreements, noncurrent	50	75
Research and development service agreements	4,074	4,916
Other receivables	315	345
Dues and subscriptions	247	230
Prepaid insurance	169	858
Right-of-use asset	$ 205	$ 266
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets, long-term	Other assets, long-term
Property and equipment, net	$ 130	$ 73
Other, current	280	475
Other, noncurrent	79	72
Other	359	547
Prepaid expenses and other current assets	5,035	6,749
Other assets, long-term	464	486
Total	5,499	7,235
Accumulated depreciation, property and equipment	$ 100	$ 100