SUPPLEMENTAL FINANCIAL INFORMATION - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Supplemental Financial Information [Abstract]
Research and development service agreements, current	$ 3,103	$ 3,527
Research and development service agreements, noncurrent	24	29
Research and development service agreements	3,127	3,556
Other receivables	772	625
Prepaid insurance	350	601
Dues and subscriptions	315	368
Right-of-use asset	$ 106	$ 140
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other long-term assets	Other long-term assets
Property and equipment, net	$ 91	$ 103
Other, current	156	266
Other, noncurrent	83	78
Other	239	344
Prepaid expenses and other current assets	4,696	5,387
Other long-term assets	304	350
Total	5,000	5,737
Accumulated depreciation, property and equipment	$ 200	$ 200