ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Significant Expense Categories (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Revenue	$ 0			$ 0			$ 1,300,000	$ 100,000
Research and development expense
Total research and development expense	(28,535,000)			(38,893,000)			(87,679,000)	(170,376,000)
General and administrative expense
Total general and administrative expense	(5,277,000)			(7,904,000)			(17,723,000)	(111,244,000)
Other income (expense)	(46,000)			41,000			(342,000)	15,000
Provision for income taxes	0			0			(2,000)	(2,000)
Net income (loss)	(35,256,000)	$ (28,654,000)	$ (43,311,000)	(43,864,000)	$ 1,858,011,000	$ (78,710,000)	(107,221,000)	1,735,437,000
Reportable Segment
Segment Reporting Information [Line Items]
Revenue	0			0			1,300,000	100,000
Research and development expense
Clinical trials	(11,853,000)			(11,691,000)			(29,200,000)	(39,339,000)
Personnel	(8,801,000)			(10,010,000)			(26,764,000)	(62,454,000)
Contract manufacturing	(1,892,000)			(10,417,000)			(14,270,000)	(46,911,000)
Equipment, depreciation, and facility	(2,536,000)			(2,583,000)			(7,682,000)	(7,200,000)
Other research and development	(3,453,000)			(4,192,000)			(9,763,000)	(14,472,000)
General and administrative expense
Merger-related	0			0			0	(68,061,000)
Personnel	(3,402,000)			(3,854,000)			(10,834,000)	(29,353,000)
Other general and administrative	(1,875,000)			(4,050,000)			(6,889,000)	(13,830,000)
Other income (expense)	(1,444,000)			2,933,000			(3,117,000)	2,016,959,000
Provision for income taxes	0			0			(2,000)	(2,000)
Net income (loss)	$ (35,256,000)			$ (43,864,000)			$ (107,221,000)	$ 1,735,437,000