SEGMENT INFORMATION - Schedule of Expenses by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting [Line Items]
Total research and development expense	$ 413,134	$ 323,621	$ 778,000	$ 588,743
Total selling, general and administrative expense	347,922	323,314	670,473	563,263
Single Reportable Segment
Segment Reporting [Line Items]
Total research and development expense	413,134	323,621	778,000	588,743
Total selling, general and administrative expense	347,922	323,314	670,473	563,263
Compensation and related \| Single Reportable Segment
Segment Reporting [Line Items]
Total selling, general and administrative expense	166,619	191,233	329,696	322,670
Consulting and professional services \| Single Reportable Segment
Segment Reporting [Line Items]
Total selling, general and administrative expense	120,721	82,637	225,898	147,324
Occupancy and all other costs \| Single Reportable Segment
Segment Reporting [Line Items]
Total selling, general and administrative expense	60,582	49,444	114,879	93,269
Clinical research and outside services \| Single Reportable Segment
Segment Reporting [Line Items]
Total research and development expense	244,226	140,692	443,483	268,035
Compensation and related \| Single Reportable Segment
Segment Reporting [Line Items]
Total research and development expense	125,390	143,450	249,688	242,637
Occupancy and all other costs \| Single Reportable Segment
Segment Reporting [Line Items]
Total research and development expense	$ 43,518	$ 39,479	$ 84,829	$ 78,071