SEGMENT REPORTING - Schedule of Segment Revenue, Segment Profit or Loss, and Significant Segment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Revenue	$ 259,432	$ 200,581	$ 494,480	$ 373,321
Cost of revenue	(531,783)	(470,355)	(995,343)	(875,151)
Research and development expenses	(273,839)	(287,170)	(525,085)	(571,797)
Selling, general, and administrative expenses	(256,857)	(210,245)	(469,032)	(423,477)
Restructuring charges	0	(20,228)	0	(20,228)
Change in fair value of common stock warrant liability	5,322	7,539	18,183	34,593
Change in fair value of equity securities	3,948	(9,390)	(9,505)	(29,323)
Change in fair value of derivative liabilities associated with redeemable convertible preferred stock (related party)			393,175	103,000
Gain on extinguishment of debt	116,360	0	116,360	0
Interest income	44,318	54,553	96,527	105,184
Interest expense	(23,749)	(6,673)	(35,632)	(14,174)
Other income (expense), net	3,572	(5,067)	6,537	(6,074)
Benefit from (provision for) income taxes	2,369	65	3,732	(123)
Net loss	(539,432)	(643,390)	(905,603)	(1,324,249)
Reportable Segment
Segment Reporting Information [Line Items]
Revenue	259,432	200,581	494,480	373,321
Research and development expenses	(273,839)	(287,170)	(525,085)	(571,797)
Selling, general, and administrative expenses	(256,857)	(210,245)	(469,032)	(423,477)
Restructuring charges	0	(20,228)	0	(20,228)
Change in fair value of common stock warrant liability	5,322	7,539	18,183	34,593
Change in fair value of equity securities	3,948	(9,390)	(9,505)	(29,323)
Change in fair value of derivative liabilities associated with redeemable convertible preferred stock (related party)	111,475	103,000	393,175	103,000
Gain on extinguishment of debt	116,360	0	116,360	0
Interest income	44,318	54,553	96,527	105,184
Interest expense	(23,749)	(6,673)	(35,632)	(14,174)
Other income (expense), net	3,572	(5,067)	6,537	(6,074)
Benefit from (provision for) income taxes	2,369	65	3,732	(123)
Net loss	(539,432)	(643,390)	(905,603)	(1,324,249)
Reportable Segment | Cost of revenue - excluding LCNRV and provision for warranty
Segment Reporting Information [Line Items]
Cost of revenue	(332,144)	(268,036)	(631,756)	(514,856)
Reportable Segment | Cost of revenue - LCNRV
Segment Reporting Information [Line Items]
Cost of revenue	(184,679)	(154,168)	(336,315)	(291,989)
Reportable Segment | Cost of revenue - provision for warranty
Segment Reporting Information [Line Items]
Cost of revenue	$ (14,960)	$ (48,151)	$ (27,272)	$ (68,306)