SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) obligation	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Revenue, Major Customer [Line Items]
Number of performance obligations | obligation			2
Basic vehicle warranty term			4 years
Revenues	$ 200,581	$ 150,874	$ 373,321	$ 300,306
Electric Vehicle Purchase Agreement | Customer Concentration Risk | Accounts Receivable | Government of Saudi Arabia
Revenue, Major Customer [Line Items]
Concentration risk (as a percent)			76.80%		68.50%
Vehicle Sales with RVG
Revenue, Major Customer [Line Items]
Revenues	118,700	$ 36,800	$ 190,900	$ 55,500
Vehicle Sales with OTA and Remarketing
Revenue, Major Customer [Line Items]
Vehicle Sales primarily with OTA and Remarketing	38,900		38,900		$ 28,700
Vehicle Sales with OTA and Remarketing | Other Current Liabilities
Revenue, Major Customer [Line Items]
Vehicle Sales primarily with OTA and Remarketing	10,900		10,900		7,700
Vehicle Sales with OTA and Remarketing | Other Noncurrent Liabilities
Revenue, Major Customer [Line Items]
Vehicle Sales primarily with OTA and Remarketing	$ 28,000		$ 28,000		$ 21,000