FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Level 1
Financial assets:
Cash and cash equivalents	$ 1,233,300	$ 1,179,297
Restricted cash	1,115	1,860
Level 2
Financial assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Level 3
Financial assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Convertible Notes | Level 1
Financial liabilities:
Debt fair value	1,001,432	880,026
Convertible Notes | Level 2
Financial liabilities:
Debt fair value	0	0
Convertible Notes | Level 3
Financial liabilities:
Debt fair value	0	0
Equipment notes | Level 1
Financial liabilities:
Debt fair value	0	0
Equipment notes | Level 2
Financial liabilities:
Debt fair value	8,817	9,737
Equipment notes | Level 3
Financial liabilities:
Debt fair value	0	0
Offtake Advances | Level 1
Financial liabilities:
Debt fair value		0
Offtake Advances | Level 2
Financial liabilities:
Debt fair value		0
Offtake Advances | Level 3
Financial liabilities:
Debt fair value		16,501
Carrying Amount
Financial assets:
Cash and cash equivalents	1,233,300	1,179,297
Restricted cash	1,115	1,860
Carrying Amount | Convertible Notes
Financial liabilities:
Debt fair value	675,804	674,927
Carrying Amount | Equipment notes
Financial liabilities:
Debt fair value	8,998	9,661
Carrying Amount | Offtake Advances
Financial liabilities:
Debt fair value		16,082
Fair Value
Financial assets:
Cash and cash equivalents	1,233,300	1,179,297
Restricted cash	1,115	1,860
Fair Value | Convertible Notes
Financial liabilities:
Debt fair value	1,001,432	880,026
Fair Value | Equipment notes
Financial liabilities:
Debt fair value	$ 8,817	9,737
Fair Value | Offtake Advances
Financial liabilities:
Debt fair value		$ 16,501