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Related Party Transactions - Statement Of Operations Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Related Party Transaction [Line Items]
General and administrative	$ 13,578	$ 7,787	$ 22,270	$ 14,097
Research and development	26,618	15,483	49,218	26,751
Project development	27,198	869	31,687	1,291
Related Party
Related Party Transaction [Line Items]
General and administrative	42	27	69	52
Research and development	20,846	12,214	39,259	20,827
Project development	19,533	0	19,533	0
Related Party | BHES
Related Party Transaction [Line Items]
Research and development	20,178	11,819	38,005	20,165
Project development	19,533	0	19,533	0
Related Party | Master services agreement administrative costs
Related Party Transaction [Line Items]
General and administrative	42	27	69	52
Related Party | Master services agreement costs for Demonstration Plant
Related Party Transaction [Line Items]
Research and development	$ 668	$ 395	$ 1,254	$ 662

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