CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Total operating revenues	$ 5,260	$ 4,238	$ 9,250	$ 8,298
Operating expenses:
Cost of production	3,423	1,931	6,010	6,356
Depreciation and amortization	4,277	4,754	8,728	9,329
Research and development expense	1,641	1,960	3,189	3,158
General and administrative expense	11,513	10,608	23,663	21,369
Project development costs	7,736	2,887	13,055	5,846
Facility idling costs	699	1,013	1,775	2,012
Total operating expenses	29,289	23,153	56,420	48,070
Loss from operations	(24,029)	(18,915)	(47,170)	(39,772)
Other income (expense)
Interest expense	(1,113)	(536)	(1,655)	(1,075)
Interest and investment income	4,143	5,038	8,736	8,822
Other income (expense), net	(3)	(7)	212	(13)
Total other income, net	3,027	4,495	7,293	7,734
Net loss	$ (21,002)	$ (14,420)	$ (39,877)	$ (32,038)
Net loss per share - basic (in dollars per share)	$ (0.09)	$ (0.06)	$ (0.17)	$ (0.13)
Net loss per share - diluted (in dollars per share)	$ (0.09)	$ (0.06)	$ (0.17)	$ (0.13)
Weighted-average number of common shares outstanding - basic (in shares)	239,014,435	237,417,618	239,929,385	237,339,583
Weighted-average number of common shares outstanding - diluted (in shares)	239,014,435	237,417,618	239,929,385	237,339,583