Quarterly report pursuant to Section 13 or 15(d)

Note 12 - Stockholders' Equity (Tables)

Note 12 - Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2023

Notes Tables

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

		Three Months Ended September 30,								Nine Months Ended September 30,
		2023				2022				2023				2022
Plant operations		$	35			$	27			$	82			$	75
Research and development cost			8				—				48				36
General and administrative expense			551				571				1,750				1,626
Total		$	594			$	598			$	1,880			$	1,737

Share-based Payment Arrangement, Option and Restricted Stock Unit, Activity [Table Text Block]

						Options Outstanding				RSUs Outstanding

		Number of
		Shares
		Available for				Number of				Number of
		Grant				Shares				RSUs
Balances, December 31, 2022			5,262,254				994,267				6,387,937
Granted			(489,569	)			—				489,569
Exercised/ Released			—				—				(2,568,621	)
Expired inducement grant			—				(840,000	)			—
Forfeited			187,550				(41,072	)			(146,478	)
Returned to Plan			947,418				—				947,418
Balances, September 30, 2023			5,907,653				113,195				5,109,825