Note 8 - Revenues From Contracts With Customers and Other Revenue - Disaggregated Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from Contract with Customer, Including Assessed Tax	$ 533	$ 5,463	$ 24,453
Other revenues	178	73	34
Total revenues	711	5,536	24,487
Transferred at Point in Time [Member]
Revenue from Contract with Customer, Including Assessed Tax	533	5,310	24,453
Other revenues	0	0	0
Total revenues	533	5,310	24,453
Transferred over Time [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	153	0
Other revenues	178	73	34
Total revenues	178	226	34
Ethanol Sales and Related Products [Member]
Revenue from Contract with Customer, Including Assessed Tax	50	3,809	22,115
Other revenues	0	0	0
Total revenues	50	3,809	22,115
Hydrocarbon [Member]
Revenue from Contract with Customer, Including Assessed Tax	483	1,501	2,338
Other revenues	0	0	0
Total revenues	483	1,501	2,338
Grant and Other [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	153	0
Other revenues	178	73	34
Total revenues	$ 178	$ 226	$ 34