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Note 10 - Segment Information (Details Textual) gal in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 gal | Mar. 31, 2022 | Dec. 31, 2022
Number of Reportable Segments | 3 |  |
California Ethanol [Member] |  |  |
GallonPerYear (Gallon) | 65 |  |
California Ethanol [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Ethanol Sales [Member] |  |  |
Number of Major Customers | 1 | 2 |
California Ethanol [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Ethanol Sales [Member] | Customer One [Member] |  |  |
Concentration Risk, Percentage | 77.00% | 73.00% |
California Ethanol [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Ethanol Sales [Member] | Customer Two [Member] |  |  |
Concentration Risk, Percentage |  | 27.00% |
India Biodiesel [Member] |  |  |
GallonPerYear (Gallon) | 50 |  |
India Biodiesel [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Biodiesel Sales [Member] |  |  |
Number of Major Customers | 1 |  | 3
India Biodiesel [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Biodiesel Sales [Member] | Customer One [Member] |  |  |
Concentration Risk, Percentage | 80.00% |  |
Dairy Renewable Natural Gas [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Sales of Biogas [Member] |  |  |
Number of Major Customers | 1 |  |
Dairy Renewable Natural Gas [Member] | Customer Concentration Risk [Member] | Revenue, Segment Benchmark [Member] | Sales of Biogas [Member] | Customer One [Member] |  |  |
Concentration Risk, Percentage | 100.00% |  |

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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-42 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-21 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-20 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482861/275-10-50-18 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482861/275-10-50-20 + Details
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