v3.26.1
Note 12 - Business Segment Information - Segment Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Revenue from Contract with Customer, Including Assessed Tax $ 7,765,000 $ 17,779,000
Research and development (2,593,000) (2,882,000)
Operating income (loss) (14,855,000) (4,331,000)
Depreciation (145,000) (155,000)
Stock option expense (2,965,000) (2,063,000)
Interest income (expense) (340,000) (33,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (15,189,000) (4,347,000)
Tangible assets 6,945,000 9,056,000
Operating lease right-of-use 1,028,000 992,000
Finance lease right-of-use 338,000 451,000
Total 8,311,000 10,513,000
Tangible assets 6,945,000 9,056,000
Investment in South Korean joint venture 0 14,000
Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   14,000
Operating Segments [Member] | Odor-No-More [Member]    
Revenue from Contract with Customer, Including Assessed Tax 5,905,000 15,597,000
Operating income (loss) (2,317,000) 5,920,000
Depreciation (41,000) (33,000)
Interest income (expense) 90,000 31,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (2,227,000) 5,951,000
Tangible assets 2,331,000 5,879,000
Operating lease right-of-use 0 0
Finance lease right-of-use 0 0
Total 2,331,000 5,879,000
Tangible assets 2,331,000 5,879,000
Operating Segments [Member] | Odor-No-More [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   0
Operating Segments [Member] | Clyra Segment [Member]    
Revenue from Contract with Customer, Including Assessed Tax 0 0
Research and development (1,168,000) (827,000)
Operating income (loss) (6,065,000) (3,324,000)
Depreciation (9,000) (9,000)
Stock option expense (1,203,000) (528,000)
Interest income (expense) (499,000) (60,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (6,564,000) (3,490,000)
Tangible assets 2,650,000 1,696,000
Operating lease right-of-use 175,000 0
Finance lease right-of-use 338,000 451,000
Total 3,163,000 2,147,000
Tangible assets 2,650,000 1,696,000
Operating Segments [Member] | Clyra Segment [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   0
Operating Segments [Member] | BioLargo Engineering, Science & Technologies, LLC [Member]    
Revenue from Contract with Customer, Including Assessed Tax 2,545,000 3,197,000
Research and development (617,000) (1,158,000)
Operating income (loss) (1,091,000) (1,453,000)
Depreciation (48,000) (71,000)
Interest income (expense) 59,000 0
Tangible assets 1,169,000 790,000
Operating lease right-of-use 615,000 659,000
Finance lease right-of-use 0 0
Total 1,784,000 1,449,000
Tangible assets 1,169,000 790,000
Operating Segments [Member] | BioLargo Engineering, Science & Technologies, LLC [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   0
Operating Segments [Member] | BioLargo Energy Technologies, Inc (BETI) [Member]    
Research and development (274,000) (379,000)
Operating income (loss) (639,000) (642,000)
Depreciation (9,000) 0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (639,000) (642,000)
Tangible assets 4,000 46,000
Operating lease right-of-use 0 0
Finance lease right-of-use 0 0
Total 4,000 46,000
Tangible assets 4,000 46,000
Operating Segments [Member] | BioLargo Energy Technologies, Inc (BETI) [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   0
Operating Segments [Member] | BioLargo Canada [Member]    
Revenue from Contract with Customer, Including Assessed Tax 86,000 72,000
Research and development (440,000) (432,000)
Operating income (loss) (534,000) (532,000)
Interest income (expense) 0 2,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (528,000) (504,000)
Tangible assets 321,000 104,000
Operating lease right-of-use 0 0
Finance lease right-of-use 0 0
Total 321,000 104,000
Tangible assets 321,000 104,000
Operating Segments [Member] | BioLargo Canada [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   0
Operating Segments [Member] | BEST [Member]    
Operating income (loss) (276,000) (273,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (276,000) (273,000)
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]    
Research and development (865,000) (1,173,000)
Operating income (loss) (3,933,000) (4,027,000)
Depreciation (38,000) (42,000)
Stock option expense (1,762,000) (1,535,000)
Interest income (expense) 10,000 (6,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (3,923,000) (4,033,000)
Tangible assets 694,000 775,000
Operating lease right-of-use 238,000 333,000
Finance lease right-of-use 0 0
Total 932,000 1,122,000
Tangible assets 694,000 775,000
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   14,000
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] | BioLargo Engineering, Science & Technologies, LLC [Member]    
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest (1,032,000) (1,356,000)
Consolidation, Eliminations [Member]    
Revenue from Contract with Customer, Including Assessed Tax (771,000) (1,087,000)
Research and development 771,000 1,087,000
Tangible assets (224,000) (234,000)
Operating lease right-of-use 0 0
Finance lease right-of-use 0 0
Total (224,000) (234,000)
Tangible assets $ (224,000) (234,000)
Consolidation, Eliminations [Member] | Investment in South Korean Joint Venture [Member]    
Investment in South Korean joint venture   $ 0