Note 1 - Business and Organization (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Number of Wholly-Owned Subsidiaries	5		5
Revenue from Contract with Customer, Including Assessed Tax	$ 1,103,000	$ 4,351,000	$ 7,148,000	$ 14,122,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(7,244,000)	$ (1,060,000)	(11,047,000)	(2,615,000)
Provision for Loan, Lease, and Other Losses			3,849,000
Cash Provided by (Used in) Operating Activity, Discontinued Operation			(6,707,000)
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation			7,269,000	$ 2,846,000
Assets, Current	5,775,000		5,775,000		$ 7,137,000
Cash and Cash Equivalent	4,546,000		4,546,000		3,548,000
Liabilities, Current	3,451,000		3,451,000		$ 2,648,000
Working Capital (Deficit)	$ 2,324,000		$ 2,324,000
Clyra Medical Technologies [Member]
Subsidiary, Ownership Percentage, Parent	48.00%		48.00%
BLEST [Member]
Subsidiary, Ownership Percentage, Parent	74.00%		74.00%
BioLargo Energy Technologies, Inc (BETI) [Member]
Subsidiary, Ownership Percentage, Parent	96.00%		96.00%