Note 1 - Business and Organization (Details Textual)	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Number of Wholly-Owned Subsidiaries	5		5
Revenue from Contract with Customer, Including Assessed Tax	$ 2,777,000	$ 5,014,000	$ 6,046,000	$ 9,773,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(1,882,000)	$ (780,000)	(3,803,000)	(1,555,000)
Cash Provided by (Used in) Operating Activity, Discontinued Operation			(3,948,000)
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation			3,699,000	$ 2,082,000
Assets, Current	9,187,000		9,187,000		$ 7,137,000
Cash and Cash Equivalent	3,471,000		3,471,000		3,548,000
Liabilities, Current	4,080,000		4,080,000		$ 2,648,000
Working Capital (Deficit)	5,107,000		5,107,000
Accounts Receivable, after Allowance for Credit Loss	$ 1,735,000		1,735,000
Conversion of Assets, Contingency, Accounts Receivable to Cash			$ 3,572,000
Clyra Medical Technologies [Member]
Subsidiary, Ownership Percentage, Parent	50.00%		50.00%
BLEST [Member]
Subsidiary, Ownership Percentage, Parent	74.00%		74.00%
BioLargo Energy Technologies, Inc (BETI) [Member]
Subsidiary, Ownership Percentage, Parent	96.00%		96.00%