Note 1 - Business and Organization (Details Textual)	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2017
Number of Wholly-Owned Subsidiaries	5
Number of Partially-Owned Subsidiaries	3
Revenue from Contract with Customer, Including Assessed Tax	$ 4,760,000	$ 3,742,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(775,000)	(494,000)
Net Cash Provided by (Used in) Operating Activities	481,000	(43,000)
Assets, Current	7,176,000		$ 6,362,000
Cash and Cash Equivalents, at Carrying Value	4,336,000		3,539,000
Liabilities, Current	3,404,000		$ 2,710,000
Working Capital (Deficit)	3,772,000
Net Cash Provided by (Used in) Operating Activities	481,000	(43,000)
Stock Issued During Period, Value, New Issues	488,000	800,000
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	52,000	$ 225,000
Conversion of Assets, Contingency, Accounts Receivable to Cash	2,473,000
The 2020 Unit Offering [Member]
Stock Issued During Period, Value, New Issues	228,000
Clyra Medical Common Stock [Member]
Proceeds from Issuance or Sale of Equity	475,000
Lincoln Park Capital Fund, LLC [Member]
Stock Issued During Period, Value, New Issues	$ 260,000
Clyra Medical Technologies [Member]
Subsidiary, Ownership Percentage, Parent	53.00%
BioLargo Engineering, Science & Technologies, LLC [Member]
Subsidiary, Ownership Percentage, Parent	82.00%			100.00%
BioLargo Energy Technologies, Inc (BETI) [Member]
Subsidiary, Ownership Percentage, Parent	96.00%
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	$ 50,000