Note 1 - Business and Organization (Details Textual)	11 Months Ended	12 Months Ended		24 Months Ended
	Dec. 13, 2022 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2022 USD ($)	Sep. 30, 2017
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total		$ (5,132,000)	$ (6,894,000)
Net Cash Provided by (Used in) Operating Activities, Total		(2,762,000)	(3,937,000)
Working Capital (Deficit)		1,587,000		$ 1,587,000
Assets, Current, Total		3,153,000	1,801,000	3,153,000
Revenue from Contract with Customer, Including Assessed Tax		5,884,000	2,531,000
Proceeds from Issuance of Common Stock		3,617,000	4,882,000
Cash and Cash Equivalents, at Carrying Value, Total		$ 1,851,000	$ 962,000	$ 1,851,000
Number of Wholly-Owned Subsidiaries		6		6
BioLargo Engineering, Science & Technologies, LLC [Member]
Noncontrolling Interest, Ownership Percentage by Parent		82.00%		82.00%	100.00%
Clyra Medical Technologies [Member]
Noncontrolling Interest, Ownership Percentage by Parent		58.00%		58.00%
Subsidiary, Clyra Medical [Member]
Notes Payable, Related Parties		$ 261,000		$ 261,000
Economic Injury Disaster Loan [Member]
Convertible Debt, Total		50,000		50,000
Long-Term Debt, Total		150,000		$ 150,000
Debt Instrument, Term (Year)				30 years
Paycheck Protection Program CARES Act [Member]
Long-Term Debt, Total		140,000		$ 140,000
Warrant Issued to Private Investors [Member]
Proceeds from Issuance of Common Stock		$ 2,364,000
Class of Warrant or Right, Issued During Period, Number of Securities Called by Warrants or Rights (in shares) | shares		27,137,048
The 2020 Unit Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares		13,568,524	5,435,966
Proceeds from Issuance of Common Stock		$ 2,364,000	$ 864,000
Lincoln Park Capital Fund, LLC [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares	6,011,701	6,011,701	24,255,920
Proceeds from Issuance of Common Stock	$ 1,253,000	$ 1,253,000	$ 4,018,000