Note 1 - Business and Organization (Details Textual)	3 Months Ended						9 Months Ended
	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	$ (847,000)	$ (1,333,000)	$ (1,544,000)	$ (1,435,000)	$ (1,790,000)	$ (1,878,000)	$ (3,724,000)	$ (5,103,000)
Net Cash Provided by (Used in) Operating Activities, Total							(2,803,000)	(2,962,000)
Working Capital (Deficit)	1,503,000						1,503,000
Assets, Current, Total	2,532,000						2,532,000		$ 1,801,000
Revenue from Contract with Customer, Including Assessed Tax	$ 1,500,000			$ 712,000			$ 3,786,000	$ 1,743,000
Number of Wholly-Owned Subsidiaries	4						4
BioLargo Engineering, Science & Technologies, LLC [Member]
Noncontrolling Interest, Ownership Percentage by Parent	89.00%						89.00%
Clyra Medical Technologies [Member]
Noncontrolling Interest, Ownership Percentage by Parent	58.00%						58.00%