Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 12, 2018
Document Information [Line Items]
Entity Registrant Name	BIOLARGO, INC.
Entity Central Index Key	0000880242
Trading Symbol	blgo
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		122,154,066
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Amendment Flag	false