Note 12 - Commitments and Contingencies (Details Textual) - USD ($)		1 Months Ended	12 Months Ended
	Jun. 18, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Operating Lease, Expense			$ 208,000	$ 213,000
Lessee, Operating Lease, Discount Rate		18.00%	18.00%
Operating Lease, Weighted Average Remaining Lease Term		4 years	4 years
Lessee, Operating Lease, Liability, Payments, Due, Total		$ 710,000	$ 710,000
Operating Lease, Liability, Total		411,000	411,000
Consulting Services, Monthly Payment			$ 23,000
Consulting Services, Period of Services			4 years
Consulting Services, Three Consecutive Month Average Revenue Threshold for Consulting Fees to Accrue		250,000
Contractual Obligation, Total		$ 1,100,000	$ 1,100,000
Corporate Office Lease [Member]
Lessee Operating, Lease Annual Escalation Rate		3.00%	3.00%
Lessee, Operating Lease, Renewal Term		4 years	4 years
Oak Ridge, Tennessee Facility Lease [Member]
Lessee, Operating Lease, Renewal Term		5 years	5 years
BioLargo/ONM Lease [Member]
Lessee, Operating Lease, Renewal Term		4 years	4 years
Lessee, Operating Lease, Discount Rate		18.00%	18.00%
Lessee, Operating Lease, Liability, Payments, Due, Total		$ 537,000	$ 537,000
President and Chief Executive Officer [Member]
Employment Agreement, Annual Base Compensation	$ 170,000
Employment Agreement, Term	5 years