Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	March 31, 2023		December 31, 2022
BioLargo, Inc. and subsidiaries	$	3,171	$	1,685
Clyra Medical Technologies, Inc.		93		166
Total	$	3,264	$	1,851

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	March 31, 2023			March 31, 2022
Customer A		86	%		29	%
Customer B	<10		%		14	%

	March 31, 2023			December 31, 2022
Customer A		70	%		24	%

Schedule of Inventory, Current [Table Text Block]

	March 31, 2023		December 31, 2022
Raw material	$	52	$	46
Finished goods		83		74
Total	$	135	$	120

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31, 2023		December 31, 2022
Patents	$	34	$	34
Security deposits		36		36
Tax credit receivable		54		54
Total	$	124	$	124

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	2023						2022
	Non Plan			2018 Plan			Non Plan			2018 Plan
Risk free interest rate		3.48	%		3.48	%	2.32	–	3.83%	2.32	–	3.83%
Expected volatility		114	%		114	%	114	–	117%	114	–	117%
Expected dividend yield		—			—			—			—
Forfeiture rate		—			—			—			—
Life in years		10			10			10			10