Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31, 2018		March 31, 2019
BioLargo, Inc. and wholly owned subsidiaries	$	193	$	183
Clyra Medical Technologies, Inc.		462		329
Total	$	655	$	512

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

	March 31, 201 8			March 31, 201 9
Customer A		39	%		43	%
Customer B		18	%		10	%
Customer C		<10	%		26	%
Customer D		18	%		<10	%

	December 31, 201 8			March 31, 201 9
Customer X		12	%		25	%
Customer Y		31	%		<10	%
Customer Z		<10	%		11	%

Schedule of Inventory, Current [Table Text Block]

	December 31, 201 8		March 31, 201 9
Raw material	$	14	$	14
Finished goods		12		12
Total	$	26	$	26

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

	2018					2019
	Non Plan			2018 Plan		Non Plan			20 18 Plan
Risk free interest rate		2.43	%		n/a		2.65	%		2.65	%
Expected volatility		252	%		n/a		152	%		152	%
Expected dividend yield		—			n/a		—			—
Forfeiture rate		—			n/a		—			—
Life in years		7			n/a		7			7