Note 2 - Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedule of Cash and Cash Equivalents [Table Text Block]

	December 31, 2018		September 30 , 2019
BioLargo, Inc. and wholly owned subsidiaries	$	193	$	2,071
Clyra Medical Technologies, Inc.		462		65
Total	$	655	$	2,136

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

	September 30 , 201 8			September 30 , 201 9
Customer A		44	%		13	%
Customer B		12	%		<10	%
Customer C		<10	%		10	%

	December 31, 201 8			September 30 , 201 9
Customer W		12	%		<10	%
Customer X		31	%		<10	%
Customer Y		<10	%		17	%
Customer Z		<10	%		15	%

Schedule of Inventory, Current [Table Text Block]

	December 31, 201 8		September 30 , 201 9
Raw material	$	14	$	10
Finished goods		12		9
Total	$	26	$	19

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	–	2.91	%			2.91	%	2.00	-	2.65	%	2.00	-	2.65	%
Expected volatility	538	-	563	%	538	-	548	%	147	-	152	%	147	-	152	%
Expected dividend yield			—				—				—				—
Forfeiture rate			—				—				—				—
Life in years			7				7				7				7