BioLargo (BLGO) 10-K 29 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 20, 2019	Jun. 30, 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	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding (in shares)		143,096,624
Entity Public Float			$ 19,657,765
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 655,000	$ 990,000
Accounts receivable, net of allowance	257,000	94,000
Inventories, net of allowance	26,000	54,000
Prepaid expenses and other current assets	17,000	20,000
Total current assets	955,000	1,158,000
In-process research and development (Note 3)	1,893,000
Equipment, net of depreciation	126,000	109,000
Other non-current assets, net of amortization	35,000	34,000
Deferred offering cost	176,000	195,000
Total assets	3,185,000	1,496,000
Current liabilities:
Accounts payable and accrued expenses	501,000	224,000
Notes payable	400,000
Line of credit	430,000
Convertible notes payable	1,365,000	5,249,000
Discount on convertible notes payable, and line of credit, net of amortization	(205,000)	(1,257,000)
Total current liabilities	2,491,000	4,216,000
Long-term liabilities:
Convertible notes and note payable	285,000	1,539,000
Clyra Medical note payable (Notes 3 and 10)	1,292,000	1,539,000
Discount on convertible notes payable, net of amortization	(118,000)	(850,000)
Total liabilities	4,308,000	4,905,000
COMMITMENTS, CONTINGENCIES (Note 13)
STOCKHOLDERS’ EQUITY (DEFICIT):
Preferred Series A, $.00067 Par Value, 50,000,000 Shares Authorized, -0- Shares Issued and Outstanding, at December 31, 2017 and December 31, 2018, respectively.
Common stock, $.00067 Par Value, 200,000,000 Shares Authorized, 104,164,465 and 141,466,071 Shares Issued, at December 31, 2017 and December 31, 2018, respectively.	95,000	70,000
Additional paid-in capital	110,222,000	97,093,000
Accumulated other comprehensive loss	(90,000)	(62,000)
Accumulated deficit	(111,723,000)	(101,205,000)
Total Biolargo Inc. and Subsidiaries stockholders’ equity (deficit)	(1,496,000)	(4,104,000)
Non-controlling interest (Note 10)	373,000	695,000
Total stockholders’ equity (deficit)	(1,123,000)	(3,409,000)
Total liabilities and stockholders’ equity (deficit)	3,185,000	1,496,000
Scion Acquisition [Member] | Clyra Acquisition, Common Stock Redeemable for BioLargo Common Shares [Member]
Long-term liabilities:
Liability to Clyra Medical shareholder (Notes 3 and 10)	643,000
Convertible Notes Issued by Clyra Medical Maturing on June 17, 2020 [Member]
Long-term liabilities:
Clyra Medical note payable (Notes 3 and 10)	$ 1,007,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Convertible Preferred Stock, Par Value (in dollars per share)	$ 0.00067	$ 0.00067
Convertible Preferred Stock, Shares Authorized (in shares)	50,000,000	50,000,000
Convertible Preferred Stock, Shares Issued (in shares)	0	0
Convertible Preferred Stock, Shares Outstanding (in shares)	0	0
Common Stock, Par Value (in dollars per share)	$ 0.00067	$ 0.00067
Common Stock, Shares Authorized (in shares)	200,000,000	200,000,000
Common Stock, Shares Issued (in shares)	141,466,071	104,164,465

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Revenue	$ 1,364,000	$ 516,000
Cost of Goods and Services Sold	(743,000)	(323,000)
Total cost of revenue	(743,000)	(323,000)
Gross profit	621,000	193,000
Operating expenses:
Selling, general and administrative expenses	5,264,000	4,429,000
Research and development	1,719,000	1,630,000
Depreciation and amortization	50,000	30,000
Total operating expenses	7,033,000	6,089,000
Operating loss	(6,412,000)	(5,896,000)
Grant income	158,000	140,000
Tax credit income	73,000	71,000
Interest expense	(3,494,000)	(3,862,000)
Debt conversion expense	(276,000)
Gain (Loss) on Extinguishment of Debt, Total	(745,000)
Total other (expense) income	(4,284,000)	(3,651,000)
Net loss	(10,696,000)	(9,547,000)
Net loss attributable to noncontrolling interest	(475,000)	(429,000)
Net loss attributable to common shareholders	$ (10,221,000)	$ (9,118,000)
Net loss per share attributable to common stockholders:
Loss per share attributable to shareholders – basic and diluted (in dollars per share)	$ (0.09)	$ (0.10)
Weighted average number of common shares outstanding: (in shares)	122,000,940	98,941,169
Comprehensive loss attributable to common shareholders
Net loss	$ (10,696,000)	$ (9,547,000)
Foreign translation adjustment	(28,000)	20,000
Comprehensive loss	(10,724,000)	(9,527,000)
Comprehensive loss attributable to noncontrolling interest	(475,000)	(429,000)
Comprehensive loss attributable to shareholders	(10,249,000)	(9,098,000)
Product [Member]
Revenue:
Revenue	1,123,000	504,000
Cost of Goods and Services Sold	(571,000)	(315,000)
Service [Member]
Revenue:
Revenue	241,000	12,000
Cost of Goods and Services Sold	$ (172,000)	$ (8,000)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity (Deficit) - USD ($)	Stock Issued for Financing Fee [Member]Common Stock [Member]	Stock Issued for Financing Fee [Member]Additional Paid-in Capital [Member]	Stock Issued for Financing Fee [Member]Retained Earnings [Member]	Stock Issued for Financing Fee [Member]AOCI Attributable to Parent [Member]	Stock Issued for Financing Fee [Member]Noncontrolling Interest [Member]	Stock Issued for Financing Fee [Member]	Extension of Convertible Note Maturity Date, Vista Capital [Member]Additional Paid-in Capital [Member]	Extension of Convertible Note Maturity Date, Vista Capital [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2016									92,975,970
Balance at Dec. 31, 2016									$ 62,000	$ 90,610,000	$ (91,915,000)	$ (82,000)	$ 555,000	$ (770,000)
Issuance of common stock for service (in shares)									984,070
Issuance of common stock for service									$ 1,000	461,000				462,000
Issuance of common stock for interest (in shares)									1,436,751
Issuance of common stock for interest									$ 1,000	673,000				674,000
Stock to CEO (in shares)									1,500,000
Stock to CEO									$ 1,000	(1,000)
Conversion of notes (in shares)									2,316,748
Conversion of notes									$ 2,000	890,000				$ 892,000
Exercise of warrants (in shares)									510,000					510,000
Exercise of warrants										153,000				$ 153,000
Exercise of stock options (in shares)									2,501,937
Exercise of stock options									$ 2,000	(2,000)
Financing fee in stock (in shares)	738,998
Financing fee in stock		$ 304,000				$ 304,000
Sale of stock for cash (in shares)									1,199,991
Sale of stock for cash									$ 1,000	510,000				511,000
Stock option compensation expense										1,103,000				1,103,000
Warrants and conversion feature issued as discount on convertible notes payable and line of credit										1,145,000				1,145,000
Purchase of Clyra Medical common stock													(40,000)	(40,000)
Issuance of Clyra Medical common stock										411,000			609,000	1,020,000
Deemed dividend for the change in accounting for derivative liability										344,000	(344,000)
Cumulative effect of change in accounting for derivative liability										492,000	172,000			664,000
Net loss											(9,118,000)		(429,000)	(9,547,000)
Foreign currency translation												20,000		20,000
Balance (in shares) at Dec. 31, 2017									104,164,465
Issuance of common stock for interest									$ (1,000)	(673,000)				(674,000)
Foreign translation adjustment												20,000		20,000
Balance at Dec. 31, 2017									$ 70,000	97,093,000	(101,205,000)	(62,000)	695,000	(3,409,000)
Issuance of common stock for service (in shares)									3,214,121
Issuance of common stock for service									$ 2,000	906,000				908,000
Issuance of common stock for interest (in shares)									2,042,196
Issuance of common stock for interest									$ (1,000)	(523,000)				(524,000)
Conversion of notes (in shares)									18,859,100
Conversion of notes									$ 13,000	6,177,000				6,190,000
Financing fee in stock (in shares)	402,385
Financing fee in stock		$ 127,000				$ 127,000								(42,000)
Sale of stock for cash (in shares)									2,891,749
Sale of stock for cash									$ 2,000	837,000				839,000
Stock option compensation expense										1,335,000				1,335,000
Warrants and conversion feature issued as discount on convertible notes payable and line of credit							$ 506,000	$ 506,000		795,000				795,000
Issuance of Clyra Medical common stock										852,000			153,000	1,005,000
Deemed dividend for the change in accounting for derivative liability										297,000	(297,000)
Net loss											(10,221,000)		(475,000)	(10,696,000)
Foreign currency translation												(28,000)		(28,000)
Balance (in shares) at Dec. 31, 2018									141,466,071
Inducement to convert notes (in shares)									2,749,197
Inducement to convert notes									$ 2,000	630,000				632,000
Issuance of common stock for interest									$ 1,000	523,000				524,000
Issuance of common stock for the acquisition of In-process research and development (in shares)									7,142,858
Issuance of common stock for the acquisition of In-process research and development									$ 5,000	(5,000)
Warrant exercise price reduction for cash										149,000				149,000
Foreign translation adjustment												(28,000)		(28,000)
Balance at Dec. 31, 2018									$ 95,000	$ 110,222,000	$ (111,723,000)	$ (90,000)	$ 373,000	$ (1,123,000)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net loss	$ (10,696,000)	$ (9,547,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock option compensation expense	1,335,000	1,103,000
Common stock issued for in lieu of salary to officers and fees for services from vendors	898,000	421,000
Common stock issued for interest	524,000	674,000
Interest expense related to amortization of the discount on convertible notes payable and line of credit and deferred financing costs	2,766,000	3,058,000
Loss on extinguishment of debt	745,000
Debt conversion expense	276,000
Deferred offering expense	19,000	11,000
Financing fee paid in stock	42,000
Amortization and depreciation expense	50,000	30,000
Bad debt expense		3,000
Changes in assets and liabilities:
Accounts receivable	(163,000)	(29,000)
Inventories	28,000	(20,000)
Accounts payable and accrued expenses	284,000	114,000
Accrued officer bonus		(80,000)
Prepaid expenses and other assets	1,000	(22,000)
Net cash used in operating activities	(3,891,000)	(4,284,000)
Cash flows from investing activities
Equipment purchases	(58,000)	(29,000)
Net cash used in investing activities	(58,000)	(29,000)
Cash flows from financing activities
Proceeds from convertible notes payable	705,000	1,799,000
Proceeds from the sale of stock in Clyra Medical	1,005,000	750,000
Repayment of Clyra Medical note payable	(243,000)
Proceeds from sale of stock to Lincoln Park Capital	839,000	511,000
Proceeds from notes payable	400,000
Proceeds from line of credit	430,000	250,000
Proceeds from conversion inducement	357,000
Proceeds from warrant buy down	149,000
Proceeds from warrant exercise		153,000
Repurchase of Clyra Medical shares		(40,000)
Repayment of letter of credit		(50,000)
Net cash provided by financing activities	3,642,000	3,373,000
Net effect of foreign currency translation	(28,000)	20,000
Net change in cash	(335,000)	(920,000)
Cash at beginning of year	990,000	1,910,000
Cash at end of year	655,000	990,000
Supplemental disclosures of cash flow information
Interest	54,000	9,000
Income taxes	13,000	5,000
Non-cash investing and financing activities
Fair value of warrants issued with convertible notes and letter of credit	795,000	3,006,000
Note payable issued for intellectual property	1,250,000
Liability to Scion Solutions, LLC	643,000
Deemed dividend	297,000	344,000
Cumulative effect of change in account for derivative liability		664,000
Conversion of Lines of Credit into Convertible Notes Payable [Member]
Non-cash investing and financing activities
Conversion of debt		250,000
Conversion of Convertible Notes Payable into Common Stock [Member]
Non-cash investing and financing activities
Conversion of debt	6,190,000	891,000
Conversion of Convertible Notes Issued with Original Issue Discount [Member]
Non-cash investing and financing activities
Conversion of debt	85,000	70,000
Stock Issued for Equipment [Member]
Non-cash investing and financing activities
Fair value of stock issued	10,000	40,000
Stock Issued for Financing Fee [Member]
Adjustments to reconcile net loss to net cash used in operating activities:
Financing fee paid in stock	(127,000)	(304,000)
Non-cash investing and financing activities
Fair value of stock issued	85,000	304,000
Stock Issued for Conversion of Clyra Line of Credit [Member]
Non-cash investing and financing activities
Fair value of stock issued		250,000
Stock Issued to CEO [Member]
Non-cash investing and financing activities
Fair value of stock issued		1,000
Stock Issued for Exercise of Stock Options [Member]
Non-cash investing and financing activities
Fair value of stock issued		$ 12,000

Note 1 - Business and Organizat

Note 1 - Business and Organization	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Description of Business BioLargo, Inc. delivers innovative and sustainable technology-based products and services, as well as environmental engineering expertise, across a broad range of industries with an overriding mission to “make life better” with a focus on clean water, clean air, and advanced wound care. Our business strategy is straightforward: we invent or acquire technologies that we believe have the potential to be disruptive in large commercial markets; we develop and validate these technologies to advance and promote their commercial success as we leverage our considerable scientific, engineering, and entrepreneurial talent; we then monetize these technical assets through a variety of business structures that may Liquidity / Going concern The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of our business. For the year ended December 31, 2018, $10,696,000, $3,891,000 December 31, 2018, $1,536,000, $955,000. not December 31, 2019, December 31, 2018, $1,364,000 two No 2, 2018, December 31, 2018, $3,642,000 $655,000. April 2019, 2019, 14 $7,500,000 no may not No No The foregoing factors raise substantial doubt about our ability to continue as a going concern. Ultimately, our ability to continue as a going concern is dependent upon our ability to attract significant new sources of capital, attain a reasonable threshold of operating efficiencies and achieve profitable operations by licensing or otherwise commercializing products incorporating our technologies. The consolidated financial statements do not Organization We are a Delaware corporation formed in 1991. five 2006; No 2009; 2014; 2016; 2017 42.3% 2012, 10

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Significant Accounting Policies [Text Block]	Note 2. Principles of Consolidation The consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries, and Clyra Medical. Management believes Clyra Medical’s financial statements are appropriately consolidated with that of the Company after reviewing the guidance of ASC Topic 810 , not 42.3% 10 All intercompany accounts and transactions have been eliminated. Foreign Currency The Company has designated the functional currency of Biolargo Water, Inc., our Canadian subsidiary, to be the Canadian dollar. Therefore, translation gains and losses resulting from differences in exchange rates are recorded in accumulated other comprehensive income. Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three one $250,000 not As of December 31, 2017 2018, 2017 2018 Biolargo, Inc. and wholly owned subsidiaries $ 462 $ 193 Clyra Medical Technologies, Inc. 528 462 Total $ 990 $ 655 Accounts Receivable Trade accounts receivable are recorded net of allowances for doubtful accounts. Estimates for allowances for doubtful accounts are determined based on payment history and individual customer circumstances. The allowance for doubtful accounts as of December 31, 2017 $3,000. December 31, 2018, Credit Concentration We have a limited number of customers that account for significant portions of our revenue. During the years ended December 31, 2017 2018, three one 10% 2017 2018 Customer A 27 % <10 % Customer B 24 % 33 % Customer C 11 % <10 % We had five 10% December 31, 2017 two December 31, 2018 2017 2018 Customer X 19 % 12 % Customer Y 10 % 31 % Customer Z 12 % <10 % Customer AA 12 % <10 % Customer BB 10 % <10 % Inventory Inventories are stated at the lower of cost or net realizable value using the average cost method. The allowance for obsolete inventory as of December 31, 2017 2018 $3,000. December 31, 2017 2018, 2017 2018 Raw material $ 34 $ 14 Finished goods 20 12 Total $ 54 $ 26 Other Assets Other Assets consisted of security deposits of $35,000 Impairment Long-lived and definite lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not December 31, 2017 2018, no Earnings (Loss) Per Share We report basic and diluted earnings (loss) per share (“EPS”) for common and common share equivalents. Basic EPS is computed by dividing reported earnings by the weighted average shares outstanding. Diluted EPS is computed by adding to the weighted average shares the dilutive effect if stock options and warrants were exercised into common stock. For the years ended December 31, 2017 2018, Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and revenues and expenses during the period reported. Actual results could differ from those estimates. Estimates are used when accounting for stock-based transactions, debt transactions, derivative liabilities, allowance for bad debt, asset depreciation and amortization, among others. The methods, estimates and judgments we use in applying these most critical accounting policies have a significant impact on the results of our financial statements. Share-Based Compensation Expense We recognize compensation expense for stock option awards on a straight-line basis for employees over the applicable service period of the award, which is the vesting period. We recognize compensation expense for stock option awards for non-employees at the fair value on the grant date. Generally, the options issued to non-employees have been earned upon issuance. For the instances that options are issued to non-employees with a vesting schedule, the fair value is recorded on each vesting date. Share-based compensation expense is based on the grant date fair value estimated using the Black-Scholes Option Pricing Model. For stock and stock options issued to consultants and other non-employees for services, the Company measures and records an expense as of the earlier of the date at which either: a commitment for performance by the non-employee has been reached or the non-employee’s performance is complete. The equity instruments are measured at the current fair value, and for stock options, the instruments are measured at fair value using the Black Scholes option model. For equity instruments issued and outstanding where performance is not The following methodology and assumptions were used to calculate share-based compensation for the years ended December 31, 2017 2018: 2017 2018 Non Plan 2007 Plan Non Plan 20 18 Plan Risk free interest rate 2.29 – 2.43 % 2.31 – 2.40 % 2.43 – 2.91 % 2.89 – 2.91 % Expected volatility 563 – 601 % 578 – 601 % 538 – 563 % 489 – 548 % Expected dividend yield — — — — Forfeiture rate — — — — Life in years 7 5 7 7 Expected price volatility is the measure by which our stock price is expected to fluctuate during the expected term of an option. Expected volatility is derived from the historical daily change in the market price of our common stock, as we believe that historical volatility is the best indicator of future volatility. The risk-free interest rate used in the Black-Scholes calculation is based on the prevailing U.S. Treasury yield as determined by the U.S. Federal Reserve. We have never paid any cash dividends on our common stock and do not Historically, we have not Warrants Warrants issued with our convertible and non-convertible debt instruments are accounted for under the fair value and relative fair value method. The warrant is first not. not If the warrant is determined to not Convertible debt instruments are recorded at fair value, limited to a relative fair value based upon the percentage of its fair value to the total fair value including the fair value of the warrant. Further, the convertible debt instrument is examined for any intrinsic beneficial conversion feature (“BCF”) of which the conversion price is less than the closing common stock price on date of issuance. If the relative fair value method is used to value the convertible debt instrument and there is an intrinsic BCF, a further analysis is undertaken of the BCF using an effective conversion price which assumes the conversion price is the relative fair value divided by the number of shares the convertible debt is converted into by its terms. The BCF value is accounted for as equity. The warrant and BCF relative fair values are also recorded as a discount to the convertible promissory notes. As present, these equity features of the convertible promissory notes have recorded a discount to the convertible notes that is substantially equal to the proceeds received. Non-Cash Transactions We have established a policy relative to the methodology to determine the value assigned to each intangible we acquire, and/or services or products received for non-cash consideration of our common stock. The value is based on the market price of our common stock issued as consideration, at the date of the agreement of each transaction or when the service is rendered or product is received. Revenue Recognition We adopted ASU 2014 09, 606, January 1, 2018. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: Step 1: Step 2: Step 3: Step 4: Step 5: We have revenue from two No No No No BLEST identifies services to be performed in a written contract, which specifies the performance obligations and the rate at which the services will be billed. Each service is separately negotiated and priced. Revenue is recognized as services are performed and completed. BLEST’s contracts typically call for invoicing for time and materials incurred for that contract. To date, there have been no In the future, we may one Government Grants We have been awarded multiple research grants from the Canadian National Research Institute – Industrial Research Assistance Program (NRC-IRAP) and the National Science and Engineering Research Council of Canada (NSERC). The grants received are considered other income and are included in our consolidated statements of operations. We received our first 2015 65 $3.6 third third six eighteen not The grants typically provide for (i) recurring monthly amounts, (ii) reimbursement of costs for research talent for which we invoice to request payment, and (iii) ancillary cost reimbursement for research talent travel related costs. All awarded grants have specific requirements on how the money is spent, typically to employ researchers. None may Not no Income Taxes The asset and liability approach is used to recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of asset and liabilities. Deferred tax assets and liabilities are determined based on the differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The effect on deferred tax asset and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We account for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by generally accepted accounting principles (“GAAP”). Under GAAP, the tax effects of a position are recognized only if it is “more-likely-than- not” not not” no Fair Value of Financial Instruments Management believes the carrying amounts of the Company’s financial instruments (excluding debt and equity instruments) as of December 31, 2017 2018 Tax Credits Our research and development activities in Canada may not Recent Accounting Pronouncements In August 2018, No. 2018 13, 820 820, The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2019, not not In June 2018, No. 2018 07, 718 718 718 718 718 not 1 2 606, December 15, 2018, not not In February 2016, No. 2016 02, January 1, 2019 July 2018. not

Note 3 - Acquisition of In-proc

Note 3 - Acquisition of In-process Research and Development	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Business Combination Disclosure [Text Block]	Note 3. On September 26, 2018, The consideration provided to Scion is subject to an escrow agreement dated September 26, 2018 ( 21,000 10,000 7,142,858 $1,250,000 $1 On December 17, 2018, $1 one 15,500 one fifth $100,000 $100,000 $500,000 $1 $2 The promissory note in the principal amount of $1,250,000 September 26, 2018 5%. 25% not 18 12 18 25% 12 5% Immediately following Clyra Medical’s purchase of Scion’s intangible assets, Clyra Medical sold to BioLargo the assets, along with 12,755 7,142,858 may 10,000 7,142,858 December 31, 2018, one may one 7,142,858 $1,286,000, one December 31, 2018

Note 4 - Lincoln Park Financing

Note 4 - Lincoln Park Financing	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Stock Purchase Agreement [Text Block]	Note 4. On August 25, 2017, $10 three 1 1933, may September 22, 2017, 50,000 $0.50 75,000 $0.50 $0.74 100,000 $0.75 $1.24 200,000 $1.25 $500,000. no may three 12 may one no first may not In consideration for entering into the LPC Purchase Agreement, on August 25, 2017, 488,998 no $10 488,998 $25,000 1,222 $25,000 $10 488,998 During the years ended December 31, 2017 2018, Year ended December 31, 2017 Year ended December 31, 2018 Shares sold to Lincoln Park 1,199,991 2,891,749 Additional Commitment Shares issued to Lincoln Park 24,991 41,016 Total shares issued to Lincoln Park: 1,224,982 2,932,765 Gross proceeds to BioLargo: $ 511,000 $ 839,000 We recorded the stock sales in our equity statement and the additional shares issued reduce the deferred offering costs.

Note 5 - Debt Obligations

Note 5 - Debt Obligations	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 5. The following table summarizes our debt obligations outstanding as of December 31, 2017 2018 201 7 201 8 C urrent liabilities : Notes payable, mature January 5, 2019 (1) $ — $ 400 Line of credit, matures September 1, 2019 or later (on 30 day demand) — 430 Convertible notes payable: Convertible notes, mature June 1, 2018 4,469 — Convertible notes, mature July 18, 2018 280 — Convertible notes, mature December 31, 2019 ( 2 ) — 75 Convertible notes, mature January 11, 2019 ( 1 ) — 300 Convertible note, matures April 15, 2019 (1) 500 550 Convertible note, matures July 20, 2019 ( 2 ) — 440 Total convertible notes payable $ 5,249 $ 1,365 Total current liabilities $ 5,249 $ 2,195 L ong-term liabilities : Note payable issued by Clyra Medical to Scion, matures June 17, 2020 (See Notes 3 and 10) — 1,007 Convertible notes payable, mature September 17, 2019 284 — Convertible notes payable, mature December 31, 2019 (1) 292 — Convertible notes payable, mature June 20, 2020 ( 1 ) 523 25 Convertible notes payable, mature July 20, 2019 440 — Convertible notes payable, mature April 20, 2021 ( 1 ) — 100 Convertible notes, mature June 15, 2021 ( 1 ) — 110 Note payable, matures March 8, 2023 (or on demand 60 days’ notice) — 50 Total long-term liabilities $ 1,539 $ 1,292 Total $ 6,788 $ 3,487 ( 1 ) 14 ( 2 For the years ended December 31, 2017 2018 $3,862,000 $3,494,000 Conversion of Debt Obligations Of the $6,788,000 December 31, 2017, December 31, 2018, $6,190,000 Early Conversion of Unit Notes In May 2018, 17,255,811 $4,626,000 2018 Convertible notes payable, mature June 1, 2018 $ 3,647 Convertible notes payable, mature September 17, 2019 284 Convertible notes payable, mature December 31, 2019 217 Convertible notes payable, mature June 20, 2020 478 Total debt converted into shares, May 2018 $ 4,626 These conversions were voluntary on the part of the noteholders and prior to the various maturity dates on notes that were issued in prior “unit” offerings conducted by the Company ( 2015 2016 2017 $0.25 $0.30 one one March 20, 2018, $0.25 $1,000 1,000 1.5 0.25 6,000 $0.30 $0.30 six twenty 6% $0.35, 20% $0.55 $0.57 not 40 $357,000 $0.30. 2,749,197 $632,000. $276,000 41 $0.30 $0.25 966,318 Conversion of 2015 On June 1, 2018, $822,000 2015 June 1, 2018 2,488,819 2,411,004 $0.25, $0.35, $0.55, 77,815 $20,000 Conversion of one July 18, 2018 On July 2, 2018, two one $280,000 July 18, 2018, 100% $280,000 $9,000 1,153,600 $0.25 Conversion of convertible note, matures October 16, 2018 ( On January 16, 2018, nine $150,000 5% $0.394 Pursuant to the FirstFire Purchase Agreement, the Company issued 75,000 $0.39 $29,000 $0.3147 February 8, 2018), 36,536 $11,000 The FirstFire Note contains a price protection provision such that if we issue a security with any term more favorable to the holder of such security that was not $0.25, $0.394 $0.25. In June 2018, $96,000 383,047 11,902 July 15, 2018, $54,000, 217,960 $0.25 Notes payable, mature January 5, 2019 On September 19, 2018, $400,000 January 5, 2019 12%, 7 two 60 January 3, 2019, 10%, 14 Convertible Note, matures January 11, 2019 ( On October 16, 2018, $225,000 $300,000 5%, January 11, 2019. $3 $75,000 In addition to the note, we issued a stock purchase warrant to Triton (the “Triton Warrant”) allowing Triton to purchase up to an aggregate 1 $0.25 October 12, 2023 ( 7 In addition to the foregoing, we donated 150,000 $0.28 $42,000 On January 8, 2019, 14 Convertible Note, matures April 15, 2019 ( On December 18, 2017, $500,000 2017 $500,000 5% $0.394 2017 September 18, 2018. Pursuant to the Vista RRA, we filed a registration statement to register the shares of common stock into which the Vista 2017 250,000 $99,000 February 8, 2018. 140,849 $20,000 September 18, 2018. The Vista 2017 not 2017 2017 $0.25, 2017 $0.394 $0.25. In June 2018, $52,000 208,100 On September 12, 2018, 2017 December 18, 2018. 20% $92,000. 1,812,000 $0.25 $488,000 6 470 50, 10% $92,000, 5% one $165,975, 10% $166,667 On December 18, 2018, $166,667 2017 $166,667 666,668 December 31, 2018, $550,000. Vista Capital agreed to further extend the December 15, 2018 14, Per the guidance of ASC 470 50, 10% 10% $578,942 5% 90 Two-Year Convertible Note, matures July 20, 2019 On July 20, 2017, $400,000 one 10% $440,000 two 12%. October 1, 2017, January 25, 2018, 12% At maturity, the note automatically converts, at the holder’s option, into either BioLargo common shares at $0.42 2,000 $171,000 July 20, 2019. Lines of credit, mature September 1, 2019 On March 1, 2018, $390,000, September 1, 2018, $40,000, 18% may 20 20 10 30 September 1, 2019. Each creditor, for no one $0.35 March 1, 2023. Convertible Notes, mature December 31, 2019 ( 2016 Of the $292,000 2016 $75,000 May 2018 ( one December 31, 2019. $0.57 Convertible Notes, mature June 20, 2020 ( 2017 On May 24, 2017, 2017 $1.5 No. 1 $0.42 $0.65 June 20, 2020, 12% 20 may may ten three In addition to the convertible promissory note, each investor received a warrant allowing for the purchase of the number of shares of BioLargo common stock equal to the investment amount divided by the unit/conversion price (e.g., one 7. June 20, 2022. may 30 10 two We received a total of $604,000 ten $524,000 2017, $80,000 2018. December 29, 2017, $0.394. February 12, 2018, third $0.30, $0.48 In May 2018, $478,000 2,372,817 1,595,670 777,146 November 11, 2018, $100,000 333,334 December 31, 2018, one $25,000 Convertible Note, matures April 20, 2021 ( 2018 On March 26, 2018, 2018 $1.5 $0.30 $0.48 April 20, 2021, 12% 20 may may ten three In addition to the convertible promissory note, each investor will receive a warrant allowing for the purchase of the number of shares of BioLargo common stock equal to the investment amount divided by the unit/conversion price (e.g., one We received one March 2018, $100,000, 333,333 7 September 2018, $0.25 $0.40 no Convertible Notes, mature June 15, 2021 ( On June 15, 2018, $75,000 $82,500. August 7, 2018, $25,000 $32,500. $0.30 $10,000, June 15, 2021, 15% 20 two 20 six Note payable, matures March 8, 2023 ( On March 8, 2018, $50,000 sixty March 8, 2023. 7

Note 6 - Share-based Compensati

Note 6 - Share-based Compensation	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Compensation and Employee Benefit Plans [Text Block]	Note 6. Common Stock On May 2, 2017, 13 1.5 13 None Issuance of Common Stock in exchange for payment of payables Payment of Officer Salaries During 2018, 1,131,036 $0.24 $0.43 $319,000. $3,000,000 $3,000,000 12 During 2017, 148,705 $0.39 $58,000 Payment of Consultant Fees and Accrued Interest During 2018, 4,125,281 $0.23 $0.42 $1,012,000 During 2017, 2,272,116 $0.39 $0.70 $1,078,000 All of these offerings and sales were made in reliance on the exemption from registration contained in Section 4 2 not Stock Option Expense During the years ended December 31, 2017 2018, $1,103,000 $1,335,000, 2018 2007 2018 On June 22, 2018, 2018 “2018 may 10 June 22, 2028. 2018 40 2018 January 1 st 2 Activity for our stock options under the 2018 June 22, 2018, December 31, 2018, Weighted Average Aggregate As of December 31 , 2018: Options Exercise Price per intrinsic Outstanding Price per share share V alue (1) Inception, June 22, 2018 — Granted 1,318,517 $ 0.22 – 0.43 $ 0.34 Expired — — — Balance, December 31, 2018 1,318,517 $ 0.22 – 0.43 $ 0.34 $ 1,000 ( 1 $0.24 December 31, 2018. The options to purchase 1,318,517 December 31, 2018 630,289 $0.22 $0.43 $187,000 688,228 $0.24 $0.43 $203,000 2007 On September 7, 2007, April 29, 2011, 2007 “2007 may 10 September 7, 2017. September 2017, On June 19, 2017, 40,000 2007 $0.43 $16,000 On February 10, 2017, 14 one 300,000 $0.69 February 10, 2027, 125,000 February 10, 2017, 25,000 March 1, 2017, $207,000 Activity for our stock options under the 2007 December 31, 2017 2018 Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding p rice per share share Value (1) Balance, December 31, 2016 9,916,586 $ 0.22 – 1.89 $ 0.44 Granted 340,000 0.39 – 0.69 0.65 Expired (425,000 ) 0.40 – 0.94 0.91 Not issued, 2007 Plan closed September 2017 — Balance, December 31, 2017 9,831,586 0.22 – 1.89 0.44 Expired (140,000 ) 0.35 – 1.89 1.41 Balance, December 31, 2018 9,691,586 $ 0.23 – 0.94 $ 0.43 $ <1,000 ( 1 $0.24 December 31, 2018. Non-Plan Options issued During the year ended December 31, 2018, 1,701,088 $0.39 $0.67 $434,000, $414,000 $20,000 2019. During the year ended December 31, 2017, 1,433,999 $0.39 $0.67 $716,000. On December 29, 2017, one 300,000 $0.39 December 19, 2027, 75,000 December 19, 2017 25,000 September 30, 2018, $117,000, December 31, 2017, $29,000 December 31, 2018, $88,000 On October 23, 2017, 100,000 $0.45 October 23, 2027, 10,000 November 23, 2017. $45,000, $9,000 2017. $34,000 December 31, 2018. October 17, 2017, two 100,000 $0.47 October 17, 2027, 10,000 November 23, 2017. $94,000, $19,000 2017. $75,000 2018 December 31, 2018. On September 5, 2017, 2 11 $0.45 ten five five 11 No On May 2, 2017, 13 3,731,322 $0.45 ten five not $1,679,000 May 2, 2022. December 31, 2017, 2018 $196,000 $336,000 Activity of our non-plan stock options issued for the years ended December 31, 2017 2018 Weighted Non-plan a verage Aggregate Options Exercise p rice per intrinsic o utstanding p rice per share share value (1) Balance, December 31, 2016 20,148,766 $ 0.18 – 1.00 $ 0.40 Granted 7,765,401 0.39 – 0.69 0.46 Exercised (3,866,630 ) 0.18 0.18 Expired (4,029,129 ) 0.18 0.18 Balance, December 31, 2017 20,018,408 0.25 – 1.00 0.51 Granted 1,701,088 0.23 – 0.43 0.26 Expired (2,400,000 ) 0.99 0.99 Balance, December 31, 2018 19,319,496 $ 0.23 – 1.00 $ 0.43 Outstanding, December 31, 2018 19,319,496 $ 0.23 – 1.00 $ 0.43 Unvested (90,000 ) 0.26 – 0.28 0.27 Vested and outstanding, December 31, 2018 19,229,496 $ 0.23 – 1.00 $ 0.43 $ 1,000 ( 1 $0.24 December 31, 2018. Exercise of Stock Option On April 30, 2017, 3,866,630 April 30, 2007. $0.18 2,501,937 $0.51 $0.18 No 3,866,629 April 30, 2017, $3 $3 12 May 2, 2017

Note 7 - Warrants

Note 7 - Warrants	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Warrants [Text Block]	Note 7. We have certain warrants outstanding to purchase our common stock, at various prices, as described in the following table: Weighted a verage Aggregate Warrants Exercise p rice per intrinsic o utstanding p rice per share share value (1) Balance, December 31, 2016 20,035,114 $ 0.25 – 1.00 $ 0.45 Granted 2,289,703 0.42 – 0.70 0.41 Exercised (510,000 ) 0.30 0.30 Expired (250,000 ) 0.40 0.40 Balance, December 31, 2017 22,104,817 0.25 – 1.00 0.45 Granted 7,451,013 0.25 – 0.48 0.29 Expired (2,683,400 ) 0.40 0.40 Balance, December 31, 2018 26,872,430 $ 0.25 – 1.00 $ 0.43 Outstanding, December 31, 2018 26,872,430 $ 0.25 – 1.00 $ 0.42 Unvested (87,500 ) 0.35 0.35 Vested and outstanding, December 31, 2018 26,784,930 $ 0.25 – 1.00 $ 0.42 $ — Warrants issued concurrently with promissory notes In conjunction with a $225,000 $300,000 5, Convertible note payable, matures January 11, 2019 ( 1,000,000 $0.25 October 12, 2023. $225,000 January 11, 2019 We may $0.50 10 30 not may On September 19, 2018, January 5, 2019 ( 5, Convertible Note s , mature January 5, 2019 1,387,500 $0.25 September 19, 2023. may $2.50 10 30 The relative fair value of these warrants resulted in $217,000 On September 12, 2018, December 18, 2017 ( 5, Convertible Note, matures April 15, 2019 ( 1,812,000 $0.25 September 12, 2023. $488,000 2018. On March 8, 2018, 150,000 $0.35 $50,000 5, Note payable, matures March 8, 202 3 (or on demand) February 28, 2023. 6,250 December 31, 2018, 56,250 $7,000 Reduction of Warrant Exercise Price In May 2018, $149,000 37 4,326,358 $0.30. $149,000. Warrants Issued Concurrently with Spring 2018 During 2018, 2018 5, Convertible Note, matures April 20, 2021 ( 2018 333,333 $0.48 2018 April 20, 2023. $49,000 333,333 400,000. $17,000 December 31, 2018. The Company may 2018 30 10 two Warrants Issued Concurrently with Line of Credit Offering During 2018, 5, Line of Credit, matures September 1, 2019 430,000 390,000 $0.35 40,000 $0.25 March 1, 2023. $98,000 The Company may 30 10 two Warrants Issued to Summer 2017 Pursuant to the terms of our Summer 2017 5 1,246,906 $0.65 June 20, 2022. $524,000 The offering documents assured the investors that in the event a subsequent pricing supplement offered a lower conversion or exercise price, prior investors would be given those favorable terms. On December 29, 2017, second $0.394. 82,283, 1,329,189 $32,000 On February 12, 2018, third $0.30. 416,478 three March 31, 2018, two $80,000, third 266,667 $103,000 Warrants Issued to One-Year Noteholders In conjunction with three one three 400,000 two July 8, 2016 ( 400,000 $0.65 December 30, 2016 ( 400,000 $0.75 July 18, 2017 ( 400,000 $0.65 $280,000 December 31, 2017 2017. Each of these warrants contained provisions that required a reduction to the exercise price and increase to the number of warrant shares in the event that we sold our common stock at a lower price than the exercise price (subject to some exceptions). During the year ended December 31, 2017, three $0.394, $344,000, December 31, 2018, $0.25, $297,000, Exercise of Warrants During the year ended December 31, 2017, 510,000 $153,000. Fair Value – Interest Expense To determine interest expense related to our outstanding warrants issued in conjunction with debt offerings, the fair value of each award grant is estimated on the date of grant using the Black-Scholes option pricing model and the relative fair values are amortized over the life of the warrant. For the determination of expense of warrants issued for services, extinguishment of debt and settlement management also uses the option-pricing model. The principal assumptions we used in applying this model were as follows: 2017 2018 Risk free interest rate 1.71 – 2.10% 2.54 – 3.00% Expected volatility 221 – 297% 105 – 127% Expected dividend yield — — Forfeiture rate — — Expected life in years 3 – 5 3 – 5 The risk-free interest rate is based on U.S. Treasury yields in effect at the time of grant. Expected volatilities are based on historical volatility of our common stock. The expected life in years is based on the contract term of the warrant.

Note 8 - Accounts Payable and A

Note 8 - Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	Note 8. Accounts payable and accrued expenses included the following (in thousands): December December 31, 2017 31, 2018 Accounts payable and accrued expense $ 88 $ 302 Accrued interest 51 122 Accrued payroll 85 77 Total accounts payable and accrued expenses $ 224 $ 501

Note 9 - Provision for Income T

Note 9 - Provision for Income Taxes	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 9. Given our historical losses from operations, income taxes have been limited to the minimum franchise tax assessed by the State of California. Our subsidiary BLEST is a Tennessee limited liability company and as such, is not not not At December 31, 2018, $58.5 may not December 22, 2017, 21%. $11.1 $4.6 may 1 2 80% 172 no 172 1 not 20 December 31, 2021. 100%

Note 10 - Noncontrolling Intere

Note 10 - Noncontrolling Interest - Clyra Medical	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Noncontrolling Interest Disclosure [Text Block]	Note 10. We consolidate the operations of our partially owned subsidiary Clyra Medical (see Note 2, On March 31, 2017, $250,000 10% 5% In April 2017, 500 $40,000. In August 2017, $160 $1 two $250,000 1,562.5 $160 1,690 On September 26, 2018, 3 December 31, 2018, $1,005,000 $200 December 17, 2018, 3 As of December 31, 2018, Shareholder Shares Percent BioLargo, Inc. 28,053 42.3 % Sanatio Capital (1) 11,520 17.4 % Scion Solutions (2) 15,500 23.4 % Other 11,222 16.9 % Total 66,295 Notes: ( 1 9,830 1,690 ( 2 not 15,500 3 Sanatio Capital purchased Series A Preferred shares in 2015. 8% five no 510 December 20, no December 31, 2018 $185,000. Holders of Preferred Shares are entitled to preferential payments in the event of a liquidation, dissolution or winding up of the company, in an amount equal to any accrued and unpaid dividends. After such preference, any remaining assets are distributed pro-rata between holders of Clyra Medical common stock and Preferred Shares as if the Preferred Shares had converted to Clyra Medical common stock. Holders of Preferred Shares may one one Preferred shares may one one one one

Note 11 - BioLargo Engineering,

Note 11 - BioLargo Engineering, Science and Technologies, LLC	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Wholly-Owned Subsidiary [Text Block]	Note 11. In September 2017, three seven 12 two 100% no five 30% 2 five March 31, 2018 ( not 90% 10% first September 2018. 8 September 8, 2017. The Compensation Committee met on September 26, 2018 not not one

Note 12 - Business Segment Info

Note 12 - Business Segment Information	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	Note 12. BioLargo currently has four four 1. Odor- No 2. BLEST -- which provides professional engineering services on a time and materials basis for outside clients and supports our internal operations as needed (located in Oak Ridge, Tennessee); 3. BioLargo Water -- which historically focused entirely on R&D, and has now shifted its focus to commercializing the AOS technology (located in Edmonton, Alberta Canada); and 4. Clyra Medical -- which is engaged in developing medical products and preparing launch into commercial activity with approval of its FDA 510 Historically, none No third December 31, 2018, No $417,000 $500,000 2017 $1 2018 The segment information for the years December 31, 2017 2018, 2017 2018 Revenues Odor-No-More $ 504 $ 1,123 BLEST 12 241 Consolidated revenue $ 516 $ 1,364 Cost of goods/services Odor-No-More $ (315 ) $ (571 ) BLEST (8 ) (172 ) Consolidated costs of goods/services $ (323 ) $ (743 ) Net loss Odor-No-More $ (500 ) $ (433 ) BLEST (90 ) (750 ) Clyra Medical (915 ) (883 ) BioLargo Water (741 ) (571 ) Corporate (7,301 ) (8,059 ) Consolidated net loss $ (9,547 ) $ (10,696 ) 2017 2018 Assets, net Odor-No-More $ 211 $ 219 BLEST — 250 Clyra Medical 529 462 BioLargo Water 64 34 Corporate 692 2,220 Consolidated assets, net $ 1,496 $ 3,185

Note 13 - Commitments and Conti

Note 13 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 13. Calvert Employment Agreement On May 2, 2017, April 30, 2007. The Calvert Employment Agreement provides that Mr. Calvert will continue to serve as our President and Chief Executive Officer and receive base compensation equal to his current rate of pay of $289,000 December 31, 2018, one $147,000 6 four may Pursuant to the Calvert Employment Agreement, we granted Mr. Calvert a non-qualified stock option (the “Option”) to purchase 3,731,322 $0.45 ten five 7 not 1,500,000 $3 $3 12 The Calvert Employment Agreement has a term of five may 120 360 one one one one The Calvert Employment Agreement requires Mr. Calvert to keep certain information confidential, not Office Leases We have long-term operating leases for office, industrial and laboratory space in Westminster, California, Oak Ridge, Tennessee, and Alberta, Canada. Payments made under operating leases are charged to the Consolidated Statement of Operations and Comprehensive Loss on a straight-line basis over the term of the operating lease agreement. For the years ended December 31, 2017 2018, $183,000 $213,000, Future minimum lease payments as of December 31, 2018 Total 2019 $ 229 2020 231 Total future minimum lease payments $ 460 Clyra Medical Consulting Agreement Our partially owned subsidiary Clyra Medical (see Note 10 10 $23,000 four not $1.1

Note 14 - Subsequent Events

Note 14 - Subsequent Events	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	Note 14. Management has evaluated subsequent events through the date of the filing of this Annual Report and management noted the following for disclosure. Debt obligations – Extension of notes due January 5, 2019 By letter dated January 3, 2019, two $400,000 first $280,000, second $120,000 60 March 6, 2019, 5 10%, two $440,000 January 3, 2019. On March 5, 2019, two June 6, 2019, may September 6, 2019 10%. March 5, 2019 12% 18%, March 7, 2019, two 1,387,500 $0.25 September 19, 2023. $0.20 1,734,375. $346,875 600,000 750,000 $0.20 Debt Obligations –Convertible Note, matures April 15, 2019 ( On January 7, 2019, December 14, 2017 ( 2017 5 April 15, 2019. $605,100. five 80% 25 20% 15%, 15% 30% 25% Per the guidance of ASC 470 50, 10% 2017 10% $746,000 5% 90 Subsequent to the January 7, 2019 $225,000 2017 1,679,248 April 15, 2019 July 15, 2019, 10%. $420,452 Concurrently with the January 7, 2019 2017 $300,000 2019 $330,000, nine October 7, 2019). 2019 one 12%. 2019 65% 25 2019 4.99% may 2019 90 10 120% 10 2019 2019 not November 6, 2018). With respect to the above transactions with Vista Capital, Lincoln Park Capital Fund, LLC agreed to waive the provisions of the Purchase Agreement dated August 25, 2017, 250,000 $0.25 five not Debt Obligations – Payment of Note due January 11, 2019 ( On January 9, 2019, October 12, 2018 ( 5 7 no Debt Obligations – Note due November 5, 2019 ( On January 31, 2019, 12% $495,000 $330,000, $300,000 February 5, 2019, 10% November 5, 2019. $150,000 March 7, 2019, $495,000. The Tangiers Note is convertible at the option of Tangiers at a conversion price equal to 75% 25 may 180 90 25%; 91 180 30%. may not 144 10 six may 22% 25% In connection with the Tangiers Note, the Company caused its transfer agent to reserve 3,000,000 With respect to the above transaction with Tangiers, Lincoln Park consented to waive the provisions of the Purchase Agreement dated August 25, 2017 50,000 $0.25 five not Chief Financial Officer Contract Extension On January 16, 2019, February 1, 2008 ( January 16, 2019 ( September 30, 2019 ( September 30, 2018. December 31, 2017 For the Extended Term, Mr. Dargan was issued an option (“Option”) to purchase 300,000 January 16, 2019 $0.223, January 16, 2029, 75,000 December 31, 2018, 25,000 January 31, 2019, 2018 The issuance of the Option is Mr. Dargan’s sole source of compensation for the Extended Term. As was the case in all prior terms of his engagement, there is no no not F- 35

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	Principles of Consolidation The consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries, and Clyra Medical. Management believes Clyra Medical’s financial statements are appropriately consolidated with that of the Company after reviewing the guidance of ASC Topic 810 , not 42.3% 10 All intercompany accounts and transactions have been eliminated.
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency The Company has designated the functional currency of Biolargo Water, Inc., our Canadian subsidiary, to be the Canadian dollar. Therefore, translation gains and losses resulting from differences in exchange rates are recorded in accumulated other comprehensive income.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three one $250,000 not As of December 31, 2017 2018, 2017 2018 Biolargo, Inc. and wholly owned subsidiaries $ 462 $ 193 Clyra Medical Technologies, Inc. 528 462 Total $ 990 $ 655
Receivables, Policy [Policy Text Block]	Accounts Receivable Trade accounts receivable are recorded net of allowances for doubtful accounts. Estimates for allowances for doubtful accounts are determined based on payment history and individual customer circumstances. The allowance for doubtful accounts as of December 31, 2017 $3,000. December 31, 2018,
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Credit Concentration We have a limited number of customers that account for significant portions of our revenue. During the years ended December 31, 2017 2018, three one 10% 2017 2018 Customer A 27 % <10 % Customer B 24 % 33 % Customer C 11 % <10 % We had five 10% December 31, 2017 two December 31, 2018 2017 2018 Customer X 19 % 12 % Customer Y 10 % 31 % Customer Z 12 % <10 % Customer AA 12 % <10 % Customer BB 10 % <10 %
Inventory, Policy [Policy Text Block]	Inventory Inventories are stated at the lower of cost or net realizable value using the average cost method. The allowance for obsolete inventory as of December 31, 2017 2018 $3,000. December 31, 2017 2018, 2017 2018 Raw material $ 34 $ 14 Finished goods 20 12 Total $ 54 $ 26
Intangible Assets, Finite-Lived, Policy [Policy Text Block]	Other Assets Other Assets consisted of security deposits of $35,000
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment Long-lived and definite lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not December 31, 2017 2018, no
Earnings Per Share, Policy [Policy Text Block]	Earnings (Loss) Per Share We report basic and diluted earnings (loss) per share (“EPS”) for common and common share equivalents. Basic EPS is computed by dividing reported earnings by the weighted average shares outstanding. Diluted EPS is computed by adding to the weighted average shares the dilutive effect if stock options and warrants were exercised into common stock. For the years ended December 31, 2017 2018,
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and revenues and expenses during the period reported. Actual results could differ from those estimates. Estimates are used when accounting for stock-based transactions, debt transactions, derivative liabilities, allowance for bad debt, asset depreciation and amortization, among others. The methods, estimates and judgments we use in applying these most critical accounting policies have a significant impact on the results of our financial statements.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Share-Based Compensation Expense We recognize compensation expense for stock option awards on a straight-line basis for employees over the applicable service period of the award, which is the vesting period. We recognize compensation expense for stock option awards for non-employees at the fair value on the grant date. Generally, the options issued to non-employees have been earned upon issuance. For the instances that options are issued to non-employees with a vesting schedule, the fair value is recorded on each vesting date. Share-based compensation expense is based on the grant date fair value estimated using the Black-Scholes Option Pricing Model. For stock and stock options issued to consultants and other non-employees for services, the Company measures and records an expense as of the earlier of the date at which either: a commitment for performance by the non-employee has been reached or the non-employee’s performance is complete. The equity instruments are measured at the current fair value, and for stock options, the instruments are measured at fair value using the Black Scholes option model. For equity instruments issued and outstanding where performance is not The following methodology and assumptions were used to calculate share-based compensation for the years ended December 31, 2017 2018: 2017 2018 Non Plan 2007 Plan Non Plan 20 18 Plan Risk free interest rate 2.29 – 2.43 % 2.31 – 2.40 % 2.43 – 2.91 % 2.89 – 2.91 % Expected volatility 563 – 601 % 578 – 601 % 538 – 563 % 489 – 548 % Expected dividend yield — — — — Forfeiture rate — — — — Life in years 7 5 7 7 Expected price volatility is the measure by which our stock price is expected to fluctuate during the expected term of an option. Expected volatility is derived from the historical daily change in the market price of our common stock, as we believe that historical volatility is the best indicator of future volatility. The risk-free interest rate used in the Black-Scholes calculation is based on the prevailing U.S. Treasury yield as determined by the U.S. Federal Reserve. We have never paid any cash dividends on our common stock and do not Historically, we have not
Warrant Policy [Policy Text Block]	Warrants Warrants issued with our convertible and non-convertible debt instruments are accounted for under the fair value and relative fair value method. The warrant is first not. not If the warrant is determined to not Convertible debt instruments are recorded at fair value, limited to a relative fair value based upon the percentage of its fair value to the total fair value including the fair value of the warrant. Further, the convertible debt instrument is examined for any intrinsic beneficial conversion feature (“BCF”) of which the conversion price is less than the closing common stock price on date of issuance. If the relative fair value method is used to value the convertible debt instrument and there is an intrinsic BCF, a further analysis is undertaken of the BCF using an effective conversion price which assumes the conversion price is the relative fair value divided by the number of shares the convertible debt is converted into by its terms. The BCF value is accounted for as equity. The warrant and BCF relative fair values are also recorded as a discount to the convertible promissory notes. As present, these equity features of the convertible promissory notes have recorded a discount to the convertible notes that is substantially equal to the proceeds received.
Non Cash Transactions [Policy Text Block]	Non-Cash Transactions We have established a policy relative to the methodology to determine the value assigned to each intangible we acquire, and/or services or products received for non-cash consideration of our common stock. The value is based on the market price of our common stock issued as consideration, at the date of the agreement of each transaction or when the service is rendered or product is received.
Revenue Recognition, Policy [Policy Text Block]	Revenue Recognition We adopted ASU 2014 09, 606, January 1, 2018. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: Step 1: Step 2: Step 3: Step 4: Step 5: We have revenue from two No No No No BLEST identifies services to be performed in a written contract, which specifies the performance obligations and the rate at which the services will be billed. Each service is separately negotiated and priced. Revenue is recognized as services are performed and completed. BLEST’s contracts typically call for invoicing for time and materials incurred for that contract. To date, there have been no In the future, we may one
Government Grants [Policy Text Block]	Government Grants We have been awarded multiple research grants from the Canadian National Research Institute – Industrial Research Assistance Program (NRC-IRAP) and the National Science and Engineering Research Council of Canada (NSERC). The grants received are considered other income and are included in our consolidated statements of operations. We received our first 2015 65 $3.6 third third six eighteen not The grants typically provide for (i) recurring monthly amounts, (ii) reimbursement of costs for research talent for which we invoice to request payment, and (iii) ancillary cost reimbursement for research talent travel related costs. All awarded grants have specific requirements on how the money is spent, typically to employ researchers. None may Not no
Income Tax, Policy [Policy Text Block]	Income Taxes The asset and liability approach is used to recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of asset and liabilities. Deferred tax assets and liabilities are determined based on the differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The effect on deferred tax asset and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We account for uncertainties in income tax law under a comprehensive model for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns as prescribed by generally accepted accounting principles (“GAAP”). Under GAAP, the tax effects of a position are recognized only if it is “more-likely-than- not” not not” no
Fair Value of Financial Instruments, Policy [Policy Text Block]	Fair Value of Financial Instruments Management believes the carrying amounts of the Company’s financial instruments (excluding debt and equity instruments) as of December 31, 2017 2018
Tax Credits [Policy Text Block]	Tax Credits Our research and development activities in Canada may not
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In August 2018, No. 2018 13, 820 820, The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2019, not not In June 2018, No. 2018 07, 718 718 718 718 718 not 1 2 606, December 15, 2018, not not In February 2016, No. 2016 02, January 1, 2019 July 2018. not

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Cash and Cash Equivalents [Table Text Block]	2017 2018 Biolargo, Inc. and wholly owned subsidiaries $ 462 $ 193 Clyra Medical Technologies, Inc. 528 462 Total $ 990 $ 655
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	2017 2018 Customer A 27 % <10 % Customer B 24 % 33 % Customer C 11 % <10 % 2017 2018 Customer X 19 % 12 % Customer Y 10 % 31 % Customer Z 12 % <10 % Customer AA 12 % <10 % Customer BB 10 % <10 %
Schedule of Inventory, Current [Table Text Block]	2017 2018 Raw material $ 34 $ 14 Finished goods 20 12 Total $ 54 $ 26
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	2017 2018 Non Plan 2007 Plan Non Plan 20 18 Plan Risk free interest rate 2.29 – 2.43 % 2.31 – 2.40 % 2.43 – 2.91 % 2.89 – 2.91 % Expected volatility 563 – 601 % 578 – 601 % 538 – 563 % 489 – 548 % Expected dividend yield — — — — Forfeiture rate — — — — Life in years 7 5 7 7

Note 4 - Lincoln Park Financi_2

Note 4 - Lincoln Park Financing (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Stock Issued [Table Text Block]	Year ended December 31, 2017 Year ended December 31, 2018 Shares sold to Lincoln Park 1,199,991 2,891,749 Additional Commitment Shares issued to Lincoln Park 24,991 41,016 Total shares issued to Lincoln Park: 1,224,982 2,932,765 Gross proceeds to BioLargo: $ 511,000 $ 839,000

Note 5 - Debt Obligations (Tabl

Note 5 - Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Debt [Table Text Block]	201 7 201 8 C urrent liabilities : Notes payable, mature January 5, 2019 (1) $ — $ 400 Line of credit, matures September 1, 2019 or later (on 30 day demand) — 430 Convertible notes payable: Convertible notes, mature June 1, 2018 4,469 — Convertible notes, mature July 18, 2018 280 — Convertible notes, mature December 31, 2019 ( 2 ) — 75 Convertible notes, mature January 11, 2019 ( 1 ) — 300 Convertible note, matures April 15, 2019 (1) 500 550 Convertible note, matures July 20, 2019 ( 2 ) — 440 Total convertible notes payable $ 5,249 $ 1,365 Total current liabilities $ 5,249 $ 2,195 L ong-term liabilities : Note payable issued by Clyra Medical to Scion, matures June 17, 2020 (See Notes 3 and 10) — 1,007 Convertible notes payable, mature September 17, 2019 284 — Convertible notes payable, mature December 31, 2019 (1) 292 — Convertible notes payable, mature June 20, 2020 ( 1 ) 523 25 Convertible notes payable, mature July 20, 2019 440 — Convertible notes payable, mature April 20, 2021 ( 1 ) — 100 Convertible notes, mature June 15, 2021 ( 1 ) — 110 Note payable, matures March 8, 2023 (or on demand 60 days’ notice) — 50 Total long-term liabilities $ 1,539 $ 1,292 Total $ 6,788 $ 3,487
Convertible Debt [Table Text Block]	2018 Convertible notes payable, mature June 1, 2018 $ 3,647 Convertible notes payable, mature September 17, 2019 284 Convertible notes payable, mature December 31, 2019 217 Convertible notes payable, mature June 20, 2020 478 Total debt converted into shares, May 2018 $ 4,626

Note 6 - Share-based Compensa_2

Note 6 - Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Share-based Compensation, Stock Options, Activity [Table Text Block]	Weighted Average Aggregate As of December 31 , 2018: Options Exercise Price per intrinsic Outstanding Price per share share V alue (1) Inception, June 22, 2018 — Granted 1,318,517 $ 0.22 – 0.43 $ 0.34 Expired — — — Balance, December 31, 2018 1,318,517 $ 0.22 – 0.43 $ 0.34 $ 1,000
The 2007 Equity Incentive Plan [Member]
Notes Tables
Share-based Compensation, Stock Options, Activity [Table Text Block]	Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding p rice per share share Value (1) Balance, December 31, 2016 9,916,586 $ 0.22 – 1.89 $ 0.44 Granted 340,000 0.39 – 0.69 0.65 Expired (425,000 ) 0.40 – 0.94 0.91 Not issued, 2007 Plan closed September 2017 — Balance, December 31, 2017 9,831,586 0.22 – 1.89 0.44 Expired (140,000 ) 0.35 – 1.89 1.41 Balance, December 31, 2018 9,691,586 $ 0.23 – 0.94 $ 0.43 $ <1,000 Weighted Non-plan a verage Aggregate Options Exercise p rice per intrinsic o utstanding p rice per share share value (1) Balance, December 31, 2016 20,148,766 $ 0.18 – 1.00 $ 0.40 Granted 7,765,401 0.39 – 0.69 0.46 Exercised (3,866,630 ) 0.18 0.18 Expired (4,029,129 ) 0.18 0.18 Balance, December 31, 2017 20,018,408 0.25 – 1.00 0.51 Granted 1,701,088 0.23 – 0.43 0.26 Expired (2,400,000 ) 0.99 0.99 Balance, December 31, 2018 19,319,496 $ 0.23 – 1.00 $ 0.43 Outstanding, December 31, 2018 19,319,496 $ 0.23 – 1.00 $ 0.43 Unvested (90,000 ) 0.26 – 0.28 0.27 Vested and outstanding, December 31, 2018 19,229,496 $ 0.23 – 1.00 $ 0.43 $ 1,000

Note 7 - Warrants (Tables)

Note 7 - Warrants (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Weighted a verage Aggregate Warrants Exercise p rice per intrinsic o utstanding p rice per share share value (1) Balance, December 31, 2016 20,035,114 $ 0.25 – 1.00 $ 0.45 Granted 2,289,703 0.42 – 0.70 0.41 Exercised (510,000 ) 0.30 0.30 Expired (250,000 ) 0.40 0.40 Balance, December 31, 2017 22,104,817 0.25 – 1.00 0.45 Granted 7,451,013 0.25 – 0.48 0.29 Expired (2,683,400 ) 0.40 0.40 Balance, December 31, 2018 26,872,430 $ 0.25 – 1.00 $ 0.43 Outstanding, December 31, 2018 26,872,430 $ 0.25 – 1.00 $ 0.42 Unvested (87,500 ) 0.35 0.35 Vested and outstanding, December 31, 2018 26,784,930 $ 0.25 – 1.00 $ 0.42 $ —
Schedule Of Assumptions Used To Determine Fair Value Of Warrants [Table Text Block]	2017 2018 Risk free interest rate 1.71 – 2.10% 2.54 – 3.00% Expected volatility 221 – 297% 105 – 127% Expected dividend yield — — Forfeiture rate — — Expected life in years 3 – 5 3 – 5

Note 8 - Accounts Payable and_2

Note 8 - Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	December December 31, 2017 31, 2018 Accounts payable and accrued expense $ 88 $ 302 Accrued interest 51 122 Accrued payroll 85 77 Total accounts payable and accrued expenses $ 224 $ 501

Note 10 - Noncontrolling Inte_2

Note 10 - Noncontrolling Interest - Clyra Medical (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Other Ownership Interests [Table Text Block]	Shareholder Shares Percent BioLargo, Inc. 28,053 42.3 % Sanatio Capital (1) 11,520 17.4 % Scion Solutions (2) 15,500 23.4 % Other 11,222 16.9 % Total 66,295

Note 12 - Business Segment In_2

Note 12 - Business Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	2017 2018 Revenues Odor-No-More $ 504 $ 1,123 BLEST 12 241 Consolidated revenue $ 516 $ 1,364 Cost of goods/services Odor-No-More $ (315 ) $ (571 ) BLEST (8 ) (172 ) Consolidated costs of goods/services $ (323 ) $ (743 ) Net loss Odor-No-More $ (500 ) $ (433 ) BLEST (90 ) (750 ) Clyra Medical (915 ) (883 ) BioLargo Water (741 ) (571 ) Corporate (7,301 ) (8,059 ) Consolidated net loss $ (9,547 ) $ (10,696 ) 2017 2018 Assets, net Odor-No-More $ 211 $ 219 BLEST — 250 Clyra Medical 529 462 BioLargo Water 64 34 Corporate 692 2,220 Consolidated assets, net $ 1,496 $ 3,185

Note 13 - Commitments and Con_2

Note 13 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Total 2019 $ 229 2020 231 Total future minimum lease payments $ 460

Note 1 - Business and Organiz_2

Note 1 - Business and Organization (Details Textual)	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	$ (10,696,000)	$ (9,547,000)
Net Cash Provided by (Used in) Operating Activities, Total	(3,891,000)	(4,284,000)
Working Capital	1,536,000
Assets, Current, Total	955,000	1,158,000
Revenue from Contract with Customer, Including Assessed Tax	1,364,000	516,000
Cash Provided by Financing Activities	3,642,000
Cash and Cash Equivalents, at Carrying Value, Ending Balance	655,000	$ 990,000	$ 1,910,000
Listing Application, Expected Proceeds from Offering	$ 7,500,000
Number of Wholly-Owned Subsidiaries	5
Clyra Medical Technology Inc [Member] | Biolargo [Member]
Noncontrolling Interest, Ownership Percentage by Parent	42.30%

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Cash, FDIC Insured Amount	$ 250,000
Allowance for Doubtful Accounts Receivable, Current, Ending Balance		$ 3,000
Inventory Valuation Reserves, Ending Balance	3,000	3,000
Security Deposit	35,000
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 0
Customer Concentration Risk [Member] | Revenue from Contract with Customer [Member]
Number of Major Customers	1	3
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers	2	5
Clyra [Member] | Biolargo [Member]
Noncontrolling Interest, Ownership Percentage by Parent	42.30%
Canadian Government Grants [Member]
Number of Grants Received	65
Grants Receivable	$ 3.60
Canadian Government Grants [Member] | Minimum [Member]
Grant Term	180 days
Canadian Government Grants [Member] | Maximum [Member]
Grant Term	1 year 180 days

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Summary of Cash Balances (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents, at Carrying Value, Ending Balance	$ 655,000	$ 990,000	$ 1,910,000
Parent Company [Member]
Cash and Cash Equivalents, at Carrying Value, Ending Balance	193,000	462,000
Noncontrolling Interest [Member]
Cash and Cash Equivalents, at Carrying Value, Ending Balance	$ 462,000	$ 528,000

Note 2 - Summary of Significa_5

Note 2 - Summary of Significant Accounting Policies - Credit Concentration (Details) - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Customer A [Member] | Revenue from Contract with Customer [Member]
Credit concentration	10.00%	27.00%
Customer X [Member] | Accounts Receivable [Member]
Credit concentration	12.00%	19.00%
Customer B [Member] | Revenue from Contract with Customer [Member]
Credit concentration		24.00%
Customer B [Member] | Revenue from Contract with Customer [Member] | Maximum [Member]
Credit concentration	33.00%
Customer Y [Member] | Accounts Receivable [Member]
Credit concentration	31.00%	10.00%
Customer C [Member] | Revenue from Contract with Customer [Member]
Credit concentration		11.00%
Customer C [Member] | Revenue from Contract with Customer [Member] | Maximum [Member]
Credit concentration	10.00%
Customer Z [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	12.00%
Customer AA [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	12.00%
Customer BB [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	10.00%

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Raw material	$ 14	$ 34
Finished goods	12	20
Total	$ 26	$ 54

Note 2 - Summary of Significa_7

Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Non Plan [Member]
Life in years (Year)	7 years	7 years
Non Plan [Member] | Minimum [Member]
Risk free interest rate	2.43%	2.29%
Expected volatility	538.00%	563.00%
Non Plan [Member] | Maximum [Member]
Risk free interest rate	2.91%	2.43%
Expected volatility	563.00%	601.00%
The 2007 Equity Incentive Plan [Member]
Life in years (Year)		5 years
The 2007 Equity Incentive Plan [Member] | Minimum [Member]
Risk free interest rate		2.31%
Expected volatility		578.00%
The 2007 Equity Incentive Plan [Member] | Maximum [Member]
Risk free interest rate		2.40%
Expected volatility		601.00%
2018 Equity Incentive Plan [Member]
Life in years (Year)	7 years
2018 Equity Incentive Plan [Member] | Minimum [Member]
Risk free interest rate	2.89%
Expected volatility	489.00%
2018 Equity Incentive Plan [Member] | Maximum [Member]
Risk free interest rate	2.91%
Expected volatility	548.00%

Note 3 - Acquisition of In-pr_2

Note 3 - Acquisition of In-process Research and Development (Details Textual) - USD ($)	Sep. 26, 2018	Dec. 31, 2018
Business Combination, Shares Acquired	12,755
Clyra [Member]
Debt Instrument, Extension Period	1 year
Debt Instrument, Term	1 year 180 days
Scion Acquisition [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	21,000
Business Combination, Consideration Transferred, Liabilities Incurred	$ 1,250,000
Business Acquisition, Base Capital Requirement for Escrow Release	1,000,000
Business Acquisition, Gross Revenue, Tranche One	100,000
Business Acquisition, Gross Revenue, Tranche Two	100,000
Business Acquisition, Gross Revenue, Tranche Three	500,000
Business Acquisition, Gross Revenue, Tranche Four	1,000,000
Business Acquisition, Gross Revenue, Tranche Five	$ 2,000,000
Scion Acquisition [Member] | Clyra [Member]
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Debt Instrument, Percent of Investment Proceeds	25.00%
Debt Instrument, Percent of Gross Revenue	5.00%
Scion Acquisition [Member] | Clyra Acquisition, Common Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	10,000	15,500
Scion Acquisition [Member] | Clyra Acquisition, Common Stock Redeemable for BioLargo Common Shares [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	7,142,858
Stock Redeemed Upon Vesting of 10,000 Clyra Acquisition Shares, Shares	10,000
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned	$ 1,286,000

Note 4 - Lincoln Park Financi_3

Note 4 - Lincoln Park Financing (Details Textual) - Lincoln Park Capital Fund, LLC [Member] - USD ($)	Aug. 25, 2017	Dec. 31, 2018	Dec. 31, 2017
Stock Purchase Agreement, Maximum Amount of Common Stock	$ 10,000,000
Stock Purchase Agreement, Maximum Shares of Common Stock to be Sold in a Single Business Day, Tier One	50,000
Stock Purchase Agreement, Maximum Shares of Common Stock to be Sold in a Single Business Day, Tier Two	75,000
Stock Purchase Agreement, Maximum Shares of Common Stock to be Sold in a Single Business Day, Tier Three	100,000
Stock Purchase Agreement, Maximum Shares of Common Stock to be Sold in a Single Business Day, Tier Four	200,000
Stock Purchase Agreement, Maximum Value of Total Common Stock to be Sold in a Single Business Day	$ 500,000
Stock Issued During Period, Shares, New Issues	488,998	2,891,749	1,199,991
Pro Forma Information, Stock Purchase Agreement, Stock Purchase Requested	$ 25,000
Pro Forma Information, Stock Purchase Agreement, Stock Purchase Requested, Additional Commitment Common Stock Issued	1,222
Pro Forma Information, Stock Purchase Agreement, Additional Commitment Shares, Numerator Value of Total Shares Calculation	$ 25,000
Pro Forma Information, Stock Purchase Agreement, Additional Commitment Shares, Denominator Value of Total Shares Calculation	$ 10,000,000
Pro Forma Information, Stock Purchase Agreement, Additional Commitment Shares, Multiplier of Total Shares Calculation	488,998
Maximum [Member]
Stock Purchase Agreement, Share Price, Tier One	$ 0.50
Stock Purchase Agreement, Share Price, Tier Two	0.74
Stock Purchase Agreement, Share Price, Tier Three	1.24
Minimum [Member]
Stock Purchase Agreement, Share Price, Tier Two	0.50
Stock Purchase Agreement, Share Price, Tier Three	0.75
Stock Purchase Agreement, Share Price, Tier Four	$ 1.25

Note 4 - Lincoln Park Financi_4

Note 4 - Lincoln Park Financing - Purchase Agreement (Details) - USD ($)	Aug. 25, 2017	Dec. 31, 2018	Dec. 31, 2017
Gross proceeds to BioLargo:		$ 839,000	$ 511,000
Lincoln Park Capital Fund, LLC [Member]
Shares sold to Lincoln Park (in shares)	488,998	2,891,749	1,199,991
Additional Commitment Shares issued to Lincoln Park (in shares)		41,016	24,991
Total shares issued to Lincoln Park: (in shares)		2,932,765	1,224,982
Gross proceeds to BioLargo:		$ 839,000	$ 511,000

Note 5 - Debt Obligations (Deta

Note 5 - Debt Obligations (Details Textual)		Jan. 07, 2019USD ($)	Dec. 18, 2018USD ($)shares	Nov. 11, 2018USD ($)shares	Oct. 16, 2018USD ($)$ / sharesshares	Sep. 19, 2018USD ($)	Sep. 12, 2018USD ($)	Sep. 01, 2018USD ($)	Aug. 07, 2018USD ($)	Jul. 15, 2018USD ($)$ / sharesshares	Jul. 02, 2018USD ($)$ / sharesshares	Jun. 15, 2018USD ($)$ / shares	Jun. 01, 2018USD ($)$ / sharesshares	Mar. 26, 2018USD ($)$ / sharesshares	Mar. 08, 2018USD ($)	Mar. 01, 2018USD ($)$ / sharesshares	Feb. 09, 2018USD ($)shares	Feb. 08, 2018USD ($)$ / sharesshares	Jan. 16, 2018USD ($)$ / sharesshares	Dec. 18, 2017USD ($)$ / sharesshares	Jul. 20, 2017USD ($)$ / shares	May 24, 2017USD ($)$ / sharesshares	Jun. 30, 2018USD ($)shares	May 31, 2018USD ($)$ / sharesshares	Mar. 31, 2018USD ($)$ / sharesshares	Mar. 31, 2018$ / sharesshares	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / shares	Jan. 16, 2019$ / shares	Sep. 30, 2018$ / shares	Feb. 12, 2018$ / shares	Dec. 29, 2017$ / shares	Sep. 30, 2017USD ($)$ / sharesshares
Interest Expense, Debt, Total																												$ 3,862,000	$ 3,494,000
Convertible Notes Payable, Total																											$ 6,788,000		6,788,000
Debt Conversion, Converted Instrument, Shares Issued | shares																												6,190,000
Debt Conversion, Original Debt, Amount																												$ 4,626,000
Debt Instrument, Convertible, Conversion Option, Percentage of Additional Funding Required, Holders With a Conversion Price Over $0.30																								20.00%
Proceeds from Conversion Inducement																												357,000
Induced Conversion of Convertible Debt Expense																												276,000
Interest Expense, Total																												$ 3,494,000	3,862,000
Shares Issued, Price Per Share | $ / shares																												$ 0.25
Share Price | $ / shares																		$ 0.3147												$ 0.223
Proceeds from Notes Payable, Total																												$ 400,000
Gain (Loss) on Extinguishment of Debt, Total																												(745,000)
Proceeds from Lines of Credit, Total																												430,000	250,000
Long-term Debt, Excluding Current Maturities, Total																											1,539,000	$ 1,292,000	1,539,000
Triton Fund LLC [Member]
Interest Expense, Total					$ 42,000
Share Price | $ / shares					$ 0.28
Shares Donated | shares					150,000
Triton Warrant [Member]
Discount On Convertible Note Payable					$ 225,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares					1,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares					$ 0.25
Class of Warrant or Right, Call Feature, Exercise Period					30 days
Vista Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares																												1,812,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																												$ 0.25
Warrants and Rights Outstanding							$ 488,000
Warrants Issued Concurrently to the Summer 2017 Unit Offering [Member]
Discount On Convertible Note Payable																																		$ 524,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares																																		1,246,906
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																																		$ 0.65
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares																						1
Class of Warrant or Right, Call Feature, Exercise Period																						30 days
Class of Warrant or Right, Exercise Period Condition, Number of Trading Days Common Stock Closes at or above 2 Times the Exercise Price																						10 years
Proceeds from Issuance of Units																						$ 604,000					524,000	$ 80,000
Warrants Issued Concurrently to the Spring 2018 Unit Offering [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																															$ 0.25
Interest Expense, Total																												$ 17,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares																									333,333	333,333		400,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																									$ 0.48	$ 0.48					$ 0.40
Class of Warrant or Right, Exercise Period Condition, Number of Trading Days Common Stock Closes at or above 2 Times the Exercise Price																										30 days
Note Payable, Maturing January 5, 2019 [Member]
Debt Instrument, Interest Rate, Stated Percentage						12.00%
Proceeds from Notes Payable, Total						$ 400,000
Debt Instrument Extension Option Increase In Principal Percentage						10.00%
Triton Fund Investment [Member]
Debt Instrument, Face Amount					$ 300,000
Debt Instrument, Interest Rate, Stated Percentage					5.00%
Bridge Loan					$ 225,000
Debt Instrument, Repayment, Financing Threshold					3,000,000
Discount On Convertible Note Payable					$ 75,000
Vista Note [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares			666,668																				208,100
Debt Conversion, Original Debt, Amount			$ 166,667																				$ 52,000
Debt Instrument, Increase (Decrease), Net, Total							92,000
Extinguishment of Debt, Amount							165,975
Gain (Loss) on Extinguishment of Debt, Total							$ (166,667)
Notes Payable, Total																												$ 550,000
Vista Note [Member] | Subsequent Event [Member]
Gain (Loss) on Extinguishment of Debt, Total		$ (578,942)
Two Year Convertible Note [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																					$ 0.42
Debt Instrument, Face Amount																					$ 440,000
Debt Instrument, Interest Rate, Stated Percentage																					12.00%
Proceeds from Convertible Debt																					$ 400,000
Debt Instrument, Discount Percent																					10.00%
Debt Instrument, Convertible, Number of Equity Instruments																					2,000
Debt Instrument, Unamortized Discount, Total																					$ 171,000
Line of Credit, Maturing September 1, 2019 [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																$ 0.35
Proceeds from Lines of Credit, Total								$ 40,000								$ 390,000
Line of Credit Facility, Interest Rate During Period																18.00%
Number of Trading Days Prior to Interest Payment Due Date if Paid by Issuance of Common Stock																20 days
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period																10 years
Debt Instrument, Call Notice Period																30 years
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares																1
Winter 2016 Unit Offering [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares													$ 0.57
Long-term Debt, Excluding Current Maturities, Total													$ 75,000											$ 292,000
Summer 2017 Unit Offering [Member]
Convertible Notes Payable, Total				$ 100,000																				$ 478,000				25,000
Debt Conversion, Converted Instrument, Shares Issued | shares				333,334																				2,372,817
Debt Instrument, Convertible, Conversion Price | $ / shares																						$ 0.42										$ 0.30	$ 0.394
Debt Instrument, Interest Rate, Stated Percentage																						12.00%
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																						$ 0.65										$ 0.48
Number of Trading Days Prior to Interest Payment Due Date if Paid by Issuance of Common Stock																						20 days
Proceeds from Issuance of Private Placement																						$ 1,500,000
Debt Conversion before Maturity, Number of Trading Days Common Stock Closes at or above 3 Times the Unit Price																						10 days
Debt Conversion, Converted Instrument, Shares Issued for Principal | shares																								1,595,670
Debt Conversion, Converted Instrument, Shares Issued for Accrued Interest | shares																								777,146
Convertible Notes, Maturing April 20, 2021 [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares														$ 0.30
Debt Instrument, Interest Rate, Stated Percentage														12.00%
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares																									333,333	333,333
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares														$ 0.48
Number of Trading Days Prior to Interest Payment Due Date if Paid by Issuance of Common Stock														20 days
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares														1
Long-term Debt, Excluding Current Maturities, Total	[1]																											100,000
Proceeds from Issuance of Private Placement														$ 1,500,000
Debt Conversion before Maturity, Number of Trading Days Common Stock Closes at or above 3 Times the Unit Price														10 days
Proceeds from Issuance of Units																									$ 100,000
OID Note [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares												$ 0.30
Debt Instrument, Face Amount									$ 32,500			$ 82,500
Debt Instrument, Interest Rate, Stated Percentage												15.00%
Proceeds from Convertible Debt									$ 25,000			$ 75,000
Debt Instrument, Unamortized Discount, Total												$ 10,000
Note Payable, Maturing March 8, 2023 [Member]
Proceeds from Notes Payable, Total															$ 50,000
Long-term Debt, Excluding Current Maturities, Total																												$ 50,000
FirstFire Purchase Agreement [Member]
Stock Issued During Period, Value, Commitment Fee																		$ 11,000
Stock Issued During Period, Additional Commitment Shares, New Issues | shares																		36,536
Vista Purchase Agreement [Member]
Stock Issued During Period, Additional Commitment Shares, New Issues | shares																	140,849
Discount On Convertible Note Payable																	$ 20,000
Stock Issued During Period, Shares, Commitment Fee | shares																				250,000
Vista Purchase Agreement [Member] | Additional Paid-in Capital [Member]
Stock Issued During Period, Value, Commitment Fee																				$ 99,000
Convertible Notes Payable [Member] | Vista Capital [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																				$ 0.394							$ 0.394	$ 0.25	$ 0.394
Debt Instrument, Face Amount																				$ 500,000
Debt Instrument, Interest Rate, Stated Percentage																				5.00%
Proceeds from Notes Payable, Total																				$ 500,000
Convertible Notes Payable [Member] | Vista Note [Member]
Debt Instrument, Increase (Decrease), Percentage							20.00%
Early Conversion of Unit Notes [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares																								17,255,811
Debt Conversion, Original Debt, Amount																								$ 4,626,000
Maximum Conversion Price Available for Conversion Option of a Convertible Debt Instrument For Holders With Debt Instruments With a Conversion Price Over $0.30 | $ / shares																								$ 0.30
Debt Conversion, Conversion Incentive, Conversion Price Reduced, Additional Shares Issued | shares																								966,318
Early Conversion of Unit Notes with 0.25 Conversion Prices [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 0.25
Debt Conversion, Converted Instrument, Incentive Shares Issuable for Payment of Interest, Calculated Price | $ / shares																								$ 0.25
Debt Conversion, Conversion Incentive, Input, Interest																								$ 1,000
Debt Conversion, Converted Instrument, Incentive Shares Issuable for Payment of Interest | $ / shares																								$ 1.50
Debt Conversion, Conversion Incentive, Output, Number of Incentive Shares | shares																								6,000
Early Conversion of Unit Notes with 0.30 Conversion Prices [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 0.30
Convertible Notes With Original Conversion Prices of $0.35 [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 0.35
Debt Instrument, Convertible, Conversion Option, Percentage of Additional Funding Required, Holders With a Conversion Price Over $0.30																								6.00%
Convertible Notes With Original Conversion Prices of $0.55 [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 0.55
Convertible Notes With Original Conversion Prices of $0.57 [Member]
Debt Instrument, Convertible, Conversion Price | $ / shares																								$ 0.57
Unit Notes Reduced Conversion Price to 0.30 [Member]
Proceeds from Conversion Inducement																								$ 357,000
Debt Conversion, Conversion Incentive, Conversion Price Reduce, Additional Share Issue Upon Conversion | shares																								2,749,197
Induced Conversion of Convertible Debt Expense																								$ 632,000
Interest Expense, Total																								$ 276,000
Conversion of Unit Notes [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares													2,488,819
Debt Conversion, Original Debt, Amount													$ 822,000
Conversion of Unit Notes, Principal, With Conversion Price 0.25, 0.35 and 0.55 [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares													2,411,004
Conversion of Unit Notes, Unpaid Interest [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares													77,815
Debt Conversion, Original Debt, Accrued Interest Amount													$ 20,000
Convertible Notes Maturing on July 18, 2018 [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares											1,153,600
Debt Conversion, Original Debt, Amount											$ 280,000
Debt Conversion, Original Debt, Accrued Interest Amount											9,000
Debt Instrument, Face Amount											$ 280,000
Shares Issued, Price Per Share | $ / shares											$ 0.25
First Fire [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares																							383,047
Debt Conversion, Original Debt, Amount																							$ 96,000
Stock Issued During Period, Share, Paid for Interest | shares																							11,902
First Fire [Member] | Convertible Debt [Member]
Debt Conversion, Converted Instrument, Shares Issued | shares										217,960
Debt Instrument, Convertible, Conversion Price | $ / shares										$ 0.25									$ 0.394								$ 0.394	$ 0.25	$ 0.394
Debt Instrument, Face Amount																			$ 150,000
Debt Instrument, Interest Rate, Stated Percentage																			5.00%
Short-term Debt, Total										$ 54,000
FirstFire Purchase Agreement [Member]
Stock Issued During Period, Shares, Commitment Shares | shares																			75,000
Share Price | $ / shares																			$ 0.39
Stock Issued During Period, Value, Commitment Fee																			$ 29,000
[1]	See Note 14 "Subsequent Events"

Note 5 - Debt Obligations - Sch

Note 5 - Debt Obligations - Schedule of Debt (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Notes payable		$ 400
Convertible notes		1,365	5,249
Total current liabilities		2,195	5,249
Long-term Debt, Excluding Current Maturities, Total		1,292	1,539
Total		3,487	6,788
Notes Payable, Maturing January 5, 2019 [Member]
Notes payable		400
Line of Credit, Maturing September 1, 2019 [Member]
Line of credit, matures September 1, 2019 or later (on 30 day demand)	[1]	430
Convertible Notes Maturing on June 1, 2018 [Member]
Convertible notes			4,469
Convertible Notes Maturing on July 18, 2018 [Member]
Convertible notes			280
Convertible Notes Maturing on December 31, 2019 [Member]
Convertible notes	[2]	75
Long-term Debt, Excluding Current Maturities, Total	[1]		292
Convertible Notes Maturing January 11, 2019 [Member]
Convertible notes	[1]	300
Convertible Note Maturing October 16, 2018 [Member]
Convertible notes	[1]	550	500
Convertible Notes Maturing on July 20, 2019 [Member]
Convertible notes	[2]	440
Convertible Notes Issued by Clyra Medical Maturing on June 17, 2020 [Member]
Long-term Debt, Excluding Current Maturities, Total		1,007
Convertible Notes Maturing on September 17, 2019 [Member]
Long-term Debt, Excluding Current Maturities, Total			284
Convertible Notes, Maturing on June 20, 2020 [Member]
Long-term Debt, Excluding Current Maturities, Total	[1]	25	523
Convertible Notes, Maturing July 20, 2019 [Member]
Long-term Debt, Excluding Current Maturities, Total			440
Convertible Notes, Maturing April 20, 2021 [Member]
Long-term Debt, Excluding Current Maturities, Total	[1]	100
Convertible Notes, Mature June 15, 2021 [Member]
Long-term Debt, Excluding Current Maturities, Total		110
Note Payable, Maturing March 8, 2023 [Member]
Long-term Debt, Excluding Current Maturities, Total		$ 50
[1]	See Note 14 "Subsequent Events"
[2]	These notes are convertible at our option at maturity.

Note 5 - Debt Obligations - Ear

Note 5 - Debt Obligations - Early Conversion of Unit Notes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Debt Conversion, Original Debt, Amount	$ 4,626
Convertible Notes Maturing on June 1, 2018 [Member]
Debt Conversion, Original Debt, Amount	3,647
Convertible Notes Maturing on June 17, 2019 [Member]
Debt Conversion, Original Debt, Amount	284
Convertible Notes Maturing on December 31, 2019 [Member]
Debt Conversion, Original Debt, Amount	217
Convertible Notes, Maturing on June 20, 2020 [Member]
Debt Conversion, Original Debt, Amount	$ 478

Note 6 - Share-based Compensa_3

Note 6 - Share-based Compensation (Details Textual) - USD ($)	Jun. 22, 2018	Dec. 29, 2017	Oct. 23, 2017	Oct. 17, 2017	Sep. 07, 2017	Sep. 05, 2017	Jun. 19, 2017	May 02, 2017	Apr. 30, 2017	Feb. 10, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 16, 2019	Feb. 08, 2018
Shares Issued, Price Per Share												$ 0.25		$ 0.25
Stock Issued During Period, Value, Issued for Services														$ 908,000	$ 462,000
Share Price																$ 0.223	$ 0.3147
2018 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												$ 0.24		$ 0.24
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross												1,318,517
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price												$ 0.34
The 2007 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												0.24		$ 0.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross															340,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period														140,000	425,000
Non Plan [Member]
Shares Issued, Price Per Share												0.24		$ 0.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross														1,701,088	7,765,401
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period														2,400,000	4,029,129
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense, Total														$ 1,335,000	$ 1,103,000
Maximum [Member] | The 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period					10 years
President and Chief Executive Officer [Member]
Employment Agreement, Common Stock, Expect to Grant, Subject to Lock-Up Agreement								1,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period								10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross								3,731,322
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period								5 years
Employment Agreement, Term								5 years
Employment Agreement, Lock-up Agreement, Successful Commercialization, Minimum Cash Receipt								$ 3,000,000
Employment Agreement, Lock-up Agreement, Minimum Revenue Recognized								$ 3,000,000
President and Chief Executive Officer [Member] | Non-Qualified Stock Option [Member]
Allocated Share-based Compensation Expense, Total														$ 336,000	$ 196,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period								10 years
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price								$ 0.45
Sharebased Compensation Arrangement by Sharebased Payment Award Options Granted in Period, Fair Value								$ 1,679,000
President and Chief Executive Officer [Member] | 2007 Stock Option [Member]
Stock Issued During Period, Shares, New Issues									3,866,630
Investment Options, Exercise Price									$ 0.18
Share Price									$ 0.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period									3,866,629
President and Chief Executive Officer [Member] | Shares Issued for the Exercise of 2007 Stock Option [Member]
Stock Issued During Period, Shares, New Issues									2,501,937
Officer [Member]
Stock Issued During Period, Shares, Issued for Services														1,131,036	148,705
Shares Issued, Price Per Share															$ 0.39
Stock Issued During Period, Value, Issued for Services														$ 319,000	$ 58,000
Lock-up Agreement, Vesting Requirement, Commercialization of Product, Receipt in Cash														3,000,000
Lock-up Agreement, Vesting Requirement, Commercialization of Product, Revenue														$ 3,000,000
Officer [Member] | Minimum [Member]
Shares Issued, Price Per Share												0.24		$ 0.24
Officer [Member] | Maximum [Member]
Shares Issued, Price Per Share												0.43		$ 0.43
Consultants [Member]
Stock Issued During Period, Shares, Issued for Services														4,125,281	2,272,116
Stock Issued During Period, Value, Issued for Services														$ 1,012,000	$ 1,078,000
Consultants [Member] | Minimum [Member]
Shares Issued, Price Per Share												0.23		$ 0.23	$ 0.39
Consultants [Member] | Maximum [Member]
Shares Issued, Price Per Share												$ 0.42		0.42	$ 0.70
Employees and Consultants [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross												630,289
Employees and Consultants [Member] | Selling, General and Administrative Expenses [Member] | 2018 Equity Incentive Plan [Member] | Employee Stock Option [Member]
Allocated Share-based Compensation Expense, Total												$ 187,000
Employees and Consultants [Member] | Minimum [Member] | 2018 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												$ 0.22		0.22
Employees and Consultants [Member] | Maximum [Member] | 2018 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												$ 0.43		0.43
Board Of Directors [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross												688,228
Board Of Directors [Member] | Selling, General and Administrative Expenses [Member] | 2018 Equity Incentive Plan [Member] | Employee Stock Option [Member]
Allocated Share-based Compensation Expense, Total												$ 203,000
Board Of Directors [Member] | Minimum [Member] | 2018 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												$ 0.24		0.24
Board Of Directors [Member] | Maximum [Member] | 2018 Equity Incentive Plan [Member]
Shares Issued, Price Per Share												0.43		$ 0.43
Non-employee Members of the Board of Directors [Member] | The 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross							40,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price							$ 0.43
Non-employee Members of the Board of Directors [Member] | Selling, General and Administrative Expenses [Member] | The 2007 Equity Incentive Plan [Member]
Allocated Share-based Compensation Expense, Total							$ 16,000
Chief Financial Officer [Member] | The 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross										300,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price										$ 0.69
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares										125,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month										25,000
Sharebased Compensation Arrangement by Sharebased Payment Award Options Granted in Period, Fair Value										$ 207,000
Chief Financial Officer [Member] | Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		300,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 0.39
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares		75,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month		25,000
Sharebased Compensation Arrangement by Sharebased Payment Award Options Granted in Period, Fair Value		$ 117,000
Chief Financial Officer [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member]
Allocated Share-based Compensation Expense, Total														$ 88,000	$ 29,000
Board of Directors and Vendors [Member] | Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross														1,701,088	1,433,999
Board of Directors and Vendors [Member] | Non Plan [Member] | Employee Stock Option [Member]
Allocated Share-based Compensation Expense, Total														$ 434,000	$ 716,000
Board of Directors and Vendors [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member] | Employee Stock Option [Member]
Allocated Share-based Compensation Expense, Total														$ 414,000
Board of Directors and Vendors [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member] | Employee Stock Option [Member] | Scenario, Forecast [Member]
Allocated Share-based Compensation Expense, Total													$ 20,000
Board of Directors and Vendors [Member] | Minimum [Member] | Non Plan [Member]
Shares Issued, Price Per Share												0.39		$ 0.39	$ 0.39
Board of Directors and Vendors [Member] | Maximum [Member] | Non Plan [Member]
Shares Issued, Price Per Share												$ 0.67		$ 0.67	$ 0.67
Secretary [Member] | Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			100,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 0.45
Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month			10,000
Sharebased Compensation Arrangement by Sharebased Payment Award Options Granted in Period, Fair Value			$ 45,000
Secretary [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member]
Allocated Share-based Compensation Expense, Total														$ 34,000	$ 9,000
Employee and Member of BioLargo Maritime Solutions [Member] | Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				100,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price				$ 0.47
Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month				10,000
Sharebased Compensation Arrangement by Sharebased Payment Award Options Granted in Period, Fair Value				$ 94,000
Employee and Member of BioLargo Maritime Solutions [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member]
Allocated Share-based Compensation Expense, Total														75,000	$ 19,000
Seven Employees Working at BioLargo Engineering, Science & Technologies, LLC [Member] | Non-Qualified Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross											2,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period											5 years
Seven Employees Working at BioLargo Engineering, Science & Technologies, LLC [Member] | Non Plan [Member] | Non-Qualified Stock Option [Member]
Allocated Share-based Compensation Expense, Total														$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period						10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross						2,000,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price						$ 0.45
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period						5 years
Employment Agreement, Term						5 years

Note 6 - Share-based Compensa_4

Note 6 - Share-based Compensation - Stock Options (Details) - 2018 Equity Incentive Plan [Member] - USD ($)		6 Months Ended
		Dec. 31, 2018	Dec. 31, 2018
Options outstanding, granted (in shares)		1,318,517
Weighted average price per share, granted (in dollars per share)		$ 0.34
Options outstanding, balance (in shares)			1,318,517
Weighted average price per share, balance (in dollars per share)			$ 0.34
Aggregate intrinsic value, balance	[1]		$ 1,000
Minimum [Member]
Exercise price per share, granted (in dollars per share)		0.22
Exercise price per share, balance (in dollars per share)		0.22	$ 0.22
Exercise price per share, balance (in dollars per share)		0.22
Maximum [Member]
Exercise price per share, granted (in dollars per share)		0.43
Exercise price per share, balance (in dollars per share)		0.43	$ 0.43
Exercise price per share, balance (in dollars per share)		$ 0.43
[1]	Aggregate intrinsic value based on closing stock price of $0.24 at December 31, 2018.

Note 6 - Share-based Compensa_5

Note 6 - Share-based Compensation - Stock Options Issued Under the 2007 Equity Incentive Plan (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares		Dec. 31, 2017$ / sharesshares
The 2007 Equity Incentive Plan [Member]
Options outstanding, Balance (in shares) | shares	9,831,586		9,916,586
Exercise price per share, Balance (in dollars per share)	$ 1.89		$ 1.89
Options outstanding, granted (in shares) | shares			340,000
Exercise price per share, granted (in dollars per share)			$ 0.69
Options outstanding, expired (in shares) | shares	(140,000)		(425,000)
Exercise price per share, expired (in dollars per share)	$ 1.89		$ 0.94
Options outstanding, Balance (in shares) | shares	9,691,586		9,831,586
Exercise price per share, balance (in dollars per share)	$ 0.94		$ 1.89
Weighted average price per share, balance (in dollars per share)	1,000	[1]
The 2007 Equity Incentive Plan [Member] | Minimum [Member]
Exercise price per share, Balance (in dollars per share)	0.22		0.22
Exercise price per share, granted (in dollars per share)			0.39
Exercise price per share, expired (in dollars per share)	0.35		0.40
Exercise price per share, balance (in dollars per share)	0.23		0.22
The 2007 Equity Incentive Plan [Member] | Maximum [Member]
Exercise price per share, Balance (in dollars per share)	0.44		0.44
Exercise price per share, granted (in dollars per share)			0.65
Exercise price per share, expired (in dollars per share)	1.41		0.91
Exercise price per share, balance (in dollars per share)	$ 0.43		$ 0.44
Non Plan [Member]
Options outstanding, Balance (in shares) | shares	20,018,408		20,148,766
Exercise price per share, Balance (in dollars per share)	$ 1		$ 1
Options outstanding, granted (in shares) | shares	1,701,088		7,765,401
Exercise price per share, granted (in dollars per share)	$ 0.43		$ 0.69
Options outstanding, expired (in shares) | shares	(2,400,000)		(4,029,129)
Exercise price per share, expired (in dollars per share)	$ 0.99		$ 0.18
Options outstanding, Balance (in shares) | shares	19,319,496		20,018,408
Exercise price per share, balance (in dollars per share)	$ 1		$ 1
Weighted average price per share, balance (in dollars per share)	$ 1,000	[1]
Options outstanding, exercised (in shares) | shares			(3,866,630)
Exercise price per share, exercised (in dollars per share)			$ 0.18
Options outstanding, unvested (in shares) | shares	(90,000)
Exercise price per share, unvested (in dollars per share)	$ 0.28
Options vested and outstanding (in shares) | shares	19,229,496
Exercise price per share, vested and outstanding (in dollars per share)	$ 1
Non Plan [Member] | Minimum [Member]
Exercise price per share, Balance (in dollars per share)	0.25		0.18
Exercise price per share, granted (in dollars per share)	0.23		0.39
Exercise price per share, expired (in dollars per share)
Exercise price per share, balance (in dollars per share)	0.23		0.25
Exercise price per share, exercised (in dollars per share)
Exercise price per share, unvested (in dollars per share)	0.26
Exercise price per share, vested and outstanding (in dollars per share)	0.23
Non Plan [Member] | Maximum [Member]
Exercise price per share, Balance (in dollars per share)	0.51		0.40
Exercise price per share, granted (in dollars per share)	0.26		0.46
Exercise price per share, expired (in dollars per share)	0.99		0.18
Exercise price per share, balance (in dollars per share)	0.43		0.51
Exercise price per share, exercised (in dollars per share)			$ 0.18
Exercise price per share, unvested (in dollars per share)	0.27
Exercise price per share, vested and outstanding (in dollars per share)	$ 0.43
[1]	Aggregate intrinsic value based on closing common stock price of $0.24 at December 31, 2018.

Note 7 - Warrants (Details Text

Note 7 - Warrants (Details Textual)	Oct. 16, 2018USD ($)$ / sharesshares	Sep. 19, 2018USD ($)$ / sharesshares	Mar. 08, 2018USD ($)$ / sharesshares	Feb. 12, 2018USD ($)$ / sharesshares	Dec. 29, 2017USD ($)$ / sharesshares	Jul. 18, 2017$ / sharesshares	May 24, 2017	Dec. 30, 2016$ / sharesshares	Jul. 08, 2016$ / sharesshares	May 31, 2018USD ($)$ / sharesshares	Mar. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Sep. 30, 2018$ / shares	Sep. 12, 2018$ / sharesshares	Sep. 30, 2017USD ($)$ / sharesshares
Interest Expense, Total												$ 3,494,000	$ 3,862,000
Proceeds from Adjustment of Warrant												$ 149,000
Discount on Notes Payable											$ 49,000
Class of Warrant or Right, Issued During Period | shares												7,451,013	2,289,703
Deemed Dividends												$ 297,000	$ 344,000
Stock Issued During Period, Shares, Exercise of Warrants | shares													510,000
Proceeds from Warrant Exercises													$ 153,000
Triton Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	1,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares	$ 0.25
Discount On Convertible Note Payable	$ 225,000
Class Of Warrant Or Right, Call Feature, Stock Price Trigger | $ / shares	$ 0.50
Class Of Warrant Or Right, Threshold Consecutive Trading Days	10
Class of Warrant or Right, Call Feature, Exercise Period	30 days
Stock Purchase Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares		1,387,500
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares		$ 0.25
Discount On Convertible Note Payable		$ 217,000
Class Of Warrant Or Right, Call Feature, Stock Price Trigger | $ / shares		$ 2.50
Class Of Warrant Or Right, Threshold Consecutive Trading Days		10
Class of Warrant or Right, Call Feature, Exercise Period		30 days
Extension of Convertible Note Maturity Date, Vista Capital [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares															1,812,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares															$ 0.25
Interest Expense, Total												$ 488,000
Warrants Issued Concurrently with Note Payable [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares			150,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares			$ 0.35
Notes Payable, Total			$ 50,000
Warrants Vested Monthly Contingent That Outstanding Note Payable is Present | shares			6,250
Warrants Vested, Cumulative Total of Warrants Vested | shares												56,250
Minimum Number of Warrants Vested For the Life of the Outstanding Note Payable, Fair Value Amount												$ 7,000
Warrants, Exercise Price Reduced [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares										4,326,358
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares										$ 0.30
Proceeds from Adjustment of Warrant										$ 149,000
Fair Value Adjustment of Warrants										$ 149,000
Warrants Issued Concurrently to the Spring 2018 Unit Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares											333,333	400,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares											$ 0.48			$ 0.40
Interest Expense, Total												$ 17,000
Class of Warrant or Right, Exercise Period Condition, Number of Trading Days Common Stock Closes at or above 2 Times the Exercise Price											30 days
Warrant Subject to Call provision, Threshold Consecutive Trading Days											10 days
Debt Instrument, Convertible, Conversion Price | $ / shares														$ 0.25
Warrants Issued Concurrently with Line of Credit [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares												430,000
Discount On Convertible Note Payable												$ 98,000
Class of Warrant or Right, Exercise Period Condition, Number of Trading Days Common Stock Closes at or above 2 Times the Exercise Price											30 days
Warrant Subject to Call provision, Threshold Consecutive Trading Days											10 days
Warrants Issued Concurrently with Line of Credit, Exercise Price One [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares												390,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares												$ 0.35
Warrants Issued Concurrently with Line of Credit, Exercise Price Two [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares												40,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares												$ 0.25
Warrants Issued Concurrently to the Summer 2017 Unit Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares																1,246,906
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares																$ 0.65
Discount On Convertible Note Payable																$ 524,000
Class of Warrant or Right, Call Feature, Exercise Period							30 days
Class of Warrant or Right, Exercise Period Condition, Number of Trading Days Common Stock Closes at or above 2 Times the Exercise Price							10 years
Warrants Issued Concurrently to the Summer 2017 Unit Offering 2 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares					1,329,189
Debt Instrument, Convertible, Conversion Price | $ / shares					$ 0.394
Class of Warrant or Right, Additional Securities Called by Warrants | shares					82,283
Debt Instrument, Unamortized Discount, Total					$ 32,000
Warrants Issued Concurrently to the Summer 2017 Unit Offering 3 [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares				$ 0.30
Discount On Convertible Note Payable				$ 103,000
Class of Warrant or Right, Issued During Period | shares				416,478							266,667
Proceeds from Convertible Debt											$ 80,000
Warrants Issued Concurrently With One Year Convertible Note [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares						$ 0.65		$ 0.75	$ 0.65			$ 0.25	$ 0.394
Discount On Convertible Note Payable													$ 280,000
Class of Warrant or Right, Issued During Period | shares						400,000		400,000	400,000
Deemed Dividends												$ 297,000	$ 344,000
Triton Fund Investment [Member]
Bridge Loan	$ 225,000
Debt Instrument, Face Amount	300,000
Discount On Convertible Note Payable	$ 75,000

Note 7 - Warrants - Warrants Ou

Note 7 - Warrants - Warrants Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Balance, outstanding (in shares)	22,104,817	20,035,114
Balance, outstanding, price range (in dollars per share)	$ 1	$ 1
Granted (in shares)	7,451,013	2,289,703
Granted, price range (in dollars per share)	$ 0.48	$ 0.70
Exercised (in shares)		(510,000)
Exercised, price range (in dollars per share)		$ 0.30
Expired (in shares)	(2,683,400)	(250,000)
Expired, price range (in dollars per share)	$ 0.40	$ 0.40
Balance, outstanding (in shares)	26,872,430	22,104,817
Balance, outstanding, price range (in dollars per share)	$ 1	$ 1
Unvested (in shares)	(87,500)
Unvested, price range (in dollars per share)	$ 0.35
Vested and outstanding (in shares)	26,784,930
Vested and outstanding, , price range (in dollars per share)	$ 1
Minimum [Member]
Balance, outstanding, price range (in dollars per share)	0.25	0.25
Granted, price range (in dollars per share)	0.25	0.42
Balance, outstanding, price range (in dollars per share)	0.25	0.25
Vested and outstanding, , price range (in dollars per share)	0.25
Maximum [Member]
Balance, outstanding, price range (in dollars per share)	0.45	0.45
Granted, price range (in dollars per share)	0.29	0.41
Exercised, price range (in dollars per share)		0.30
Expired, price range (in dollars per share)	0.40	0.40
Balance, outstanding, price range (in dollars per share)	0.43	$ 0.45
Unvested, price range (in dollars per share)	0.35
Vested and outstanding, , price range (in dollars per share)	$ 0.42

Note 7 - Warrants - Assumptions

Note 7 - Warrants - Assumptions Used to Determine Fair Value of Warrants (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Expected life (Year)
Minimum [Member]
Risk free interest rate	2.54%	1.71%
Expected volatility	105.00%	221.00%
Expected life (Year)	3 years	3 years
Maximum [Member]
Risk free interest rate	3.00%	2.10%
Expected volatility	127.00%	297.00%
Expected life (Year)	5 years	5 years

Note 8 - Accounts Payable and_3

Note 8 - Accounts Payable and Accrued Expenses - Summary of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts payable and accrued expense	$ 302	$ 88
Accrued interest	122	51
Accrued payroll	77	85
Total accounts payable and accrued expenses	$ 501	$ 224

Note 9 - Provision for Income_2

Note 9 - Provision for Income Taxes (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Operating Loss Carryforwards, Total	$ 58.5
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$ 11.1
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	$ 4.6
Net Operating Loss Carryforward Expiration Term	20 years
Valuation Allowance Percentage	100.00%

Note 10 - Noncontrolling Inte_3

Note 10 - Noncontrolling Interest - Clyra Medical (Details Textual) - USD ($)	Sep. 26, 2018	Aug. 04, 2017	Apr. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Payments to Noncontrolling Interests					$ 40,000
Shares Issued, Price Per Share				$ 0.25
Noncontrolling Interest, Increase from Subsidiary Equity Issuance				$ 1,005,000	1,020,000
Proceeds from Issuance of Common Stock				$ 839,000	$ 511,000
Preferred Stock, Shares Outstanding, Ending Balance				0	0
Scion Acquisition [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	21,000
Scion Acquisition [Member] | Clyra Acquisition, Common Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	10,000			15,500
Clyra [Member]
Minority Interest Decrease From Redemption, Shares Purchased			500
Payments to Noncontrolling Interests			$ 40,000
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		$ 250,000
Stock Issued During Period, Shares, New Issues		1,562.5
Clyra Medical Technology Inc [Member]
Shares Issued, Price Per Share		$ 160
Proceeds from Issuance of Private Placement		$ 1,000,000
Clyra Medical Technology Inc [Member] | Scion Acquisition [Member]
Shares Issued, Price Per Share				$ 200
Proceeds from Issuance of Common Stock				$ 1,005,000
Clyra Medical Technology Inc [Member] | Sanatio [Member]
Shares Issued, Price Per Share		$ 160
Stock Issued During Period, Shares, New Issues		1,690
Common Stock, Shares, Outstanding, Ending Balance				1,690
Preferred Stock, Dividend Rate, Percentage				8.00%
Preferred Shares Dividend, Period				5 years
Dividends Payable, Current				$ 185,000
Clyra Medical Technology Inc [Member] | Sanatio [Member] | Preferred Class A [Member]
Preferred Stock, Shares Outstanding, Ending Balance				9,830
Clyra Medical Technology Inc [Member] | Sanatio [Member]
Line of Credit Facility, Maximum Borrowing Capacity						$ 250,000
Debt Instrument, Interest Rate, Stated Percentage						10.00%
Original Issue Discount, Percentage						5.00%

Note 10 - Noncontrolling Inte_4

Note 10 - Noncontrolling Interest - Clyra Medical Common and Preferred Shares Outstanding (Details) - Clyra Medical Technology Inc [Member]	Dec. 31, 2018shares
Shares, Outstanding (in shares)	66,295
Biolargo [Member]
Shares, Outstanding (in shares)	28,053
Percent	42.30%
Sanatio [Member]
Shares, Outstanding (in shares)	11,520	[1]
Percent	17.40%	[1]
Scion Solutions [Member]
Shares, Outstanding (in shares)	15,500	[2]
Percent	23.40%	[2]
Other [Member]
Shares, Outstanding (in shares)	11,222
Percent	16.90%
[1]	Includes 9,830 Series A Preferred shares (see below), and 1,690 common shares.
[2]	Does not include an additional 15,500 shares held in escrow subject to performance metrics (see Note 3).

Note 11 - BioLargo Engineerin_2

Note 11 - BioLargo Engineering, Science and Technologies, LLC (Details Textual) shares in Millions	1 Months Ended
	Sep. 30, 2017shares
Seven Employees Working at BioLargo Engineering, Science & Technologies, LLC [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period	5 years
Potential Ownership Percentage of Subsidiary Held by Subsidiary Employees Based on Performance	30.00%
Incentive Issuance Stipulations for Subsidiary Employees, Accounts Receivable Collected by Year One of Operation	90.00%
Incentive Issuance Stipulations for Subsidiary Employees, Profit Earned in Year One of Operation	10.00%
Seven Employees Working at BioLargo Engineering, Science & Technologies, LLC [Member] | Non-Qualified Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	2
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
BioLargo Engineering, Science & Technologies, LLC [Member]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Leased Property in Knoxville, Tennessee for BioLargo Engineering, Science & Technologies, LLC [Member]
Lessee, Operating Lease, Term of Contract	3 years

Note 12 - Business Segment In_3

Note 12 - Business Segment Information (Details Textual)	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Number of Operating Segments	4
Payments of Distributions to Affiliates	$ 417,000
Revenue from Contract with Customer, Including Assessed Tax	1,364,000	$ 516,000
Odor-No-More [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 1,123,000	$ 504,000

Note 12 - Business Segment In_4

Note 12 - Business Segment Information - Segment Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 1,364,000	$ 516,000
Cost of Goods and Services Sold	(743,000)	(323,000)
Net loss	(10,696,000)	(9,547,000)
Assets, net	3,185,000	1,496,000
Odor-No-More [Member]
Revenue	1,123,000	504,000
Cost of Goods and Services Sold	(571,000)	(315,000)
Net loss	(433,000)	(500,000)
Assets, net	219,000	211,000
BioLargo Engineering, Science & Technologies, LLC [Member]
Revenue	241,000	12,000
Cost of Goods and Services Sold	(172,000)	(8,000)
Net loss	(750,000)	(90,000)
Assets, net	250,000
Clyra Segment [Member]
Net loss	(883,000)	(915,000)
Assets, net	462,000	529,000
BioLargo Water [Member]
Net loss	(571,000)	(741,000)
Assets, net	34,000	64,000
Corporate Segment [Member]
Net loss	(8,059,000)	(7,301,000)
Assets, net	$ 2,220,000	$ 692,000

Note 13 - Commitments and Con_3

Note 13 - Commitments and Contingencies (Details Textual) - USD ($)	May 02, 2017	Dec. 30, 2015	Dec. 31, 2018	Dec. 31, 2017
Operating Leases, Rent Expense, Total			$ 213,000	$ 183,000
Consulting Services, Monthly Payment		$ 23,000
Consulting Services, Period of Services		4 years
Contractual Obligation, Total			1,100,000
President and Chief Executive Officer [Member]
Employment Agreement, Annual Base Compensation	$ 289,000
Payments to Employees			$ 147,000
Employment Agreement, Option, Number of Shares, Expected to Grant	3,731,322
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	5 years
Employment Agreement, Common Stock, Expect to Grant, Subject to Lock-Up Agreement	1,500,000
Employment Agreement, Lock-up Agreement, Successful Commercialization, Minimum Cash Receipt	$ 3,000,000
Employment Agreement, Lock-up Agreement, Minimum Revenue Recognized	$ 3,000,000
Employment Agreement, Term	5 years
President and Chief Executive Officer [Member] | Non-Qualified Stock Option [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 0.45
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years

Note 13 - Commitments and Con_4

Note 13 - Commitments and Contingencies - Minimum Payments on Office Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
2019	$ 229
2020	231
Total future minimum lease payments	$ 460

Note 14 - Subsequent Events (De

Note 14 - Subsequent Events (Details Textual) - USD ($)

Feb. 05, 2019

Jan. 31, 2019

Jan. 16, 2019

Jan. 07, 2019

Jan. 03, 2019

Feb. 10, 2017

Mar. 28, 2019

Dec. 31, 2018

Dec. 31, 2017

Mar. 07, 2019

Mar. 06, 2019

Mar. 05, 2019

Mar. 04, 2019

Jan. 06, 2019

Feb. 08, 2018

Dec. 18, 2017

Debt Conversion, Original Debt, Amount

$ 4,626,000

Debt Conversion, Converted Instrument, Shares Issued

6,190,000

Common Stock, Shares Authorized

200,000,000

200,000,000

Share Price

$ 0.223

$ 0.3147

The 2007 Equity Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

340,000

The 2007 Equity Incentive Plan [Member] | Chief Financial Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

300,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares

125,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month

25,000

Convertible Notes Payable [Member] | Vista Capital [Member]

Debt Instrument, Face Amount

$ 500,000

Debt Instrument, Interest Rate, Stated Percentage

5.00%

Subsequent Event [Member] | The 2007 Equity Incentive Plan [Member] | Chief Financial Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

300,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares

75,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month

25,000

Subsequent Event [Member] | Lincoln Park Capital Fund, LLC [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights

50,000

250,000

Class of Warrant or Right, Exercise Price of Warrants or Rights

$ 0.25

$ 0.25

Class of Warrant or Right, Expiration Term

5 years

5 years

Subsequent Event [Member] | Vista Capital 2017 Note [Member]

Debt Instrument Extension Option Increase In Principal Percentage

10.00%

Debt Conversion, Original Debt, Amount

$ 225,000

Debt Conversion, Converted Instrument, Shares Issued

1,679,248

Subsequent Event [Member] | Convertible Notes Payable [Member] | Tangiers Global [Member]

Debt Instrument, Face Amount

$ 330,000

$ 495,000

Debt Instrument, Convertible, Conversion Price, Percentage of Lowest Closing Bid Price

75.00%

Debt Instrument, Convertible, Number of Consecutive Trade Days Prior to Conversion Date

25 days

Debt Instrument, Convertible, Prepayment Penalty

30.00%

Proceeds from Convertible Debt

$ 300,000

Debt Instrument, Convertible, Interest Rate on Remaining Principal

12.00%

Debt Instrument, Convertible, Aggregate Principal Amount

$ 495,000

Proceeds from Convertible Debt, Additional Consideration

$ 150,000

Debt Instrument, Convertible, Days to Prepay Following Effective Date

180 days

Common Stock, Shares Authorized

3,000,000

Subsequent Event [Member] | Convertible Notes Payable [Member] | Tangiers Global [Member] | Tangiers Global Convertible Note, Prepayment Period First 90 Days [Member]

Debt Instrument, Convertible, Prepayment Penalty

25.00%

Subsequent Event [Member] | Vernal Bay Investments, LLC [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights

1,734,375

1,387,500

Class of Warrant or Right, Exercise Price of Warrants or Rights

$ 0.20

$ 0.25

Maximum Investment Amount under Warrant

$ 346,875

Subsequent Event [Member] | Chappy Bean, LLC [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights

750,000

600,000

Class of Warrant or Right, Exercise Price of Warrants or Rights

$ 0.20

Notes Payable, Maturing January 5, 2019 [Member] | Subsequent Event [Member]

Debt Instrument, Face Amount

$ 400,000

Debt Instrument Extension Option Increase In Principal Percentage

10.00%

Debt Instrument, Face Value, After Increase from Maturity Date Extension

$ 440,000

Debt Instrument, Interest Rate, Stated Percentage

18.00%

12.00%

Notes Payable, Maturing January 5, 2019 [Member] | Subsequent Event [Member] | Vernal Bay Investments, LLC [Member]

Debt Instrument, Face Amount

280,000

Notes Payable, Maturing January 5, 2019 [Member] | Subsequent Event [Member] | Chappy Bean, LLC [Member]

Debt Instrument, Face Amount

$ 120,000

Vista Capital 2017 Note [Member] | Subsequent Event [Member]

Debt Instrument, Face Amount

$ 420,452

Vista Capital 2017 Note [Member] | Subsequent Event [Member] | Convertible Notes Payable [Member] | Vista Capital [Member]

Debt Instrument, Face Value, After Increase from Maturity Date Extension

$ 605,100

Debt Instrument, Interest Rate, Stated Percentage

5.00%

Debt Instrument, Convertible, Conversion Price, Percentage of Lowest Closing Bid Price

80.00%

Debt Instrument, Convertible, Number of Consecutive Trade Days Prior to Conversion Date

25 days

Debt Instrument, Convertible, Prepayment Penalty

15.00%

20.00%

Debt Instrument, Convertible, Default Penalty

25.00%

30.00%

Vista Capital 2019 Note [Member] | Subsequent Event [Member] | Convertible Notes Payable [Member] | Vista Capital [Member]

Debt Instrument, Face Amount

$ 330,000

Debt Instrument, Interest Rate, Stated Percentage

12.00%

Debt Instrument, Convertible, Conversion Price, Percentage of Lowest Closing Bid Price

65.00%

Debt Instrument, Convertible, Number of Consecutive Trade Days Prior to Conversion Date

25 days

Extinguishment of Debt, Amount

$ 746,000

Proceeds from Convertible Debt

$ 300,000

Common Stock, Limit on Ownership Interest, Percent

4.99%

Debt Instrument, Convertible, Number of Business Days Notice of Prepayment

10 days

Debt Instrument, Convertible, Outstanding Balance Including Prepayment Penalty, Percent

120.00%