BioLargo (BLGO) 10-K 30 Mar 21 2020 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 24, 2021	Jun. 30, 2020
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 Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		238,776,271
Entity Public Float			$ 30,512,541
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Title of 12(b) Security	Common Stock

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 716,000	$ 655,000
Accounts receivable, net of allowance	484,000	355,000
Inventories, net of allowance	277,000	16,000
Prepaid expenses and other current assets	28,000	39,000
Total current assets	1,505,000	1,065,000
In-process research and development (Note 9)	2,150,000	1,893,000
Equipment, net of depreciation	60,000	95,000
Other non-current assets	35,000	35,000
Investment in South Korean joint venture	63,000
Right of use, operating lease, net of amortization	341,000	411,000
Deferred offering cost		122,000
Clyra Medical prepaid marketing (Note 10)	788,000
Total assets	4,942,000	3,621,000
Current liabilities:
Accounts Payable and Accrued Liabilities, Current, Total	513,000	394,000
Deferred revenue	48,000	35,000
Lease liability, current	114,000	125,000
Total	513,000	394,000
Total current liabilities	3,544,000	4,354,000
Long-term liabilities:
Debt obligations (Note 4)	507,000	700,000
Discount on convertible notes payable, net of amortization		(182,000)
Lease liability	226,000	286,000
Common stock held for redemption (Note 9)	900,000	643,000
Total liabilities	5,177,000	5,801,000
COMMITMENTS AND CONTINGENCIES (Note 13)
STOCKHOLDERS’ EQUITY (DEFICIT):
Preferred Series A, $0.00067 Par Value, 50,000,000 Shares Authorized, -0- Shares Issued and Outstanding, at December 31, 2019 and December 31, 2020
Common stock, $0.00067 Par Value, 400,000,000 Shares Authorized, 166,256,024 and 225,885,682 Shares Issued, at December 31, 2019 and December 31, 2020	151,000	111,000
Additional paid-in capital	135,849,000	121,327,000
Accumulated other comprehensive loss	(101,000)	(99,000)
Accumulated deficit	(132,041,000)	(123,492,000)
Total BioLargo Inc. and subsidiaries stockholders’ equity (deficit)	3,858,000	(2,153,000)
Non-controlling interest (Note 10)	(4,093,000)	(27,000)
Total stockholders’ equity (deficit)	(235,000)	(2,180,000)
Total liabilities and stockholders’ equity (deficit)	4,942,000	3,621,000
Entities, Excluding Partially Owned Subsidiary [Member]
Current liabilities:
Accounts Payable and Accrued Liabilities, Current, Total	513,000	394,000
Debt obligations	1,206,000	4,057,000
Discount on debt, net of amortization	(104,000)	(1,472,000)
Total	513,000	394,000
Partially Owned Subsidiary [Member]
Current liabilities:
Accounts Payable and Accrued Liabilities, Current, Total	536,000	208,000
Debt obligations	1,231,000	1,007,000
Total	$ 536,000	$ 208,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares shares in Thousands	Dec. 31, 2020	Dec. 31, 2019
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)	400,000,000	400,000,000
Common stock, shares issued (in shares)	166,256,024	225,885,682

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Revenue	$ 2,432,000	$ 1,861,000
Cost of revenue
Cost of Goods and Services Sold	(1,204,000)	(945,000)
Gross profit	1,228,000	916,000
Operating expenses:
Selling, general and administrative expenses	7,473,000	6,140,000
Research and development	1,338,000	1,472,000
Total operating expenses	8,811,000	7,612,000
Operating loss	(7,583,000)	(6,696,000)
Other income (expense):
Grant income	137,000	218,000
Tax credit income	111,000	63,000
Interest expense	(1,923,000)	(3,996,000)
Loss on extinguishment of debt	(442,000)	(1,029,000)
Total other (expense) income	(2,117,000)	(4,744,000)
Net loss	(9,700,000)	(11,440,000)
Net loss attributable to noncontrolling interest	(1,268,000)	(750,000)
Net loss attributable to common stockholders	$ (8,432,000)	$ (10,690,000)
Net loss per share attributable to common stockholders:
Loss per share attributable to stockholders – basic and diluted (in dollars per share)	$ (0.05)	$ (0.08)
Weighted average number of common shares outstanding: (in shares)	195,993,575	152,086,221
Comprehensive loss attributable to common stockholders
Net loss	$ (9,700,000)	$ (11,440,000)
Foreign currency translation adjustment	(2,000)	(9,000)
Comprehensive loss	(9,702,000)	(11,449,000)
Comprehensive loss attributable to noncontrolling interest	(1,268,000)	(750,000)
Comprehensive loss attributable to stockholders	(8,434,000)	(10,699,000)
Product [Member]
Revenue:
Revenue	1,825,000	1,460,000
Cost of revenue
Cost of Goods and Services Sold	(743,000)	(627,000)
Service [Member]
Revenue:
Revenue	607,000	401,000
Cost of revenue
Cost of Goods and Services Sold	$ (461,000)	$ (318,000)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity (Deficit) - USD ($)	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, 2018	141,466,071
Balance at Dec. 31, 2018	$ 95,000	$ 110,222,000	$ (111,723,000)	$ (90,000)	$ 373,000	$ (1,123,000)
Conversion of notes (in shares)	12,105,699
Conversion of notes	$ 8,000	1,727,000				$ 1,735,000
Warrant exercise (in shares)	7,544,456					7,544,456
Warrant exercise	$ 5,000	555,000				$ 560,000
Issuance of common stock for service (in shares)	3,318,490
Issuance of common stock for service	$ 2,000	708,000				710,000
Issuance of common stock for interest (in shares)	915,164
Issuance of common stock for interest	$ 1,000	199,000				200,000
Financing fee in common stock cancelled (in shares)	(150,000)
Financing fee in common stock cancelled		(42,000)				(42,000)
Stock issuance to officer (in shares)	500,000
Stock issuance to officer
Sale of stock for cash (in shares)	556,144
Sale of stock for cash		125,000				125,000
Stock option compensation expense		1,522,000				1,522,000
Warrants and conversion feature issued as discount on convertible notes payable and line of credit		3,931,000				3,931,000
Issuance of Clyra common stock for cash		186,000			350,000	536,000
Debt extinguishment expense		619,000				619,000
Warrant reprice		56,000				56,000
Exchange Clyra ownership for BioLargo debt		440,000				440,000
Preferred Series A Clyra dividend, converted to Clyra common shares		270,000	(270,000)
Deemed dividend		809,000	(809,000)
Net loss			(10,690,000)		(750,000)	(11,440,000)
Foreign currency translation				(9,000)		(9,000)
Balance (in shares) at Dec. 31, 2019	166,256,024
Balance at Dec. 31, 2019	$ 111,000	121,327,000	(123,492,000)	(99,000)	(27,000)	(2,180,000)
Conversion of notes (in shares)	33,157,961
Conversion of notes	$ 22,000	3,504,000				3,526,000
Issuance of common stock for service (in shares)	4,458,731
Issuance of common stock for service	$ 3,000	663,000				666,000
Issuance of common stock for interest (in shares)	1,728,331
Issuance of common stock for interest	$ 1,000	183,000				184,000
Sale of stock for cash (in shares)	17,356,064
Sale of stock for cash	$ 12,000	2,771,000				2,783,000
Stock option compensation expense		1,821,000				1,821,000
Issuance of Clyra common stock for cash		492,000			359,000	851,000
Deemed dividend		117,000	(117,000)
Net loss			(8,432,000)		(1,268,000)	(9,700,000)
Foreign currency translation				(2,000)		(2,000)
Stock issued as a commitment fee (in shares)	2,928,571
Stock issued as a commitment fee	$ 2,000	(124,000)				(122,000)
Loss on extinguishment		442,000				442,000
Noncontrolling interest allocation		3,157,000			(3,157,000)
Clyra stock options issued for service		638,000				638,000
Clyra stock issued for consulting agreement		788,000				788,000
Clyra stock issued as line of credit commitment fee		70,000				70,000
Balance (in shares) at Dec. 31, 2020	225,885,682
Balance at Dec. 31, 2020	$ 151,000	$ 135,849,000	$ (132,041,000)	$ (101,000)	$ (4,093,000)	$ (235,000)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (9,700,000)	$ (11,440,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock option compensation expense	2,459,000	1,522,000
Common stock issued in lieu of salary to officers and fees for services from vendors	666,000	710,000
Common stock issued for interest	184,000	200,000
Interest expense related to amortization of the discount on convertible notes payable and line of credit and deferred financing costs	1,618,000	3,376,000
Loss on extinguishment of debt	442,000	1,029,000
Loss on investment in South Korean joint venture	37,000
Deferred offering expense		53,000
Financing fee paid in stock (cancellation)		(42,000)
Warrant reprice		56,000
Amortization and depreciation expense	58,000	65,000
Bad debt expense	13,000	24,000
Changes in assets and liabilities:
Accounts receivable	(142,000)	(121,000)
Inventories	(261,000)	(9,000)
Deferred revenue	14,000	35,000
Prepaid expenses and other assets	9,000	(21,000)
Net cash used in operating activities	(4,154,000)	(4,422,000)
Cash flows from investing activities
Equipment purchases	(23,000)	(35,000)
Investment in South Korean joint venture	(100,000)
Net cash used in investing activities	(123,000)	(35,000)
Cash flows from financing activities
Proceeds from sale of common stock	2,783,000	125,000
Proceeds from convertible notes payable		1,632,000
Proceeds from OID offering		2,703,000
Proceeds from notes payable		400,000
Proceeds from SBA loans	507,000
Proceeds from warrant exercise		560,000
Repayment of note payable	(25,000)	(915,000)
Proceeds received by Clyra from inventory line of credit	260,000	430,000
Repayment by Clyra on inventory line of credit	(36,000)	(175,000)
Net cash provided by financing activities	4,340,000	4,466,000
Net effect of foreign currency translation	(2,000)	(9,000)
Net change in cash	61,000
Cash at beginning of year	655,000	655,000
Cash at end of year	716,000	655,000
Supplemental disclosures of cash flow information
Interest	118,000	195,000
Income taxes	2,000	3,000
Non-cash investing and financing activities
Fair value of warrants issued with convertible notes and letter of credit		3,931,000
Deemed dividend	117,000	809,000
Fair value of right of use and operating lease		411,000
Deferred offering costs recorded as additional paid in capital	(122,000)
Fair value of Clyra shares issued as commitment fee	70,000
Allocation of stock option expense within noncontrolling interest	3,157,000
Clyra preferred shares dividend exchange for Clyra common stock		270,000
Conversion of Convertible Notes Payable into Common Stock [Member]
Non-cash investing and financing activities
Conversion of debt	3,526,000	1,735,000
Convertible Notes Issued with Original Issue Discount [Member]
Non-cash investing and financing activities
Convertible notes issued with original Issue Discount		1,008,000
Stock Issued for In Process Research and Development [Member]
Non-cash investing and financing activities
Shares Issued	257,000
Conversion of Convertible Note Payable into Shares of Clyra [Member]
Non-cash investing and financing activities
Conversion of debt		440,000
Exchange of Consulting Services for Shares [Member]
Non-cash investing and financing activities
Shares Issued	788,000
Clyra Medical Common Stock [Member]
Cash flows from financing activities
Proceeds from sale of common stock	851,000	536,000
Entities, Excluding Partially Owned Subsidiary [Member]
Changes in assets and liabilities:
Accounts payable and accrued expenses	122,000	(65,000)
Partially Owned Subsidiary [Member]
Changes in assets and liabilities:
Accounts payable and accrued expenses	$ 327,000	$ 188,000

Note 1 - Business and Organizat

Note 1 - Business and Organization	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. Description of Business BioLargo, Inc. is an innovative technology developer and environmental engineering company driven by a mission to “make life better” by delivering robust, sustainable solutions for a broad range of industries and applications, with a focus on clean water, clean air. The company also owns a minority interest in an advanced wound care subsidiary that has licensed BioLargo's technologies. 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, 2020, $9,700,000, $4,154,000 December 31, 2020, $2,039,000, $1,505,000. not 2021 12 During the year ended December 31, 2020, $2,432,000 12. not 2020, 3 10 As of December 31, 2020, $716,000, $1,006,000 $100,000 may April 2021 $100,000 $224,000 June 2021, $1,007,000 4 10 June. December 30, 2020, $2 3 $650,000 14 two August, 2021, ( 4, Notes payable, mature August 12 16, 2021 may $0.14 not no $0.10 not August, 2021. If we are unable to rely on our current arrangement with Lincoln Park to fund our working capital requirements, we will have to rely on other forms of financing, and there is no To reduce our operational cash burdens, we regularly issue officers and vendors stock or options in lieu of cash, and anticipate that we will continue to be able to do so in the future. In the year ended December 31, 2020, $300,000 The foregoing factors raise substantial doubt about our ability to continue as a going concern, unless we are able to continue to raise funds through stock sales to Lincoln Park or other private financings, and in the long term, our ability to 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. four 2006; No 2009; 2019, 2014; 2016. 94% 9 2017. 45% 2012, 2, 10

Note 2 - Summary of Significant

Note 2 - Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
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, BLEST, 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 45% 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, 2020 2019, 2020 2019 BioLargo, Inc. and subsidiaries $ 637 $ 652 Clyra Medical Technologies, Inc. 79 3 Total $ 716 $ 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, 2020 2019 $13,000 $24,000. Credit Concentration We have a limited number of customers that account for significant portions of our revenue. During the year ended December 31, 2020, two 10% December 31, 2019, no 10% 2020 2019 Customer A 13 % <10 % Customer B 11 % <10 % We had two 10% December 31, 2020 three December 31, 2019 2020 2019 Customer D 32 % <10 % Customer E 10 % <10 % C,ustomer F <10 % 20 % Customer G <10 % 14 % Customer H <10 % 13 % 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, 2020 2019 $3,000 December 31, 2020, 2019, 2020 2019 Raw material $ 111 $ 11 Finished goods 166 5 Total $ 277 $ 16 Other Assets Other Assets consisted of security deposits of $35,000 Equity Method of Accounting On March 20, 2020, $100,000 40% 30% $150,000 We account for our investment in the joint venture under the equity method of accounting. We have determined that while we have significant influence over the joint venture through our technology license and our position on the Board of Directors, we do not nine December 31, 2020, 40% $37,000. 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, 2020 2019, no 9 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 convertible notes payable, stock options and warrants were exercised into common stock. For the years ended December 31, 2020 2019, 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 over the applicable service period of the award, which is the vesting period. Fair value is determined on the grant 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. The following methodology and assumptions were used to calculate share-based compensation for the years ended December 31, 2020 2019: 2020 2019 Non Plan 2007 Plan Non Plan 2018 Plan Risk free interest rate 0.66 – 1.02% 0.64 – 1.90% 1.68 – 2.65% 1.68 – 2.65% Expected volatility 125 – 131% 126 – 133% 133 – 152% 133 – 152% Expected dividend yield — — — — Forfeiture rate — — — — Life in years 10 10 10 10 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 four 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. A few contracts have called for milestone or fixed cost payments, where BLEST invoices an agreed-to amount per month for the life of the contract. In these instances, completed work, billed hourly, is recognized as revenue. If the billing amount is greater or lesser than the completed work, a receivable or payable is created. These accounts are adjusted upon additional billings as the work is completed. To date, there have been no In the event that we generate revenues from royalties or license fees from our intellectual property, we anticipate a licensee would pay a license fee in 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 80 $3.7 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 no December 31, 2020 2019. The Company assessed its earnings history, trends and estimates of future earnings and determined that the deferred tax asset could not December 31, 2020. The Company recognizes interest and penalties on income taxes as a component of income tax expense, should such an expense be realized. 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, 2020 2019 Tax Credits Our research and development activities in Canada may not Leases In February 2016, No. 2016 02, 13 January 1, 2019 July 2018, $399,000 may 842, No December 31, 2020, $ 341,000 Recent Accounting Pronouncements In August 2020, No. 2020 06, 470 20 815 40 1 not not 2 December 15, 2021, December 15, 2023, not In January 2020, No 2020 01, 321 323 815 321, 323, 815”. 321 323 2016 01. 321 10 35 2, 321 December 15, 2020, December 15, 2021, not

Note 3 - Sale of Stock for Cash

Note 3 - Sale of Stock for Cash	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Stock Purchase Agreement [Text Block]	Note 3. Lincoln Park Financing On August 25, 2017, “2017 $10 three On March 30, 2020, “2020 $10,250,000 three may three 12 no first August 2017 2020 1 April 10, 2020. April 21, 2020, April 29, 2020, Pursuant to the 2020 2,928,571 $527,000 During the years ended December 31, 2020 2019, 13,388,642 556,144 $2,058,000 $125,000 December 31, 2020, 2020 14 2020 Pursuant to an offering commenced in May 2020, 2,374,335 $367,000 six six five 6, Warrants Issued in 2020 BKT Joint Venture On February 12, 2020, $350,000 1,593,087 $100,000 40%

Note 4 - Debt Obligations

Note 4 - Debt Obligations	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 4. The following table summarizes our debt obligations outstanding as of December 31, 2020 2019 not 10, Debt Obligations of Clyra Medical December 31, 2020 2019 Current portion of debt: Note payable, matures on demand 60 days' notice (or March 8, 2023) $ 50 $ 50 Line of credit, matures on 30-day demand 50 50 Total notes payable and line of credit $ 100 $ 100 Convertible notes payable: Convertible note, matured April 7, 2020 — 270 Convertible note, matured June 20, 2020 (1) — 25 Convertible twelve-month OID notes, mature beginning June 2020 (1) — 3,112 Convertible note payable, matures April 20, 2021 (1) 100 — Convertible note payable, matures August 9, 2021 600 — Convertible notes, mature August 12 and 16, 2021 (2) 406 550 Total convertible notes payable 1,106 3,957 Total current liabilities $ 1,206 $ 4,057 Long-term debt: Convertible note payable, matures August 9, 2021 $ — $ 600 SBA Paycheck Protection Program loans, mature April 2022 357 — SBA EIDL Loan, matures July 2050 150 — Convertible notes payable, mature April 20, 2021 (1) — 100 Total long-term liabilities $ 507 $ 700 Total $ 1,713 $ 4,757 ( 1 These notes are convertible at our option at maturity. ( 2 These notes are convertible by the noteholders, and not For the years ended December 31, 2020 2019, $1,923,000 $3,996,000 Note payable, matures on demand 60 s notice (or March 8, 2023) On March 8, 2018, $50,000 sixty March 8, 2023. ( 14, Q1 Lines of credit, due on demand On March 1, 2018, $390,000, September 1, 2018, $40,000, 18% may 20 20 10 The holders of the line of credit has the right to call due the outstanding principal amount on 30 September 1, 2019. During July August 2019, $205,000, $256,000 12 August 2020, 25% 1,130,515 6 $0.17 18% 5% The total of the fair value of the warrant and the fair value of the new note and its beneficial conversion feature exceeded the carrying value of the old note by $315,000, During the three December 31, 2019, $175,000 December 31, 2020, 2019, $50,000. 14. Convertible Note, matured April 7, 2020 ( On January 7, 2019, $300,000 2019 $330,000, nine October 7, 2019). 2019 one 12%, 2019 65% 25 2019 $300,000, On August 13, 2019, April 7, 2020. On November 22, 2019 December 17, 2019, $50,000, $100,000, 690,530 December 31, 2019, $270,000. During the three March 31, 2020, $270,000 2,417,059 Convertible Notes, mature June 20, 2020 ( 2017 We received a total of $604,000 2017 $0.42 As of December 31, 2019, one $25,000 On June 20, 2020, $25,000 2017 83,334 Convertible Twelve-month OID notes From June 7, 2019 September 30, 2019, $2,235,000 $2,794,000, 25% 34 $559,000 $2,235,000, twelve During the three September 30, 2019, $305,000 $381,000 25% $76,000 $381,000 twelve Each Twelve-month OID Note was convertible by the investor at any time at $0.17 five 5% $0.17, may 70% 25 During 2020, $3,112,000 30,208,453 1,415,221 Convertible Note, matures April 20, 2021 ( 2018 In March 2018 one $100,000 $0.30 September 2018, $0.25 $0.25 December 31, 2020 2019, $100,000 April 20, 2021 Convertible note, matures August 9, 2021 On August 9, 2019, $600,000 one $600,000, two 15% $0.30 1,200,000 $0.30 five 6 December 31, 2020, 14 Convertible notes, mature August 12 16, 2021 On September 19, 2018, $400,000 January 5, 2019 12% two We and the noteholders agreed to extend the maturity dates of the notes multiple times in 2019. August, 2019, one $440,000 12 25% $0.17 18% 5% 6 $550,000. $422,000, On August 10, 2020, August 12, 2021. $0.17 $0.14, September 18, 2023 September 18, 2025, 1,734,375 August 12, 2024 August 12, 2025 2,095,588 $228,000, $119,000 848,214 $24,000 169,643 December 31, 2020 $356,000. On August 10, 2020, $25,000 August 16, 2021. December 31, 2020 $50,000 SBA Program Loans In April 2020, $218,000, $96,000 $43,000, two 1%. December 31, 2020, Our subsidiary ONM received an Economic Injury Disaster loan from the U.S. Small Business Administration of $150,000. 30 3.75% $800 July 2021.

Note 5 - Share-based Compensati

Note 5 - Share-based Compensation	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Compensation and Employee Benefit Plans [Text Block]	Note 5. Restricted Stock Units On May 28, 2019, 500,000 $3,000,000 $3,000,000 12 Issuance of Common Stock in exchange for payment of payables Payment of Officer Salaries During the year ended December 31, 2020, $299,000 2,017,928 December 31, 2020, 652,100 $0.12 September 30, 2020, 349,670 $0.15; June 30, 2020, 367,403 $0.16; March 31, 2020, 648,755 $0.17 During the year ended December 31, 2019, $210,000 1,080,951 September 30, 2019, 35,080 $0.31 June 28, 2019, 465,875 $0.23 March 29, 2019, 579,996 $0.16 Shares issued to Officers are unvested at the date of grant and subject to a lock-up agreement restricting vesting and sale until the earlier of (i) the consummation of a sale (in a single transaction or in a series of related transactions) of BioLargo by means of a sale of (a) a majority of the then outstanding common stock of BioLargo (whether by merger, consolidation, sale or transfer of common stock, reorganization, recapitalization or otherwise) or (b) all or substantially all of the assets of BioLargo; and (ii) the successful commercialization of BioLargo's products or technologies as demonstrated by its receipt of at least $3,000,000 $3,000,000 12 Payment of Consultant Fees During 2020, $366,000 2,440,803 December 31, 2020, 373,438 $0.12 September 30, 2020, 270,000 $0.15 June 30, 2020, 1,406,630 $0.16 March 31, 2020, 390,735 $0.17 During 2019, $500,000 2,237,539 December 31, 2019, 528,001 $0.23 September 30, 2019, 594,118 $0.26 June 30, 2019, 515,809 $0.21 March 29, 2019, 649,545 $0.17 All of these offerings and sales were made in reliance on the exemption from registration contained in Section 4 2 not Payment of Interest During 2020, $184,000 1,728,331 September 30, 2020, 1,412,052 $0.11 June 30, 2020, 297,001 $0.16 March 31, 2020, 19,278 $0.17 During 2019, $200,000 927,318 December 31, 2019 292,380 $0.18 395,944 $0.27 three June 30, 2019, 87,478 $0.17 three March 31, 2019, 139,362 $0.18 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, 2020 2019, $1,821,000 $1,552,000, 2018 2007 8 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 December 31, 2019, December 31, 2020, Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding Price per share share Value (1) Balance, December 31, 2018 1,318,517 $0.22 – 0.43 $ 0.30 Granted 7,895,839 $0.16 – 0.40 $ 0.25 Balance, December 31, 2019 9,214,356 $0.16 – 0.43 $ 0.25 Granted 11,197,687 $0.12 – 0.40 $ 0.15 Expired (1,546,518 ) Balance, December 31, 2020 18,865,525 $0.16 – 0.40 $ 0.19 Non-vested (6,418,622 ) $0.17 – 0.45 $ 0.19 Vested, December 31, 2020 12,446,903 $0.16 – 0.45 $ 0.18 $ — ( 1 $0.12 December 31, 2020. The options granted under the 2018 11,197,687 2020 4,880,945 $0.14 19 one $616,000; 517,500 $0.14 $0.21 492,500 2020, 25,000 January 31, 2021, $100,000; 1,746,434 $0.17 ,$0.16, $0.15 $0.12 $250,000; 2,019,556 $0.17, $0.16, $0.15 $0.12 $277,000 four 531,298 $74,000; 1,501,954 $0.14 $0.17 $198,000. The options to purchase 7,895,839 December 31, 2019 6,614,381 $0.16 $0.40 four 1,281,458 $0.16 $0.32 Chief Financial Officer Contract Extension On January 16, 2019, February 1, 2008 ( January 16, 2019 ( September 30, 2019 ( September 30, 2018. December 31, 2018 For the Extended Term, Mr. Dargan was issued an option (“Option”) to purchase 300,000 January 16, 2019 $0.22, 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 See also Note 14, Vice President of Operations Contract Extension On May 28, 2019, 1,000,000 2018 May 28, 2019 $0.17 200,000 five may ten not Vice President of Sales On May 28, 2019, 1,200,000 2018 first 200,000 May 28 $0.17 third third first third second 1,000,000 none no July 5, 2019, 300,000 July 5 ( $0.25 100,000 second third Director of Business Development for ONM On July 23, 2019, 1,000,000 $0.35 2018 first 400,000 100,000, 90 100,000 first 200,000 second 600,000 none no August, 2020, 2007 On September 7, 2007, April 29, 2011, 2007 “2007 may 10 September 7, 2017. September 2017, Activity for our stock options under the 2007 December 31, 2019 2020 Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding price per share share Value (1) Balance, December 31, 2018 9,691,586 0.22 – 0.94 0.43 Expired (922,135 ) 0.45 – 0.55 0.49 Balance, December 31, 2019 8,769,451 $0.22 – 0.94 $ 0.43 Expired (3,080,088 ) 0.22 – 0.58 0.38 Balance, December 31, 2020 5,689,363 $0.23 – 0.94 $ 0.44 $ — ( 1 $0.12 December 31, 2020. Non-Plan Options issued During the year ended December 31, 2020, 1,145,476 $0.12 $0.21 $167,000 During the year ended December 31, 2019, 1,226,586 $0.16 $0.32 $260,000 Activity of our non-plan stock options issued for the years ended December 31, 2020 2019 Weighted Non-plan average Aggregate Options Exercise price per intrinsic outstanding price per share share value (1) Balance, December 31, 2018 19,319,496 0.23 – 1.00 0.43 Granted 1,226,586 0.16 – 0.32 0.21 Expired (941,975 ) 0.45 – 0.55 0.52 Balance, December 31, 2019 19,604,107 $0.16 – 1.00 $ 0.43 Granted 1,145,476 0.12 – 0.21 0.15 Balance, December 31, 2020 20,749,583 $0.12 – 1.00 $ 0.41 Unvested (2,369,708 ) 0.45 0.45 Vested and outstanding, December 31, 2020 18,379,875 $0.23 – 1.00 $ 0.41 $ — ( 1 $0.12 December 31, 2020.

Note 6 - Warrants

Note 6 - Warrants	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Warrants [Text Block]	Note 6. We have certain warrants outstanding to purchase our common stock, at various prices, as described in the following table: Weighted average Aggregate Warrants Exercise price per intrinsic outstanding price per share share value (1) Balance, December 31, 2018 26,872,430 $0.25 – 1.00 $ 0.43 Granted 24,490,687 0.25 – 0.48 0.29 Exercised (7,544,456 ) 0.30 0.30 Expired (587,500 ) 0.40 0.40 Balance, December 31, 2019 43,231,161 $0.25 – 1.00 $ 0.35 Granted 5,594,314 0.13 – 0.27 0.20 Expired (15,844,486 ) 0.18 – 0.70 0.43 Balance, December 31, 2020 32,980,989 $0.13 – 1.00 $ 0.29 $ — ( 1 $0.12 December 31, 2020. Warrants issued in 2020 During the year ended December 31, 2020, 2020 3 six 2,318,194 $0.18 $0.22 five 2,318,194 $0.23 $0.27 Warrants Issued to One-Year Noteholders In conjunction with two one 4, Convertible notes, mature August 12 16, 2021 July 2017 400,000 two $0.65 December 31, 2020, $0.13, 957,926 $117,000, Warrants issued as part of debt extension and extinguishment On March 5, 2019, 4, Notes payable, mature August 12 16, 2020 September 6, 2019) ). $0.25 $0.20 1,987,500 2,484,375. In conjunction with the refinance of the Vernal and Chappy Bean notes in August 2019, 2,095,588 five may $0.25 330,882 Warrants issued as part of line of credit extinguishment In July August 2019, 1,130,515 three 4, five may $0.25 Warrants issued as part of 2018 On September 12 September 16, 2019, $100,000, 12 September 12 September 16, 2020, 25% 4 551,471 five may $0.25 Warrants issued as consent for variable rate debt waiver On January 7 January 31, 2019, August 25, 2017, 300,000 $0.25 five $54,000 2019 4. Warrants issued concurrently with the Nine-month OID notes In conjunction with the issuance of nine $0.25 5 three March 31, 2019, 637,500 three $89,000 June 7, 2019, $0.25 $0.17, 300,000 937,500, $84,000, Warrants Issued concurrently with Twelve-month OID notes During the year ended December 31, 2019, 12,325,370 4 $0.25 5 75% $0.17 $300,000 $375,000, 1,654,412 $2,240,000 Warrants Issued concurrently with the Convertible Note due August 9, 2021 In conjunction with an August 2019 August 9, 2021 ( 4 1,200,000 $0.30 5 $198,000 Exercise of Warrants During the year ended December 31, 2019, 7,544,456 $560,000. On June 24, 2019, September 12, 2018, 2,877,790 2,520,780 $355,000, 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: 2020 2019 Risk free interest rate 0.10 – 0.23% 1.42 – 2.13% Expected volatility 100 – 112% 101 – 110% Expected dividend yield — — Forfeiture rate — — Expected life in years 2 – 5 1 – 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 7 - Accounts Payable and A

Note 7 - Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	Note 7. Accounts payable and accrued expenses included the following (in thousands): As of December 31, 2020 ( Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 125 $ 73 $ 56 $ 103 $ (42 ) $ 315 Accrued payroll 23 42 91 — — 156 Accrued interest 42 — — — — 42 Total $ 513 As of December 31, 2019 ( Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 102 $ 35 $ 46 $ 43 $ (31 ) $ 195 Accrued payroll 11 34 82 — — 128 Accrued interest 71 — — — — 71 Total $ 394 See Note 10, Accounts Payable and Accrued Expenses

Note 8 - Provision for Income T

Note 8 - Provision for Income Taxes	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 8. Given our historical losses from operations, income taxes have been limited to the minimum franchise tax assessed by the State of California. Since 2016, not 80%. not not not At December 31, 2020, $104,000,000 $47,000,000 may not December 22, 2018, post‑2018 may pre‑2018 20 1 2 80% 172 no 172 1 2018 not 20 December 31, 2021. March 27, 2020, five not not 100%

Note 9 - In-process Research an

Note 9 - In-process Research and Development	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
In Process Research and Development [Text Block]	Note 9. 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 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 7,142,858 December 31, 2019, $1,893,000. During the year ended December 31, 2020, $200,000, first second 6,200 2,200 1,428,571 $257,000. December 31, 2020.

Note 10 - Noncontrolling Intere

Note 10 - Noncontrolling Interest - Clyra Medical	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Noncontrolling Interest Disclosure [Text Block]	Note 10. Clyra Medical As discussed in Note 2, 45% December 31, 2020. Debt Obligations of Clyra Medical Note Payable (Scion) In conjunction with the Scion Transaction (see Note 9 $1,250,000 September 26, 2018 ( 5%. 25% 5% June 26, 2021 June 26 th December 31, 2020 2019, $1,007,000 Line of Credit On June 30, 2020, $1,000,000 $260,000 $36,000. December 31, 2020, $224,000. Clyra is required to use funds from the line of credit to produce inventory. Additional draws are conditional upon Clyra presenting invoices or purchase orders to the lender equal to the greater of one $200,000. 15%, one first 180 30% 60% 323 $70,000. may Consulting Agreement On December 30, 2015, $23,000 four June 30, 2020, 3,639 $250,000 three not $788,000 Equity Transactions As of December 31, 2020, Shareholder Shares Percent BioLargo, Inc. 49,207 45% Sanatio Capital 18,704 17% Scion Solutions (1) 21,700 20% Other 19,118 18% Total 108,729 ( 1 Does not 9,300 Common Shares During the year ended December 31, 2020, 2,742 $851,000 $310 In June 2020, 23,004 22,513 22,513 490 $310 During the year ended December 31, 2019, 2,680 $536,000 $200 Series A Preferred shares Sanatio Capital purchased Clyra Series A Preferred shares in 2015. 8% five On December 31, 2019, $270,000, 3,544 December 31, 2019 Stock Options During 2019, December 31, 2019, 7,624 2020, 3,943 $1.00 10 2020, $853,000, $214,000 $310 no 30%. Accounts Payable and Accrued Expenses At December 31, 2020, Category Amount (in thousands) Accounts payable $ 402 Accrued payroll 32 Accrued interest 102 Total $ 536

Note 11 - BioLargo Engineering,

Note 11 - BioLargo Engineering, Science and Technologies, LLC	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Wholly-Owned Subsidiary [Text Block]	Note 11. In September 2017, three six 12 two 100% no five 30% 1,750,000 five March 31, 2018 ( not 90% 10% first September 2018. The BLEST Compensation Committee has met regularly since the subsidiary commenced operations. In 2018, not not November 2019, one 2.5% one 10% 175,000 $44,000, not January 2021, one one 3.75% one 15% 262,500 $65,000, December 31, 2020.

Note 12 - Business Segment Info

Note 12 - Business Segment Information	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	Note 12. BioLargo currently has four four 1. ONM Environmental (formerly Odor- No 2. Clyra Medical Technologies (“Clyra Medical”) -- which develops and sells medical products based on our technologies; 3. 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); and 4. BioLargo Water (“Water”) -- which historically focused entirely on R&D, and has now shifted its focus to commercializing the AOS technology (located in Edmonton, Alberta Canada). Historically, none third The segment information for the years December 31, 2020 2019, 2020 2019 Revenues BioLargo corporate $ 14 $ — ONM Environmental 1,568 1,459 Clyra Medical 240 — BLEST 1,050 999 BioLargo Water 37 — Intersegment revenue (477 ) (597 ) Total $ 2,432 $ 1,861 Operating loss BioLargo corporate $ (3,947 ) $ (3,651 ) ONM Environmental (493 ) (335 ) Clyra Medical (1,827 ) (1,233 ) BLEST (619 ) (749 ) BioLargo Water (697 ) (728 ) Total $ (7,583 ) $ (6,696 ) Interest expense BioLargo corporate $ (1,823 ) $ (3,944 ) ONM Environmental — (2 ) Clyra Medical (100 ) (50 ) Total $ (1,923 ) $ (3,996 ) Research and development BioLargo corporate $ (754 ) $ (892 ) BLEST (351 ) (354 ) Clyra Medical (164 ) (219 ) BioLargo Water (505 ) (610 ) BioLargo corporate - intercompany 436 603 Total $ (1,338 ) $ (1,472 ) As of December 31, 2020 BioLargo ONM Clyra BLEST Water Elimination Total Tangible assets $ 603 $ 624 $ 1,125 $ 314 $ 105 $ (42 ) $ 2,729 Investment in South Korean joint venture 63 — — — — — 63 Intangible assets 2,150 — — — — — 2,150 As of December 31, 2019 BioLargo ONM Clyra BLEST Water Elimination Total Tangible assets $ 1,050 $ 420 $ 3 $ 264 $ 50 $ (59 ) $ 1,728 Intangible assets 1,893 — — — — — 1,893

Note 13 - Commitments and Conti

Note 13 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	Note 13. Provenzano Employment Agreement On June 18, 2019, January 1, 2008. The Provenzano Employment Agreement provides that Mr. Provenzano will serve as our Executive Vice President of Operations, as well as the President and Chief Executive Officer of our wholly owned subsidiary ONM. Mr. Provenzano's base compensation will remain at his current rate of $170,000 four may In conjunction with this agreement, our Compensation Committee awarded Mr. Provenzano an option to purchase common stock and restricted stock units under our 2018 5 The Provenzano Employment Agreement has a term of five may 120 360 one one one one The Provenzano Employment Agreement requires Mr. Provenzano 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, 2020 2019, $228,000 $208,000, January 1, 2019, 842 not not August 2016, August 2020, 3%, four 2020, four four four not one three September 2022, one five No five one None no not no 18% As of December 31, 2020, three $522,000. five Years ending BioLargo Corp / ONM BLEST Total December 31, 2021 $ 111,000 $ 65,000 $ 176,000 December 31, 2022 115,000 43,000 158,000 December 31, 2023 118,000 -- 118,000 December 31, 2024 70,000 -- 70,000 December 31, 2025 -- -- -- Total minimum lease payments $ 414,000 $ 108,000 $ 522,000

Note 14 - Subsequent Events

Note 14 - Subsequent Events	12 Months Ended
	Dec. 31, 2020
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. Lincoln Park Capital Purchase of Shares From January 1, 2021, March 24, 2021, 12,511,674 2020 3 $2,020,000 1 333 237651 Satisfaction of Notes On March 1, 2021, $600,000, $7,371 August 9, 2019, August 9, 2021 On March 1, 2021, $50,000, $1,455 September 1, 2019. no no Amendment to Note payable matures on 60 s notice (or March 8, 2023) On March 1, 2021, $50,000 March 1, 2023, $0.16 a 225,000 $0.16 five Chief Financial Officer Contract Extension On March 18, 2021, February 1, 2008 ( March 18, 2021 ( one January 31, 2022 ( As the sole compensation for the Extended Term, Mr. Dargan was issued an option (“Option”) to purchase 25,000 300,000 12 25,000 March 15, 2021, 25,000 March 31, 2021, $0.174 March 18, 2021 ten 2018 The Option is Mr. Dargan's sole compensation for the Extended Term. As was the case in all prior terms of his engagement, there is no no not PPP loan forgiveness We received a notice dated March 19, 2021, $43,000.

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
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, BLEST, 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 45% 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, 2020 2019, 2020 2019 BioLargo, Inc. and subsidiaries $ 637 $ 652 Clyra Medical Technologies, Inc. 79 3 Total $ 716 $ 655
Receivable [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, 2020 2019 $13,000 $24,000.
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 year ended December 31, 2020, two 10% December 31, 2019, no 10% 2020 2019 Customer A 13 % <10 % Customer B 11 % <10 % We had two 10% December 31, 2020 three December 31, 2019 2020 2019 Customer D 32 % <10 % Customer E 10 % <10 % C,ustomer F <10 % 20 % Customer G <10 % 14 % Customer H <10 % 13 %
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, 2020 2019 $3,000 December 31, 2020, 2019, 2020 2019 Raw material $ 111 $ 11 Finished goods 166 5 Total $ 277 $ 16
Other Assets, Policy [Policy Text Block]	Other Assets Other Assets consisted of security deposits of $35,000
Equity Method Investments [Policy Text Block]	Equity Method of Accounting On March 20, 2020, $100,000 40% 30% $150,000 We account for our investment in the joint venture under the equity method of accounting. We have determined that while we have significant influence over the joint venture through our technology license and our position on the Board of Directors, we do not nine December 31, 2020, 40% $37,000.
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, 2020 2019, no 9
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 convertible notes payable, stock options and warrants were exercised into common stock. For the years ended December 31, 2020 2019,
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 Payment Arrangement [Policy Text Block]	Share-Based Compensation Expense We recognize compensation expense for stock option awards on a straight-line basis over the applicable service period of the award, which is the vesting period. Fair value is determined on the grant 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. The following methodology and assumptions were used to calculate share-based compensation for the years ended December 31, 2020 2019: 2020 2019 Non Plan 2007 Plan Non Plan 2018 Plan Risk free interest rate 0.66 – 1.02% 0.64 – 1.90% 1.68 – 2.65% 1.68 – 2.65% Expected volatility 125 – 131% 126 – 133% 133 – 152% 133 – 152% Expected dividend yield — — — — Forfeiture rate — — — — Life in years 10 10 10 10 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 from Contract with Customer [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 four 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. A few contracts have called for milestone or fixed cost payments, where BLEST invoices an agreed-to amount per month for the life of the contract. In these instances, completed work, billed hourly, is recognized as revenue. If the billing amount is greater or lesser than the completed work, a receivable or payable is created. These accounts are adjusted upon additional billings as the work is completed. To date, there have been no In the event that we generate revenues from royalties or license fees from our intellectual property, we anticipate a licensee would pay a license fee in 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 80 $3.7 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 no December 31, 2020 2019. The Company assessed its earnings history, trends and estimates of future earnings and determined that the deferred tax asset could not December 31, 2020. The Company recognizes interest and penalties on income taxes as a component of income tax expense, should such an expense be realized.
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, 2020 2019
Tax Credits [Policy Text Block]	Tax Credits Our research and development activities in Canada may not
Lessee, Leases [Policy Text Block]	Leases In February 2016, No. 2016 02, 13 January 1, 2019 July 2018, $399,000 may 842, No December 31, 2020, $341,000
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In August 2020, No. 2020 06, 470 20 815 40 1 not not 2 December 15, 2021, December 15, 2023, not In January 2020, No 2020 01, 321 323 815 321, 323, 815”. 321 323 2016 01. 321 10 35 2, 321 December 15, 2020, December 15, 2021, not

Note 2 - Summary of Significa_2

Note 2 - Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Cash and Cash Equivalents [Table Text Block]	2020 2019 BioLargo, Inc. and subsidiaries $ 637 $ 652 Clyra Medical Technologies, Inc. 79 3 Total $ 716 $ 655
Schedules of Concentration of Risk, by Risk Factor [Table Text Block]	2020 2019 Customer A 13 % <10 % Customer B 11 % <10 % 2020 2019 Customer D 32 % <10 % Customer E 10 % <10 % C,ustomer F <10 % 20 % Customer G <10 % 14 % Customer H <10 % 13 %
Schedule of Inventory, Current [Table Text Block]	2020 2019 Raw material $ 111 $ 11 Finished goods 166 5 Total $ 277 $ 16
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	2020 2019 Non Plan 2007 Plan Non Plan 2018 Plan Risk free interest rate 0.66 – 1.02% 0.64 – 1.90% 1.68 – 2.65% 1.68 – 2.65% Expected volatility 125 – 131% 126 – 133% 133 – 152% 133 – 152% Expected dividend yield — — — — Forfeiture rate — — — — Life in years 10 10 10 10

Note 4 - Debt Obligations (Tabl

Note 4 - Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Debt [Table Text Block]	December 31, 2020 2019 Current portion of debt: Note payable, matures on demand 60 days' notice (or March 8, 2023) $ 50 $ 50 Line of credit, matures on 30-day demand 50 50 Total notes payable and line of credit $ 100 $ 100 Convertible notes payable: Convertible note, matured April 7, 2020 — 270 Convertible note, matured June 20, 2020 (1) — 25 Convertible twelve-month OID notes, mature beginning June 2020 (1) — 3,112 Convertible note payable, matures April 20, 2021 (1) 100 — Convertible note payable, matures August 9, 2021 600 — Convertible notes, mature August 12 and 16, 2021 (2) 406 550 Total convertible notes payable 1,106 3,957 Total current liabilities $ 1,206 $ 4,057 Long-term debt: Convertible note payable, matures August 9, 2021 $ — $ 600 SBA Paycheck Protection Program loans, mature April 2022 357 — SBA EIDL Loan, matures July 2050 150 — Convertible notes payable, mature April 20, 2021 (1) — 100 Total long-term liabilities $ 507 $ 700 Total $ 1,713 $ 4,757

Note 5 - Share-based Compensa_2

Note 5 - Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding Price per share share Value (1) Balance, December 31, 2018 1,318,517 $0.22 – 0.43 $ 0.30 Granted 7,895,839 $0.16 – 0.40 $ 0.25 Balance, December 31, 2019 9,214,356 $0.16 – 0.43 $ 0.25 Granted 11,197,687 $0.12 – 0.40 $ 0.15 Expired (1,546,518 ) Balance, December 31, 2020 18,865,525 $0.16 – 0.40 $ 0.19 Non-vested (6,418,622 ) $0.17 – 0.45 $ 0.19 Vested, December 31, 2020 12,446,903 $0.16 – 0.45 $ 0.18 $ — Weighted Non-plan average Aggregate Options Exercise price per intrinsic outstanding price per share share value (1) Balance, December 31, 2018 19,319,496 0.23 – 1.00 0.43 Granted 1,226,586 0.16 – 0.32 0.21 Expired (941,975 ) 0.45 – 0.55 0.52 Balance, December 31, 2019 19,604,107 $0.16 – 1.00 $ 0.43 Granted 1,145,476 0.12 – 0.21 0.15 Balance, December 31, 2020 20,749,583 $0.12 – 1.00 $ 0.41 Unvested (2,369,708 ) 0.45 0.45 Vested and outstanding, December 31, 2020 18,379,875 $0.23 – 1.00 $ 0.41 $ —
The 2007 Equity Incentive Plan [Member]
Notes Tables
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Weighted Average Aggregate Options Exercise Price per intrinsic Outstanding price per share share Value (1) Balance, December 31, 2018 9,691,586 0.22 – 0.94 0.43 Expired (922,135 ) 0.45 – 0.55 0.49 Balance, December 31, 2019 8,769,451 $0.22 – 0.94 $ 0.43 Expired (3,080,088 ) 0.22 – 0.58 0.38 Balance, December 31, 2020 5,689,363 $0.23 – 0.94 $ 0.44 $ —

Note 6 - Warrants (Tables)

Note 6 - Warrants (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]	Weighted average Aggregate Warrants Exercise price per intrinsic outstanding price per share share value (1) Balance, December 31, 2018 26,872,430 $0.25 – 1.00 $ 0.43 Granted 24,490,687 0.25 – 0.48 0.29 Exercised (7,544,456 ) 0.30 0.30 Expired (587,500 ) 0.40 0.40 Balance, December 31, 2019 43,231,161 $0.25 – 1.00 $ 0.35 Granted 5,594,314 0.13 – 0.27 0.20 Expired (15,844,486 ) 0.18 – 0.70 0.43 Balance, December 31, 2020 32,980,989 $0.13 – 1.00 $ 0.29 $ —
Schedule Of Assumptions Used To Determine Fair Value Of Warrants [Table Text Block]	2020 2019 Risk free interest rate 0.10 – 0.23% 1.42 – 2.13% Expected volatility 100 – 112% 101 – 110% Expected dividend yield — — Forfeiture rate — — Expected life in years 2 – 5 1 – 5

Note 7 - Accounts Payable and_2

Note 7 - Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 125 $ 73 $ 56 $ 103 $ (42 ) $ 315 Accrued payroll 23 42 91 — — 156 Accrued interest 42 — — — — 42 Total $ 513 Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 102 $ 35 $ 46 $ 43 $ (31 ) $ 195 Accrued payroll 11 34 82 — — 128 Accrued interest 71 — — — — 71 Total $ 394

Note 10 - Noncontrolling Inte_2

Note 10 - Noncontrolling Interest - Clyra Medical (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Other Ownership Interests [Table Text Block]	Shareholder Shares Percent BioLargo, Inc. 49,207 45% Sanatio Capital 18,704 17% Scion Solutions (1) 21,700 20% Other 19,118 18% Total 108,729
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 125 $ 73 $ 56 $ 103 $ (42 ) $ 315 Accrued payroll 23 42 91 — — 156 Accrued interest 42 — — — — 42 Total $ 513 Category BioLargo ONM BLEST Water Elim Totals Accounts payable $ 102 $ 35 $ 46 $ 43 $ (31 ) $ 195 Accrued payroll 11 34 82 — — 128 Accrued interest 71 — — — — 71 Total $ 394
Clyra Medical [Member]
Notes Tables
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	Category Amount (in thousands) Accounts payable $ 402 Accrued payroll 32 Accrued interest 102 Total $ 536

Note 12 - Business Segment In_2

Note 12 - Business Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	2020 2019 Revenues BioLargo corporate $ 14 $ — ONM Environmental 1,568 1,459 Clyra Medical 240 — BLEST 1,050 999 BioLargo Water 37 — Intersegment revenue (477 ) (597 ) Total $ 2,432 $ 1,861 Operating loss BioLargo corporate $ (3,947 ) $ (3,651 ) ONM Environmental (493 ) (335 ) Clyra Medical (1,827 ) (1,233 ) BLEST (619 ) (749 ) BioLargo Water (697 ) (728 ) Total $ (7,583 ) $ (6,696 ) Interest expense BioLargo corporate $ (1,823 ) $ (3,944 ) ONM Environmental — (2 ) Clyra Medical (100 ) (50 ) Total $ (1,923 ) $ (3,996 ) Research and development BioLargo corporate $ (754 ) $ (892 ) BLEST (351 ) (354 ) Clyra Medical (164 ) (219 ) BioLargo Water (505 ) (610 ) BioLargo corporate - intercompany 436 603 Total $ (1,338 ) $ (1,472 ) As of December 31, 2020 BioLargo ONM Clyra BLEST Water Elimination Total Tangible assets $ 603 $ 624 $ 1,125 $ 314 $ 105 $ (42 ) $ 2,729 Investment in South Korean joint venture 63 — — — — — 63 Intangible assets 2,150 — — — — — 2,150 As of December 31, 2019 BioLargo ONM Clyra BLEST Water Elimination Total Tangible assets $ 1,050 $ 420 $ 3 $ 264 $ 50 $ (59 ) $ 1,728 Intangible assets 1,893 — — — — — 1,893

Note 13 - Commitments and Con_2

Note 13 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Years ending BioLargo Corp / ONM BLEST Total December 31, 2021 $ 111,000 $ 65,000 $ 176,000 December 31, 2022 115,000 43,000 158,000 December 31, 2023 118,000 -- 118,000 December 31, 2024 70,000 -- 70,000 December 31, 2025 -- -- -- Total minimum lease payments $ 414,000 $ 108,000 $ 522,000

Note 1 - Business and Organiz_2

Note 1 - Business and Organization (Details Textual)	Mar. 01, 2021USD ($)	Mar. 24, 2021USD ($)	Dec. 31, 2020USD ($)$ / shares	Dec. 31, 2019USD ($)	Aug. 10, 2020$ / shares	Aug. 09, 2020$ / shares	Sep. 30, 2017
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total			$ (9,700,000)	$ (11,440,000)
Net Cash Provided by (Used in) Operating Activities, Total			(4,154,000)	(4,422,000)
Working Capital (Deficit)			(2,039,000)
Assets, Current, Total			1,505,000	1,065,000
Revenue from Contract with Customer, Including Assessed Tax			2,432,000	1,861,000
Cash and Cash Equivalents, at Carrying Value, Ending Balance			716,000	655,000
Convertible Debt, Total			1,006,000
Proceeds from Issuance of Common Stock			2,783,000	125,000
Stock Issued During Period, Value, Issued for Unpaid Salary and Business Expenses			$ 300,000
Number of Wholly-Owned Subsidiaries			4
BioLargo Engineering, Science & Technologies, LLC [Member]
Noncontrolling Interest, Ownership Percentage by Parent			94.00%				100.00%
Clyra Medical Technologies [Member]
Noncontrolling Interest, Ownership Percentage by Parent			45.00%
Subsequent Event [Member]
Repayments of Long-term Debt, Total	$ 650,000
Lincoln Park Capital Fund, LLC [Member]
Proceeds from Issuance of Common Stock			$ 2,058,000	$ 125,000
Sale of Stock, Daily Basis, Requirement, Minimum Share Price (in dollars per share) | $ / shares			$ 0.10
Lincoln Park Capital Fund, LLC [Member] | Subsequent Event [Member]
Proceeds from Issuance of Common Stock	$ 2,000,000	$ 2,020,000
Debt Convertible to Equity at April 2021 Maturity Date [Member]
Convertible Debt, Total			$ 100,000
Notes Due on Demand [Member]
Convertible Debt, Total			100,000
Notes Owed by Partially Owned Subsidiary Due June, 2021 [Member]
Convertible Debt, Total			224,000
Notes Owed by Partially Owned Subsidiary Must Paid Out of Operational Cash [Member]
Convertible Debt, Total			1,007,000
Convertible Promissory Note with August 12, 2021 Maturity [Member]
Convertible Debt, Total			$ 356,000
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares			$ 0.14		$ 0.14	$ 0.17

Note 2 - Summary of Significa_3

Note 2 - Summary of Significant Accounting Policies (Details Textual)	Mar. 20, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Jan. 01, 2019USD ($)
Accounts Receivable, Allowance for Credit Loss, Current		$ 13,000	$ 24,000
Inventory Valuation Reserves, Ending Balance		3,000	3,000
Security Deposit		35,000
Payments to Acquire Interest in Joint Venture		100,000
Income (Loss) from Equity Method Investments, Total		(37,000)
Impairment of Long-Lived Assets Held-for-use		$ 0	0
Number of Wholly-Owned Subsidiaries		4
Operating Lease, Liability, Total		$ 341,000
Operating Lease, Right-of-Use Asset		$ 341,000	$ 411,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Liability, Total				$ 399,000
Operating Lease, Right-of-Use Asset				$ 399,000
Canadian Government Grants [Member]
Number of Grants Received		80
Grants Receivable		$ 3,700,000
Canadian Government Grants [Member] | Minimum [Member]
Grant Term (Month)		180 days
Canadian Government Grants [Member] | Maximum [Member]
Grant Term (Month)		1 year 180 days
Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Number of Major Customers		2
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Number of Major Customers		2	3
Clyra Medical Technologies [Member]
Noncontrolling Interest, Ownership Percentage by Parent		45.00%
Odin Co Ltd [Member]
Payments to Acquire Interest in Joint Venture	$ 100,000
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	40.00%	40.00%
Income (Loss) from Equity Method Investments, Total		$ 37,000
Odin Co Ltd [Member] | Tomorrow Water [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	30.00%
Odin Co Ltd [Member] | BKT and Tomorrow Water [Member]
Payments to Acquire Interest in Joint Venture	$ 150,000

Note 2 - Summary of Significa_4

Note 2 - Summary of Significant Accounting Policies - Summary of Cash Balances (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents, at Carrying Value, Ending Balance	$ 716,000	$ 655,000
Parent Company [Member]
Cash and Cash Equivalents, at Carrying Value, Ending Balance	637,000	652,000
Noncontrolling Interest [Member]
Cash and Cash Equivalents, at Carrying Value, Ending Balance	$ 79,000	$ 3,000

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, 2020	Dec. 31, 2019
Customer A [Member] | Revenue from Contract with Customer Benchmark [Member]
Credit concentration	13.00%	10.00%
Customer D [Member] | Accounts Receivable [Member]
Credit concentration	32.00%	10.00%
Customer B [Member] | Revenue from Contract with Customer Benchmark [Member]
Credit concentration	11.00%	10.00%
Customer E [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	10.00%
Customer F [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	20.00%
Customer G [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	14.00%
Customer H [Member] | Accounts Receivable [Member]
Credit concentration	10.00%	13.00%

Note 2 - Summary of Significa_6

Note 2 - Summary of Significant Accounting Policies - Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Raw material	$ 111	$ 11
Finished goods	166	5
Total	$ 277	$ 16

Note 2 - Summary of Significa_7

Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Non Plan [Member]
Life in years (Year)	10 years	10 years
Non Plan [Member] | Minimum [Member]
Risk free interest rate	0.66%	1.68%
Expected volatility	125.00%	133.00%
Non Plan [Member] | Maximum [Member]
Risk free interest rate	1.02%	2.65%
Expected volatility	131.00%	152.00%
2018 Equity Incentive Plan [Member]
Life in years (Year)	10 years	10 years
2018 Equity Incentive Plan [Member] | Minimum [Member]
Risk free interest rate	0.64%	1.68%
Expected volatility	126.00%	133.00%
2018 Equity Incentive Plan [Member] | Maximum [Member]
Risk free interest rate	1.90%	2.65%
Expected volatility	133.00%	152.00%

Note 3 - Sale of Stock for Ca_2

Note 3 - Sale of Stock for Cash (Details Textual) - USD ($)	Mar. 30, 2020	Feb. 12, 2020	May 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Aug. 25, 2017
Stock Issued During Period, Value, Commitment Fee				$ (122,000)
Proceeds from Issuance of Common Stock				2,783,000	$ 125,000
Payments to Acquire Interest in Joint Venture				$ 100,000
BKT Joint Venture [Member]
Payments to Acquire Interest in Joint Venture		$ 100,000
Equity Method Investment, Ownership Percentage		40.00%
Warrants Issued with 2020 Unit Offering [Member] | Minimum [Member]
Warrants and Rights Outstanding, Term (Month)				180 days
Warrants Issued with 2020 Unit Offering [Member] | Maximum [Member]
Warrants and Rights Outstanding, Term (Month)				5 years
The 2020 Unit Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,374,335
Proceeds from Issuance of Common Stock			$ 367,000
Lincoln Park Capital Fund, LLC [Member]
Stock Purchase Agreement, Maximum Amount of Common Stock	$ 10,250,000					$ 10,000,000
Stock Issued During Period, Shares, Commitment Fee (in shares)	2,928,571
Stock Issued During Period, Value, Commitment Fee	$ 527,000
Stock Issued During Period, Shares, New Issues (in shares)				13,388,642	556,144
Proceeds from Issuance of Common Stock				$ 2,058,000	$ 125,000
BKT Co. Ltd. [Member]
Stock Issued During Period, Shares, New Issues (in shares)		1,593,087
Proceeds from Issuance of Common Stock		$ 350,000

Note 4 - Debt Obligations (Deta

Note 4 - Debt Obligations (Details Textual) - USD ($)	Aug. 10, 2020	Jun. 20, 2020	Dec. 17, 2019	Nov. 22, 2019	Aug. 12, 2019	Aug. 09, 2019	Jan. 07, 2019	Sep. 19, 2018	Sep. 01, 2018	Mar. 08, 2018	Mar. 01, 2018	May 24, 2017	Apr. 30, 2020	Dec. 17, 2019	Mar. 31, 2018	Aug. 31, 2019	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Aug. 09, 2020	Aug. 20, 2019	Aug. 15, 2019	Aug. 11, 2019	Sep. 30, 2018
Interest Expense, Debt, Total																					$ 1,923,000	$ 3,996,000
Proceeds from Notes Payable, Total																						400,000
Gain (Loss) on Extinguishment of Debt, Total	$ (228,000)																				(442,000)	(1,029,000)
Long-term Line of Credit, Total																		$ 50,000			50,000	50,000
Convertible Debt, Total																					1,006,000
Clyra Medical [Member]
Gain (Loss) on Extinguishment of Debt, Total																					(214,000)
Warrants Issued in Conversion of Secured Line of Credit to Twelve Month OID Notes [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																1,130,515
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)																$ 0.25
Warrants and Rights Outstanding, Term (Month)																5 years
Warrants Issued Concurrently to the Summer 2017 Unit Offering [Member]
Proceeds from Issuance of Units												$ 604,000
Warrants Issued Concurrently to the Spring 2018 Unit Offering [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)																											$ 0.25
Warrant In Connection With Convertible Note [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)						1,200,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)						$ 0.30																			$ 0.25
Warrants and Rights Outstanding, Term (Month)						5 years																			5 years
Warrant with September 18, 2025 Expiration [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1,734,375
Warrant with August 12, 2025 Expiration [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	2,095,588
Conversion of Secured Line of Credit to Twelve Month OID Notes [Member] | Three Holders [Member]
Debt Conversion, Original Debt, Amount																$ 205,000
Debt Instrument, Face Amount																$ 256,000
Original Issue Discount, Percentage																25.00%
Gain (Loss) on Extinguishment of Debt, Total																$ (315,000)
Vista Capital Note Converted into Common Stock [Member]
Debt Conversion, Original Debt, Amount			$ 50,000	$ 50,000										$ 100,000			$ 270,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)														690,530			2,417,059
Conversion of Summer 2017 Unit Offering Convertible Notes into Common Stock [Member]
Debt Conversion, Original Debt, Amount		$ 25,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)		83,334
Conversion of Convertible Note Into Twelve Month OID Note [Member]
Debt Conversion, Original Debt, Amount																			$ 305,000
Conversion of OID Notes to Common Stock [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)																			$ 0.17	$ 0.17
Conversion of Convertible Notes Payable into Common Stock [Member]
Debt Conversion, Original Debt, Amount																					$ 3,112,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)																					30,208,453
Conversion of Convertible Notes Payable into Common Stock to Pay for Interest [Member]
Debt Conversion, Converted Instrument, Shares Issued (in shares)																					1,415,221
Conversion from Convertible Promissory Note with August 12, 2021 Maturity to Common Stock [Member]
Debt Conversion, Original Debt, Amount	$ 119,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)	848,214
Conversion from Convertible Promissory Note Accrued Interest with August 12, 2021 Maturity to Common Stock [Member]
Debt Conversion, Converted Instrument, Shares Issued (in shares)	169,643
Debt Conversion, Accrued Interest, Amount	$ 24,000
Note Payable, Maturing March 8, 2023 [Member]
Proceeds from Notes Payable, Total										$ 50,000
Line of Credit, Maturing September 1, 2019 [Member]
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 (Day)											20 days
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)											10 years
Debt Instrument, Call Notice Period (Day)											30 days
Line of Credit, Due on Demand After September 1, 2019 [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)																$ 0.17
Debt Instrument, Interest Rate, Stated Percentage																5.00%
Repayments of Lines of Credit																		175,000
Long-term Line of Credit, Total																		50,000				50,000
Vista Capital 2019 Note [Member] | Convertible Notes Payable [Member] | Vista Capital [Member]
Debt Instrument, Face Amount							$ 330,000
Proceeds from Convertible Debt							$ 300,000
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 (Day)							25 days
Debt Instrument, Convertible, Beneficial Conversion Feature							$ 300,000
Convertible Notes Payable, Total																		270,000				270,000
Summer 2017 Unit Offering [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)												$ 0.42
Convertible Debt, Total																		25,000				25,000
Convertible Twelve Months OID Notes [Member]
Debt Instrument, Face Amount																			$ 2,794,000	$ 2,794,000
Debt Instrument, Interest Rate, Stated Percentage																			5.00%	5.00%
Proceeds from Convertible Debt																				$ 2,235,000
Debt Instrument, Convertible, Beneficial Conversion Feature																				2,235,000
Debt Instrument, Unamortized Discount, Total																			$ 559,000	$ 559,000
Debt Instrument, Term (Month)																				1 year
Convertible Twelve Months OID Notes [Member] | Thirty Four Accredited Investors [Member]
Original Issue Discount, Percentage																			25.00%	25.00%
Convertible Twelve Months OID Notes [Member] | Convertible Notes Payable [Member]
Debt Instrument, Face Amount																			$ 381,000	$ 381,000				$ 330,882
Original Issue Discount, Percentage																			25.00%	25.00%
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																									2,095,588
Debt Instrument, Convertible, Beneficial Conversion Feature																			$ 381,000
Debt Instrument, Unamortized Discount, Total																			$ 76,000	$ 76,000
Debt Instrument, Term (Month)																			1 year
Convertible Notes, Maturing April 20, 2021 [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)															$ 0.30
Proceeds from Issuance of Units															$ 100,000
Long-term Debt, Gross																		$ 100,000			$ 100,000	100,000
Convertible Note, Maturing August 9, 2021 [Member]
Debt Instrument, Face Amount						$ 600,000
Original Issue Discount, Percentage						15.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share)						$ 0.30
Proceeds from Convertible Debt						$ 600,000
Note Payable, Maturing January 5, 2019 [Member]
Proceeds from Notes Payable, Total								$ 400,000
Debt Instrument, Interest Rate, Stated Percentage								12.00%
Notes Payable, Maturing September 6, 2019 [Member]
Debt Conversion, Original Debt, Amount					$ 440,000
Original Issue Discount, Percentage					25.00%
Debt Instrument, Interest Rate, Stated Percentage					5.00%																					18.00%
Gain (Loss) on Extinguishment of Debt, Total																						$ (422,000)
Convertible Notes Payable, Total																					$ 550,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)					$ 0.17
Convertible Promissory Note with August 12, 2021 Maturity [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 0.14																				$ 0.14		$ 0.17
Convertible Debt, Total																					$ 356,000
Convertible Promissory Note with August 16, 2021 Maturity [Member]
Convertible Debt, Total																					50,000
Debt Instrument, Extension Fee Amount	$ 25,000
Paycheck Protection Program CARES Act [Member] | ONM [Member]
Proceeds from Issuance of Debt													$ 218,000
Paycheck Protection Program CARES Act [Member] | BLEST [Member]
Proceeds from Issuance of Debt													96,000
Paycheck Protection Program CARES Act [Member] | Clyra Medical [Member]
Proceeds from Issuance of Debt													$ 43,000
Economic Injury Disaster Loan [Member] | ONM [Member]
Debt Instrument, Face Amount																					$ 150,000
Debt Instrument, Interest Rate, Stated Percentage																					3.75%
Debt Instrument, Term (Month)																					30 years
Debt Instrument, Periodic Payment, Total																					$ 800

Note 4 - Debt Obligations - Sch

Note 4 - Debt Obligations - Schedule of Debt (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Long-term Line of Credit, Total		$ 50	$ 50
Total notes payable and line of credit		100	100
Convertible notes		1,106	3,957
Total current liabilities		1,206	4,057
Long-term debt		507	700
Total		1,713	4,757
Note Payable, Maturing March 8, 2023 [Member]
Notes Payable, Current, Total		50	50
Convertible Note, Maturing April 7, 2020 [Member]
Convertible notes			270
Convertible Notes, Maturing on June 20, 2020 [Member]
Convertible notes	[1]		25
Convertible Twelve Months OID Notes [Member]
Convertible notes	[1]		3,112
Convertible Note, Maturing April 20 2021 [Member]
Convertible notes	[1]	100
Convertible Note, Maturing August 9, 2021 [Member]
Convertible notes		600
Long-term debt			600
Convertible Notes, Maturing August 12 and 16, 2020 [Member]
Convertible notes	[2]	406	550
Paycheck Protection Program CARES Act [Member]
Long-term debt		357
Economic Injury Disaster Loan [Member]
Long-term debt		150
Convertible Notes, Maturing April 20, 2021 [Member]
Long-term debt	[1]		$ 100
[1]	These notes are convertible at our option at maturity.
[2]	These notes are convertible by the noteholders, and not convertible by the Company.

Note 5 - Share-based Compensa_3

Note 5 - Share-based Compensation (Details Textual) - USD ($)		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jul. 23, 2019	Jul. 05, 2019	Jun. 30, 2019	Jun. 28, 2019	May 28, 2019	Mar. 29, 2019	Jan. 31, 2019	Jan. 16, 2019	Jun. 22, 2018	Sep. 07, 2017	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Issued During Period, Value, Issued for Services																				$ 666,000	$ 710,000
Stock Issued During Period, Value, New Issues																				$ 2,783,000	125,000
Share Price (in dollars per share)		$ 0.12																		$ 0.12
Accounts Payable and Accrued Liabilities, Current, Total		$ 513,000				$ 394,000														$ 513,000	$ 394,000
2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																10 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)																40,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Per Year (in shares)																2,000,000
Share Price (in dollars per share)		$ 0.12																		$ 0.12
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				11,197,687	7,895,839
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.15	$ 0.25
The 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	[1]
Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				1,145,476	1,226,586
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.15	$ 0.21
Selling, General and Administrative Expenses [Member]
Share-based Payment Arrangement, Expense																				$ 1,821,000	$ 1,552,000
Common Stock Issued for Accrued Interest Due on Promissory Note [Member]
Shares Issued, Price Per Share (in dollars per share)			$ 0.11	$ 0.16	$ 0.17	$ 0.18	$ 0.27			$ 0.17								$ 0.17	$ 0.18		$ 0.18
Stock Issued During Period, Value, New Issues																				$ 184,000	$ 200,000
Stock Issued During Period, Shares, New Issues (in shares)			1,412,052	297,001	19,278	292,380	395,944											87,478	139,362	1,728,331	927,318
Officer [Member]
Stock Issued During Period, Value, Issued for Services																				$ 299,000	$ 210,000
Stock Issued During Period, Shares, Issued for Services (in shares)		652,100	349,670	367,403	648,755		35,080				465,875		579,996							2,017,928	1,080,951
Shares Issued, Price Per Share (in dollars per share)		$ 0.12	$ 0.15	$ 0.16	$ 0.17		$ 0.31				$ 0.23		$ 0.16							$ 0.12
Lock-up Agreement, Vesting Requirement, Commercialization of Product, Receipt in Cash																				$ 3,000,000
Consultants [Member]
Stock Issued During Period, Value, Issued for Services																				$ 366,000	$ 500,000
Stock Issued During Period, Shares, Issued for Services (in shares)		373,438	270,000	1,406,630	390,735	528,001	594,118			515,809			649,545							2,440,803	2,237,539
Shares Issued, Price Per Share (in dollars per share)		$ 0.12	$ 0.15	$ 0.16	$ 0.17	$ 0.23	$ 0.26			$ 0.21			$ 0.17					$ 0.21		$ 0.12	$ 0.23
Accounts Payable and Accrued Liabilities, Current, Total		$ 74,000																		$ 74,000
Consultants [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				531,298
Employees, Consultations, Officers, and Directors [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				11,197,687	7,895,839
Employees and Consultants [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				4,880,945	6,614,381
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.14
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)																				1 year	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		616,000																		$ 616,000
Employees and Consultants [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]
Shares Issued, Price Per Share (in dollars per share)						0.16															$ 0.16
Employees and Consultants [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]
Shares Issued, Price Per Share (in dollars per share)						0.40															$ 0.40
Chief Executive Officer [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				517,500
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member]
Share Price (in dollars per share)															$ 0.22
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)															300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		100,000																		$ 100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares (in shares)																				492,500
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member] | Vesting Monthly [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options Expected to Vest, Number of Shares (in shares)																				25,000
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.14
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.21
Chief Financial Officer [Member] | Equity Incentive Plan 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares (in shares)																						75,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Remaining Number of Shares to Vest Each Month (in shares)														25,000
Board Of Directors [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																					1,281,458
Board Of Directors [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]
Shares Issued, Price Per Share (in dollars per share)						0.16															$ 0.16
Board Of Directors [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]
Shares Issued, Price Per Share (in dollars per share)						0.32															$ 0.32
Board Of Directors [Member] | Equity Incentive Plan 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				1,746,434
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		250,000																		$ 250,000
Board Of Directors [Member] | Equity Incentive Plan 2007 [Member] | Award Date One [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.17
Board Of Directors [Member] | Equity Incentive Plan 2007 [Member] | Award Date Two [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				0.16
Board Of Directors [Member] | Equity Incentive Plan 2007 [Member] | Award Date Three [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				0.15
Board Of Directors [Member] | Equity Incentive Plan 2007 [Member] | Award Date Four [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.12
Employees [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				2,019,556
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)																				4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 277,000																		$ 277,000
Employees [Member] | 2018 Equity Incentive Plan [Member] | Award Date One [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.17
Employees [Member] | 2018 Equity Incentive Plan [Member] | Award Date Two [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				0.16
Employees [Member] | 2018 Equity Incentive Plan [Member] | Award Date Three [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				0.15
Employees [Member] | 2018 Equity Incentive Plan [Member] | Award Date Four [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.12
Vice President of Operation and President of Subsidiary [Member] | 2018 Equity Incentive Plan [Member]
Share Price (in dollars per share)									$ 0.25			$ 0.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)									300,000			1,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares (in shares)												200,000
Share-based Compensation Arrangement by Share-based Payment Award Options Annual Vesting Installment Shares (in shares)									100,000
Vice President of Operation and President of Subsidiary [Member] | 2018 Equity Incentive Plan [Member] | Vesting At Various Metrics [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)												1,000,000
Vice President of Operation and President of Subsidiary [Member] | Equity Incentive Plan 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)												10 years
Share Price (in dollars per share)												$ 0.17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)												1,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)												5 years
Share-based Compensation Arrangement by Share-based Payment Award Options Annual Vesting Installment Shares (in shares)												200,000
Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								1,000,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)								$ 0.35
Vendors [Member] | Non Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				1,145,476	1,226,586
Vendors [Member] | Non Plan [Member] | Minimum [Member]
Shares Issued, Price Per Share (in dollars per share)		$ 0.12				0.16														$ 0.12	$ 0.16
Vendors [Member] | Non Plan [Member] | Maximum [Member]
Shares Issued, Price Per Share (in dollars per share)		$ 0.21				$ 0.32														$ 0.21	$ 0.32
Sale of Products and License of Technology [Member]
Contract with Customer, Liability, Revenue Recognized												$ 3,000,000
Restricted Stock Units (RSUs) [Member] | Vice President of Operation and President of Subsidiary [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)												500,000
Proceeds Cash, Trigger for Award as Unvested												$ 3,000,000
Converted Accrued and Unpaid Obligations for Previous Issued Expired Options [Member] | Employees [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)																				1,501,954
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 198,000																		$ 198,000
Converted Accrued and Unpaid Obligations for Previous Issued Expired Options [Member] | Employees [Member] | 2018 Equity Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.14
Converted Accrued and Unpaid Obligations for Previous Issued Expired Options [Member] | Employees [Member] | 2018 Equity Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)																				$ 0.17
Non Contingent Options [Member] | Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								400,000
Non Contingent Options [Member] | Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								100,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)								90 days
Non Contingent Options [Member] | Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								100,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)								1 year
Non Contingent Options [Member] | Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								200,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)								2 years
Contingent Options [Member] | Director of Business Development for Odor-No-More [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)								600,000
Share-based Payment Arrangement, Option [Member] | Vendors [Member] | Selling, General and Administrative Expenses [Member] | Non Plan [Member]
Share-based Payment Arrangement, Expense																				$ 167,000	$ 260,000
[1]	Aggregate intrinsic value based on closing common stock price of $0.12 at December 31, 2020.

Note 5 - Share-based Compensa_4

Note 5 - Share-based Compensation - Stock Options (Details) - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020
2018 Equity Incentive Plan [Member]
Options outstanding, balance (in shares)		9,214,356	1,318,517
Weighted average exercise price per share, balance (in dollars per share)		$ 0.25	$ 0.30
Options granted (in shares)		11,197,687	7,895,839
Weighted average exercise price per share, granted (in dollars per share)		$ 0.15	$ 0.25
Options expired (in shares)		(1,546,518)
Options outstanding, balance (in shares)		18,865,525	9,214,356
Weighted average exercise price per share, balance (in dollars per share)		$ 0.19	$ 0.25
Options Non-vested (in shares)				(6,418,622)
Weighted average exercise price per share, Non-vested (in dollars per share)				$ 0.19
Options Vested (in shares)				12,446,903
Weighted average exercise price per share, Vested (in dollars per share)				$ 0.18
Vested, aggregate intrinsic value	[1]
2018 Equity Incentive Plan [Member] | Minimum [Member]
Exercise price per share, balance (in dollars per share)		0.16	0.22
Exercise price per share, granted (in dollars per share)		0.12	0.16
Exercise price per share, balance (in dollars per share)		0.16	0.16
Exercise price per share, Non-vested (in dollars per share)		0.17
Exercise price per share, Vested (in dollars per share)				$ 0.16
Exercise price per share, balance (in dollars per share)		0.16	0.16	0.16
2018 Equity Incentive Plan [Member] | Maximum [Member]
Exercise price per share, balance (in dollars per share)		0.43	0.43
Exercise price per share, granted (in dollars per share)		0.40	0.40
Exercise price per share, balance (in dollars per share)		0.40	0.43
Exercise price per share, Non-vested (in dollars per share)		0.45
Exercise price per share, Vested (in dollars per share)				0.45
Exercise price per share, balance (in dollars per share)		$ 0.40	$ 0.43	$ 0.40
Non Plan [Member]
Options outstanding, balance (in shares)		19,604,107	19,319,496
Weighted average exercise price per share, balance (in dollars per share)		$ 0.43	$ 0.43
Options granted (in shares)		1,145,476	1,226,586
Weighted average exercise price per share, granted (in dollars per share)		$ 0.15	$ 0.21
Options expired (in shares)			(941,975)
Options outstanding, balance (in shares)		20,749,583	19,604,107
Weighted average exercise price per share, balance (in dollars per share)		$ 0.41	$ 0.43
Options Non-vested (in shares)				(2,369,708)
Exercise price per share, Non-vested (in dollars per share)		0.45
Weighted average exercise price per share, Non-vested (in dollars per share)				$ 0.45
Options Vested (in shares)				18,379,875
Weighted average exercise price per share, Vested (in dollars per share)				$ 0.41
Vested, aggregate intrinsic value	[1]
Weighted average exercise price per share, Expired (in dollars per share)			0.52
Non Plan [Member] | Minimum [Member]
Exercise price per share, balance (in dollars per share)		0.16	0.23
Exercise price per share, granted (in dollars per share)		0.12	0.16
Exercise price per share, balance (in dollars per share)		0.12	0.16
Exercise price per share, Vested (in dollars per share)				$ 0.23
Exercise price per share, Expired (in dollars per share)			0.45
Exercise price per share, balance (in dollars per share)		0.12	0.16	0.12
Non Plan [Member] | Maximum [Member]
Exercise price per share, balance (in dollars per share)		1	1
Exercise price per share, granted (in dollars per share)		0.21	0.32
Exercise price per share, balance (in dollars per share)		1	1
Exercise price per share, Vested (in dollars per share)				1
Exercise price per share, Expired (in dollars per share)			0.55
Exercise price per share, balance (in dollars per share)		$ 1	$ 1	$ 1
[1]	Aggregate intrinsic value based on closing common stock price of $0.12 at December 31, 2020.

Note 5 - Share-based Compensa_5

Note 5 - Share-based Compensation - Stock Options Issued Under the 2007 Equity Incentive Plan (Details) - The 2007 Equity Incentive Plan [Member] - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Options outstanding, balance (in shares)		8,769,451	9,691,586
Options expired (in shares)		(3,080,088)	(922,135)
Options outstanding, balance (in shares)		5,689,363	8,769,451
Outstanding, aggregate intrinsic value	[1]
Minimum [Member]
Exercise price per share, balance (in dollars per share)		$ 0.22	$ 0.22
Exercise price per share, Expired (in dollars per share)		0.22	0.45
Exercise price per share, balance (in dollars per share)		0.23	0.22
Maximum [Member]
Exercise price per share, balance (in dollars per share)		0.94	0.94
Exercise price per share, Expired (in dollars per share)		0.58	0.55
Exercise price per share, balance (in dollars per share)		0.94	0.94
Weighted Average [Member]
Weighted average exercise price per share, balance (in dollars per share)		0.43	0.43
Weighted average exercise price per share, Expired (in dollars per share)		0.38	0.49
Weighted average exercise price per share, balance (in dollars per share)		$ 0.44	$ 0.43
[1]	Aggregate intrinsic value based on closing common stock price of $0.12 at December 31, 2020.

Note 6 - Warrants (Details Text

Note 6 - Warrants (Details Textual) - USD ($)

Sep. 16, 2019

Jun. 24, 2019

Jun. 07, 2019

Jul. 31, 2017

Sep. 30, 2019

Sep. 30, 2019

Dec. 31, 2020

Dec. 31, 2019

Aug. 31, 2019

Aug. 20, 2019

Aug. 15, 2019

Aug. 09, 2019

Mar. 31, 2019

Mar. 05, 2019

Mar. 04, 2019

Jan. 31, 2019

Share Price (in dollars per share)

$ 0.12

Class of Warrant or Right, Issued During Period (in shares)

5,594,314

24,490,687

Deemed Dividends

$ 355,000

$ 117,000

$ 809,000

Stock Issued During Period, Shares, Exercise of Warrants (in shares)

7,544,456

Proceeds from Warrant Exercises

$ 560,000

Nine Months OID Notes In Connection With Warrant [Member]

Debt Instrument, Convertible, Conversion Price (in dollars per share)

$ 0.17

$ 0.25

Vista Warrant [Member]

Class of Warrant or Right, Increase Shares Available for Purchase (in shares)

2,520,780

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

2,877,790

Convertible Twelve Months OID Notes [Member]

Debt Instrument, Face Amount

$ 2,794,000

$ 2,794,000

Debt Instrument, Term (Month)

1 year

Convertible Twelve Months OID Notes [Member] | Convertible Notes Payable [Member]

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

2,095,588

Debt Instrument, Face Amount

$ 381,000

$ 381,000

$ 330,882

Debt Instrument, Term (Month)

1 year

Original Issue Discount, Percentage

25.00%

25.00%

Convertible Notes Maturing June 15, 2021 [Member] | Convertible Notes Payable [Member]

Debt Instrument, Face Amount

$ 100,000

Debt Instrument, Term (Month)

1 year

Original Issue Discount, Percentage

25.00%

Warrants Issued in Connection with Investment from Five Investors [Member]

Warrants and Rights Outstanding, Term (Month)

180 days

Class of Warrant or Right, Issued During Period, Number of Securities Called by Warrants or Rights (in shares)

2,318,194

Warrants Issued in Connection with Investment from Five Investors [Member] | Minimum [Member]

Class of Warrant or Right, Issued During Period, Exercise Price (in dollars per share)

$ 0.18

Warrants Issued in Connection with Investment from Five Investors [Member] | Maximum [Member]

Class of Warrant or Right, Issued During Period, Exercise Price (in dollars per share)

$ 0.22

Five Year Warrant [Member]

Class of Warrant or Right, Issued During Period, Number of Securities Called by Warrants or Rights (in shares)

2,318,194

Five Year Warrant [Member] | Minimum [Member]

Class of Warrant or Right, Issued During Period, Exercise Price (in dollars per share)

$ 0.23

Five Year Warrant [Member] | Maximum [Member]

Class of Warrant or Right, Issued During Period, Exercise Price (in dollars per share)

0.27

Warrants Issued Concurrently With One Year Convertible Note [Member]

Class of Warrant or Right, Issued During Period (in shares)

400,000

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.65

$ 0.13

Class of Warrant or Right, Increase Shares Available for Purchase (in shares)

957,926

Deemed Dividends

$ 117,000

Warrants Issued as Part of Debt Extension [Member] | Vernal Bay Investments, LLC [Member]

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.20

$ 0.25

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

2,484,375

1,987,500

Warrant In Connection With Convertible Note [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

$ 0.30

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

1,200,000

Warrants and Rights Outstanding

$ 198,000

Warrants Issued in Conversion of Secured Line of Credit to Twelve Month OID Notes [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

1,130,515

Warrants Issued in Connection with Conversion of Notes Due June 15, 2021 [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)

551,471

Warrants Issued as Consent for Variable Rate Date [Member] | Lincoln Park Capital Fund, LLC [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

300,000

Discount On Convertible Note Payable

$ 54,000

Warrants Issued Concurrently with the Nine-month Note Payable [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

637,500

Discount On Convertible Note Payable

$ 89,000

Nine Months OID Notes In Connection With Warrant [Member]

Deemed Dividends

$ 84,000

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

937,500

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

$ 300,000

Twelve Months OID Notes In Connection With Warrant [Member]

Warrants and Rights Outstanding, Term (Month)

5 years

Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)

$ 0.25

Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)

12,325,370

Stock Purchase Warrant, Percentage of Principal

75.00%

Class of Warrant or Right, Percentage of Principal Value of Note Calculation, Investment

$ 300,000

Class of Warrant or Right, Percentage of Principal Value of Note Calculation, Numerator Value of Calculation

$ 375,000

Class of Warrant or Right, Percentage of Principal Value of Note Calculation, Denominator Value of Calculation (in shares)

1,654,412

Discount on Notes Payable

$ 2,240,000

Note 6 - Warrants - Warrants Ou

Note 6 - Warrants - Warrants Outstanding (Details) - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance, outstanding (in shares)		43,231,161	26,872,430
Granted (in shares)		5,594,314	24,490,687
Exercised (in shares)			(7,544,456)
Exercised, price range (in dollars per share)			$ 0.30
Expired (in shares)		(15,844,486)	(587,500)
Expired (in dollars per share)			$ 0.40
Balance, outstanding (in shares)		32,980,989	43,231,161
Balance, aggregate intrinsic value	[1]
Minimum [Member]
Balance, outstanding, price range (in dollars per share)		$ 0.13	$ 0.25	$ 0.25
Granted, price range (in dollars per share)		0.13	0.25
Expired (in dollars per share)		0.18
Maximum [Member]
Balance, outstanding, price range (in dollars per share)		1	1	1
Granted, price range (in dollars per share)		0.27	0.48
Expired (in dollars per share)		0.70
Weighted Average [Member]
Balance, outstanding, price range (in dollars per share)		0.29	0.35	$ 0.43
Granted, price range (in dollars per share)		0.20	0.29
Exercised, price range (in dollars per share)			0.30
Expired (in dollars per share)		$ 0.43	$ 0.40
[1]	Aggregate intrinsic value based on closing common stock price of $0.12 at December 31, 2020.

Note 6 - Warrants - Assumptions

Note 6 - Warrants - Assumptions Used to Determine Fair Value of Warrants (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Minimum [Member]
Risk free interest rate	0.10%	1.42%
Expected volatility	100.00%	101.00%
Expected life (Year)	2 years	1 year
Maximum [Member]
Risk free interest rate	0.23%	2.13%
Expected volatility	112.00%	110.00%
Expected life (Year)	5 years	5 years

Note 7 - Accounts Payable and_3

Note 7 - Accounts Payable and Accrued Expenses - Summary of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts payable	$ 315	$ 195
Accrued payroll	156	128
Accrued interest	42	71
Total	513	394
Corporate, Non-Segment [Member]
Accounts payable	125	102
Accrued payroll	23	11
Accrued interest	42	71
Total
Operating Segments [Member] | Odor-No-More [Member]
Accounts payable	73	35
Accrued payroll	42	34
Accrued interest
Total
Operating Segments [Member] | BLEST [Member]
Accounts payable	56	46
Accrued payroll	91	82
Accrued interest
Total
Operating Segments [Member] | BioLargo Water [Member]
Accounts payable	103	43
Accrued payroll
Accrued interest
Total
Consolidation, Eliminations [Member]
Accounts payable	(42)	(31)
Accrued payroll
Accrued interest
Total

Note 8 - Provision for Income_2

Note 8 - Provision for Income Taxes (Details Textual)	12 Months Ended
	Dec. 31, 2020USD ($)
Net Operating Loss Carryforward Expiration Term (Year)	20 years
Valuation Allowance Percentage	100.00%
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 104,000,000
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member]
Operating Loss Carryforwards, Total	$ 47,000,000

Note 9 - In-process Research _2

Note 9 - In-process Research and Development (Details Textual) - Clyra Medical [Member] - USD ($)	Dec. 17, 2018	Sep. 26, 2018	Dec. 31, 2020	Dec. 31, 2019
Revenues, Total			$ 200,000
Scion Acquisition [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)		21,000
Business Combination, Consideration Transferred, Liabilities Incurred		$ 1,250,000
Business Acquisition, Base Capital Requirement for Escrow Release	$ 1,000,000	$ 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 Five	$ 2,000,000
Scion Acquisition [Member] | Clyra Acquisition, Common Stock [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)	15,500	10,000
Scion Acquisition [Member] | Clyra Acquisition, Common Stock Redeemable for BioLargo Common Shares [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)		7,142,858	6,200
Business Combination, Shares Acquired (in shares)		12,755
Stock Redeemed Upon Vesting of 10,000 Clyra Acquisition Shares, Shares (in shares)		10,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable			$ 257,000	$ 1,893,000
Common Stock, Redeemable, Issuer Option, Shares (in shares)			2,200
Common Stock, Shares Issued upon Redemption (in shares)			1,428,571

Note 10 - Noncontrolling Inte_3

Note 10 - Noncontrolling Interest - Clyra Medical (Details Textual) - USD ($)	Aug. 10, 2020	Jun. 30, 2020	Sep. 26, 2018	Dec. 30, 2015	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Long-term Line of Credit, Total							$ 50,000	$ 50,000
Stock Issued During Period, Value, Commitment Fee							(122,000)
Stock Issued During Period, Value, Issued for Services							666,000	710,000
Stock Issued During Period, Value, New Issues							2,783,000	125,000
Conversion of Accrued Dividends , Amount Converted								$ 270,000
Stock Issued During Period, Shares Issued for Conversion of Dividend (in shares)								3,544
Gain (Loss) on Extinguishment of Debt, Total	$ (228,000)						$ (442,000)	$ (1,029,000)
Share Price (in dollars per share)							$ 0.12
Clyra Medical [Member]
Stock Issued During Period, Shares, New Issues (in shares)							2,742	2,680
Stock Issued During Period, Value, New Issues							$ 851,000	$ 536,000
Shares Issued, Price Per Share (in dollars per share)		$ 310			$ 310	$ 310	$ 310	$ 200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)							3,943	7,624
Gain (Loss) on Extinguishment of Debt, Total							$ (214,000)
Share Price (in dollars per share)							$ 310
Clyra Medical [Member] | Vendors and Employees [Member]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in dollars per share)							$ 1
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)							10 years
Clyra Medical [Member] | Vendors and Employees [Member] | Share-based Payment Arrangement, Option [Member]
Share-based Payment Arrangement, Expense							$ 853,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount Rate							30.00%
Clyra Medical [Member] | Beach House Consulting, LLC [Member]
Consulting Services, Monthly Payment				$ 23,000
Consulting Services, Period of Services (Year)				4 years
Stock Issued During Period, Shares, Issued for Services (in shares)		3,639
Consulting Services, Three Consecutive Month Average Revenue Threshold for Consulting Fees to Accrue							$ 250,000
Stock Issued During Period, Value, Issued for Services							$ 788,000
Clyra Medical [Member] | Revolving Credit Facility [Member] | Vernal Bay Capital Group, LLC [Member] | Inventory Line of Credit [Member]
Debt Instrument, Interest Rate, Stated Percentage							15.00%
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,000,000			$ 1,000,000	$ 1,000,000
Proceeds from Lines of Credit, Total							$ 260,000
Repayments of Lines of Credit							36,000
Long-term Line of Credit, Total							$ 224,000
Line of Credit Facility, Covenant, Additional Draws, Maximum Percentage of Total Principal Outstanding Allowed							50.00%
Line of Credit Facility, Covenant, Additional Draws, Minimum Amount Allowed							$ 200,000
Debt Instrument, Term (Month)							1 year
Line of Credit Facility, Monthly Percentage of Gross Product Sales Required to be Used as Payment of Debt on First 180 Days							30.00%
Line of Credit Facility, Monthly Percentage of Gross Product Sales Required to be Used as Payment of Debt after the First 180 Days							60.00%
Stock Issued During Period, Shares, Commitment Fee (in shares)							323
Stock Issued During Period, Value, Commitment Fee							$ 70,000
Clyra Medical Technology Inc [Member] | Sanatio [Member]
Preferred Stock, Dividend Rate, Percentage							8.00%
Preferred Shares Dividend, Period (Year)							5 years
Scion Acquisition [Member] | Clyra Medical [Member]
Business Combination, Consideration Transferred, Liabilities Incurred			$ 1,250,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)			21,000
Scion Solutions [Member] | Clyra Medical [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%
Notes Payable, Current, Total							$ 1,007,000	$ 1,007,000
Clyra Acquisition, Common Stock [Member] | Clyra Medical [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)							9,300
Clyra Medical Technologies [Member]
Noncontrolling Interest, Ownership Percentage by Parent							45.00%
Clyra Medical Technology Inc [Member]
Stock Issued During Period, Shares, New Issues (in shares)						22,513
Noncontrolling Interest, Increased Investment, Shares (in shares)						23,004
Noncontrolling Interest, Increased Investment, Additional Shares (in shares)					490

Note 10 - Noncontrolling Inte_4

Note 10 - Noncontrolling Interest - Clyra Medical Common and Preferred Shares Outstanding (Details) - Clyra Medical Technology Inc [Member]	Dec. 31, 2020shares
Shares, Outstanding (in shares)	108,729	[1]
Biolargo [Member]
Shares, Outstanding (in shares)	49,207
Percent	45.00%
Sanatio [Member]
Shares, Outstanding (in shares)	18,704
Percent	17.00%
Scion Solutions [Member]
Shares, Outstanding (in shares)	21,700	[2]
Percent	20.00%	[2]
Other [Member]
Shares, Outstanding (in shares)	19,118
Percent	18.00%
[1]	Does not include options to purchase 10,153 of shares of Clyra stock.
[2]	Does not include an additional 12,400 shares held in escrow subject to performance metrics.

Note 10 - Noncontrolling Inte_5

Note 10 - Noncontrolling Interest - Summary of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts payable	$ 315	$ 195
Accrued payroll	156	128
Accrued interest	42	71
Total	513	$ 394
Clyra Medical [Member]
Accounts payable	402
Accrued payroll	32
Accrued interest	102
Total	$ 536

Note 11 - BioLargo Engineerin_2

Note 11 - BioLargo Engineering, Science and Technologies, LLC (Details Textual) - USD ($)	Nov. 04, 2019	Sep. 30, 2017	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Share-based Payment Arrangement, Noncash Expense, Total			$ 2,459,000	$ 1,522,000
Percentage of Profits Interests Vested	2.50%
Percentage of Option to Purchase Shares of Common Stock	10.00%
Seven Employees Working at BioLargo Engineering, Science & Technologies, LLC [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period (Year)		5 years
Potential Ownership Percentage of Subsidiary Held by Subsidiary Employees Based on Performance		30.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	175,000		262,500
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%
Percentage of Profits Interests Vested			3.75%
Percentage of Option to Purchase Shares of Common Stock			15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 44,000		$ 65,000
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 (in shares)		1,750,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		5 years
Share-based Payment Arrangement, Noncash Expense, Total					$ 0
BioLargo Engineering, Science & Technologies, LLC [Member]
Noncontrolling Interest, Ownership Percentage by Parent		100.00%	94.00%

Note 12 - Business Segment In_3

Note 12 - Business Segment Information (Details Textual)	12 Months Ended
	Dec. 31, 2020
Number of Operating Segments	4

Note 12 - Business Segment In_4

Note 12 - Business Segment Information - Segment Information (Details) - USD ($)		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Revenue		$ 2,432,000	$ 1,861,000
Operating loss		(7,583,000)	(6,696,000)
Interest expense		(1,923,000)	(3,996,000)
Research and development		(1,338,000)	(1,472,000)
Tangible assets		2,729,000	1,728,000
Investment in South Korean joint venture		63,000
Intangible assets		2,150,000	1,893,000
Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture		63,000
Corporate, Non-Segment [Member]
Revenue		14,000
Operating loss		(3,947,000)	(3,651,000)
Interest expense		(1,823,000)	(3,944,000)
Research and development		(754,000)	(892,000)
Tangible assets		603,000	1,050,000
Intangible assets		2,150,000	1,893,000
Corporate, Non-Segment [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture		63,000
Operating Segments [Member] | Odor-No-More [Member]
Revenue		1,568,000	1,459,000
Operating loss		(493,000)	(335,000)
Interest expense			(2,000)
Tangible assets		624,000	420,000
Intangible assets
Operating Segments [Member] | Odor-No-More [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture
Operating Segments [Member] | Clyra Medical [Member]
Tangible assets		1,125,000	3,000
Intangible assets
Operating Segments [Member] | Clyra Medical [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture
Operating Segments [Member] | BLEST [Member]
Tangible assets		314,000	264,000
Intangible assets
Operating Segments [Member] | BLEST [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture
Operating Segments [Member] | BioLargo Water [Member]
Revenue		37,000
Operating loss		(697,000)	(728,000)
Research and development		(505,000)	(610,000)
Tangible assets		105,000	50,000
Intangible assets
Operating Segments [Member] | BioLargo Water [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture
Operating Segments [Member] | Clyra Segment [Member]
Revenue		240,000
Operating loss		(1,827,000)	(1,233,000)
Interest expense		(100,000)	(50,000)
Research and development		(164,000)	(219,000)
Operating Segments [Member] | BioLargo Engineering, Science & Technologies, LLC [Member]
Revenue		1,050,000	999,000
Operating loss		(619,000)	(749,000)
Research and development		(351,000)	(354,000)
Consolidation, Eliminations [Member]
Revenue		(477,000)	(597,000)
Research and development		436,000	603,000
Tangible assets	[1]	(42,000)	(59,000)
Intangible assets	[1]
Consolidation, Eliminations [Member] | Investment in South Korean Joint Venture [Member]
Investment in South Korean joint venture	[1]
[1]	the "elimination" column reflects the net adjustment for receivables and payables generated between our related entities that are eliminated in consolidation.

Note 13 - Commitments and Con_3

Note 13 - Commitments and Contingencies (Details Textual) - USD ($)	Jun. 18, 2019	Dec. 31, 2020	Dec. 31, 2019
Operating Lease, Expense		$ 228,000	$ 208,000
Lessee, Operating Lease, Renewal Term (Year)		3 years
Lessee, Operating Lease, Discount Rate		18.00%
Lessee, Operating Lease, Liability, to be Paid, Total		$ 522,000
Corporate Office Lease [Member]
Lessee Operating, Lease Annual Escalation Rate		3.00%
Lessee, Operating Lease, Renewal Term (Year)		4 years
Oak Ridge, Tennessee Facility Lease [Member]
Lessee, Operating Lease, Renewal Term (Year)		5 years
Lessee, Operating Lease, Option to Extend Term (Year)		3 years
President and Chief Executive Officer [Member]
Employment Agreement, Annual Base Compensation	$ 170,000
Employment Agreement, Term (Year)	5 years

Note 13 - Commitments and Con_4

Note 13 - Commitments and Contingencies - Minimum Lease Payments (Details)	Dec. 31, 2020USD ($)
December 31, 2021	$ 176,000
December 31, 2022	158,000
December 31, 2023	118,000
December 31, 2024	70,000
December 31, 2025
Total minimum lease payments	522,000
BioLargo/ONM Lease [Member]
December 31, 2021	111,000
December 31, 2022	115,000
December 31, 2023	118,000
December 31, 2024	70,000
December 31, 2025
Total minimum lease payments	414,000
BLEST Lease [Member]
December 31, 2021	65,000
December 31, 2022	43,000
December 31, 2023
December 31, 2024
December 31, 2025
Total minimum lease payments	$ 108,000

Note 14 - Subsequent Events (De

Note 14 - Subsequent Events (Details Textual) - USD ($)	Mar. 19, 2021	Mar. 18, 2021	Mar. 15, 2021	Mar. 01, 2021	Jan. 16, 2019	Jun. 22, 2018	Mar. 01, 2018	Mar. 24, 2021	Dec. 31, 2020	Dec. 31, 2019	Aug. 09, 2019
Proceeds from Issuance of Common Stock									$ 2,783,000	$ 125,000
Repayments of Long-term Lines of Credit									36,000	175,000
Long-term Line of Credit, Total									$ 50,000	$ 50,000
Clyra Medical [Member]
Stock Issued During Period, Shares, New Issues (in shares)									2,742	2,680
2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)									11,197,687	7,895,839
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)						10 years
Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)					300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares (in shares)									492,500
Convertible Note, Maturing August 9, 2021 [Member]
Debt Instrument, Face Amount											$ 600,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)											$ 0.30
Line of Credit, Maturing September 1, 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)							10 years
Lincoln Park Capital Fund, LLC [Member]
Stock Issued During Period, Shares, New Issues (in shares)									13,388,642	556,144
Proceeds from Issuance of Common Stock									$ 2,058,000	$ 125,000
Subsequent Event [Member] | Chief Financial Officer [Member]
Engagement Agreement, Extended Term (Year)		1 year
Subsequent Event [Member] | Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross, Per Month (in shares)		25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		300,000
Share-based Compensation Arrangement by Share-based Payment Award, Options Vesting Each Month During Extended Term, Number of Shares (in shares)		25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)		$ 0.174
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)		10 years
Subsequent Event [Member] | Chief Financial Officer [Member] | 2018 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares (in shares)			25,000
Subsequent Event [Member] | Warrants Issued in Connection with Conversion of Interest on Note Payable Maturing March 8, 2023 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				225,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)				$ 0.16
Warrants and Rights Outstanding, Term (Month)				5 years
Subsequent Event [Member] | Conversion from Interest Accrued on Note Payable Maturing March 8, 2023 [Member]
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares)				1
Subsequent Event [Member] | Convertible Note, Maturing August 9, 2021 [Member]
Repayments of Convertible Debt				$ 600,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total				7,371
Subsequent Event [Member] | Line of Credit, Maturing September 1, 2019 [Member]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities, Total				1,455
Repayments of Long-term Lines of Credit				50,000
Long-term Line of Credit, Total				0
Subsequent Event [Member] | Note Payable, Maturing March 8, 2023 [Member]
Debt Instrument, Face Amount				$ 50,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)				$ 0.16
Subsequent Event [Member] | Paycheck Protection Program CARES Act [Member] | Clyra Medical [Member]
Extinguishment of Debt, Amount	$ 43,000
Subsequent Event [Member] | Lincoln Park Capital Fund, LLC [Member]
Stock Issued During Period, Shares, New Issues (in shares)								12,511,674
Proceeds from Issuance of Common Stock				$ 2,000,000				$ 2,020,000