Note 8 - Noncontrolling Interest - Clyra Medical (Details Textual)				1 Months Ended			3 Months Ended						9 Months Ended		12 Months Ended	63 Months Ended
		Oct. 01, 2025 USD ($) shares	Dec. 04, 2024 USD ($)	Oct. 31, 2025 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) shares	Oct. 31, 2023 USD ($) $ / shares shares	Sep. 30, 2025 USD ($) $ / shares shares	Jun. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Sep. 30, 2024 USD ($) $ / shares	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2025 USD ($) $ / shares shares	Sep. 30, 2024 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) shares	Sep. 30, 2025 USD ($) $ / shares shares	Dec. 31, 2023	Jun. 30, 2020
Warrants and Rights Outstanding	[1]						$ 2,000						$ 2,000			$ 2,000
Class of Warrant or Right, Issued During Period (in shares) | shares														4,127,516
Stock Issued During Period, Value, Issued for Services							$ 55,000	$ 212,000	$ 61,000	$ 63,000	$ 116,000	$ 83,000
Share Price (in dollars per share) | $ / shares							$ 0.17						$ 0.17			$ 0.17
Clyra Medical [Member] | Common Stock [Member]
Investment Owned, Balance, Shares (in shares) | shares							5,305,156						5,305,156			5,305,156
Clyra Medical [Member] | Preferred Stock, Series A [Member]
Investment Owned, Balance, Shares (in shares) | shares							165,765						165,765			165,765
Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input							0						0			0
Maximum [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input															0.95
Minimum [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input															0.64
Clyra Medical [Member]
Shares, Outstanding (in shares) | shares							11,268,795						11,268,795		10,544,527	11,268,795
Shares, Issued (in shares) | shares							11,268,795						11,268,795		10,544,527	11,268,795
Stock Issued During Period, Shares, New Issues (in shares) | shares													49,167
Proceeds from Issuance or Sale of Equity													$ 295,000
Finance Lease, Liability							$ 383						383			$ 383
Clyra Medical [Member] | Sale Leaseback of Equipment [Member]
Proceeds from Sale of Property, Plant, and Equipment			$ 350,000
Financing Receivable, after Allowance for Credit Loss			$ 82,000
Receivable with Imputed Interest, Effective Yield (Interest Rate)			15.00%
Lessee, Finance Lease, Purchase Option, Amount			$ 82,000
Lessee, Finance Lease, Term of Contract (Year)			49 years
Finance Lease, Liability							$ 486,000						$ 486,000			$ 486,000
Clyra Medical [Member] | Vendors [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares													31,391
Stock Issued During Period, Value, Issued for Services													$ 60,000	$ 29,000
Stock Issued During Period, Shares, Issued for Services (in shares) | shares														11,331
Clyra Medical [Member] | Employees and Consultants [Member] | Share-Based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value													$ 164,000	$ 131,000
Share Price (in dollars per share) | $ / shares							$ 4.5						$ 4.5			$ 4.5
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount Rate													30.00%
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount							$ 508,000						$ 508,000			$ 508,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)													1 year
Clyra Medical [Member] | Preferred Shares Issued for Debt Owed to Biolargo [Member]
Debt Conversion, Converted Instrument, Amount					$ 741,000
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares					148,156
Clyra Medical [Member] | Series A Preferred Stock [Member]
Shares, Outstanding (in shares) | shares							746,418						746,418		746,418	746,418
Shares Issued, Price Per Share (in dollars per share) | $ / shares						$ 3.1
Preferred Stock, Dividend Rate, Percentage						15.00%
Preferred Stock, Convertible, Sale of Stock Amount						$ 5,000,000
Clyra Medical [Member] | Series B Preferred Stock [Member]
Shares, Outstanding (in shares) | shares							330,000						330,000			330,000
Clyra Medical [Member] | Preferred Class A [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares						746,618
Proceeds from Issuance of Preferred Stock and Preference Stock						$ 1,800,000
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																126,000
Debt Instrument, Percentage of Principal Payment, Cap																	15.00%
Long-Term Line of Credit							134,000						134,000		$ 134,000	134,000
Clyra Medical [Member] | Warrants Issued Concurrently with Note Payable [Member]
Debt Instrument, Face Amount							$ 575,000						$ 575,000			$ 575,000
Debt Instrument, Interest Rate, Stated Percentage							15.00%						15.00%			15.00%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares							$ 6						$ 6			$ 6
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares							72,667						72,667			72,667
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares							$ 6.5						$ 6.5			$ 6.5
Clyra Medical [Member] | Warrant In Connection With Convertible Note [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares							41,667						41,667			41,667
Warrants and Rights Outstanding, Measurement Input							6						6			6
Clyra Medical [Member] | Warrant In Connection With Convertible Note [Member] | Maximum [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares							$ 7.5						$ 7.5			$ 7.5
Clyra Medical [Member] | Warrant in Connection with Guaranteed Note [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | shares							88,462						88,462			88,462
Warrants and Rights Outstanding							$ 80,000						$ 80,000			$ 80,000
Long-Term Debt, Gross							$ 575,000						$ 575,000			$ 575,000
Clyra Medical [Member] | Warrants Issued With Secured Promissory Notes and Convertible Promissory Notes [Member]
Class of Warrant or Right, Discount Percentage							30.00%						30.00%			30.00%
Clyra Medical [Member] | Warrants Expiring February 28, 2027 [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares							$ 7.5			$ 7.5			$ 7.5	$ 7.5		$ 7.5
Warrants and Rights Outstanding							$ 38,000						$ 38,000			$ 38,000
Stock Issued During Period, Shares, New Issues (in shares) | shares														297,397
Class of Warrant or Right, Issued During Period (in shares) | shares													24,584	146,083
Number of Accredited Investors							5			5			5	5		5
Proceeds from Issuance or Sale of Equity														$ 1,290,000
Clyra Medical [Member] | March 31, 2025 Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares							$ 6						$ 6			$ 6
Warrants and Rights Outstanding							$ 6,000						$ 6,000			$ 6,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares							7,849						7,849			7,849
Warrants and Rights Outstanding, Term (Month)							5 years						5 years			5 years
Clyra Medical [Member] | Vendor Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares										$ 7.5				$ 7.5
Warrants and Rights Outstanding										$ 8,000				$ 8,000
Warrants and Rights Outstanding, Term (Month)										3 years				3 years
Class of Warrant or Right, Issued During Period (in shares) | shares														13,847
Clyra Medical [Member] | Warrants Issued in Conjunction With the Sale of Series A Preferred Stock [Member]
Warrants and Rights Outstanding						$ 524,000
Warrants and Rights Outstanding, Term (Month)						3 years
Shares Issued, Price Per Share (in dollars per share) | $ / shares						$ 3.72
Clyra Medical [Member] | Notes Payable, Other Payables [Member]
Debt Instrument, Face Amount							$ 436,000						$ 436,000			$ 436,000
Debt Instrument, Interest Rate, Stated Percentage							15.00%						15.00%			15.00%
Warrants and Rights Outstanding							$ 99,000						$ 99,000			$ 99,000
Long-Term Debt, Gross							1,300,000						1,300,000		864,000	1,300,000
Clyra Medical [Member] | Convertible Debt [Member]
Debt Instrument, Face Amount							$ 250,000						$ 250,000			$ 250,000
Debt Instrument, Interest Rate, Stated Percentage							10.00%						10.00%			10.00%
Warrants and Rights Outstanding							$ 52,000						$ 52,000			$ 52,000
Long-Term Debt, Gross							$ 250,000						$ 250,000			$ 250,000
Debt Instrument, Term (Year)													2 years
Clyra Medical Technologies [Member]
Preferred Stock Dividends and Other Adjustments													$ 849,000		$ 590,000
Clyra Medical Technologies [Member] | Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares		23,077
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares		11,538
Proceeds from Issuance or Sale of Equity		$ 150,000
Clyra Medical Technologies [Member] | Series B Preferred Stock [Member] | Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares				330,000
Proceeds from Issuance of Preferred Stock and Preference Stock				$ 2,145,000
Clyra Medical Technologies [Member] | Warrants Issued With Secured Promissory Notes and Convertible Promissory Notes [Member] | Maximum [Member] | Valuation Technique, Black-Scholes-Merton Model [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input							43						43			43
Clyra Medical Technologies [Member] | Warrants Issued With Secured Promissory Notes and Convertible Promissory Notes [Member] | Minimum [Member] | Valuation Technique, Black-Scholes-Merton Model [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input							35						35			35
Clyra Medical Technologies [Member] | Warrants Issued in October 2025 Offering [Member] | Subsequent Event [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares				$ 7.5
Warrants and Rights Outstanding				$ 94,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares				165,000
Warrants and Rights Outstanding, Term (Month)				3 years
Clyra Medical Technologies [Member] | Warrant Holder Unit Offering [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares							$ 7.5						$ 7.5			$ 7.5
Warrants and Rights Outstanding							$ 212,000						$ 212,000			$ 212,000
Class of Warrant or Right, Issued During Period (in shares) | shares													336,916
Proceeds from Issuance or Sale of Equity													$ 1,894,000

[1] Aggregate intrinsic value based on closing common stock price of $0.21 at June 30, 2025.