Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Clyra Medical Technologies [Member] Common Stock [Member]	Clyra Medical Technologies [Member] Additional Paid-in Capital [Member]	Clyra Medical Technologies [Member] Retained Earnings [Member]	Clyra Medical Technologies [Member] AOCI Attributable to Parent [Member]	Clyra Medical Technologies [Member] Noncontrolling Interest [Member]	Clyra Medical Technologies [Member]	BioLargo Energy Technologies, Inc (BETI) [Member] Common Stock [Member]	BioLargo Energy Technologies, Inc (BETI) [Member] Additional Paid-in Capital [Member]	BioLargo Energy Technologies, Inc (BETI) [Member] Retained Earnings [Member]	BioLargo Energy Technologies, Inc (BETI) [Member] AOCI Attributable to Parent [Member]	BioLargo Energy Technologies, Inc (BETI) [Member] Noncontrolling Interest [Member]	BioLargo Energy Technologies, Inc (BETI) [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2023													292,945,747
Balance at Dec. 31, 2023													$ 196	$ 154,023	$ (147,098)	$ (277)	$ (2,642)	$ 4,202
Sale of common stock for cash, net of offering costs (in shares)													2,160,348
Issuance of common stock for services (unaudited) (in shares)													288,997
Issuance of common stock for services (unaudited)	$ 0	$ 0	$ 0	$ 0	$ 52	$ 52							$ 1	82	0	0	0	83
Stock option compensation expense (unaudited)													0	429	0	0	0	429
Clyra Medical stock option compensation expense (unaudited)	0	0	0	0	59	59
Clyra Medical stock unit offering (unaudited)	0	0	0	0	475	475
Clyra Medical dividend Series A Preferred stock (unaudited)	0	0	0	0	(86)	(86)
Noncontrolling interest allocation (unaudited)							$ 0	$ 0	$ 0	$ 0	$ 50	$ 50	0	288	0	0	(288)	0
Net loss (unaudited)													0	0	(410)	0	(365)	(775)
Foreign currency translation (unaudited)													0	0	0	96	0	96
Foreign currency translation (unaudited)													0	0	0	96	0	96
Sale of stock for cash, net of offering costs													1	487	0	0	0	488
Warrant exercise (unaudited)													0	75	0	0	0	75
Stock for service Clyra (unaudited)	0	0	0	0	52	52							$ 1	82	0	0	0	83
Balance (in shares) at Mar. 31, 2024													295,801,370
Balance at Mar. 31, 2024													$ 198	155,384	(147,508)	(181)	(2,745)	5,148
Common stock offering costs													$ (1)	(487)	0	0	0	(488)
Balance (in shares) at Dec. 31, 2023													292,945,747
Balance at Dec. 31, 2023													$ 196	154,023	(147,098)	(277)	(2,642)	4,202
Foreign currency translation (unaudited)																		47
Foreign currency translation (unaudited)																		47
Balance (in shares) at Sep. 30, 2024													301,163,538
Balance at Sep. 30, 2024													$ 202	156,869	(148,486)	(230)	(2,374)	5,981
Warrant exercise (unaudited) (in shares)													406,278
Balance (in shares) at Mar. 31, 2024													295,801,370
Balance at Mar. 31, 2024													$ 198	155,384	(147,508)	(181)	(2,745)	5,148
Sale of common stock for cash, net of offering costs (in shares)													454,547
Issuance of common stock for services (unaudited) (in shares)													446,989
Issuance of common stock for services (unaudited)													$ 0	116	0	0	0	116
Stock option compensation expense (unaudited)													$ 0	476	0	0	0	476
Stock option exercise (unaudited) (in shares)													497,024
Stock option exercise (unaudited)													$ 0	85	0	0	0	85
Clyra Medical stock option compensation expense (unaudited)	0	0	0	0	63	63
Clyra Medical stock issued for services (unaudited)	0	0	0	0	14	14
Clyra Medical stock unit offering (unaudited)	0	0	0	0	640	640
Clyra Medical dividend Series A Preferred stock (unaudited)	0	0	0	0	(86)	(86)
Noncontrolling interest allocation (unaudited)													0	(2,565)	0	0	2,565	0
Net loss (unaudited)													0	0	(441)	0	(339)	(780)
Foreign currency translation (unaudited)													0	0	0	(61)	0	(61)
Exchange of BETI stock for BioLargo common stock (unaudited) (in shares)							378,788
Exchange of BETI stock for BioLargo common stock (unaudited)							$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Foreign currency translation (unaudited)													0	0	0	(61)	0	(61)
Sale of stock for cash, net of offering costs													1	135	0	0	0	136
Stock for service Clyra (unaudited)													$ 0	116	0	0	0	116
Balance (in shares) at Jun. 30, 2024													298,140,188
Warrant exercise (unaudited) (in shares)													561,470
Warrant exercise (unaudited)													$ 1	140	0	0	0	141
Balance at Jun. 30, 2024													200	153,771	(147,949)	(242)	112	5,892
Common stock offering costs													$ (1)	(135)	0	0	0	(136)
Issuance of common stock for services (unaudited) (in shares)													260,903
Issuance of common stock for services (unaudited)													$ 0	63	0	0	0	63
Stock option compensation expense (unaudited)													$ 0	194	0	0	0	194
Stock option exercise (unaudited) (in shares)													451,858
Stock option exercise (unaudited)													$ 0	68	0	0	0	68
Clyra Medical stock option compensation expense (unaudited)	0	0	0	0	43	43
Clyra Medical stock issued for services (unaudited)	0	0	0	0	37	37
Clyra Medical stock unit offering (unaudited)		0			175	175
Clyra Medical dividend Series A Preferred stock (unaudited)	0	0	0	0	(87)	(87)
Noncontrolling interest allocation (unaudited)													0	2,250	0	0	(2,250)	0
Net loss (unaudited)													0	0	(537)	0	(523)	(1,060)
Foreign currency translation (unaudited)													0	0	0	12	0	12
Foreign currency translation (unaudited)													0	0	0	12	0	12
Sale of stock for cash, net of offering costs													(0)	15	(0)	(0)	(0)	15
Warrant exercise (unaudited)													2	538				540
Stock for service Clyra (unaudited)													$ 0	63	0	0	0	63
Balance (in shares) at Sep. 30, 2024													301,163,538
Balance at Sep. 30, 2024													$ 202	156,869	(148,486)	(230)	(2,374)	5,981
Common stock offering costs													$ 0	(15)	0	0	0	(15)
Clyra conversion of note payable and interest (unaudited)	0	0	0	0	119	119
Warrant exercise (unaudited) (in shares)													2,310,589
Balance (in shares) at Dec. 31, 2024													301,274,243
Balance at Dec. 31, 2024													$ 202	158,332	(149,500)	(183)	(2,795)	6,056
Sale of common stock for cash, net of offering costs (in shares)													0
Sale of common stock for cash, net of offering costs													$ 0	(15)	0	0	0	(15)
Issuance of common stock for services (unaudited) (in shares)													220,330
Issuance of common stock for services (unaudited)													$ 0	61	0	0	0	61
Stock option compensation expense (unaudited)													$ 0	409	0	0	0	409
Stock option exercise (unaudited) (in shares)													265,800
Stock option exercise (unaudited)													$ 0	0	0	0	0	0
Clyra Medical stock option compensation expense (unaudited)	0	0	0	0	206	206
Clyra Medical stock issued for services (unaudited)	0	0	0	0	36	36
Clyra Medical stock unit offering (unaudited)	0	0	0	0	295	295
Clyra Medical dividend Series A Preferred stock (unaudited)	0	0	0	0	(86)	(86)
Clyra Medical fair value warrant issued with debt (unaudited)	0	0	0	0	69	69
Noncontrolling interest allocation (unaudited)													0	(522)	0	0	522	0
Net loss (unaudited)													0	0	(1,155)	0	(766)	(1,921)
Foreign currency translation (unaudited)													0	0	0	(20)	0	(20)
Foreign currency translation (unaudited)													0	0	0	(20)	0	(20)
Stock for service Clyra (unaudited)													$ 0	61	0	0	0	61
Balance (in shares) at Mar. 31, 2025													301,760,373
Balance at Mar. 31, 2025													$ 202	158,265	(150,655)	(203)	(2,519)	5,090
Balance (in shares) at Dec. 31, 2024													301,274,243
Balance at Dec. 31, 2024													$ 202	158,332	(149,500)	(183)	(2,795)	6,056
Foreign currency translation (unaudited)																		(12)
Foreign currency translation (unaudited)																		(12)
Balance (in shares) at Sep. 30, 2025													311,452,683
Balance at Sep. 30, 2025													$ 208	164,894	(158,327)	(195)	(3,365)	3,215
Balance (in shares) at Mar. 31, 2025													301,760,373
Balance at Mar. 31, 2025													$ 202	158,265	(150,655)	(203)	(2,519)	5,090
Sale of common stock for cash, net of offering costs (in shares)													4,077,285
Sale of common stock for cash, net of offering costs													$ 3	805	0	0	0	808
Issuance of common stock for services (unaudited) (in shares)													915,003
Issuance of common stock for services (unaudited)													$ 0	212	0	0	0	212
Stock option compensation expense (unaudited)													0	292	0	0	0	292
Clyra Medical stock option compensation expense (unaudited)	0	0	0	0	200	200
Clyra Medical stock issued for services (unaudited)	0	0	0	0	24	24
Clyra Medical dividend Series A Preferred stock (unaudited)	0	0	0	0	(86)	(86)
Clyra Medical fair value warrant issued with debt (unaudited)	0	0	0	0	93	93
Noncontrolling interest allocation (unaudited)													0	1,027	0	0	(1,027)	0
Net loss (unaudited)													0	0	(1,193)	0	(689)	(1,882)
Clyra Medical Unit Warrant offering (unaudited)	$ 0	$ 0	$ 0	$ 0	$ 1,309	$ 1,309
Stock for service Clyra (unaudited)													$ 0	212	0	0	0	212
Balance (in shares) at Jun. 30, 2025													306,752,661
Balance at Jun. 30, 2025													$ 205	160,601	(151,848)	(203)	(2,695)	6,060
Sale of common stock for cash, net of offering costs (in shares)													4,222,467
Sale of common stock for cash, net of offering costs													$ 3	746	0	0	0	749
Issuance of common stock for services (unaudited) (in shares)													324,294
Issuance of common stock for services (unaudited)													$ 0	55	0	0	0	55
Stock option compensation expense (unaudited)													0	651	0	0	0	651
Clyra Medical stock option compensation expense (unaudited)													0	0	0	0	193	193
Clyra Medical stock unit offering (unaudited)													0	0	0	0	2,145	2,145
Clyra Medical dividend Series A Preferred stock (unaudited)													0	0	0	0	(87)	(87)
Noncontrolling interest allocation (unaudited)													0	2,841	0	0	(2,841)	0
Net loss (unaudited)													0	0	(6,479)	0	(765)	(7,244)
Foreign currency translation (unaudited)													0	0	0	8	0	8
Clyra Medical Unit Warrant offering (unaudited)													$ 0	0	0	0	585	585
Exchange of BETI stock for BioLargo common stock (unaudited) (in shares)													153,261
Exchange of BETI stock for BioLargo common stock (unaudited)													$ 0	0	0	0	0	0
BETI unit offering (unaudited)													0	0	0	0	100	100
Foreign currency translation (unaudited)													0	0	0	8	0	8
Stock for service Clyra (unaudited)													$ 0	55	0	0	0	55
Balance (in shares) at Sep. 30, 2025													311,452,683
Balance at Sep. 30, 2025													$ 208	164,894	(158,327)	(195)	(3,365)	3,215
Balance (in shares) at Sep. 30, 2025													311,452,683
Balance at Sep. 30, 2025													$ 208	$ 164,894	$ (158,327)	$ (195)	$ (3,365)	$ 3,215