Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024
Expected volatility		49.00%
Expected dividend yield	0.00%	0.00%
Forfeiture rate	0.00%	0.00%
Expected life in years (Year)	10 years	10 years
Minimum [Member]
Risk free interest rate	4.36%	4.16%
Expected volatility	35.00%
Maximum [Member]
Risk free interest rate	4.45%	4.34%
Expected volatility	43.00%
Non Plan [Member]
Risk free interest rate	4.23%	4.34%
Expected volatility	91.00%	96.00%
Expected dividend yield	0.00%	0.00%
Forfeiture rate	0.00%	0.00%
Expected life in years (Year)	10 years	10 years
Non Plan [Member] \| Minimum [Member]
Risk free interest rate	4.23%
Expected volatility	90.00%
2024 Equity Incentive Plan [Member]
Expected dividend yield	0.00%	0.00%
Forfeiture rate	0.00%	0.00%
Expected life in years (Year)	10 years	10 years
2024 Equity Incentive Plan [Member] \| Minimum [Member]
Risk free interest rate		3.75%
Expected volatility		91.00%
2024 Equity Incentive Plan [Member] \| Maximum [Member]
Risk free interest rate	4.58%	4.58%
Expected volatility	91.00%	96.00%
2018 Equity Incentive Plan [Member]
Risk free interest rate		4.16%
Expected volatility		99.00%
Expected dividend yield		0.00%
Forfeiture rate		0.00%
Expected life in years (Year)		10 years

Represents expected forfeiture rate for share-based payment awards.

No definition available.

Name:	blgo_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate
Namespace Prefix:	blgo_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iv)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=blgo_NonPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=blgo_EquityIncentivePlan2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=blgo_EquityIncentivePlan2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: