Note 13 - Long-term Debt (Details Textual) - The 2022 Term Loan 3 [Member] - USD ($) $ in Millions	Sep. 20, 2022	Mar. 31, 2023
Debt Instrument, Maximum Borrowing Capacity	$ 50
Debt Instrument, Maximum Borrowing Capacity at Closing	30	$ 30
Debt Instrument, Additional Maximum Amount Within Nine Months After Closing	10
Debt Instrument, Additional Maximum Amount Upon Certain Milestone Acheivements	10
Debt Instrument, Additional Maximum At Discretion of Lender	10
Debt Instrument, Face Amount	$ 20	$ 20
Debt Instrument, Interest Rate, Maximum Stated Percentage for Each Tranche Borrowed	1.00%
Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%

Amount of additional maximum capacity upon achievement of certain milestones.

No definition available.

Name:	blfs_DebtInstrumentAdditionalMaximumAmountUponCertainMilestoneAcheivements
Namespace Prefix:	blfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maximum amount of addiotnal borrowing capacity within 9 months of closing.

+ References

No definition available.

+ Details

Name:	blfs_DebtInstrumentAdditionalMaximumAmountWithinNineMonthsAfterClosing
Namespace Prefix:	blfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of additional maximum borrowing at the discretion of the lender.

+ References

No definition available.

+ Details

Name:	blfs_DebtInstrumentAdditionalMaximumAtDiscretionOfLender
Namespace Prefix:	blfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents maximum stated intertest rate for each tranche borrowed.

+ References

No definition available.

+ Details

Name:	blfs_DebtInstrumentInterestRateMaximumStatedPercentageForEachTrancheBorrowed
Namespace Prefix:	blfs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents maximum borrowing capacity.

+ References

No definition available.

+ Details

Name:	blfs_DebtInstrumentMaximumBorrowingCapacity
Namespace Prefix:	blfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents maximum borrowing capacity at closing.

+ References

No definition available.

+ Details

Name:	blfs_DebtInstrumentMaximumBorrowingCapacityAtClosing
Namespace Prefix:	blfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482900/835-30-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481568/470-20-55-69C

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482925/835-30-45-2

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482949/835-30-55-8

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=blfs_The2022TermLoan3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: