Commitments and contingencies.

No definition available.

Name:	isco_CommitmentsAndContingenciesLineItems
Namespace Prefix:	isco_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Finance leases.

+ References

No definition available.

+ Details

Name:	isco_FinanceLeases
Namespace Prefix:	isco_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Lease costs incurred percentage.

+ References

No definition available.

+ Details

Name:	isco_LeaseCostsIncurredPercentage
Namespace Prefix:	isco_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease expiration month and year.

+ References

No definition available.

+ Details

Name:	isco_LeaseExpirationMonthAndYear
Namespace Prefix:	isco_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of operating leases.

+ References

No definition available.

+ Details

Name:	isco_NumberOfOperatingLeases
Namespace Prefix:	isco_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of base rent abated.

+ References

No definition available.

+ Details

Name:	isco_PercentageOfBaseRentAbated
Namespace Prefix:	isco_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of increase rent per annum over lease term.

+ References

No definition available.

+ Details

Name:	isco_PercentageOfIncreaseRentPerAnnumOverLeaseTerm
Namespace Prefix:	isco_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Date which lease or group of leases is set to expire, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_OperatingLeaseCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of operating lease expense. Excludes sublease income.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-4

+ Details

Name:	us-gaap_OperatingLeaseExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	srt_StatementGeographicalAxis=isco_SanDiegoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=isco_CorporateHeadquartersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=isco_SupplementalOfficeSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=isco_FrederickMember
Namespace Prefix:
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Commitments and Contingencies - Additional Information (Detail) $ in Thousands		1 Months Ended					3 Months Ended		6 Months Ended
	Dec. 15, 2021	Mar. 31, 2025	Feb. 28, 2025	Jan. 31, 2025 USD ($)	Nov. 30, 2021 USD ($)	Oct. 31, 2021 USD ($)	Jun. 30, 2026 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) Lease	Jun. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)
Commitments And Contingencies [Line Items]
Number of operating leases for real estate \| Lease									3
Lease costs incurred percentage	40.00%			75.00%
Right-of-use assets							$ 175		$ 175		$ 344
Operating lease liabilities							199		199
Lease expense							93	$ 93	186	$ 179
Finance leases							$ 0		$ 0		$ 0
San Diego
Commitments And Contingencies [Line Items]
Expiry of lease						Dec. 31, 2026
San Diego \| Corporate Headquarters [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12
Lease costs incurred percentage			75.00%
Base rent due under lease						$ 11
Percentage of increase rent per annum over lease term						3.50%
Percentage of base rent abated of lease term						50.00%
Right-of-use assets						$ 232
Operating lease liabilities						$ 232
San Diego \| Supplemental Office Space [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12
Expiry of lease					Dec. 31, 2026
Base rent due under lease				$ 4	$ 4
Right-of-use assets				93	247
Operating lease liabilities				$ 93	$ 247
Frederick, Maryland [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12
Lease extended term		1 year
Expiry of lease		Dec. 31, 2026