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

No definition available.

+ 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

- 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:
Data Type:	na
Balance Type:
Period Type:

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	Nov. 30, 2021 USD ($)	Oct. 31, 2021 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) Lease	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Commitments And Contingencies [Line Items]
Number of operating leases for real estate \| Lease									3
Lease extended term		1 year
Expiry of lease		Dec. 31, 2026			Dec. 31, 2026	Dec. 31, 2026
Lease costs incurred percentage	40.00%		75.00%	75.00%
Base rent due under lease					$ 4	$ 11
Percentage of increase rent per annum over lease term						3.50%
Percentage of base rent abated of lease term						50.00%
Lease expense							$ 93	$ 70	$ 179	$ 140
Finance leases							$ 0		$ 0		$ 0
San Diego \| Corporate Headquarters [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12
San Diego \| Supplemental Office Space [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12
Frederick, Maryland [Member]
Commitments And Contingencies [Line Items]
Operating leases with termination date									2026-12