Termination notice effective period.

No definition available.

Name:	cara_AgreementTerminationNoticeEffectivePeriod
Namespace Prefix:	cara_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of milestone payment receivable under the collaboration and license agreement.

+ References

No definition available.

+ Details

Name:	cara_CollaborationAndLicensingAgreementMilestonePaymentReceivable
Namespace Prefix:	cara_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of days to terminate agreement upon material breach.

+ References

No definition available.

+ Details

Name:	cara_NumberOfDaysToTerminateAgreementUponMaterialBreach
Namespace Prefix:	cara_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of net profits sharing.

+ References

No definition available.

+ Details

Name:	cara_PercentageOfNetProfitsSharing
Namespace Prefix:	cara_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of potential milestone payment of common stock investment.

+ References

No definition available.

+ Details

Name:	cara_PotentialMilestonePayment
Namespace Prefix:	cara_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of potential payment upon achievement of certain sales-based milestones.

+ References

No definition available.

+ Details

Name:	cara_PotentialSalesMilestonePayment
Namespace Prefix:	cara_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

+ Details

Name:	us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

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

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 5: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479941/924-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-5

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-30

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-42

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-40

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-22

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-4

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=cara_LicenseAndMilestoneFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=cara_ViforFreseniusMedicalCareRenalPharmaLtdAgreementNo1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=cara_ViforFreseniusMedicalCareRenalPharmaLtdAgreementNo2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=cara_LicenseAgreementWithMaruishiPharmaceuticalCo.LtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cara_CslViforMaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=srt_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=cara_CslViforMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=cara_ViforFreseniusMedicalCareRenalPharmaLimitedMember
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:	srt_CounterpartyNameAxis=cara_MaruishiPharmaceuticalCompanyLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Collaboration and Licensing Agreements - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended			12 Months Ended
	May 17, 2018	Apr. 30, 2022	Oct. 31, 2020	May 31, 2018	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Collaboration and Licensing Agreements:
Net proceeds from sales of common stock under open market sales agreement						$ 1,117
Revenue from contract with customer					$ 7,137	20,968	$ 41,867
License and milestone fees [Member]
Collaboration and Licensing Agreements:
Revenue from contract with customer						910	15,000
Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1 [Member]
Collaboration and Licensing Agreements:
Percentage of net profit sharing			60.00%
Number of days to terminate agreement					60 days
Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member]
Collaboration and Licensing Agreements:
Percentage of net profit sharing				50.00%
License Agreement with Maruishi Pharmaceutical Co. Ltd [Member]
Collaboration and Licensing Agreements:
Earned milestone payment						1,449
CSL Vifor Maximum [Member] \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1 [Member]
Collaboration and Licensing Agreements:
Potential sales-based milestone payments			$ 240,000
Affiliated Entity \| CSL Vifor \| License and milestone fees [Member]
Collaboration and Licensing Agreements:
Revenue from contract with customer							$ 15,000
Affiliated Entity \| CSL Vifor \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1 [Member]
Collaboration and Licensing Agreements:
Percentage of net profit sharing			40.00%
Affiliated Entity \| Vifor Fresenius Medical Care Renal Pharma Ltd \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member]
Collaboration and Licensing Agreements:
Number of days to terminate agreement	60 days
Termination notice effective period	12 months
Affiliated Entity \| Vifor Fresenius Medical Care Renal Pharma Ltd \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member] \| License and milestone fees [Member]
Collaboration and Licensing Agreements:
Revenue from contract with customer		$ 15,000
Affiliated Entity \| Vifor Fresenius Medical Care Renal Pharma Ltd \| Maximum [Member] \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2 [Member]
Collaboration and Licensing Agreements:
Potential milestone payments	$ 440,000
Affiliated Entity \| Maruishi Pharmaceutical Co., Ltd. [Member] \| License Agreement with Maruishi Pharmaceutical Co. Ltd [Member] \| License and milestone fees [Member]
Collaboration and Licensing Agreements:
Revenue from contract with customer						$ 1,449