Prepaid expenses - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Prepaid Expenses
Prepaid expenses	$ 529	$ 8,154
Prepaid R&D clinical costs	13	7,245
Prepaid insurance	149	492
Other prepaid costs	$ 367	$ 417

Amount of asset related to consideration paid in advance for research and development expenses that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

No definition available.

+ Details

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

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Amount of asset related to consideration paid in advance for other costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 340
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483032/340-10-45-1

+ Details

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

- Definition

Amount of asset related to consideration paid in advance for costs that provide economic benefits within a future period of one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483467/210-10-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 340
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482955/340-10-05-5

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 340
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483032/340-10-45-1

+ Details

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

- Definition

Amount of asset related to consideration paid in advance for insurance that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (g)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483467/210-10-45-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 340
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483032/340-10-45-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 340
-SubTopic 10
-Name Accounting Standards Codification
-Section 05
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482955/340-10-05-5

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant