Aggregate offering price of securities.

No definition available.

Name:	cara_AggregateOfferingPriceOfSecurities
Namespace Prefix:	cara_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of gross proceeds on sales of stock that makes up the commission.

+ References

No definition available.

+ Details

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

- Definition

The amount of stock subscription receivable.

+ References

No definition available.

+ Details

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

- Definition

Amount of subscription receivable from investors who have been allocated common stock.

+ References

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

+ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

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

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(02)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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

No definition available.

+ Details

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

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended								2 Months Ended	3 Months Ended						9 Months Ended
	Jun. 30, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Feb. 28, 2022	Oct. 31, 2021	Aug. 31, 2021	Jun. 30, 2021	Feb. 28, 2021	Mar. 31, 2021	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Sale Of Stock [Line Items]
Stock Subscription Receivable.														$ 44,969				$ 44,969
Revenue From Contract With Customer Excluding Assessed Tax											$ 10,813			$ 20,272			$ 38,606	$ 22,207
Regulatory Milestones [Member] \| Vifor International Ltd. [Member]
Sale Of Stock [Line Items]
Common stock, shares issued						3,282,391
Share Price							$ 15.23							$ 15.23				$ 15.23
Proceeds from the sale of common stock						$ 50,000
Stock subscription receivable														$ 44,969				$ 44,969
Maximum [Member]
Sale Of Stock [Line Items]
Aggregate offering price of securities				$ 300,000									$ 300,000
License and Milestone Fees
Sale Of Stock [Line Items]
Revenue From Contract With Customer Excluding Assessed Tax														20,031			$ 15,000	21,223
License and Milestone Fees \| Regulatory Milestones [Member] \| Vifor International Ltd. [Member]
Sale Of Stock [Line Items]
Revenue From Contract With Customer Excluding Assessed Tax														$ 5,031				$ 5,031
Unsold Securities Under Shelf Registration Statement dated April 4, 2019 [Member]
Sale Of Stock [Line Items]
Aggregate offering price of securities				154,525									154,525
Open Market Sales Agreement [Member] \| Jeffries LLC [Member]
Sale Of Stock [Line Items]
Common stock, shares issued																	0
Aggregate offering price of securities				$ 80,000									$ 80,000
Stock Sale Commission Percentage				3.00%
Common Stock
Sale Of Stock [Line Items]
Restricted stock units vested shares											7,500	89,075	109,943	44,002	36,000	109,419
Restricted Stock Units [Member] \| Common Stock \| Board of Directors Chairman [Member] \| June 2022 [Member]
Sale Of Stock [Line Items]
Restricted stock units vested shares			11,876
Restricted Stock Units [Member] \| Common Stock \| Director [Member] \| June 2022 [Member]
Sale Of Stock [Line Items]
Vesting period of awards granted			1 year
Restricted stock units, vested			43,200
Restricted Stock Units [Member] \| Common Stock \| Director [Member] \| June 2021 [Member]
Sale Of Stock [Line Items]
Vesting period of awards granted								1 year
Restricted stock units vested shares								36,000
Restricted Stock Units [Member] \| Common Stock \| Former Chief Executive Officer [Member] \| June 2022 [Member]
Sale Of Stock [Line Items]
Restricted stock units vested shares	33,999
Performance Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| March 2022 [Member]
Sale Of Stock [Line Items]
Vesting period of awards granted				3 years
Restricted stock units, vested				37,999
Performance Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| August 2021 [Member]
Sale Of Stock [Line Items]
Restricted stock units, vested							44,002
Performance Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| February and March 2021 [Member]
Sale Of Stock [Line Items]
Restricted stock units vested shares										76,750
Time-based Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| March 2022 [Member]
Sale Of Stock [Line Items]
Restricted stock units vested shares				39,278
Time-based Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| February 2022 [Member]
Sale Of Stock [Line Items]
Vesting period of awards granted					3 years
Restricted stock units vested shares					32,666
Time-based Restricted Stock Units [Member] \| Common Stock \| Executive Officers [Member] \| February 2021 [Member]
Sale Of Stock [Line Items]
Vesting period of awards granted									3 years
Restricted stock units vested shares									32,669
Time-based Restricted Stock Units [Member] \| Common Stock \| Interim Principal Financial and Accounting Officer [Member] \| September 2022 [Member]
Sale Of Stock [Line Items]
Restricted stock units, vested		7,500