Amount of minimum royalty payable maturity terms not met.

No definition available.

Name:	cprx_AmountOfMinimumRoyaltyPayableMaturityTermsNotMet
Namespace Prefix:	cprx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Asset acquisition equity interests issued or issuable number of shares issued.

+ References

No definition available.

+ Details

Name:	cprx_AssetAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	cprx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Asset acquisition percentage of outstanding ordinary shares.

+ References

No definition available.

+ Details

Name:	cprx_AssetAcquisitionPercentageOfOutstandingOrdinaryShares
Namespace Prefix:	cprx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum amount of time in which compensation cost from stock options is amortized on a straight line basis.

+ References

No definition available.

+ Details

Name:	cprx_MaximumAmortizationPeriodOfCompensationCostOnStraightLineBasis
Namespace Prefix:	cprx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum length of time to maturity for instruments included as cash equivalents.

+ References

No definition available.

+ Details

Name:	cprx_MaximumMaturityPeriodOfCashAndCashEquivalent
Namespace Prefix:	cprx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum royalty.

+ References

No definition available.

+ Details

Name:	cprx_MinimumRoyalty
Namespace Prefix:	cprx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Royalty payment.

+ References

No definition available.

+ Details

Name:	cprx_RoyaltyPayment
Namespace Prefix:	cprx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Summary of basis of presentation and significant accounting policies.

+ References

No definition available.

+ Details

Name:	cprx_SummaryOfBasisOfPresentationAndSignificantAccountingPoliciesLineItems
Namespace Prefix:	cprx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

+ Details

Name:	srt_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 720
-SubTopic 35
-Name Accounting Standards Codification
-Section 55
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483385/720-35-55-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 720
-SubTopic 35
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483406/720-35-50-1

+ Details

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

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

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

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482662/260-10-50-1

+ Details

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

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 49
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-49

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-18

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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

- Definition

Indicates title and position of individual or name of group identified as chief operating decision maker (CODM) for segment reporting.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-21

+ Details

Name:	us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of how chief operating decision maker (CODM) uses reported segment profit (loss) measure to assess performance and allocate resource.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (bb)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 29
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-29

+ Details

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

- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-SubTopic 10
-Topic 505
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478448/946-505-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(4)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-03(i)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

+ Details

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

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ShareRepurchaseProgramAxis=cprx_SharePurchaseProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SellingGeneralAndAdministrativeExpensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Basis of Presentation and Significant Accounting Policies - Additional Information (Detail)					1 Months Ended	3 Months Ended		12 Months Ended	42 Months Ended
	Jul. 11, 2025 USD ($)	Jul. 11, 2024 USD ($)	Jul. 11, 2023 USD ($)	Jul. 11, 2022 USD ($)	Jul. 31, 2023 shares	Mar. 31, 2026 USD ($) Segment shares	Mar. 31, 2025 USD ($) shares	Dec. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)	Oct. 31, 2025 USD ($)
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Maximum maturity period of cash and cash equivalent						three months
Maximum amortization period of compensation cost on straight line basis						5 years
Potential equivalent common stock excluded \| shares						3,900,000	2,400,000
Number of operating segments \| Segment						1
Asset acquisition equity interests issued or issuable number of shares issued \| shares					1,414,688
Asset acquisition percentage of outstanding ordinary shares					11.26%
Allowance for expected credit losses, written off						$ 0		$ 0
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]						President and Chief Executive Officer [Member]
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description						The CODM uses consolidated operating margin (operating income divided by product revenue, net) and net income to assess financial performance and allocate resources.
Common Stock [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Shares repurchased \| shares						615,765
Share Purchase Program [Member] \| Common Stock [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Shares repurchased \| shares							0
Share repurchase program, authorized										$ 200,000,000
Restricted Stock [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Maximum amortization period of compensation cost on straight line basis						5 years
License Agreement For RUZURGI [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Minimum royalty	$ 3,000,000	$ 3,000,000	$ 3,000,000	$ 3,000,000					$ 3,000,000
Amount of minimum royalty payable maturity terms not met						$ 5,000,000
Selling, General and Administrative Expenses [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Advertising expense						2,300,000	$ 2,600,000
Minimum [Member] \| License Agreement For RUZURGI [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Royalty payment						$ 5,000,000
Minimum [Member] \| Furniture and Equipment [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						5 years
Minimum [Member] \| Computer Equipment [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						3 years
Minimum [Member] \| Leasehold Improvements [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						5 years
Maximum [Member] \| Furniture and Equipment [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						7 years
Maximum [Member] \| Computer Equipment [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						5 years
Maximum [Member] \| Leasehold Improvements [Member]
Summary Of Basis Of Presentation And Significant Accounting Policies [Line Items]
Useful life of assets						10 years