Adjustments To Additional Paid In Capital, Issuance Of Capped Calls

No definition available.

Name:	cdlx_AdjustmentsToAdditionalPaidInCapitalIssuanceOfCappedCalls
Namespace Prefix:	cdlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Convertible, Covenant Noncompliance, Additional Interest, Stated Percentage

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleCovenantNoncomplianceAdditionalInterestStatedPercentage
Namespace Prefix:	cdlx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Convertible, Covenant Noncompliance, Period Of Additional Interest

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleCovenantNoncompliancePeriodOfAdditionalInterest
Namespace Prefix:	cdlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Liability Component, Discount Rate

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleLiabilityComponentDiscountRate
Namespace Prefix:	cdlx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Notice Of Change, Covenant, Period Of Failed Compliance

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleNoticeOfChangeCovenantPeriodOfFailedCompliance
Namespace Prefix:	cdlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Obligation To Convert, Covenant, Period Of Failed Compliance

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleObligationToConvertCovenantPeriodOfFailedCompliance
Namespace Prefix:	cdlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Percentage Of Holders To Require Written Notice Of Noncompliance

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertiblePercentageOfHoldersToRequireWrittenNoticeOfNoncompliance
Namespace Prefix:	cdlx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Redemption Period, Days Before Maturity Date

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleRedemptionPeriodDaysBeforeMaturityDate
Namespace Prefix:	cdlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Convertible, Redemption Requirement, Amount Of Other Debt Called Due

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleRedemptionRequirementAmountOfOtherDebtCalledDue
Namespace Prefix:	cdlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Convertible, Threshold Principal Outstanding Amount For Partial Redemption

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentConvertibleThresholdPrincipalOutstandingAmountForPartialRedemption
Namespace Prefix:	cdlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Covenant, Cast To Funded Senior Debt Ratio

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentCovenantCastToFundedSeniorDebtRatio
Namespace Prefix:	cdlx_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Required Compliance Period, Period After Written Notice

+ References

No definition available.

+ Details

Name:	cdlx_DebtInstrumentRequiredCompliancePeriodPeriodAfterWrittenNotice
Namespace Prefix:	cdlx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit Facility, Maximum Borrowing Capacity, Percentage Of Eligible Accounts Receivable

+ References

No definition available.

+ Details

Name:	cdlx_LineOfCreditFacilityMaximumBorrowingCapacityPercentageOfEligibleAccountsReceivable
Namespace Prefix:	cdlx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Option Indexed to Issuer's Equity, Cap Price

+ References

No definition available.

+ Details

Name:	cdlx_OptionIndexedToIssuersEquityCapPrice
Namespace Prefix:	cdlx_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031898-161870

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21521-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21506-112644

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 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=123599511&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ 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 210.5-02.22)
-URI http://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 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1336-112600

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1314-112600

+ Details

Name:	us-gaap_LongTermLineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Exercise or strike price stated in the contract for options indexed to the issuer's equity shares.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=123477628&loc=d3e90205-114008

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(1)
-URI http://asc.fasb.org/extlink&oid=109262807&loc=d3e22047-110879

+ Details

Name:	us-gaap_OptionIndexedToIssuersEquityStrikePrice1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585

+ Details

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

- Details

Name:	cdlx_DebtCovenantAxis=cdlx_DebtCovenantNoncomplianceScenarioOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=cdlx_DebtConversionScenarioOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=cdlx_DebtConversionScenarioTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtConversionByUniqueDescriptionAxis=cdlx_DebtConversionScenarioThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cdlx_ConvertibleSeniorNotesAdditionalPrincipalOption
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cdlx_A2020ConvertibleSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DEBT AND FINANCING ARRANGEMENTS - Narrative (Details)		9 Months Ended
DEBT AND FINANCING ARRANGEMENTS - Narrative (Details)	Sep. 22, 2020 USD ($) numberOfDays $ / shares	Sep. 30, 2022 USD ($)	Sep. 30, 2021	Dec. 31, 2020 USD ($)	Nov. 30, 2020 USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount	$ 230,000,000
Stated percentage	1.00%
Proceeds from issuance of convertible senior notes, net of issuance costs paid of $6,900	$ 222,700,000
Adjustments to additional paid in capital, issuance of capped calls	$ 26,500,000
Threshold consecutive trading days \| numberOfDays	10,000
Threshold percentage of stock price trigger	98.00%
Conversion ratio	11.7457
Conversion price (in dollars per share) \| $ / shares	$ 85,140
Redemption period, days before maturity date	36 days
Redemption price, percentage	100.00%
Threshold principal outstanding amount for partial redemption		$ 75,000,000
Required compliance period, period after written notice	60 days
Percentage of holders to require written notice of noncompliance	25.00%	25.00%
Amount of other debt called due	$ 35,000,000
Covenant noncompliance, period of additional interest		365 days
Liability component, discount rate		6.50%
Strike price (in dollars per share) \| $ / shares	$ 85.14
Cap price (in dollars per share) \| $ / shares	$ 128.51
Outstanding borrowings		$ 0
Unused borrowing capacity		$ 60,000,000
Maximum borrowing capacity, percentage of accounts receivable		85.00%
Debt instrument, interest rate		1.64%	5.56%
Debt Covenant Noncompliance, Scenario One
Debt Instrument [Line Items]
Covenant noncompliance, period of additional interest		180 years
Covenant noncompliance, additional interest, stated percentage		0.25%
Debt Covenant Noncompliance, Scenario Two
Debt Instrument [Line Items]
Covenant noncompliance, additional interest, stated percentage		0.50%
Debt Covenant Noncompliance, Scenario Two \| Minimum
Debt Instrument [Line Items]
Covenant noncompliance, period of additional interest		181 days
Debt Covenant Noncompliance, Scenario Two \| Maximum
Debt Instrument [Line Items]
Covenant noncompliance, period of additional interest		365 days
Debt Conversion Scenario One
Debt Instrument [Line Items]
Threshold trading days \| numberOfDays	20,000
Threshold consecutive trading days \| numberOfDays	30,000
Threshold percentage of stock price trigger	130.00%
Debt Conversion Scenario Two
Debt Instrument [Line Items]
Threshold trading days \| numberOfDays	5,000
Debt Conversion Scenario Three
Debt Instrument [Line Items]
Threshold trading days \| numberOfDays	20
Threshold consecutive trading days \| numberOfDays	30
Threshold percentage of stock price trigger	130.00%
Convertible Senior Notes, Additional Principal Option
Debt Instrument [Line Items]
Debt instrument, face amount	$ 30,000,000
Senior Notes \| 2020 Convertible Senior Notes
Debt Instrument [Line Items]
Obligation to convert, period of failed compliance	3 days
Notice of change, period of failed compliance	1 day
Lines of credit
Debt Instrument [Line Items]
Debt instrument, interest rate		6.25%
Commitment fee percentage		0.15%
Revolving Credit Facility \| Lines of credit
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 50,000,000	$ 40,000,000
Cast to funded senior debt ratio				1.25
Unused borrowing capacity		$ 60,000,000