Name:	cldx_OtherNonCurrentLiabilitiesLineItems
Namespace Prefix:	cldx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents period for which base of operations must be maintained in New Jersey.

No definition available.

Name:	cldx_PeriodForWhichBaseOfOperationsMustBeMaintained
Namespace Prefix:	cldx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The amount of net proceeds received or will be received from the sale of net operating losses and research and development tax credits under New Jersey.

No definition available.

Name:	cldx_ProceedsFromSaleOfOperatingLossesAndTaxCredits
Namespace Prefix:	cldx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of current state and local tax expense (benefit) attributable to income (loss) from continuing operations. Includes, but is not limited to, current regional, territorial, and provincial tax expense (benefit) for non-US (United States of America) jurisdiction.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 6.I.7)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479360/740-10-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(1)(Note 1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-SubTopic 10
-Topic 740
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-9

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

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.