Represents the period from the first commercial sale of licensed product for royalty payment under the collaborative arrangement.

No definition available.

+ Details

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Namespace Prefix:	cldx_
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Balance Type:	na
Period Type:	duration

- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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Balance Type:	credit
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

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Balance Type:	na
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- Definition

Costs incurred and are directly related to generating license revenue. Licensing arrangements include, but are not limited to, rights to use a patent, copyright, technology, manufacturing process, software or trademark.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Collaboration Agreements (Details) - USD ($) $ in Millions	12 Months Ended
Collaboration Agreements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Agreements
License fee expense	$ 0.7	$ 1.6	$ 0.9
Medarex
Collaborative Agreements
Period from the first commercial sale of licensed product for royalty payment	10 years
Rockefeller
Collaborative Agreements
Potential milestone payment	$ 3.8
Southampton
Collaborative Agreements
Potential milestone payment	1.0
Amgen
Collaborative Agreements
Potential milestone payment	0.9
Seattle Genetics \| Glembatumumab Vedotin
Collaborative Agreements
Potential milestone payment	5.0
Seattle Genetics \| CDX-014
Collaborative Agreements
Potential milestone payment	8.5
Yale
Collaborative Agreements
Potential milestone payment	3.0
MedImmune \| Obtaining specified regulatory and development
Collaborative Agreements
Potential milestone payment	45.0
MedImmune \| Specified annual net sales thresholds are met
Collaborative Agreements
Potential milestone payment	$ 125.0