n/a

No definition available.

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Namespace Prefix:	ecyt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration issued for the license agreement excluding shares of common stock and warrants.

+ References

No definition available.

+ Details

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Namespace Prefix:	ecyt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Future milestone payments that could be paid upon achievement of certain milestones per agreement.

+ References

No definition available.

+ Details

Name:	ecyt_FutureMilestonePayments
Namespace Prefix:	ecyt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of parties in the agreement for the drug trial.

+ References

No definition available.

+ Details

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Namespace Prefix:	ecyt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of patients included in a randomized clinical study.

+ References

No definition available.

+ Details

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Namespace Prefix:	ecyt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of warrants to purchase common stock issued per the license agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	ecyt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares of stock issued during the period pursuant to asset acquisition.

+ References

No definition available.

+ Details

Name:	ecyt_StockIssuedDuringPeriodSharesAssetAcquisition
Namespace Prefix:	ecyt_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of upfront fees paid per agreement.

+ References

No definition available.

+ Details

Name:	ecyt_UpfrontFeesPaid
Namespace Prefix:	ecyt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CounterpartyNameAxis=ecyt_AbXMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=ecyt_AchievementOfRegulatoryMilestonesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=ecyt_AchievementOfSalesMilestonesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_CounterpartyNameAxis=ecyt_UniversityOfSydneyMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	dei_LegalEntityAxis=ecyt_AnzupMember
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- Details

Name:	us-gaap_TypeOfArrangementAxis=ecyt_ThreePartyAgreementMember
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Collaborations and Other Arrangements - ABX (Details) $ in Millions		1 Months Ended		3 Months Ended
	Sep. 29, 2017 USD ($) item shares	Oct. 31, 2017 person	Sep. 30, 2017 person	Mar. 31, 2018 item
ABX Development and License Agreement
Number of patients with mCRPC included in study \| person			750
ABX \| License Agreement
ABX Development and License Agreement
Upfront cash payment	$ 11.9
Total consideration excluding common stock shares and warrants	$ 12.0
Issuance of common stock in connection with development and license agreement (in shares) \| shares	2,000,000
Number of warrants issued per agreement \| item	2
Aggregate number of common stock shares that may be purchased by exercise of warrants \| shares	4,000,000
ABX \| Maximum \| License Agreement
ABX Development and License Agreement
Aggregate number of common stock shares that may be purchased by exercise of warrants \| shares	4,000,000
ABX \| Achievement Of Regulatory Milestones \| License Agreement
ABX Development and License Agreement
Potential milestone payments to be paid	$ 25.0
ABX \| Achievement Of Sales Milestones \| License Agreement
ABX Development and License Agreement
Potential milestone payments to be paid	$ 135.0
University of Sydney \| Anzup \| Three Party Agreement [Member]
ABX Development and License Agreement
Number of parties in the agreement \| item				3
Number of patients with mCRPC included in study \| person		200