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.

No definition available.

+ Details

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

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of derivative instruments of a particular group held by the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=dnli_ForeignExchangeForwardEurosMember
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- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=dnli_ForeignExchangeForwardBritishPoundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=dnli_ForeignExchangeForwardSwissFrancsMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
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Derivative Financial Instruments - Summary of Forward Foreign Currency Exchange Contracts Outstanding (Details) - Designated as Hedging Instrument € in Thousands, £ in Thousands, SFr in Thousands	Jun. 30, 2020 EUR (€) derivative_instrument	Jun. 30, 2020 GBP (£) derivative_instrument	Jun. 30, 2020 CHF (SFr) derivative_instrument	Dec. 31, 2019 EUR (€) derivative_instrument	Dec. 31, 2019 GBP (£) derivative_instrument	Dec. 31, 2019 CHF (SFr) derivative_instrument
Euros
Derivative [Line Items]
Number of Contracts	26	26	26	23	23	23
Aggregate Notional Amount in Foreign Currency \| €	€ 3,535			€ 1,500
British Pounds
Derivative [Line Items]
Number of Contracts	19	19	19	15	15	15
Aggregate Notional Amount in Foreign Currency \| £		£ 2,868			£ 2,285
Swiss Francs
Derivative [Line Items]
Number of Contracts	2	2	2	10	10	10
Aggregate Notional Amount in Foreign Currency \| SFr			SFr 21			SFr 129
Foreign Exchange Contracts
Derivative [Line Items]
Number of Contracts	47	47	47	48	48	48