Amount of liability recognized from contingent consideration in asset acquisition.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 50
-Name Accounting Standards Codification
-Section 15
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480123/805-50-15-3

+ Details

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

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-3

+ Details

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

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ntla_USTreasuryAndOtherGovernmentBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ntla_FinancialInstitutionDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value Measurements - Summary of Financial Assets and Liabilities Recognized at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Marketable securities:
Contingent consideration	$ 0	$ 10,541	$ 0
Fair Value on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and restricted cash equivalents	136,254	534,581
Marketable securities:
Marketable securities	785,339	738,454
Total	921,593	1,273,035
Contingent consideration		24,026
Fair Value on Recurring Basis [Member] \| U S Treasury And Other Government Backed Securities [Member]
Marketable securities:
Marketable securities	382,308	242,686
Fair Value on Recurring Basis [Member] \| Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	246,119	379,861
Fair Value on Recurring Basis [Member] \| Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	97,408	101,550
Fair Value on Recurring Basis [Member] \| Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	59,504	14,357
Fair Value on Recurring Basis [Member] \| Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and restricted cash equivalents	136,254	534,581
Marketable securities:
Marketable securities	120,556	172,939
Total	256,810	707,520
Fair Value on Recurring Basis [Member] \| Level 1 [Member] \| U S Treasury And Other Government Backed Securities [Member]
Marketable securities:
Marketable securities	120,556	172,939
Fair Value on Recurring Basis [Member] \| Level 2 [Member]
Marketable securities:
Marketable securities	664,783	565,515
Total	664,783	565,515
Fair Value on Recurring Basis [Member] \| Level 2 [Member] \| U S Treasury And Other Government Backed Securities [Member]
Marketable securities:
Marketable securities	261,752	69,747
Fair Value on Recurring Basis [Member] \| Level 2 [Member] \| Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	246,119	379,861
Fair Value on Recurring Basis [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	97,408	101,550
Fair Value on Recurring Basis [Member] \| Level 2 [Member] \| Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	$ 59,504	14,357
Fair Value on Recurring Basis [Member] \| Level 3 [Member]
Marketable securities:
Contingent consideration		$ 24,026