Collaboration agreement, deemed discount on shares sold.

No definition available.

Name:	aclx_CollaborationAgreementDeemedDiscountOnSharesSold
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Collaboration agreement estimated transaction price.

+ References

No definition available.

+ Details

Name:	aclx_CollaborationAgreementEstimatedTransactionPrice
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Collaboration agreement, fixed transaction price.

+ References

No definition available.

+ Details

Name:	aclx_CollaborationAgreementFixedTransactionPrice
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Collaboration agreement, upfront payment.

+ References

No definition available.

+ Details

Name:	aclx_CollaborationAgreementUpfrontPayment
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Collaboration agreement variable consideration.

+ References

No definition available.

+ Details

Name:	aclx_CollaborationAgreementVariableConsideration
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of out-of-pocket development costs for co-promote products.

+ References

No definition available.

+ Details

Name:	aclx_PercentageOfOutOfPocketDevelopmentCostsForCoPromoteProducts
Namespace Prefix:	aclx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of reimbursement costs.

+ References

No definition available.

+ Details

Name:	aclx_PercentageOfReimbursementCosts
Namespace Prefix:	aclx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

potential payments of clinical, regulatory and commercial milestones.

+ References

No definition available.

+ Details

Name:	aclx_PotentialPaymentsOfClinicalRegulatoryAndCommercialMilestones
Namespace Prefix:	aclx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Standstill restrictions, expiration by month.

+ References

No definition available.

+ Details

Name:	aclx_StandstillRestrictionsExpirationByMonth
Namespace Prefix:	aclx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 310
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126942793&loc=d3e3073-115593

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(5))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

Name:	us-gaap_AccountsReceivableNet
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

No definition available.

+ Details

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

- Definition

Discount on common shares, or any unamortized balance thereof, shown separately as a deduction from the applicable account(s) as circumstances require.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.4-07)
-URI https://asc.fasb.org/extlink&oid=120397183&loc=d3e187103-122770

+ Details

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

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(10))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8813-108599

+ Details

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

- Definition

Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21463-112644

+ Details

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

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=aclx_KitePharmaIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=us-gaap_NonUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=aclx_CartDdbcmaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=aclx_NextGenerationAutologousCarTCellTherapyProductMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=aclx_NonAutologousCarTCellTherapyProductMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=aclx_GileadMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Collaboration Agreement - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended
	Jan. 26, 2023	Jan. 31, 2023	Dec. 31, 2022	Mar. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Receivable from collaboration partner				$ 1.2
Kite Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment		$ 225.0
Shares purchased price per share	$ 4.39
Estimated transaction price			$ 198.1
Fixed transaction price			221.0
Variable consideration			22.8
Reduction of deemed discount on shares sold	$ 15.3		$ 15.3
Kite Collaboration Agreement \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of reimbursement costs				0.00%
Kite Collaboration Agreement \| Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of reimbursement costs				0.00%
Kite Collaboration Agreement \| United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of out-of-pocket development costs for co-promote products				40.00%
Kite Collaboration Agreement \| Kite Pharma, Inc. \| Outside United States
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of out-of-pocket development costs for co-promote products				60.00%
Kite Collaboration Agreement \| CART-ddBCMA [Member] \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential payments of clinical, regulatory and commercial milestones		335.0
Kite Collaboration Agreement \| Next Generation Autologous CAR-T Cell Therapy Product \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential payments of clinical, regulatory and commercial milestones		635.0
Kite Collaboration Agreement \| Non-autologous CAR-T Cell Therapy Product \| Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential payments of clinical, regulatory and commercial milestones		$ 507.5
Stock Purchase Agreement and Standstill Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Standstill restrictions, expiration by month				18 months
Gilead Common Stock Purchase Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Shares purchased		3,478,261
Shares purchased price per share		$ 28.75
Discount on sale of common stock		$ 15.3
Gilead Common Stock Purchase Agreement \| Gilead
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Equity investment		$ 100.0