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Period Type:	duration

The amount of milestone payments that may become due under a settlement agreement.

No definition available.

Name:	beam_PotentialMilestonePaymentsDueUnderSettlementAgreement
Namespace Prefix:	beam_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount paid during the period for achievement of milestones as part of a settlement agreement.

No definition available.

Name:	beam_SettlementAgreementMilestoneAmountPaid
Namespace Prefix:	beam_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of upfront payment the Company has agreed to pay upon signing of a settlement agreement.

No definition available.

Name:	beam_SettlementAgreementUpfrontPayment
Namespace Prefix:	beam_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount paid during the period for an upfront payment as part of a settlement agreement.

No definition available.

Name:	beam_SettlementAgreementUpfrontPaymentPaid
Namespace Prefix:	beam_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479402/808-10-50-1

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

Name:	us-gaap_ContingentConsiderationByTypeAxis=beam_DevelopmentAndRegulatoryMilestonesMember
Namespace Prefix:
Data Type:	na
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