Aggregate Base rent over the initial term, net of rent abatement.

No definition available.

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

- Definition

Payment for termination fee.

+ References

No definition available.

+ Details

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Namespace Prefix:	olma_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:areaItemType
Balance Type:	na
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 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

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date which lease or group of leases is set to expire, in YYYY-MM-DD format.

+ References

No definition available.

+ Details

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

- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- Definition

The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=olma_DropboxIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=olma_TheCambridgeRedevelopmentAuthorityMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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- Details

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

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CounterpartyNameAxis=olma_OysterPointLeaseAgreementPhaseIIMember
Namespace Prefix:
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Leases - Additional Information (Details)	Apr. 27, 2026 USD ($) ft²	Aug. 17, 2023 USD ($) ft²	Dec. 15, 2020 USD ($) ft²	Mar. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Aug. 23, 2023 USD ($) ft²
Lease
Operating lease right-of-use assets				$ 921,000	$ 1,146,000
Lease liabilities				956,000
Tennieh LLC
Lease
Area of property \| ft²			9,800
Term of contract			5 years
Security deposit			$ 400,000
Expiration date			Jan. 31, 2027
Operating lease right-of-use assets			$ 800,000
Dropbox, Inc.
Lease
Area of property \| ft²		6,713
Term of contract		2 years
Expiration date		Dec. 31, 2026
Operating lease right-of-use assets		$ 100,000
Cambridge Redevelopment Authority
Lease
Area of property \| ft²						4,020
Term of contract						3 years
Operating lease right-of-use assets						$ 700,000
Lease liabilities						700,000
Cambridge Redevelopment Authority \| Minimum
Lease
Security deposit						100,000
Operating lease right-of-use assets						100,000
Lease liabilities						$ 100,000
KR Oyster Point II, LLC
Lease
Operating lease right-of-use assets				0
Lease liabilities				$ 0
KR Oyster Point II, LLC \| Subsequent Event
Lease
Area of property \| ft²	38,176
Aggregate base rent over the initial term, net of rent abatement	$ 18,500,000
Security deposit	400,000
Payment for termination fee	$ 1,700,000
Oyster Point Lease Agreement Phase I \| Subsequent Event
Lease
Area of property \| ft²	25,048
Aggregate base rent over the initial term, net of rent abatement	$ 12,400,000
Oyster Point Lease Agreement Phase II \| Subsequent Event
Lease
Area of property \| ft²	13,128
Aggregate base rent over the initial term, net of rent abatement	$ 6,100,000