Area of office space in square feet.

No definition available.

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- Definition

Commitments and contingencies.

+ References

No definition available.

+ Details

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Namespace Prefix:	sage_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease commencement date.

+ References

No definition available.

+ Details

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Namespace Prefix:	sage_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessor operating lease remaining lease rerms.

+ References

No definition available.

+ Details

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

- Definition

Reclassification from prepaid expenses and other current assets to right-of-use asset related to build out costs.

+ References

No definition available.

+ Details

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

- Definition

Security deposit amount reduced for third anniversary.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
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

Description of terms and conditions of option to extend lessor's operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

+ Details

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

- Definition

Term of lessor's operating lease renewal, 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 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

+ Details

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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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Leases, Commitments and Contingencies - Operating Leases - Additional Information (Detail) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) ft²	Dec. 31, 2023 USD ($) ft²	Dec. 31, 2022 ft²	Aug. 02, 2024 USD ($)
Commitments And Contingencies [Line Items]
Operating lease option to extend		true
Operating lease renewal term		5 years
Operating lease, right-of-use asset		$ 10,753	$ 4,458
Operating lease, liability		$ 11,836	$ 5,165
Lease Agreements [Member]
Commitments And Contingencies [Line Items]
Lease expire date	Feb. 28, 2030
Operating lease option to extend		The Company has the option to extend the New Lease one time for an additional five-year period,
Operating lease renewal term	5 years
Operating lease, right-of-use asset					$ 11,600
Operating lease, liability					10,000
Reclassification from prepaid expenses and other current assets to right-of-use asset related to build out costs					$ 1,500
Lease Commencement Date	Sep. 01, 2024
Initial term	66 months
Lease Agreements [Member] \| Letter of Credit [Member]
Commitments And Contingencies [Line Items]
Security Deposit	$ 1,400
Security deposit amount reduced for third anniversary	$ 1,200
Operating Lease One [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		63,017	63,017	63,017
Lease expire date		Aug. 31, 2024
Operating Lease Two [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		40,419	40,419	40,419
Lease expire date		Aug. 31, 2024	Aug. 31, 2024	Aug. 31, 2024
Operating Lease Three [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		15,525	15,525	15,525
Lease expire date		Nov. 30, 2024	Nov. 30, 2024	Nov. 30, 2024
Operating Lease Five [Member]
Commitments And Contingencies [Line Items]
Office space rent under operating lease \| ft²		30,567	30,567	30,567
Lease expire date		Feb. 28, 2030	Feb. 28, 2030	Feb. 28, 2030
Minimum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		1 year
Maximum [Member]
Commitments And Contingencies [Line Items]
Operating lease remaining lease terms		5 years