Leasee, Operating Lease, Leased Area

No definition available.

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Namespace Prefix:	goss_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Lessee, Operating Lease, Base Rent

+ References

No definition available.

+ Details

Name:	goss_LesseeOperatingLeaseBaseRent
Namespace Prefix:	goss_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Lessee, Operating Lease, Base Rent Annual Increase Percentage

+ References

No definition available.

+ Details

Name:	goss_LesseeOperatingLeaseBaseRentAnnualIncreasePercentage
Namespace Prefix:	goss_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessee, Operating Lease, Extension Term

+ References

No definition available.

+ Details

Name:	goss_LesseeOperatingLeaseExtensionTerm
Namespace Prefix:	goss_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Lessee, Operating Lease, Termination Fee, Number Of Months Of Base Rent

+ References

No definition available.

+ Details

Name:	goss_LesseeOperatingLeaseTerminationFeeNumberOfMonthsOfBaseRent
Namespace Prefix:	goss_
Data Type:	xbrli:integerItemType
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 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 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:stringItemType
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

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

- Definition

Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

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

- Definition

Weighted average discount rate for operating lease calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

Name:	us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining lease term for 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/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (g)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-4

+ Details

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

- Details

Name:	us-gaap_LeaseContractualTermAxis=goss_LeaseAgreementEnteredInJuly2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=goss_NonCancelableLeaseAgreementEnteredInAugust2018Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Additional Information (Details) $ in Thousands		12 Months Ended
	Jul. 09, 2024 USD ($) ft² month	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Termination tee, number of monthly base rent \| month	4
Operating lease, weighted average discount rate		12.40%
Weighted average remaining lease term		4 years 8 months 12 days
Cash paid for operating lease liabilities		$ 3,800	$ 3,300
Lease Agreement Entered in August 2024
Lessee, Lease, Description [Line Items]
Leased area \| ft²	18,421
Operating lease, term of contract	63 months
Base rent	$ 109,605
Operating sublease, annual increase percentage for base rent	3.00%
Extension term	1 year
Operating lease, weighted average discount rate		12.40%
Non-cancelable Lease Agreement Entered in August 2018
Lessee, Lease, Description [Line Items]
Operating lease, weighted average discount rate		7.00%