The number of ordinary shares available for future issuance of share-based equity awards.

No definition available.

Name:	ghrs_NumberOfOrdinarySharesAvailableForFutureIssuanceOfShareBasedEquityAwards
Namespace Prefix:	ghrs_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Remaining period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

No definition available.

+ Details

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Namespace Prefix:	ghrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Percentage of vesting of share-based compensation awards.

+ References

No definition available.

+ Details

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Namespace Prefix:	ghrs_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share option award granted period, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

No definition available.

+ Details

Name:	ghrs_ShareOptionAwardGrantedPeriod
Namespace Prefix:	ghrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

For vesting requirements for a type of share-based payment arrangement that existed at any time during the period, this element represents the period which an employees' right to exercise an award is no longer contingent on satisfaction of a service condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	ghrs_VestingRequirementsForShareBasedPaymentArrangementAwardVestingPeriod
Namespace Prefix:	ghrs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The exercise price of share options granted.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2025-01-01
-Paragraph 47
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-URIDate 2025-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	dtr-2022:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of share options granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-URIDate 2025-03-27

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares authorised.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
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-URIDate 2025-03-27

+ Details

Name:	ifrs-full_NumberOfSharesAuthorised
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issue under options and contracts for the sale of shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
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-URIDate 2025-03-27

+ Details

Name:	ifrs-full_SharesReservedForIssueUnderOptionsAndContractsForSaleOfShares
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=ghrs_ShareOptionExpirationPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfAntidilutiveInstrumentsAxis=ifrs-full_ShareOptionsMember
Namespace Prefix:
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Balance Type:
Period Type:

Share based compensation, Share Options (Details)	3 Months Ended	6 Months Ended
Share based compensation, Share Options (Details)	Jun. 30, 2026 shares	Jun. 30, 2026 shares $ / shares	Jun. 30, 2021 shares
Share based payment arrangement [Abstract]
Number of shares reserved for future issuance (in shares)			1,202,734
Number of ordinary shares available for future issuance (in shares)	925,853	925,853
Number of options granted (in shares)	17,100	219,050
Share Option, Expiration Period One [Member]
Share based payment arrangement [Abstract]
Number of options granted (in shares)	17,100	69,600
Award vest percentage		25.00%
Remaining vesting period		3 years
Vesting condition		2 years
Share option award granted period		8 years
Share Option, Expiration Period Two [Member]
Share based payment arrangement [Abstract]
Number of options granted (in shares)		149,450
Award vest percentage		25.00%
Remaining vesting period		3 years
Share option award granted period		7 years
Exercise price for option granted (in dollars per share) \| $ / shares		$ 0.025
Share Options [Member]
Share based payment arrangement [Abstract]
Number of shares authorized (in shares)	3,721,251	3,721,251