Marketable securities, Overall Movement through OCI (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Overall movement through OCI [Abstract]
Revaluation adjustments	$ (85)	$ (107)	$ (94)
Movement of ECL on assets measured at FVOCI	(42)	(66)	(1)
Movement on marketable securities through OCI	$ (127)	$ (173)	$ (95)
Bottom of Range [Member]
Overall movement through OCI [Abstract]
Marketable securities at FVOCI interest rates	0.63%	0.25%
Top of Range [Member]
Overall movement through OCI [Abstract]
Marketable securities at FVOCI interest rates	2.60%	3.35%

The percentage of interest rates of marketable securities at fair value through other comprehensive income.

No definition available.

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

- References

No definition available.

+ Details

Name:	ifrs-full_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of other comprehensive income, net of tax, related to changes in the fair value of financial liabilities attributable to the changes in the credit risk of those liabilities. [Refer: Other comprehensive income; Credit risk [member]; Financial liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 91
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_91_a&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 7
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_7&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_OtherComprehensiveIncomeNetOfTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of other comprehensive income, net of tax, after reclassification adjustments, related to financial assets measured at fair value through other comprehensive income applying paragraph 4.1.2A of IFRS 9. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]

+ References

+ Details

Name:	ifrs-full_OtherComprehensiveIncomeNetOfTaxFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of reclassification adjustments related to financial assets measured at fair value through other comprehensive income, net of tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 92
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_92&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeNetOfTax
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: