Represents the number of lease renewal periods allowed under the operating lease.

No definition available.

Name:	gkos_LesseeLeasingArrangementsOperatingLeasesNumberOfRenewalPeriods
Namespace Prefix:	gkos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of tenant improvement allowance under the operating lease.

+ References

No definition available.

+ Details

Name:	gkos_LesseeLeasingArrangementsOperatingLeasesTenantImprovementAllowance
Namespace Prefix:	gkos_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of adjacent facilities rented.

+ References

No definition available.

+ Details

Name:	gkos_NumberOfAdjacentFacilitiesRented
Namespace Prefix:	gkos_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of buildings leased.

+ References

No definition available.

+ Details

Name:	gkos_NumberOfBuildingsLeased
Namespace Prefix:	gkos_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of properties leased.

+ References

No definition available.

+ Details

Name:	gkos_NumberOfPropertiesLeased
Namespace Prefix:	gkos_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	num: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

No definition available.

+ Details

Name:	us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee'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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

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

- 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919359-209981

+ Details

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

- Definition

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

+ References

+ Details

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

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

Leases - Leases Details (Details) $ in Millions		1 Months Ended	12 Months Ended
Leases - Leases Details (Details) $ in Millions	Nov. 14, 2018 USD ($) ft² item	Dec. 31, 2018 USD ($) item	Dec. 31, 2019 ft² item
Minimum
Operating Leases
Optional lease extension term			10 years
Domestic Office Leases
Operating Leases
The number of adjacent facilities rented \| item			2
Extended lease term		3 years
Number of lease renewal periods \| item		1
Optional lease extension term		3 years
Area of leased space \| ft²			98,000
Domestic Office Leases \| Maximum
Operating Leases
Tenant improvement allowance \| $		$ 0.3
Foreign Subsidiaries Office Leases
Operating Leases
Area of leased space \| ft²			14,000
Aliso Facility
Operating Leases
Number of properties leased \| item	1
Number of buildings leased \| item	3
Number of lease renewal periods \| item	2
Optional lease extension term	5 years
Area of leased space \| ft²	160,000
Tenant improvement allowance \| $	$ 12.6
Term of lease	13 years
Waltham Massachusetts Facility
Operating Leases
Area of leased space \| ft²			27,000
Burlington Massachusetts Facility
Operating Leases
Area of leased space \| ft²			19,000