Area of a real estate property.

No definition available.

Name:	akba_AreaOfLeasedProperty
Namespace Prefix:	akba_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Lessee leasing arrangements, operating leases, number of lease period extension options.

+ References

No definition available.

+ Details

Name:	akba_LesseeLeasingArrangementsOperatingLeasesNumberOfLeasePeriodExtensionOptions
Namespace Prefix:	akba_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Operating lease payments commencement date.

+ References

No definition available.

+ Details

Name:	akba_OperatingLeasePaymentsCommencementDate
Namespace Prefix:	akba_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before accumulated depreciation of additions or improvements to assets held under a lease arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765

+ Details

Name:	us-gaap_LeaseholdImprovementsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Term of the lessor's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LessorLeasingArrangementsOperatingLeasesRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_LessorLeasingArrangementsOperatingLeasesTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the payments that the lessee is obligated to make or can be required to make in connection with a property under the terms of an agreement classified as an operating lease, excluding contingent rentals and a guarantee by the lessee of the lessor's debt and the lessee's obligation to pay (apart from the rental payments) executory costs such as insurance, maintenance, and taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 25
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=7661868&loc=d3e34039-112682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 3)
-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

+ Details

Name:	us-gaap_OperatingLeasesRentExpenseMinimumRentals
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=akba_ThirdAmendmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=akba_LabSpaceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Event - Additional Information (Details)		1 Months Ended		6 Months Ended
Subsequent Event - Additional Information (Details)	Jul. 25, 2016 USD ($) ft² Extension_Option	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 30, 2016 USD ($)
Subsequent Event [Line Items]
Monthly lease payments		$ 45,000	$ 31,000	$ 32,000
Landlord contribution for leasehold improvements		$ 100,000
Subsequent Event \| Third Amendment \| Lab Space
Subsequent Event [Line Items]
Square feet of leased property \| ft²	5,951
Monthly lease payments	$ 35,000
Operating lease payments commencement date	Dec. 01, 2016
Landlord contribution for leasehold improvements	$ 89,265
Lease period	5 years
Lease period, number of extension options \| Extension_Option	1
Lease extension period	2 years