Capital lease commencement date.

No definition available.

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Balance Type:	na
Period Type:	duration

- Definition

Capital lease term.

+ References

No definition available.

+ Details

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- Definition

Commitments and contingencies.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

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

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Loss contingency expected appeal process period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating lease payments commencement date.

+ References

No definition available.

+ Details

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

- Definition

Purchase committed program remaining contract costs.

+ References

No definition available.

+ Details

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Namespace Prefix:	akba_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the deferred credit for an incentive or inducement received by a lessee from a lessor, in order to motivate the lessee to enter the lease agreement, which incentive or inducement is to be recognized as a reduction of rental expense over the lease term.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 55
-Paragraph 3
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-Topic 840
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
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)
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-Section 45
-Paragraph 4
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6812-107765

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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/2003/role/presentationRef
-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

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

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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
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-SubTopic 20
-Section 50
-Paragraph 1
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- Definition

The amount of costs incurred under a research and development arrangement accounted for as a contract to perform research and development for others.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
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-Paragraph 1
-Subparagraph (SX 210.5-02.8,17)
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Period Type:	instant

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Commitments and Contingencies - Additional Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) Extension_Option	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Extension_Option	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Jul. 31, 2016 ft²
Commitments And Contingencies [Line Items]
Area of property leased \| ft²						45,362
Monthly lease payments			$ 242,000
Operating lease payments commencement date			Jan. 01, 2017
Landlord contributions accounted for deferred lease incentive	$ 2,169,920		$ 2,169,920
Landlord contribution for leasehold improvements	70,526		70,526
Rent expense associated with lease	800,000	$ 700,000	1,600,000	$ 1,000,000
Contract cost incurred in research and development activities			26,500,000		$ 24,900,000
Total remaining contract costs	$ 334,700,000		$ 334,700,000
FibroGen, Inc. \| Minimum
Commitments And Contingencies [Line Items]
Expected appeal process period			2 years
FibroGen, Inc. \| Maximum
Commitments And Contingencies [Line Items]
Expected appeal process period			3 years
Office Space
Commitments And Contingencies [Line Items]
Lease expiration date			Sep. 11, 2026
Lease period, number of extension options \| Extension_Option	1		1
Lease extension period			5 years
Lab Space
Commitments And Contingencies [Line Items]
Lease period, number of extension options \| Extension_Option	1		1
Lease extension period			2 years
Lease period			5 years
Office Equipment One
Commitments And Contingencies [Line Items]
Capital leases term			3 years
Capital lease commencement period			2014-02
Office Equipment Two
Commitments And Contingencies [Line Items]
Capital leases term			3 years
Capital lease commencement period			2015-04
Office Equipment Three
Commitments And Contingencies [Line Items]
Capital leases term			3 years
Capital lease commencement period			2016-02
Other Assets
Commitments And Contingencies [Line Items]
Total security deposit in connection with lease	$ 1,280,857		$ 1,280,857		$ 1,280,857
Lease Monthly Payments On Or About January 1 2017
Commitments And Contingencies [Line Items]
Monthly lease payments			$ 22,000