LIABILITY RELATED TO SALE OF FUTURE ROYALTIES - Activity within Liability Related to Sale of Future Royalties, net (Details) $ in Thousands	9 Months Ended
Sep. 30, 2023 USD ($)
Contractual Arrangement, Royalties Agreement, Liability, Noncurrent [Roll Forward]
Liability related to sale of future royalties, beginning balance at December 31, 2022	$ 57,484
MTPC royalties payable	(1,423)
Liability related to sale of future royalties, ending balance at September 30, 2023	$ 56,061

Contractual Arrangement, Royalties Agreement, Royalties, Earned And Payable

No definition available.

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