Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Jul. 31, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Trading Symbol AKBA  
Entity Registrant Name Akebia Therapeutics, Inc.  
Entity Central Index Key 0001517022  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Common Stock, Shares Outstanding   118,863,735
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Address, Address Line One 245 First Street  
Entity Address, City or Town Cambridge  
Entity Address, State or Province MA  
City Area Code 617  
Local Phone Number 871-2098  
Entity Address, Postal Zip Code 02142  
Entity Tax Identification Number 208756903  
Entity File Number 001-36352