Stockholders' Equity - Reserved Shares of Common Stock for Future Issuance (Details) - shares	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020	Dec. 31, 2022	Dec. 31, 2021	Feb. 28, 2014
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)				27,744,206	26,423,704
Warrant to purchase common stock
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)				0	509,611
Common stock options, RSUs and PSUs outstanding
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)				17,407,227	16,065,218
Akebia Equity Plans
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)				5,498,984	4,675,734
2014 Plans
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)						1,785,000
Increase in common stock, shares reserved for future issuance (in shares)	6,046,288	5,807,270	4,880,775
Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock, shares reserved for future issuance (in shares)				4,837,995	5,173,141