XML 61 R50.htm IDEA: XBRL DOCUMENT
v3.25.1

INDEBTEDNESS - Narrative (Details) $ / shares in Units, $ in Thousands |  |  |  | 3 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 03, 2025 USD ($) $ / shares shares | Apr. 19, 2024 USD ($) | Jan. 29, 2024 USD ($) tranche $ / shares shares | Mar. 31, 2025 USD ($) | Mar. 31, 2024 USD ($) | Feb. 28, 2025 $ / shares shares | Dec. 31, 2024 USD ($) | Nov. 11, 2019 USD ($)
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] |  |  | Secured Overnight Financing Rate (SOFR) [Member] |  |  |  |  |
Warrant to purchase common stock (in shares) | shares | 1,153,846 |  | 3,076,923 |  |  | 1,153,846 |  |
Exercise price (in dollars per share) | $ / shares | $ 1.30 |  | $ 1.30 |  |  | $ 1.30 |  |
Warrant exercise period | 8 years |  |  |  |  | 8 years |  |
Warrant liability |  |  |  | $ 7,200 |  |  | $ 5,200 |
Loss on extinguishment of debt |  |  |  | $ 0 | $ 517 |  |  |
Secured Debt | Term Loan Facility | Line of Credit |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Line of credit, maximum borrowing capacity |  |  | $ 55,000 |  |  |  |  |
Line of credit, maximum borrowing capacity, number of available tranches | tranche |  |  | 3 |  |  |  |  |
Variable rate, floor |  |  | 4.25% |  |  |  |  |
Basis spread on variable rate |  |  | 6.75% |  |  |  |  |
Debt instrument, cap rate |  |  | 15.00% |  |  |  |  |
Debt instrument, interest rate |  |  |  | 11.07% |  |  |  |
Interest expense |  |  |  | $ 2,100 | 1,000 |  |  |
Annual interest rate, increase |  |  | 3.00% |  |  |  |  |
Late fee percentage |  |  | 2.00% |  |  |  |  |
Exit fee percentage |  |  | 0.75% |  |  |  |  |
Interest payable period following prepayment |  |  | 12 months |  |  |  |  |
Debt covenant, cash and cash equivalents |  |  | $ 15,000 |  |  |  |  |
Debt covenant, revenue period |  |  | 12 months |  |  |  |  |
Debt covenant, revenue |  |  | $ 150,000 |  |  |  |  |
Secured Debt | Term Loan Facility | Line of Credit | Minimum |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Transaction fee percentage |  |  | 1.00% |  |  |  |  |
Prepayment fee percentage |  |  | 1.00% |  |  |  |  |
Secured Debt | Term Loan Facility | Line of Credit | Maximum |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Transaction fee percentage |  |  | 1.25% |  |  |  |  |
Prepayment fee percentage |  |  | 4.00% |  |  |  |  |
Secured Debt | Term Loan Facility, Tranche A | Line of Credit |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Line of credit, maximum borrowing capacity |  |  | $ 37,000 |  |  |  |  |
Proceeds from line of credit |  |  | 34,500 |  |  |  |  |
Secured Debt | Term Loan Facility, Tranche B | Line of Credit |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Line of credit, maximum borrowing capacity |  |  | 8,000 |  |  |  |  |
Proceeds from line of credit |  | $ 7,500 |  |  |  |  |  |
Secured Debt | Term Loan Facility, Tranche C | Line of Credit |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Line of credit, maximum borrowing capacity |  |  | 10,000 |  |  |  |  |
Proceeds from line of credit | $ 9,300 |  |  |  |  |  |  |
Term Loan | Tranche A and B | Keryx | Biopharma Credit Investments V (Master) LP | Collateral Agent, Pharmakon |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |
Line of credit, maximum borrowing capacity |  |  |  |  |  |  |  | $ 100,000
Interest expense |  |  |  | $ 0 | 0 |  |  |
Extinguishment of debt |  |  | 35,000 |  |  |  |  |
Payment of outstanding debt interest and prepayment fee |  |  | $ 200 |  |  |  |  |
Loss on extinguishment of debt |  |  |  |  | $ 500 |  |  |

X
- Definition Debt Instrument, Annual Interest Rate, Increase (Decrease) + References No definition available. + Details
Name: | akba_DebtInstrumentAnnualInterestRateIncreaseDecrease
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt Instrument, Covenant, Cash And Cash Equivalents + References No definition available. + Details
Name: | akba_DebtInstrumentCovenantCashAndCashEquivalents
Namespace Prefix: | akba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Debt Instrument, Covenant, Revenue + References No definition available. + Details
Name: | akba_DebtInstrumentCovenantRevenue
Namespace Prefix: | akba_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Debt Instrument, Covenant, Revenue, Period + References No definition available. + Details
Name: | akba_DebtInstrumentCovenantRevenuePeriod
Namespace Prefix: | akba_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt Instrument, Exit Fee Percentage + References No definition available. + Details
Name: | akba_DebtInstrumentExitFeePercentage
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Interest Payable Period Following Prepayment + References No definition available. + Details
Name: | akba_DebtInstrumentInterestPayablePeriodFollowingPrepayment
Namespace Prefix: | akba_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | akba_DebtInstrumentInterestRateCap
Namespace Prefix: | akba_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Debt Instrument, Late Fee Percentage + References No definition available. + Details
Name: | akba_DebtInstrumentLateFeePercentage
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Prepayment Fee Percentage + References No definition available. + Details
Name: | akba_DebtInstrumentPrepaymentFeePercentage
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Transaction Fee Percentage + References No definition available. + Details
Name: | akba_DebtInstrumentTransactionFeePercentage
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Debt Instrument, Variable Rate Floor + References No definition available. + Details
Name: | akba_DebtInstrumentVariableRateFloor
Namespace Prefix: | akba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line Of Credit Facility, Maximum Borrowing Capacity, Number Of Available Tranches + References No definition available. + Details
Name: | akba_LineOfCreditFacilityMaximumBorrowingCapacityNumberOfAvailableTranches
Namespace Prefix: | akba_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Payment For Debt Extinguishment Or Debt Prepayment Cost And Accrued Interest + References No definition available. + Details
Name: | akba_PaymentForDebtExtinguishmentOrDebtPrepaymentCostAndAccruedInterest
Namespace Prefix: | akba_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Indicates type of variable interest rate on debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 470 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477734/942-470-50-3 + Details
Name: | us-gaap_DebtInstrumentVariableInterestRateTypeExtensibleEnumeration
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 16: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478795/946-210-50-6 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(e)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(d)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479170/946-210-S99-1 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)(Footnote 8)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5C Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5A Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477271/946-320-S99-5B Reference 27: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 28: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-22 Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-10 Reference 30: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Gross amount of debt extinguished. + References No definition available. + Details
Name: | us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481303/470-50-40-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481303/470-50-40-4 + Details
Name: | us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(8)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69E -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69F -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69F Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1F -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-6 + Details
Name: | us-gaap_InterestExpenseDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481544/470-10-50-6 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481544/470-10-50-6 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-14 + Details
Name: | us-gaap_ProceedsFromLongTermLinesOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=akba_TermLoanFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=akba_TermLoanFacilityTrancheAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=akba_TermLoanFacilityTrancheBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=akba_TermLoanFacilityTrancheCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=akba_TermLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=akba_TrancheAAndBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=akba_KeryxMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=akba_BiopharmaCreditInvestmentsVMasterLimitedPartnerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=akba_CollateralAgentPharmakonMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |