Income taxes - Current income tax provision (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Current income tax provision:
Income tax benefit related to operating losses and research and development tax credits	$ 0	$ 0

Amount of current income tax expense (benefit) directly related to operating loss carryforwards and certain tax credits.

No definition available.

Name:	akro_IncomeTaxExpenseBenefitRelatedToOperatingLossesAndCredits
Namespace Prefix:	akro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration