Net Loss Per Share - Additional Information (Details) - shares shares in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Net Loss Per Share
Potential common shares that would have been included in diluted income per share were not anti-dilutive effect caused by the net loss, computed by converting these securities using the treasury stock method	11.9	9.9

Securities that were not included in the computation of diluted EPS or EPU computed by converting these securities using the treasury stock method.

No definition available.

Name:	ardx_AntidilutiveSecuritiesIncludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	ardx_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration