Income Taxes - Components of the Income Tax (Benefit) Expense from Discontinuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred:
Federal	$ (1,624)	$ (1,017)	$ (103)
State	(52)	(47)	(5)
Total	(1,676)	(1,064)	(108)
Change in valuation allowance	$ 1,676	$ 1,064	$ 108

Deferred federal income tax expense benefit discontinuing operations.

No definition available.

Name:	atnx_DeferredFederalIncomeTaxExpenseBenefitDiscontinuingOperations
Namespace Prefix:	atnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred income tax expense benefit discontinuing operations.

No definition available.

Name:	atnx_DeferredIncomeTaxExpenseBenefitDiscontinuingOperations
Namespace Prefix:	atnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Deferred income tax expense benefit discontinuing operations.

No definition available.

Name:	atnx_DeferredIncomeTaxExpenseBenefitDiscontinuingOperationsAbstract
Namespace Prefix:	atnx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Deferred state and local income tax expense benefit discontinuing operations.

No definition available.

Name:	atnx_DeferredStateAndLocalIncomeTaxExpenseBenefitDiscontinuingOperations
Namespace Prefix:	atnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Valuation allowance deferred tax asset change in amount discontinuing operations.

No definition available.

Name:	atnx_ValuationAllowanceDeferredTaxAssetChangeInAmountDiscontinuingOperations
Namespace Prefix:	atnx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration