Represents period within which termination of agreement under non-collaborative arrangement will become effective due to written notice provided by entity, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	aplt_NonCollaborativeCollaborativeArrangementPeriodWithinWhichTerminationOfAgreementWillBeEffective
Namespace Prefix:	aplt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

SUBSEQUENT EVENTS (Details) - Subsequent Event. - $ / shares	Aug. 02, 2022	Jul. 15, 2022
2019 Plan
Subsequent event
Option exercise price upon option repricing (in dollars per share)	$ 1.05
Columbia University \| 2019 license agreement
Subsequent event
Period within which termination of agreement will become effective		90 days