Name:	aplt_IncomeTaxesLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

No definition available.

Name:	aplt_OperatingLossCarryforwardsNotSubjectToExpiration
Namespace Prefix:	aplt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws, subject to expiration.

No definition available.

Name:	aplt_OperatingLossCarryforwardsSubjectToExpiration
Namespace Prefix:	aplt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Threshold offsetting percentage of future taxable income.

No definition available.

Name:	aplt_ThresholdOffsettingPercentageOfFutureTaxableIncome
Namespace Prefix:	aplt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are not subject to expiration dates.

No definition available.

Name:	us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

Name:	us-gaap_OperatingLossCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=116821951&loc=d3e32123-109318