Name:	ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The increase (decrease) in the number of shares outstanding. [Refer: Number of shares outstanding]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2018-01-01
-Paragraph 79
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2018-03-01&anchor=para_79_a_iv&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_IncreaseDecreaseInNumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The amount of revenue arising from the rendering of services in related party transactions. [Refer: Revenue; Related parties [member]]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2018-01-01
-Paragraph 21
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=24&date=2018-03-01&anchor=para_21_c&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_RevenueFromRenderingOfServicesRelatedPartyTransactions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of remuneration paid or payable to the entity's directors.

No definition available.

Name:	ptm_AmountOfAccruedIndependentDirectorsFeesAndServices
Namespace Prefix:	ptm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Units issued - financing (Shares)

No definition available.