Fixed purchase commitment .

No definition available.

Name:	ptla_FixedPurchaseCommitment
Namespace Prefix:	ptla_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of the loss on termination of a contract for default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=51676457&loc=d3e52595-109384

+ Details

Name:	us-gaap_LossOnContractTerminationForDefault
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Subsequent Events - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	May. 31, 2016	Apr. 30, 2016	Mar. 31, 2016
Subsequent Event [Line Items]
Options granted			980,215
Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
RSUs granted			215,655
Subsequent Event
Subsequent Event [Line Items]
Non-cancellable purchase commitments		$ 6,000,000
Subsequent Event \| Management Team
Subsequent Event [Line Items]
Options granted	271,122
Subsequent Event \| Employee Stock Option
Subsequent Event [Line Items]
Options granted	510,593
Subsequent Event \| Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
RSUs granted	255,301
Maximum \| Subsequent Event
Subsequent Event [Line Items]
Termination fees payment under obligation		$ 34,000,000