Deferred revenue, period of recognition

No definition available.

Name:	pega_DeferredRevenuePeriodOfRecognition
Namespace Prefix:	pega_
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- Definition

More-likely-than-not benefit likelihood percentage being realized upon ultimate settlement with taxing authority resulting from sustainability of tax examination

+ References

No definition available.

+ Details

Name:	pega_MoreLikelyThanNotBenefitLikelihoodPercentageBeingRealizedUponUltimateSettlementWithTaxingAuthorityResultingFromSustainabilityOfTaxExamination
Namespace Prefix:	pega_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	pega_SignificantAccountingPoliciesLineItems
Namespace Prefix:	pega_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of license agreements, years.

+ References

No definition available.

+ Details

Name:	pega_TermOfLicenseAgreements
Namespace Prefix:	pega_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

+ Details

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

- Definition

Additions made to capitalized computer software costs during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

+ Details

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

- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DeferredRevenueArrangementTypeAxis=pega_MaintenanceRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_DeferredRevenueArrangementTypeAxis=pega_ProfessionalServicesRevenuesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DeferredRevenueArrangementTypeAxis=pega_SoftwareLicensesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeForwardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=pega_CapitalizedComputerSoftwareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
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Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Computer software capitalized during period	$ 0	$ 0	$ 0
Impairments recognized on assets	0us-gaap_AssetImpairmentCharges	0us-gaap_AssetImpairmentCharges	0us-gaap_AssetImpairmentCharges
Acquisition-related costs	$ 488,000	$ 1,306,000
More-likely-than-not benefit likelihood percentage being realized upon ultimate settlement with taxing authority resulting from sustainability of tax examination	50.00%
Equipment
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years	3 years
Furniture and fixtures
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years	5 years
Capitalized Computer Software \| Minimum
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years	3 years
Capitalized Computer Software \| Maximum
Significant Accounting Policies [Line Items]
Property and equipment, average useful life, years	5 years
Foreign Exchange Forward \| Maximum
Significant Accounting Policies [Line Items]
Term of derivative contracts	90 days
Software Licenses \| Minimum
Significant Accounting Policies [Line Items]
Term of license agreements	3 years
Software Licenses \| Maximum
Significant Accounting Policies [Line Items]
Term of license agreements	5 years
Maintenance Revenue
Significant Accounting Policies [Line Items]
Deferred revenue, period of recognition	One year
Professional Services Revenues \| Maximum
Significant Accounting Policies [Line Items]
Deferred revenue, period of recognition	Four months