Capital Leases, Direct Financing Leases, Amount Funded As Deposits On Equipment

Name:	powi_CapitalLeasesDirectFinancingLeasesAmountFundedAsDepositsOnEquipment
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Capital Leases, Direct Financing Leases, Amount Funded To Finance Capital Equipment

+ Details

Name:	powi_CapitalLeasesDirectFinancingLeasesAmountFundedToFinanceCapitalEquipment
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Capital Leases, Direct Financing Leases, Maximum Borrowing Capacity

+ Details

Name:	powi_CapitalLeasesDirectFinancingLeasesMaximumBorrowingCapacity
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Capital Leases, Direct Financing Leases, Outstanding Amount

+ Details

Name:	powi_CapitalLeasesDirectFinancingLeasesOutstandingAmount
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Contingent Purchase Commitment

+ Details

Name:	powi_ContingentPurchaseCommitment
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Investees Proceeds From Other Financing Activities

+ Details

Name:	powi_InvesteesProceedsFromOtherFinancingActivities
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Letter Of Credit Issued To Financing Company

+ Details

Name:	powi_LetterOfCreditIssuedToFinancingCompany
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Open Put or Call Option, Fair Value Disclosure

+ Details

Name:	powi_OpenPutOrCallOptionFairValueDisclosure
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Potential Business Acquisition, Minimum Purchase Price

+ Details

Name:	powi_PotentialBusinessAcquisitionMinimumPurchasePrice
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Potential Business Acquisition, Triggering Event, Multiple of Base Quarterly Revenue

+ Details

Name:	powi_PotentialBusinessAcquisitionTriggeringEventMultipleOfBaseQuarterlyRevenue
Namespace Prefix:	powi
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Prepaid royalty in exchange for the right to use SemiSouth’s technology

+ Details

Name:	powi_PrepaidRoyaltyForUseOfSemiSouthTechnology
Namespace Prefix:	powi
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This serves as a place to record data that is not specified elsewhere in the taxonomy but is useful for readers of the financial statements as it relates to the details of cost method investments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

+ Details

Name:	us-gaap_CostMethodInvestmentsAdditionalInformation
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the aggregate carrying amount of all cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment. The cost method and lower-of-cost or market, an adaptation of the cost method, is generally followed for most investments in noncontrolled corporations, in some corporate joint ventures, and to a lesser extent in unconsolidated subsidiaries, particularly foreign.

+ References

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 4

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 6

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 03-1

-Paragraph 22

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 18

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6872867&loc=d3e40691-111596

+ Details

Name:	us-gaap_CostMethodInvestmentsAggregateCarryingAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_ScheduleOfCostMethodInvestmentsLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

INVESTMENT IN THIRD PARTY (Details) (USD $)				3 Months Ended	9 Months Ended		1 Months Ended		1 Months Ended
INVESTMENT IN THIRD PARTY (Details) (USD $)	Sep. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2011 Noncontrolling Interest [Member] SemiSouth [Member]	Sep. 30, 2011 Noncontrolling Interest [Member] SemiSouth [Member]	Oct. 22, 2010 Noncontrolling Interest [Member] SemiSouth [Member]	Jul. 31, 2011 Developed Technology Rights [Member]	Aug. 31, 2011 Developed Technology Rights [Member]	Jul. 31, 2011 SemiSouth [Member]	Sep. 30, 2011 SemiSouth [Member]
Schedule of Cost-method Investments [Line Items]
Lease line funded amount				$ 8,000,000	$ 8,000,000
Lease line funded amount, less payments withheld under arrangement to finance capital equipment				3,900,000	3,900,000
Lease line funded as deposits on equipment				4,100,000	4,100,000
Cost-method Investment in SemiSouth				7,000,000	7,000,000	7,000,000
Prepaid royalty to SemiSouth	10,000,000		10,000,000	10,000,000	10,000,000	10,000,000
Lease line maximum borrowing capacity		15,500,000		8,600,000	8,600,000
Potential minimum purchase price						36,000,000
Multiple of level of quarterly revenues in third quarter of 2011				27
Investees proceeds from other financing activities									15,000,000
Contingent Purchase Commitment							15,000,000
Cost-method investment, ownership percentage in SemiSouth					less than 20%
Fair value of Put/Call Option										0
Letter Of Credit Issued To Financing Company								$ 15,000,000