MARKETABLE SECURITIES Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Interest receivable	$ 1,300	$ 1,500
Amortized Cost	236,991	373,400
Gross Unrealized Gains	0	21
Gross Unrealized Losses	(7,237)	(1,186)
Estimated Fair Market Value	229,754	372,235
Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,412	97,250
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(36)	(3)
Estimated Fair Market Value	8,376	97,247
Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	159,313	25,054
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4,369)	(42)
Estimated Fair Market Value	154,944	25,012
Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	69,266	251,096
Gross Unrealized Gains	0	21
Gross Unrealized Losses	(2,832)	(1,141)
Estimated Fair Market Value	66,434	249,976
Commercial paper \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		89,965
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Market Value		89,965
Corporate securities \| Investments due in 3 months or less:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,412	7,285
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(36)	(3)
Estimated Fair Market Value	8,376	7,282
Corporate securities \| Investments due in 4-12 months:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	159,313	25,054
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4,369)	(42)
Estimated Fair Market Value	154,944	25,012
Corporate securities \| Investments due in 12 months or greater:
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	69,266	251,096
Gross Unrealized Gains	0	21
Gross Unrealized Losses	(2,832)	(1,141)
Estimated Fair Market Value	$ 66,434	$ 249,976

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

+ Details

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

- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

+ Details

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

- Definition

Carrying amount as of the balance sheet date of current interest earned but not received. Also called accrued interest or accrued interest receivable. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Amount of investment in marketable security.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_MarketableSecurities
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.

+ References

No definition available.

+ Details

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

- Details

Name:	powi_DebtSecuritiesMaturityAxis=powi_ShortTermInvestmentsDueInLessThanThreeMonthsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	powi_DebtSecuritiesMaturityAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	powi_DebtSecuritiesMaturityAxis=us-gaap_OtherLongTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: