SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNITNG PRONOUNCEMENTS Recent Accounting Pronouncements (Details) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2016	Dec. 31, 2015
Accounting Standards Update 2014-09 [Member] \| Revenues, Net
Income Statement Line Item Effected
New Accounting Pronouncements Adopted in Future Periods, Effect of Adoption on Net Revenues (Less Than)	$ 1,000,000	$ 1,000,000

Amount of the effect of a change in accounting principle on net revenues for new accounting pronouncements to be adopted in future periods.

No definition available.

Name:	powi_NewAccountingPronouncementsAdoptedinFuturePeriodsEffectofChangeonNetRevenues
Namespace Prefix:	powi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration