DOCUMENT AND ENTITY INFORMATION Document - shares	6 Months Ended
	Jun. 30, 2019	Jul. 18, 2019
Document Information [Line Items]
Title of 12(b) Security	Common Stock
Entity Address, Address Line One	5245 Hellyer Avenue
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Incorporation, State or Country Code	DE
Document Type	10-Q
Document Quarterly Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	000-23441
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	POWER INTEGRATIONS INC
Trading Symbol	POWI
Entity Central Index Key	0000833640
Entity Filer Category	Large Accelerated Filer
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		29,330,982
Entity Tax Identification Number	94-3065014
Entity Address, Postal Zip Code	95138
Security Exchange Name	NASDAQ
City Area Code	408
Local Phone Number	414-9200
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false