STOCKHOLDERS' EQUITY - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	$ 11,258	$ 10,077	$ 17,565	$ 18,760
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfRevenue
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	707	592	1,176	1,249
Location, Statement of Income, Balance [Axis]: us-gaap:OtherOperatingIncomeExpenseNet
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	522	0	(897)	0
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	3,036	3,190	4,940	5,440
Location, Statement of Income, Balance [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	6,993	6,295	10,519	12,071
Location, Statement of Income, Balance [Axis]: powi:RestructuringAndRelatedChargesIncludedInOperatingExpenses
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Total stock-based compensation expense	$ 0	$ 0	$ 1,827	$ 0