Note 4 - Balance Sheet Components (Details Textual) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Prepaid Expenses, Deposit from Vendor	$ 170.0
Inventory, Stock Rotation Reserve	$ 22.4	$ 5.5

Prepaid expenses from a deposit made to a vendor included in prepaid expenses.

No definition available.

Name:	mpwr_PrepaidExpensesDepositToVendor
Namespace Prefix:	mpwr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant