Segment and Geographic Information - Revenue by Location and Product Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Revenues from External Customers and Long-Lived Assets
Revenue	$ 163,792	$ 164,635	$ 508,556	$ 519,678
Power discrete
Revenues from External Customers and Long-Lived Assets
Revenue	115,051	106,822	324,542	342,232
Power IC
Revenues from External Customers and Long-Lived Assets
Revenue	46,890	54,576	178,425	161,251
Packaging and testing services and other
Revenues from External Customers and Long-Lived Assets
Revenue	1,851	438	5,589	2,354
License and development services
Revenues from External Customers and Long-Lived Assets
Revenue		2,799		13,841
Hong Kong
Revenues from External Customers and Long-Lived Assets
Revenue	155,655	141,316	489,833	445,451
China
Revenues from External Customers and Long-Lived Assets
Revenue	4,602	18,701	9,623	55,871
South Korea
Revenues from External Customers and Long-Lived Assets
Revenue	520	515	1,468	1,214
United States
Revenues from External Customers and Long-Lived Assets
Revenue	2,151	1,167	4,595	2,939
Other countries
Revenues from External Customers and Long-Lived Assets
Revenue	$ 864	$ 2,936	$ 3,037	$ 14,203