Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Segment reporting information [Line Items]
Net sales	$ 416,047	$ 329,156	$ 1,151,479	$ 1,044,265
Gross Profit	200,428	185,488	599,420	603,648
Semiconductor products [Member]
Segment reporting information [Line Items]
Net sales	394,709	306,099	1,089,738	978,577
Gross Profit	179,090	162,441	537,679	538,465
Technology licensing [Member]
Segment reporting information [Line Items]
Net sales	21,338	23,057	61,741	65,688
Gross Profit	$ 21,338	$ 23,047	$ 61,741	$ 65,183