Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Segment reporting information [Line Items]
Net sales	$ 329,156	$ 367,824	$ 1,044,265	$ 1,107,220
Gross Profit	183,779	216,397	598,521	648,845
Semiconductor products [Member]
Segment reporting information [Line Items]
Net sales	306,099	348,766	978,577	1,055,532
Gross Profit	161,696	198,347	536,230	600,179
Technology licensing [Member]
Segment reporting information [Line Items]
Net sales	23,057	19,058	65,688	51,688
Gross Profit	$ 22,083	$ 18,050	$ 62,291	$ 48,666