Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Segment reporting information [Line Items]
Net sales	$ 462,792	$ 352,134
Gross Profit	266,574	204,797
Semiconductor products [Member]
Segment reporting information [Line Items]
Net sales	440,274	331,852
Gross Profit	244,056	184,515
Technology licensing [Member]
Segment reporting information [Line Items]
Net sales	22,518	20,282
Gross Profit	$ 22,518	$ 20,282