Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment reporting information [Line Items]
Net sales	$ 492,669	$ 383,298	$ 955,461	$ 735,432
Gross Profit	288,863	194,195	555,437	398,992
Semiconductor products [Member]
Segment reporting information [Line Items]
Net sales	467,843	363,177	908,117	695,029
Gross Profit	264,037	174,074	508,093	358,589
Technology licensing [Member]
Segment reporting information [Line Items]
Net sales	24,826	20,121	47,344	40,403
Gross Profit	$ 24,826	$ 20,121	$ 47,344	$ 40,403