Special Charges (Details) (USD $)	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended
	Dec. 31, 2012 SMSC Acquisition [Member] Unusual or Infrequent Item [Member]	Dec. 31, 2012 SMSC Acquisition [Member] Unusual or Infrequent Item [Member]	Sep. 30, 2012 Silicon Storage Technology Inc Acquisition Member Unusual or Infrequent Item [Member]	Dec. 31, 2012 Silicon Storage Technology Inc Acquisition Member Unusual or Infrequent Item [Member]	Dec. 31, 2011 Unusual or Infrequent Item [Member]
Unusual or Infrequent Item [Line Items]
Severance related, office closing, and other costs	$ 2,600,000	$ 13,400,000
Legal settlement costs			11,500,000	11,500,000
Other Nonrecurring Income					700,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability					1,000,000
Severance Costs					$ 300,000