Note 11 Employee Equity Incentive Plans (Narratives) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Dec. 31, 2012	Dec. 31, 2012
Plan 2009 Approved on September 10, 2009 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	900,000	900,000
Plan 2011 Approved on September 16, 2011 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	600,000	600,000
Stock Options of Plans 2009 and 2011 [Member]
Employee Equity Incentive Plans [Line Items]
Percent of Fair Market Value on Grant Date Not Less Than	100.00%	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	over four years
Share-based Compensation Arrangement by Share-based Payment Award Expiration Date	ten years from the date of grant
Stock Appreciation Rights of Plans 2009 and 2011 [Member]
Employee Equity Incentive Plans [Line Items]
Percent of Fair Market Value on Grant Date Not Less Than	100.00%	100.00%
Share-based Compensation Arrangement by Share-based Payment Award Expiration Date	no later than 10 years from the grant date
Zilog 2004 Plan [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award Number of Shares Assumed	652,963	652,963
Employee Stock Purchase Plan 1999 Approved in May 1999 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	500,000	500,000
ESPP Discounted Purchase Price Percentage	85.00%	85.00%
ESPP Purchase Period	semi-annual
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	15.00%	15.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans		115,516
Number of Employee Stock Purchase Plan Shares Available for Future Issuance	186,355	186,355
Subsequent ESPP Purchase Approval on July 31, 2007 [Member]
Employee Equity Incentive Plans [Line Items]
Number of Shares Approved in Subsequent Amendments of Original Purchase Plan	350,000	350,000
Subsequent ESPP Purchase Approval on July 9, 2010 [Member]
Employee Equity Incentive Plans [Line Items]
Number of Shares Approved in Subsequent Amendments of Original Purchase Plan	350,000	350,000
Equity Incentive Plans Total [Member]
Employee Equity Incentive Plans [Line Items]
Unrecognized Compensation Cost of Stock Option Granted	5.4	5.4
Weighted Average Period of the Unrecognized Compensation Cost to be Recognized	2.7