Note 9 Employee Equity Incentive Plans (Narratives) (Details) (USD $) In Millions, except Share data, unless otherwise specified						12 Months Ended			12 Months Ended										12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012		Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2013 Range of Exercise Price $5.01 to $99.99 [Member]	Mar. 31, 2013 Plan 2009 [Member]	Mar. 31, 2013 Plan 2011 [Member]	Mar. 31, 2013 Stock Options of Plans 2009 and 2011 [Member]	Mar. 31, 2013 Stock Appreciation Rights of Plans 2009 and 2011 [Member]	Mar. 31, 2013 Stock Options of the 1999 Equity Incentive Plans [Member]	Mar. 31, 2013 Initial Option Grants Under the 1999 Non-Employee Directors' Equity Incentive Plan [Member]	Mar. 31, 2013 Subsequent Annual Grants Under the 1999 Non-Employee Directors' Equity Incentive Plan [Member]	Mar. 31, 2013 Zilog 2004 Plan [Member]	Mar. 31, 2013 Zilog 2002 Plan [Member]	Mar. 31, 2013 Employee Stock Purchase Plan 1999 Approved in May 1999 [Member]	Mar. 31, 2013 Subsequent ESPP Purchase Approved on July 31, 2007 [Member]	Mar. 31, 2013 Subsequent ESPP Purchase Approved on July 9, 2010 [Member]	Mar. 31, 2013 Equity Incentive Plans Total [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		600,000	[1]				900,000	600,000								500,000	350,000	350,000
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than									100.00%	100.00%	85.00%	85.00%	85.00%	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period									4 years 0 months 0 days		4 years 0 months 0 days	4 years 0 months 0 days	1 year 0 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date									ten years from the date of grant	no later than 10 years from the grant date	ten years from the date of grant	ten years from the date of grant	ten years from the date of grant		not exceed ten years
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date											May 2009	May 2009	May 2009		May 2012
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Assumed														652,963	366,589
ESPP Discounted Purchase Price Percentage																85.00%
ESPP Purchase Period																semi-annual
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate																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
Unrecognized Compensation Cost of Stock Option Granted																			$ 6.0
Weighted Average Period of the Unrecognized Compensation Cost to be Recognized																			2 years 8 months 12 days
Intrinsic Value of Options Exercisable																			4.1
Weighted Average Remaining Contractual Life of Options Exercisable																			4 years 7 months 6 days
Fair Value of Options Vested During the Current Fiscal Year																			$ 3.6
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,327,473	5,472,004		5,199,768	5,188,273	5,327,473
Weighted Average Contractual Life						5 years 7 months 6 days
Number of Shares Exercisable						4,065,473
Weighted Average Exercise Price Per Share (Options Exercisable)						$ 9.74

[1] On September 16, 2011, our stockholders approved the 2011 Plan, under which 600,000 shares of our common stock are reserved for the grant of stock options.