Note 10 Employee Equity Incentive Plans (Narratives) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Mar. 31, 2014		Mar. 31, 2013	Mar. 31, 2012		Mar. 31, 2011
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		2,000,000	[1]		600,000	[2]
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		5,201,635		5,327,473	5,472,004		5,199,768
Number of Shares Exercisable		3,865,885
Weighted Average Exercise Price Per Share (Options Exercisable)		$ 10.00
Common Stock, Dividends, Per Share	$ 0.03	$ 0.12		$ 0.06	$ 0.00
Range of Exercise Price $5.01 to $99.99 [Member]
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		5,201,635
Weighted Average Contractual Life		5 years 4 months 24 days
Plan 2013 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		2,000,000
Plan 2009 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		900,000
Plan 2011 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		600,000
Stock Options of The 2009 2011 and 2013 Plans [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years 0 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date		ten years from the date of grant
Stock Appreciation Rights of The 2009 2011 and 2013 Plans [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date		no later than 10 years from the grant date
Stock Options of the 1999 Equity Incentive Plans [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years 0 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date		ten years from the date of grant
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date		May 2009
Initial Option Grants Under the 1999 Non-Employee Directors' Equity Incentive Plan [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years 0 months 0 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date		ten years from the date of grant
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date		May 2009
Subsequent Annual Grants Under the 1999 Non-Employee Directors' Equity Incentive Plan [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		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
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date		May 2009
Zilog 2004 Plan [Member]
Employee Equity Incentive Plans [Line Items]
Per Share Option Exercise Price as a Percentage of Fair Market Value on Grant Date Not Less than		100.00%
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date		February 2014
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Assumed		652,963
Zilog 2002 Plan [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Date		not exceed ten years
Share Based Compensation Arrangement by Share Based Payment Award, Plan Expiration Date		May 2012
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Assumed		366,589
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
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		98,865
Number of Employee Stock Purchase Plan Shares Available for Future Issuance		87,490
Subsequent ESPP Purchase Approved on July 31, 2007 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		350,000
Subsequent ESPP Purchase Approved on July 9, 2010 [Member]
Employee Equity Incentive Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		350,000
Equity Incentive Plans Total [Member]
Employee Equity Incentive Plans [Line Items]
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		7.5
Weighted Average Remaining Contractual Life of Options Exercisable		4 years 3 months 18 days
Fair Value of Options Vested During the Current Fiscal Year		$ 2.4

[1] On August 30, 2013, our stockholders approved the 2013 Plan, under which 2,000,000 shares of our common stock are reserved for the grant of stock options.

[2] 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.