Legal Proceedings (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended		6 Months Ended	1 Months Ended	0 Months Ended
	Oct. 05, 2009	Sep. 01, 2009	Oct. 29, 2011	Apr. 30, 2002 Initial Public Offering [Member]	Jan. 26, 2011 Minor [Member]	May 01, 2009 Minor [Member]	Oct. 06, 2009 Stockholder Derivative Litigation [Member]	Aug. 31, 2009 Stockholder Derivative Litigation [Member]	Dec. 05, 2006 Stockholder Derivative Litigation [Member]	Dec. 21, 2010 Strugala [Member]	Mar. 21, 2011 Microsoft [Member]	Aug. 05, 2010 Lina [Member]	Aug. 12, 2010 Burstein [Member]
Loss Contingencies [Line Items]
Number of individuals filed in United States District Court				1,000
Number of corporations filed in United States District Court				300
Number of cases where district courts decision reversed									6
Payments for legal settlements	$ 0
Total number of employees under subclass one						500
Total number of employees under subclass two						200
Number of plaintiffs added to case management conference					2
Consolidated cases, number of lawsuits		5
Number of affirmative defenses			6
Number of shareholder derivative complaints filed							1	5		1	1	1	1