Employee Benefit Plans (including Share-based Compensation) (Narratives) (Details) (USD $)	12 Months Ended				12 Months Ended					0 Months Ended			12 Months Ended		12 Months Ended			12 Months Ended			12 Months Ended			0 Months Ended		12 Months Ended			133 Months Ended	174 Months Ended	12 Months Ended					0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012	Jul. 03, 2011	Jun. 30, 2014 Unvested Stock Awards	Jun. 30, 2014 Performance Shares [Member]	Jun. 30, 2014 Stock Options	Jun. 30, 2013 Stock Options	Jun. 30, 2012 Stock Options	Nov. 20, 2013 The 2013 Equity Incentive Plan [Member]	Jun. 30, 2014 The 2013 Equity Incentive Plan [Member]	Nov. 20, 2013 The 2013 Equity Incentive Plan [Member]	Jun. 30, 2014 Enterasys Networks Inc. 2013 Stock Plan [Member]	Jun. 30, 2014 2005 Equity Incentive Plan	Jun. 30, 2014 2005 Equity Incentive Plan Maximum	Jun. 30, 2014 Amended 1996 Stock Option Plan	Dec. 02, 2005 Amended 1996 Stock Option Plan	Jun. 30, 2013 2000 Plan	Jun. 30, 2014 2000 Plan	Mar. 31, 2000 2000 Plan	Jun. 30, 2013 2001 Plan	Jun. 30, 2014 2001 Plan	May 31, 2001 2001 Plan	Jan. 26, 2010 1999 Employee Stock Purchase Plan	Dec. 02, 2005 1999 Employee Stock Purchase Plan	Jun. 30, 2014 1999 Employee Stock Purchase Plan	Jun. 30, 2013 1999 Employee Stock Purchase Plan	Jun. 30, 2012 1999 Employee Stock Purchase Plan	Jan. 26, 2010 1999 Employee Stock Purchase Plan	Jun. 30, 2013 1999 Employee Stock Purchase Plan	Jun. 30, 2014 401(k) Plan	Jun. 30, 2013 401(k) Plan	Jun. 30, 2012 401(k) Plan	Jun. 30, 2014 Non-Executive	Jun. 30, 2014 Executive Employees	Oct. 31, 2013 Enterasys Networks, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	5,193,000	3,220,000	739,000																																	2,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 5.50	$ 3.49	$ 3.11																																	$ 5.30
Number of options granted (in shares)	6,347,000	4,163,000	2,593,000																																	4,200,000
Authorized shares for issuance												9,000,000													12,000,000
Additional authorized shares for issuance										6,900,000															5,000,000
Shares subject to previously expired awards reinstated												9,500,000
Shares included in outstanding options and awards														9,183,034
Shares available for grant											6,350,048
Contractual term for options granted (in years)							4 years 4 months 24 days	5 years 22 days	4 years 6 months 29 days
Shares reserved for issuance	24,897,000																56,382,867			4,000,000			4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period													7 years			10 years		10 years			10 years
Shares outstanding for options and awards	11,732,000	9,145,000	9,006,000	9,132,000							2,149,398		5,700,360			303,763			5,000			0
Total intrinsic value of options exercised	$ 4,100,000	$ 1,100,000	$ 500,000
Total fair value of options vested	2,900,000	1,500,000	2,300,000
Award vesting period for shares placed in escrow (in months)															24 months
Unrecognized compensation costs for non-vested stock awards	20,400,000
Recognition period for compensation cost not yet recognized (in years, months, and days)					1 year 10 months 24 days	2 years 6 months	2 years 9 months 25 days
Maximum of total compensation permitted to acquire shares (percent)																										15.00%
Maximum number of shares per employee																								1,000					625
Maximum offering period (in months)																										3 months
Percent of fair market value for price per share to employees (percent)																										85.00%
Shares purchased under plan																														10,795,209
Total unrecognized compensation cost for unvested stock options							12,600,000
Weighted-average grant-date fair value of options granted (in dollars per share)	$ 2.36	$ 1.74	$ 1.67			$ 1.53																				$ 1.64	$ 0.88	$ 0.98
Estimated forfeiture rate (percent)																																		12.00%	14.00%
Maximum annual contribution per employee																															17,500
Additional annual contribution per employee over age of 50																															5,500
Employer matching contribution per dollar contributed by employee																															50.00%
Maximum employer matching contribution of employee total compensation (percent)																															2.50%
Matching contributions to the Plan																															$ 800,000	$ 500,000	$ 500,000
Weighted average exercise price of grants in period (usd per share)	$ 5.15	$ 3.35	$ 3.30																																	$ 5.30