Income Taxes (Narratives) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Operating Loss Carryforwards [Line Items]
Change in valuation allowance for fiscal year		$ (2,200,000)	$ 63,500,000
Federal tax net operating loss carry-forwards		242,000.0
State tax net operating loss carry-forwards		156,200
Tax credit carry-forwards	$ 67,364,000	68,003,000	67,364,000	$ 54,745,000
Amount of cumulative undistributed earnings to be reinvested indefinitely of non-U.S. subsidiaries		29,100,000
Deferred tax liability related to withholding taxes of certain foreign subsidiaries	551,000	578,000	551,000	505,000
Unrecorded deferred tax liability for potential withholding tax of unrecognized foreign earnings		5,300,000
Additions resulting from the acquisition of Aerohive	75,000,000
Unrecognized tax benefits	$ 23,897,000	19,064,000	23,897,000	17,168,000	$ 17,506,000
Unrecognized tax benefits that would affect the effective tax rate if recognized		400,000
Unrecognized tax benefit future impact if recognized		18,700,000
Estimated interest and penalties related to underpayment of income taxes, less than		$ 100,000	$ 100,000	$ 100,000
Aerohive Networks, Inc.
Operating Loss Carryforwards [Line Items]
Amortization period of intangible assets and goodwill resulting from acquisition		10 years
IRELAND
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards		$ 17,200,000
AUSTRALIA
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards		7,700,000
BRAZIL
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards		14,700,000
Foreign
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards		9,100
State
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards		31,900
State | Subject To Expiration
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards		900
State | Not Subject To Expiration
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards		31,000.0
Federal
Operating Loss Carryforwards [Line Items]
Deferred tax assets operating loss carryforwards subject to expiration		144,900,000
Deferred tax assets operating loss carryforwards not subject to expiration		97,100,000
Tax credit carry-forwards		42,800
Federal | Subject To Expiration
Operating Loss Carryforwards [Line Items]
Tax credit carry-forwards		$ 33,700