Income Taxes (Narratives) (Details) - USD ($)		3 Months Ended			6 Months Ended	9 Months Ended
	Dec. 22, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Operating Loss Carryforwards [Line Items]
Provision for income taxes		$ 1,729,000		$ 1,166,000		$ 1,787,000	$ 3,252,000
U.S. Federal tax rate		21.00%			35.00%
Tax provision offset by tax benefit						$ 2,500,000
Description of effective date of enacted tax rate implementation						Effective for tax years beginning on or after January 1, 2018.
Tax benefit			$ 2,500,000
Additional tax provision resulting corresponding reduction in valuation allowance		$ 0				$ 0
Unrecognized tax benefits		18,500,000				18,500,000
Unrecognized tax benefit future impact if recognized		18,500,000				18,500,000
Enterasys, Zebra WLAN Business and Campus Fabric Business
Operating Loss Carryforwards [Line Items]
Tax amortization deduction for capitalized goodwill		1,800,000				5,500,000
Deferred tax liability, goodwill		$ 5,300,000				$ 5,300,000
Amortization period for tax purposes						15 years
Fiscal 2018
Operating Loss Carryforwards [Line Items]
U.S. Federal tax rate	28.00%