Intangible Assets and Goodwill - Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill	$ 36.1us-gaap_Goodwill	$ 72.1us-gaap_Goodwill	$ 73.5us-gaap_Goodwill
Goodwill impairment	(35.4)us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	(23.3)us-gaap_GoodwillImpairmentLoss
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	249.3us-gaap_GoodwillGross	250.7us-gaap_GoodwillGross
Accumulated impairment losses, beginning balance	(177.2)	(177.2)
Goodwill, beginning balance	72.1us-gaap_Goodwill	73.5us-gaap_Goodwill
Nexsan purchase price adjustment		(1.6)
Foreign currency translation	(0.6)us-gaap_GoodwillTranslationAdjustments	0.2us-gaap_GoodwillTranslationAdjustments
Goodwill impairment	(35.4)us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	(23.3)us-gaap_GoodwillImpairmentLoss
Goodwill, gross, ending balance	248.7us-gaap_GoodwillGross	249.3us-gaap_GoodwillGross	250.7us-gaap_GoodwillGross
Accumulated impairment losses, ending balance	(212.6)	(177.2)	(177.2)
Goodwill, ending balance	36.1us-gaap_Goodwill	72.1us-gaap_Goodwill	73.5us-gaap_Goodwill
TSS
Goodwill [Line Items]
Goodwill	36.1	72.1
Goodwill impairment	(35.4)
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	199.9	201.3
Accumulated impairment losses, beginning balance	(127.8)	(127.8)
Goodwill, beginning balance	72.1	73.5
Nexsan purchase price adjustment		(1.6)
Foreign currency translation	(0.6)	0.2
Goodwill impairment	(35.4)
Goodwill, gross, ending balance	199.3	199.9
Accumulated impairment losses, ending balance	(163.2)	(127.8)
Goodwill, ending balance	36.1	72.1
CSA
Goodwill [Line Items]
Goodwill		0
Goodwill impairment	0
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	49.4	49.4
Accumulated impairment losses, beginning balance	(49.4)	(49.4)
Goodwill, beginning balance	0	0
Nexsan purchase price adjustment		0
Foreign currency translation	0	0
Goodwill impairment	0
Goodwill, gross, ending balance	49.4	49.4
Accumulated impairment losses, ending balance	(49.4)	(49.4)
Goodwill, ending balance		0
Income approach valuation technique \| Goodwill
Goodwill [Line Items]
Discounted forecasted cash flows period	10 years	10 years
Discount rate	16.50%
Terminal growth rate	3.00%	3.00%
Discount rate adjustment	2.00%
Discount rate before adjustment	14.50%
Mobile Security
Goodwill [Line Items]
Fair value in excess of carrying amount, percent	107.40%	34.20%
Mobile Security \| Income approach valuation technique \| Goodwill
Goodwill [Line Items]
Discount rate		15.50%
Storage and Security Solutions
Goodwill [Line Items]
Goodwill	28.1
Fair value in excess of carrying amount, percent	8.20%	25.70%
Goodwill impairment	(35.4)
Goodwill [Roll Forward]
Goodwill impairment	(35.4)
Goodwill, ending balance	$ 28.1
Storage and Security Solutions \| Income approach valuation technique \| Goodwill
Goodwill [Line Items]
Discount rate		13.50%

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