Acquisitions and Divestitures - Acquisitions (Details) (USD $)	0 Months Ended	12 Months Ended		0 Months Ended
	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2014
Business Acquisition [Line Items]
Common stock paid to acquired entity, shares			3,319,324
Nexsan purchase price adjustment		$ 1,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	73,500,000	72,100,000	73,500,000	73,500,000	36,100,000
Earnings contributed to the Company since date of acquisition	0
Revenue contributed to the Company since date of acquisition	0
Nexsan Corporation
Business Acquisition [Line Items]
Cash paid to acquired entity	104,600,000
Common stock paid to acquired entity, shares	3,319,324
Common stock paid to acquired entity, value	15,500,000
Nexsan purchase price adjustment		1,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Cash		800,000
Accounts receivable		14,600,000
Inventory		6,900,000
Prepaid and other		9,000,000
Property, plant, and equipment		5,200,000
Intangible assets		42,600,000
Goodwill	65,500,000	63,900,000	65,500,000	65,500,000
Other assets		600,000
Accounts payable		(5,300,000)
Accrued expenses		(10,000,000)
Deferred revenue - current		(4,300,000)
Deferred revenue - non-current		(2,500,000)
Other long-term liabilities		(3,000,000)
Total purchase price		118,500,000
Acquired finite-lived intangible assets				42,600,000
Net revenue			1,088,700,000
Loss from continuing operations			(328,500,000)
Nexsan Corporation | Other - research and development technology
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired indefinite-lived intangible assets				1,700,000
Nexsan Corporation | Trade name
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired finite-lived intangible assets				3,100,000
Acquired finite-lived intangible assets, weighted average life		5 years
Nexsan Corporation | Other - developed technology
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired finite-lived intangible assets				19,400,000
Nexsan Corporation | Other - developed technology | Minimum
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired finite-lived intangible assets, weighted average life		3 years
Nexsan Corporation | Other - developed technology | Maximum
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired finite-lived intangible assets, weighted average life		7 years
Nexsan Corporation | Customer relationships
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Acquired finite-lived intangible assets				18,400,000
Acquired finite-lived intangible assets, weighted average life		12 years
Finite-Lived Intangible Assets | Nexsan Corporation
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Pro Forma Information, Adjustment		5,100,000
Deferred Revenue | Nexsan Corporation
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Pro Forma Information, Adjustment		600,000
Variable Compensation Expense | Nexsan Corporation
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Pro Forma Information, Adjustment		15,400,000
Interest Expense | Nexsan Corporation
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Pro Forma Information, Adjustment		900,000
Transaction Cost | Nexsan Corporation
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Business Combination, Pro Forma Information, Adjustment		$ 4,300,000