Intangible Assets and Goodwill - Schedule of Changes in Goodwill Allocated to Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, gross	$ 67.3
Accumulated impairment losses	(63.5)
Goodwill	3.8	$ 28.1
Goodwill impairment - Nexsan	0.0	(28.1)
Goodwill	$ 3.8	3.8
Connected Data, Inc.
Goodwill [Roll Forward]
Goodwill from acquisition of Connected Data, Inc.		$ 3.8