Segment Information (Details) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 23, 2017 director	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 segment	Jan. 22, 2017
Segment Reporting Information [Line Items]
Number of reporting segments | segment							3
Segment Reporting Information, Profit (Loss) [Abstract]
Net revenue			$ 8.8	$ 10.6	$ 18.4	$ 21.3
Operating loss			(5.1)	(5.8)	(12.5)	(22.2)
Restructuring and other			0.6	1.0	0.1	(5.8)
Interest income			0.0	0.2	0.0	0.2
Other income (expense), net			(0.7)	(1.1)	(0.7)	(1.0)
Loss from continuing operations before income taxes			(5.8)	(6.7)	(13.2)	(23.0)
Nexsan Business
Segment Reporting Information, Profit (Loss) [Abstract]
Net revenue			8.8	10.6	18.4	21.3
Asset Management Business
Segment Reporting Information, Profit (Loss) [Abstract]
Net revenue			0.0	0.0	0.0	0.0
Operating Segments
Segment Reporting Information, Profit (Loss) [Abstract]
Operating loss			(4.4)	(4.8)	(9.6)	(10.0)
Operating Segments | Nexsan Business
Segment Reporting Information, Profit (Loss) [Abstract]
Operating loss			(3.6)	(4.8)	(7.9)	(10.0)
Operating Segments | Asset Management Business
Segment Reporting Information, Profit (Loss) [Abstract]
Operating loss			(0.8)	0.0	(1.7)	0.0
Corporate and Unallocated
Segment Reporting Information, Profit (Loss) [Abstract]
Operating loss			(1.3)	(2.0)	(3.0)	(6.4)
Segment Reconciling Items
Segment Reporting Information, Profit (Loss) [Abstract]
Restructuring and other			$ 0.6	$ 1.0	$ 0.1	$ (5.8)
GBAM Fund
Segment Reporting Information [Line Items]
Investment amount		$ 10.0
NXSN Acquisition Corp
Segment Reporting Information [Line Items]
Noncontrolling interest, percentage held by parent	50.00%							100.00%
Noncontrolling interest, percentage held by noncontrolling owners	50.00%
Number of board directors designated to company | director	2
Number of board directors | director	5