Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_CashCashEquivalentsAndShortTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Basis of Presentation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Related Party Transaction [Line Items]
Working capital				$ (9.8)
Cash balance and short-term investments				5.3
Deferred revenue	$ 10.7			10.3
Nexsan Business
Related Party Transaction [Line Items]
Decrease in operating expenses, percent	40.00%
Deferred revenue				7.1
Nexsan Business \| Scenario, Forecast
Related Party Transaction [Line Items]
Decrease in operating expenses due to cost savings			$ 10.0
Corporate, Non-Segment \| Scenario, Forecast
Related Party Transaction [Line Items]
Decrease in expected cash flows		$ 0.5
ECJ Copyright Levy
Related Party Transaction [Line Items]
Levy accruals	$ 5.6			5.8
ECJ Copyright Levy \| Corporate, Non-Segment
Related Party Transaction [Line Items]
Levy accruals				$ 5.5