Note 9 - Segment Information - Segment Total Assets (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 3,863,000	$ 4,781,000
Accounts receivable, net	2,366,000	1,809,000
Inventories, net	2,540,000	2,897,000
Property and equipment	122,000	112,000
Other assets	160,000	119,000
	10,038,000	9,998,000
Restricted cash	100,000	100,000
Right of use	676,000
Power Supplies [Member]
Cash and cash equivalents	527,000	381,000
Accounts receivable, net	840,000	1,048,000
Inventories, net	872,000	1,576,000
Property and equipment	11,000	47,000
Other assets	107,000	102,000
	2,357,000	3,154,000
Data Storage [Member]
Cash and cash equivalents	3,336,000	4,400,000
Accounts receivable, net	1,526,000	761,000
Inventories, net	1,668,000	1,321,000
Property and equipment	111,000	65,000
Other assets	264,000	197,000
	7,681,000	6,844,000
Restricted cash	100,000	100,000
Right of use	$ 676,000