Note 5 - Sale of Business Component (Details Textual) - USD ($)			3 Months Ended	12 Months Ended
	Dec. 28, 2018	Jan. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Gain (Loss) on Disposition of Business				$ 1,140,000	$ 321,000
Tech Site Services LLC [Member]
Proceeds from Divestiture of Businesses		$ 343,000
Gain (Loss) on Disposition of Business			$ 321,000
Asset Purchase Agreement, Consideration Transferred		$ 350,000
Asset Purchase Agreement, Earnout Payment, Fee for Revenues Exceeding Measurement Period Revenue Threshold, Percentage		10.00%
Asset Purchase Agreement, Earnout Payment, Measurement Period Revenue Threshold		$ 2,500,000
Asset Purchase Agreement, Earnout Payment, Measurement Period		1 year
Asset Purchase Agreement, Earnout Payment, Period of Potential Payment		2 years
Asset Purchase Agreement, Liabilities Assumed		$ 7,000
Asset Purchase Agreement, Transaction Costs		29,000
Tech Site Services LLC [Member] | Customer Contracts and Intellectual Property [Member]
Asset Purchase Agreement, Intangible Assets Disposed of, Book Value		$ 0
Virginia-based Critical Data Center [Member] | MHW [Member]
Notes Payable, Total	$ 1,595,000
Virginia-based Critical Data Center [Member] | Innovative Power LLC [Member]
Disposal Group, Including Discontinued Operation, Consideration	2,500,000
Disposal Group, Including Discontinued Operation, Intangible Assets	1,176,000
Disposal Group, Including Discontinued Operation, Assets, Total	3,000
Disposal Group, Including Discontinued Operations, Amount Placed in Escrow	175,000
Proceeds from Divestiture of Businesses	2,325,000
Sale of Business, Expense	$ 184,000
Gain (Loss) on Disposition of Business				$ 1,140,000