Note 7 - Property and Equipment (Details Textual)		12 Months Ended
	Feb. 16, 2017 USD ($) ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2017 USD ($)
Depreciation		$ 548,000	$ 429,000	$ 423,000
Eontec [Member]
Purchase Price for Machinery and Equipment					$ 780,000
Valencia Circle, LLC [Member]
Area of Real Estate Property | ft²	41,000
Payments to Acquire Buildings	$ 7,818,000
Cost of Sales [Member]
Depreciation		42,000	20,000	29,000
Selling, General and Administrative Expenses [Member]
Depreciation		$ 506,000	$ 409,000	$ 394,000