Note 9 - Segment Reporting - Summary of Operating Results by Reportable Segments (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Net revenues	$ 2,962,000	$ 1,867,000
Cost of revenues	1,704,000	1,515,000
Gross profit	1,258,000	352,000
Operating expenses	2,164,000	3,608,000
Operating loss	(906,000)	(3,256,000)
Depreciation and amortization	212,000	159,000
Stock-based compensation expense	81,000	137,000
Goodwill	781,000	13,976,000	$ 781,000
Total assets	15,630,000	50,181,000	14,611,000
Goodwill	781,000	13,976,000	781,000
Total assets	15,630,000	50,181,000	$ 14,611,000
Clinical Development [Member]
Net revenues	11,000	62,000
Clinical Development [Member] | Operating Segments [Member]
Net revenues	11,000	62,000
Cost of revenues	43,000	71,000
Gross profit	(32,000)	(9,000)
Operating expenses	471,000	1,179,000
Operating loss	(503,000)	(1,188,000)
Depreciation and amortization	95,000	68,000
Stock-based compensation expense	54,000	98,000
Goodwill		13,195,000
Total assets	4,281,000	38,941,000
Goodwill		13,195,000
Total assets	4,281,000	38,941,000
Device [Member]
Net revenues	2,951,000	1,805,000
Device [Member] | Operating Segments [Member]
Net revenues	2,951,000	1,805,000
Cost of revenues	1,661,000	1,444,000
Gross profit	1,290,000	361,000
Operating expenses	1,693,000	2,429,000
Operating loss	(403,000)	(2,068,000)
Depreciation and amortization	117,000	91,000
Stock-based compensation expense	27,000	39,000
Goodwill	781,000	781,000
Total assets	11,349,000	11,240,000
Goodwill	781,000	781,000
Total assets	$ 11,349,000	$ 11,240,000