Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net revenues	$ 2,242,000	$ 4,305,000	$ 5,442,000	$ 7,268,000
Device [Member] | AXP [Member]
Net revenues	669,000	3,082,000	2,901,000	4,404,000
Device [Member] | BioArchive [Member]
Net revenues	459,000	784,000	955,000	1,797,000
Device [Member] | CAR-TXpress [Member]
Net revenues	634,000	182,000	869,000	490,000
Device [Member] | Manual Disposables [Member]
Net revenues	198,000	242,000	401,000	543,000
Device [Member] | Other Subsegments [Member]
Net revenues	282,000	15,000	316,000	34,000
Device Revenue [Member]
Net revenues	1,772,000	3,885,000	4,513,000	6,364,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	621,000	3,028,000	2,829,000	4,295,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	165,000	433,000	329,000	1,031,000
Device Revenue [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	550,000	182,000	702,000	490,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	198,000	242,000	401,000	543,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	238,000		252,000	5,000
Service [Member]
Net revenues	355,000	412,000	723,000	882,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	48,000	54,000	72,000	109,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	294,000	351,000	626,000	766,000
Service [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	13,000		25,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues		7,000		7,000
Other [Member]
Net revenues	115,000	8,000	206,000	22,000
Other [Member] | Device [Member] | AXP [Member]
Net revenues
Other [Member] | Device [Member] | BioArchive [Member]
Net revenues
Other [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	71,000		142,000
Other [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	$ 44,000	$ 8,000	$ 64,000	$ 22,000