Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net revenues	$ 2,355,000	$ 4,058,000	$ 7,797,000	$ 11,325,000
Device [Member] | AXP [Member]
Net revenues	1,169,000	2,306,000	4,112,000	6,710,000
Device [Member] | BioArchive [Member]
Net revenues	619,000	594,000	1,575,000	2,391,000
Device [Member] | CAR-TXpress [Member]
Net revenues	425,000	918,000	1,296,000	1,404,000
Device [Member] | Manual Disposables [Member]
Net revenues	100,000	221,000	499,000	764,000
Device [Member] | Other Subsegments [Member]
Net revenues	42,000	19,000	315,000	56,000
Device Revenue [Member]
Net revenues	1,932,000	3,594,000	6,494,000	9,958,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	1,137,000	2,255,000	4,009,000	6,550,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	337,000	243,000	675,000	1,274,000
Device Revenue [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	332,000	875,000	1,035,000	1,365,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	100,000	221,000	499,000	764,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	26,000		276,000	5,000
Service [Member]
Net revenues	336,000	412,000	1,050,000	1,294,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	32,000	51,000	103,000	160,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	282,000	351,000	900,000	1,117,000
Service [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	22,000	10,000	47,000	6,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues				11,000
Other [Member]
Net revenues	87,000	52,000	253,000	73,000
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	33,000	214,000	33,000
Other [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	$ 16,000	$ 19,000	$ 39,000	$ 40,000