Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net revenues	$ 4,058,000	$ 3,113,000	$ 11,325,000	$ 6,984,000
Device [Member]
Net revenues	4,045,000	3,059,000	11,256,000	6,822,000
Device [Member] | AXP [Member]
Net revenues	2,306,000	1,466,000	6,710,000	3,131,000
Device [Member] | BioArchive [Member]
Net revenues	594,000	799,000	2,391,000	2,326,000
Device [Member] | Manual Disposables [Member]
Net revenues	212,000	254,000	711,000	716,000
Device [Member] | CAR-TXpress [Member]
Net revenues	914,000	517,000	1,404,000	547,000
Device [Member] | Other Subsegments [Member]
Net revenues	19,000	23,000	40,000	102,000
Clinical Development [Member]
Net revenues	13,000	54,000	69,000	162,000
Clinical Development [Member] | Manual Disposables [Member]
Net revenues	9,000	8,000	53,000	31,000
Clinical Development [Member] | Other Subsegments [Member]
Net revenues	4,000	6,000	16,000	30,000
Clinical Development [Member] | Bone Marrow [Member]
Net revenues		40,000		101,000
Device Revenue [Member]
Net revenues	3,594,000	2,660,000	9,958,000	5,627,000
Device Revenue [Member] | Device [Member]
Net revenues	3,585,000	2,652,000	9,900,000	5,596,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	2,255,000	1,396,000	6,550,000	2,930,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	243,000	485,000	1,274,000	1,357,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	212,000	254,000	711,000	716,000
Device Revenue [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	875,000	517,000	1,365,000	547,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues				46,000
Device Revenue [Member] | Clinical Development [Member]
Net revenues	9,000	8,000	58,000	31,000
Device Revenue [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues	9,000	8,000	53,000	31,000
Device Revenue [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues			5,000
Device Revenue [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues
Service [Member]
Net revenues	412,000	430,000	1,294,000	1,301,000
Service [Member] | Device [Member]
Net revenues	408,000	384,000	1,283,000	1,170,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	51,000	70,000	160,000	201,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	351,000	314,000	1,117,000	969,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	6,000		6,000
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Service [Member] | Clinical Development [Member]
Net revenues	4,000	46,000	11,000	131,000
Service [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues	4,000	6,000	11,000	30,000
Service [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues		40,000		101,000
Other [Member]
Net revenues	52,000	23,000	73,000	56,000
Other [Member] | Device [Member]
Net revenues	52,000	23,000	73,000	56,000
Other [Member] | Device [Member] | AXP [Member]
Net revenues
Other [Member] | Device [Member] | BioArchive [Member]
Net revenues
Other [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	33,000		33,000
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	19,000	23,000	40,000	56,000
Other [Member] | Clinical Development [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues