Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net revenues	$ 4,305,000	$ 2,004,000	$ 7,268,000	$ 3,871,000
Device [Member]
Net revenues	4,261,000	1,958,000	72,120,000	3,763,000
Device [Member] | AXP [Member]
Net revenues	3,082,000	915,000	4,404,000	1,665,000
Device [Member] | BioArchive [Member]
Net revenues	784,000	760,000	1,797,000	1,527,000
Device [Member] | CAR-TXpress [Member]
Net revenues	182,000	30,000	490,000	30,000
Device [Member] | Manual Disposables [Member]
Net revenues	205,000	229,000	499,000	462,000
Device [Member] | Other Subsegments [Member]
Net revenues	8,000	24,000	22,000	79,000
Clinical Development [Member]
Net revenues	44,000	46,000	56,000	108,000
Clinical Development [Member] | Manual Disposables [Member]
Net revenues	37,000	1,000	44,000	23,000
Clinical Development [Member] | Other Subsegments [Member]
Net revenues	7,000	7,000	12,000	24,000
Clinical Development [Member] | Bone Marrow [Member]
Net revenues		38,000		61,000
Device Revenue [Member]
Net revenues	3,885,000	1,566,000	6,364,000	2,967,000
Device Revenue [Member] | Device [Member]
Net revenues	3,848,000	1,565,000	6,315,000	2,944,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	3,028,000	849,000	4,295,000	1,534,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	433,000	449,000	1,031,000	872,000
Device Revenue [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	182,000	30,000	490,000	30,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	205,000	229,000	499,000	462,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues		8,000		46,000
Device Revenue [Member] | Clinical Development [Member]
Net revenues	37,000	1,000	49,000	23,000
Device Revenue [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues	37,000	1,000	44,000	23,000
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	422,000	882,000	871,000
Service [Member] | Device [Member]
Net revenues	405,000	377,000	875,000	786,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	54,000	66,000	109,000	131,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	351,000	311,000	766,000	655,000
Service [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Service [Member] | Clinical Development [Member]
Net revenues	7,000	45,000	7,000	85,000
Service [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues	7,000	7,000	7,000	24,000
Service [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues		38,000		61,000
Other [Member]
Net revenues	8,000	16,000	22,000	33,000
Other [Member] | Device [Member]
Net revenues	8,000	16,000	22,000	33,000
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
Other [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	8,000	16,000	22,000	33,000
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