Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net revenues	$ 2,004,000	$ 3,501,000	$ 3,871,000	$ 6,753,000
Device [Member]
Net revenues	1,958,000		3,763,000
Device [Member] | AXP [Member]
Net revenues	945,000		1,695,000
Device [Member] | BioArchive [Member]
Net revenues	760,000		1,527,000
Device [Member] | Manual Disposables [Member]
Net revenues	229,000		462,000
Device [Member] | Other Subsegments [Member]
Net revenues	24,000		79,000
Device [Member] | Bone Marrow [Member]
Net revenues	38,000		61,000
Clinical Development [Member]
Net revenues	46,000		108,000
Clinical Development [Member] | Manual Disposables [Member]
Net revenues	1,000		23,000
Clinical Development [Member] | Other Subsegments [Member]
Net revenues	7,000		24,000
Device Revenue [Member]
Net revenues	1,566,000		2,967,000
Device Revenue [Member] | Device [Member]
Net revenues	1,565,000		2,944,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	879,000		1,564,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	449,000		872,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	229,000		462,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	8,000		46,000
Device Revenue [Member] | Device [Member] | Bone Marrow [Member]
Net revenues
Device Revenue [Member] | Clinical Development [Member]
Net revenues	1,000		23,000
Device Revenue [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues	1,000		23,000
Device Revenue [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues
Service [Member]
Net revenues	422,000		871,000
Service [Member] | Device [Member]
Net revenues	377,000		786,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	66,000		131,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	311,000		655,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Service [Member] | Device [Member] | Bone Marrow [Member]
Net revenues	38,000		61,000
Service [Member] | Clinical Development [Member]
Net revenues	45,000		85,000
Service [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues	7,000		24,000
Other [Member]
Net revenues	16,000		33,000
Other [Member] | Device [Member]
Net revenues	16,000		33,000
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] | Other Subsegments [Member]
Net revenues	16,000		33,000
Other [Member] | Device [Member] | Bone Marrow [Member]
Net revenues
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