Note 2 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net revenues	$ 1,867,000	$ 3,252,000
Device [Member]
Net revenues	1,805,000
Device [Member] | AXP [Member]
Net revenues	750,000
Device [Member] | BioArchive [Member]
Net revenues	767,000
Device [Member] | Manual Disposables [Member]
Net revenues	233,000
Device [Member] | Bone Marrow [Member]
Net revenues	38,000
Device [Member] | Other Subsegments [Member]
Net revenues	17,000
Clinical Development [Member]
Net revenues	62,000
Clinical Development [Member] | Manual Disposables [Member]
Net revenues	22,000
Clinical Development [Member] | Bone Marrow [Member]
Net revenues	23,000
Clinical Development [Member] | Other Subsegments [Member]
Net revenues	17,000
Device Revenue [Member]
Net revenues	1,401,000
Device Revenue [Member] | Device [Member]
Net revenues	1,379,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	685,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	423,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	233,000
Device Revenue [Member] | Device [Member] | Bone Marrow [Member]
Net revenues	38,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Device Revenue [Member] | Clinical Development [Member]
Net revenues	22,000
Device Revenue [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues	22,000
Device Revenue [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues
Device Revenue [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues
Service [Member]
Net revenues	449,000
Service [Member] | Device [Member]
Net revenues	409,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	65,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	344,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Bone Marrow [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Service [Member] | Clinical Development [Member]
Net revenues	40,000
Service [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues	23,000
Service [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues	17,000
Other [Member]
Net revenues	17,000
Other [Member] | Device [Member]
Net revenues	17,000
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] | Bone Marrow [Member]
Net revenues
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	17,000
Other [Member] | Clinical Development [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Bone Marrow [Member]
Net revenues
Other [Member] | Clinical Development [Member] | Other Subsegments [Member]
Net revenues