Note 3 - Summary of Significant Accounting Policies - Revenues (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net revenues	$ 1,517,000	$ 3,200,000
Device [Member] | AXP [Member]
Net revenues	264,000	2,232,000
Device [Member] | BioArchive [Member]
Net revenues	750,000	496,000
Device [Member] | CAR-TXpress [Member]
Net revenues	354,000	235,000
Device [Member] | Manual Disposables [Member]
Net revenues	129,000	203,000
Device [Member] | Other Subsegments [Member]
Net revenues	20,000	34,000
Device Revenue [Member]
Net revenues	824,000	2,741,000
Device Revenue [Member] | Device [Member] | AXP [Member]
Net revenues	225,000	2,208,000
Device Revenue [Member] | Device [Member] | BioArchive [Member]
Net revenues	208,000	164,000
Device Revenue [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	255,000	152,000
Device Revenue [Member] | Device [Member] | Manual Disposables [Member]
Net revenues	129,000	203,000
Device Revenue [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	7,000	14,000
Service [Member]
Net revenues	609,000	368,000
Service [Member] | Device [Member] | AXP [Member]
Net revenues	39,000	24,000
Service [Member] | Device [Member] | BioArchive [Member]
Net revenues	542,000	332,000
Service [Member] | Device [Member] | CAR-TXpress [Member]
Net revenues	28,000	12,000
Service [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Service [Member] | Device [Member] | Other Subsegments [Member]
Net revenues
Other [Member]
Net revenues	84,000	91,000
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	71,000
Other [Member] | Device [Member] | Manual Disposables [Member]
Net revenues
Other [Member] | Device [Member] | Other Subsegments [Member]
Net revenues	$ 13,000	$ 20,000