Note 2 - Summary of Significant Accounting Policies - Revenue by Major Source (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues	$ 24,909	$ 21,360	$ 37,678
Testing [Member]
Revenues	21,894	19,068	34,555
Shipping/Collection (Hair) [Member]
Revenues	2,847	2,174	2,876
Other Revenue [Member]
Revenues	$ 168	$ 118	$ 247