Note 9 - Revenue - Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues	$ 3,314	$ 9,289	$ 10,851	$ 19,111
Testing [Member]
Revenues	2,941	8,451	9,774	17,474
Shipping/Collection (Hair) [Member]
Revenues	353	777	1,013	1,511
Other Revenue [Member]
Revenues	$ 20	$ 61	$ 64	$ 126

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details