Note 8 - Revenue - Revenue by Major Source (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues	$ 6,673	$ 5,174	$ 18,473	$ 16,025
Testing [Member]
Revenues	5,859	4,590	16,275	14,363
Shipping/Collection (Hair) [Member]
Revenues	774	562	2,069	1,576
Other Revenue [Member]
Revenues	$ 40	$ 22	$ 129	$ 86

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