Note 4 - Trade Receivables (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

Schedule of Receivables from Collaborations [Table Text Block]

	December 31, 2021
	Billed		Unbilled		Total
U.S. Department of Health and Human Services, net	$	5	$	1,670	$	1,675
Royalty receivables from partners		305		−		305
Total receivables from collaborators	$	310	$	1,670	$	1,980

	December 31, 2020
	Billed		Unbilled		Total
U.S. Department of Health and Human Services, net	$	−	$	5,402	$	5,402
Royalty receivables from partners		2,816		25		2,841
Total receivables from collaborators	$	2,816	$	5,427	$	8,243