Note 14 - Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Common Shares Reserved for Future Issuance, Warrants [Table Text Block]

	December 31,						Expiration
(in thousands, except price per share data)	2019		2018		Exercise Price		Date
Investors - December 2019 financing		4,375		-	$	4.03	12/06/24
Investors - AEROSURF		2,963		2,963	$	-	02/14/24
Investors - December 2018 financing - long-term		3,889		3,889	$	4.05	12/04/23
Investors - December 2018 financing - short-term		2,004		2,004	$	3.68	06/24/20
Battelle - 2018 payables restructuring agreement (1)		75		75	$	6.50	12/07/23
Panacea Venture Management Company Ltd.		188		188	$	4.00	07/02/23
LPH II Investments Limited		135		135	$	5.52	04/04/25
Investors - February 2017 financing		352		352	$	27.40	02/15/24
Investors - July 2015 financing		240		240	$	196.00	07/22/22
Battelle - 2014 collaboration agreement		4		4	$	1,400.00	10/10/24
Total		14,225		9,850