Note 7 - Embedded Derivatives and Derivative Warrant Liabilities (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Assumptions Used [Table Text Block]

	June 30,			December 31,
	2018			2017
Stock price	$	3.80			0.59
Conversion Rate per $1,000		67.9			1,358.90
Conversion Price	$	14.72		$	0.74
Maturity date		March 15, 2020		March 15, 2020
Risk-free interest rate		2.43	%		1.89	%
Estimated stock volatility		125	%		75	%
Estimated credit spread		27	%		28	%

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

	Issuance Date	Expiration Date	Exercise Price as of June 30, 2018			Shares Underlying Warrants on Issuance Date		Shares Issued upon Warrant Exercises as of June 30, 2018		Shares Underlying Warrants Outstanding as of June 30, 2018 (4)
2013 Warrants	12/16/2013	12/16/2018	$	85.05			3,551		762		2,789
2014 Warrants	08/05/2014	08/05/2019	$	65.50			2,500		1,526		974
Series A Warrants	02/03/2015	02/03/2020	$	3.80			5,542		5,222		320
Series B Warrants	02/03/2015	08/03/2015		-	(1)		5,542		5,542		-
Series C Warrants	05/19/2015	05/19/2020	$	53.43			1,075		-		1,075
Series D Warrants	12/11/2015	12/11/2020	$	40.00			25,125		25,078		47
Series E Warrants	12/11/2015	12/11/2020		-	(1)		20,000		20,000		-
Series F Warrants	04/01/2016	04/01/2021	$	40.00			25,733		11,692		14,041
Series G Warrants	04/01/2016	04/01/2017		-	(1)		16,429		16,429		-
Series H Warrants	04/01/2016	10/01/2016		-	(1)		51,465		51,465		-
Series I Warrants	09/13/2016	09/13/2021	$	220.00			35,650		-		35,650
Series J Warrants	09/13/2016	09/13/2017		-	(1)		9,250		9,250		-
Series K Warrants	02/17/2017	2/17/2022	$	3.80			312,516		308,510		4,006
Series L Warrants	02/17/2017	02/17/2018		-	(1)		28,500		28,500		-
Series M-A Warrants	02/17/2017	11/17/2017		-	(1), (2)		115,250		74,250		-
Series M-B Warrants	02/17/2017	11/17/2017		-	(1), (3)		197,250		197,250		-
							855,378		755,476		58,902

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details