Note 4 - Stockholders' Equity, Stock Options and Warrants (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Share-based Compensation, Activity [Table Text Block]

	Stock Options					Warrants
	Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price
Outstanding at December 31, 2016		165,643		$	11.22		871,101		$	52.22
Issued		2,612,070			1.45		1,082,946			1.49
Expired		(12,730	)		10.39		(2,790	)		281.46
Exercised		-			-		-			-
Outstanding at December 31, 2017		2,764,983		$	2.00		1,951,257		$	23.74
Issued		482,402			1.11		957,000			1.00
Expired		(127,130	)		2.22		(10,706	)		199.55
Exercised		-			-		(341,169	)		1.00
Outstanding at June 30, 2018		3,120,255		$	1.85		2,556,382		$	5.97

Schedule of Share-based Compensation Shares Authorized Under Stock Option and Warrant Plans by Exercise Price Range [Table Text Block]

Range of Prices		Shares		Weighted Remaining Life
Options
$	0.91		10,000		9.80
$	0.965		3,000		9.88
$	0.97		191,753		9.52
$	1.01		124,358		9.51
$	1.10		22,730		9.76
$	1.13		143,807		10.00
$	1.35		111,112		9.71
$	1.454		17,200		9.26
$	1.47		2,373,226		8.99
$	2.10		14,286		8.76
$	2.25		293		8.16
$	2.42		20,640		8.14
$	2.80		57,145		8.51
$	3.75		3,998		8.01
$	4.125		3,636		8.26
$	4.1975		7,147		8.22
$	4.25		3,529		7.76
$	5.125		3,902		8.19
$	65.75		190		7.32
$	73.50		1,157		7.51
$	77.50		2,323		7.01
$	80.25		187		7.26
$	86.25		232		6.76
$	131.25		81		4.19
$	148.125		928		4.72
$	150.00		1,760		4.13
$	162.50		123		6.51
$	206.25		121		6.26
$	248.4375		121		5.04
$	262.50		130		5.04
$	281.25		529		4.55
$	318.75		3		4.86
$	346.875		72		5.76
$	431.25		306		5.69
$	506.25		188		5.51
$	596.25		42		5.25
			3,120,255
Warrants
$	1.00		1,372,828		4.36
$	1.07		697,946		4.35
$	2.25		385,000		3.57
$	123.75		94,084		2.17
$	243.75		2,529		1.10
$	309.375		2,850		1.11
$	309.50		222		1.36
$	506.25		59		0.63
$	609.375		862		0.60
			2,556,382

Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]

Stock Options:
Year	Shares		Price
2011		173		$281.25
2012		1,841	131.25	–	150.00
2013		1,553	148.13	–	596.25
2014		836	162.50	–	431.25
2015		4,088	65.75	–	86.25
2016		100,292	2.25	–	5.13
2017		2,529,070	1.01	–	2.10
2018		482,402	0.91	–	1.35
Total		3,120,255	$0.91	–	$596.25

Warrants:
Year	Shares		Price
2014		6,455	$243.75	–	$609.38
2015		94,151	0.00	–	243.75
2016		504,666		1.00
2017		1,082,946	1.07	–	2.25
2018		868,164		1.00
Total		2,556,382	$0.00	–	$609.38