Note 3 - Stockholders' Equity, Stock Options and Warrants (Tables)

3 Months Ended

Mar. 31, 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		325,595			1.11		957,000			1.00
Expired		-			-		(9,580	)		180.12
Exercised		-			-		(38,625	)		1.00
Outstanding at March 31, 2018		3,090,578		$	1.89		2,860,052		$	5.61

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
$	0.97		191,753		9.77
$	1.01		124,358		9.76
$	1.10		22,730		10.00
$	1.35		111,112		9.96
$	1.454		17,200		9.51
$	1.47		2,456,226		9.24
$	2.10		14,286		9.01
$	2.25		293		8.41
$	2.42		24,768		8.39
$	2.80		57,145		8.76
$	3.75		44,000		8.26
$	4.125		3,636		8.51
$	4.1975		7,147		8.47
$	4.25		3,529		8.01
$	5.125		3,902		8.44
$	65.75		190		7.56
$	73.50		1,157		7.76
$	77.50		2,323		7.25
$	80.25		187		7.51
$	86.25		232		7.01
$	131.25		81		4.44
$	148.125		928		4.97
$	150.00		1,760		4.38
$	162.50		123		6.76
$	206.25		121		6.51
$	248.4375		121		5.29
$	262.50		130		5.29
$	281.25		529		4.80
$	318.75		3		5.11
$	346.875		72		6.01
$	431.25		306		5.94
$	506.25		188		5.76
$	596.25		42		5.50
			3,090,578
Warrants
$	1.00		1,675,374		4.39
$	1.07		697,946		4.60
$	2.25		385,000		3.82
$	123.75		94,084		2.42
$	243.75		2,529		1.35
$	309.375		2,850		1.36
$	309.50		222		1.61
$	337.50		178		0.22
$	371.25		946		0.16
$	506.25		59		0.88
$	609.375		862		0.85
			2,860,052

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	148.125	–	596.25
2014		836	162.50	–	431.25
2015		4,088	65.75	–	86.25
2016		144,422	2.25	–	5.13
2017		2,612,070	1.01	–	2.10
2018		325,595	0.97	–	1.35
Total		3,090,578	$0.97	–	596.25

Warrants:
Year	Shares		Price
2013		1,126	337.50	–	371.25
2014		6,455	243.75	–	609.38
2015		94,151	0.00	–	243.75
2016		756,999		4.46
2017		1,082,946	1.07	–	2.25
2018		918,375		1.00
Total		2,860,052	$0.00	–	609.38