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

3 Months Ended

Mar. 31, 2019

Notes Tables

Share-based Payment Arrangement, Activity [Table Text Block]

	Stock Options					Warrants
	Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price
Outstanding at December 31, 2017		2,764,983		$	2.00		1,951,257		$	23.74
Issued		1,098,858			1.01		2,336,154			1.07
Expired		(194,564	)		2.00		(10,706	)		199.55
Exercised		-			-		(650,062	)		1.00
Outstanding at December 31, 2018		3,669,277		$	1.70		3,626,643		$	4.17
Issued		459,169			0.73		2,325,406			0.92
Expired		(56,867	)		2.00		(919	)		603.89
Outstanding at March 31, 2019		4,071,579		$	1.59		5,951,130		$	3.29

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
$	0.619		524,958		9.77
$	0.75		33,335		10.00
$	0.82		60,000		9.67
$	0.849		3,534		9.80
$	0.90		30,000		9.92
$	0.91		10,000		9.05
$	0.965		3,000		9.13
$	0.97		191,753		8.77
$	1.01		149,110		8.88
$	1.06		23,585		9.51
$	1.10		86,958		9.22
$	1.125		69,250		4.92
$	1.13		195,931		9.31
$	1.15		21,740		9.34
$	1.16		66,451		9.35
$	1.18		30,000		9.36
$	1.20		41,668		9.34
$	1.21		30,000		9.86
$	1.35		111,112		8.96
$	1.454		17,200		8.51
$	1.47		2,271,476		8.24
$	2.10		14,286		8.01
$	2.25		293		7.41
$	2.42		20,640		7.39
$	2.80		57,145		7.76
$	3.75		4,000		7.25
$	4.125		3,636		7.51
$	4.1975		7,147		7.47
$	4.25		3,529		7.01
$	5.125		3,902		7.44
$	65.75		190		6.56
$	73.50		1,157		6.76
$	77.50		2,323		6.25
$	80.25		187		6.51
$	86.25		232		6.01
$	131.25		81		3.44
$	148.125		928		3.97
$	150.00		1,760		3.38
$	162.50		123		5.76
$	206.25		121		5.51
$	248.4375		121		4.29
$	262.50		77		4.26
$	281.25		529		3.80
$	318.75		3		4.11
$	346.875		72		5.01
$	431.25		306		4.94
$	506.25		188		4.76
$	596.25		42		4.50
			4,071,579
Warrants
$	0.70		754,642		4.78
$	0.836		221,292		4.67
$	1.00		2,495,811		4.34
$	1.07		697,946		3.60
$	1.155		1,071,776		4.50
$	1.188		138,889		4.78
$	1.3125		86,086		4.51
$	2.25		385,000		2.82
$	123.75		94,084		1.42
$	243.75		2,529		0.35
$	309.375		2,850		0.86
$	309.50		223		0.60
			5,951,130

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		1,500	148.13	–	596.25
2014		836	162.50	–	431.25
2015		4,088	65.75	–	86.25
2016		100,294	2.25	–	5.13
2017		2,427,320	1.01	–	2.10
2018		1,076,358	0.62	–	1.35
2019		459,169	0.62	–	1.13
Total		4,071,579	$0.62	–	$596.25

Warrants:
Year	Shares		Price
2014		5,536	$243.75	–	$309.50
2015		94,151	0.00	–	243.75
2016		252,333		1.00
2017		1,082,946	1.07	–	2.25
2018		2,190,758	0.84	–	1.155
2019		2,325,406	0.704	–	1.19
Total		5,951,130	$0.00	–	$309.50