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

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

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		836,950			1.12		2,028,776			1.08
Expired		(153,048	)		2.00		(10,706	)		199.55
Exercised		-			-		(650,062	)		1.00
Outstanding at September 30, 2018		3,448,885		$	1.78		3,319,265		$	4.55

	Stock Options					Warrants
	Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price
Outstanding at December 31, 2015		31,350		$	133.23		323,099		$	128.40
Issued		157,982			3.14		1,487,881			0.71
Expired		(22,377	)		122.13		-			-
Exercised		(1,312	)		65.75		(939,879	)		-
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

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		9.55
$	0.965		3,000		9.63
$	0.97		191,753		9.27
$	1.01		149,110		9.38
$	1.06		23,585		10.00
$	1.10		86,958		9.71
$	1.13		195,931		9.80
$	1.15		21,740		9.84
$	1.16		66,451		9.84
$	1.18		30,000		9.86
$	1.20		41,668		9.84
$	1.21		30,000		9.86
$	1.35		111,112		9.45
$	1.454		17,200		9.01
$	1.47		2,347,308		8.73
$	2.10		14,286		8.50
$	2.25		293		7.90
$	2.42		20,640		7.84
$	2.80		57,145		8.26
$	3.75		3,998		5.24
$	4.125		3,636		8.01
$	4.1975		7,147		7.97
$	4.25		3,529		7.50
$	5.125		3,902		7.94
$	65.75		190		7.06
$	73.50		1,157		7.26
$	77.50		2,323		6.75
$	80.25		187		7.01
$	86.25		232		6.50
$	131.25		81		3.94
$	148.125		928		4.47
$	150.00		1,760		3.88

$	162.50	123	6.26
$	206.25	121	6.01
$	248.4375	121	4.79
$	262.50	130	4.79
$	281.25	529	4.30
$	318.75	3	4.60
$	346.875	72	5.50
$	431.25	306	5.44
$	506.25	188	5.25
$	596.25	42	5.00
		3,448,885

Warrants
$	1.00	1,063,935	4.60
$	1.07	697,946	4.10
$	1.155	1,071,776	5.00
$	2.25	385,000	3.32
$	123.75	94,084	1.92
$	243.75	2,529	0.84
$	309.375	2,850	0.86
$	309.50	222	1.10
$	506.25	59	0.38
$	609.375	862	0.34
		3,319,265

Range of Exercise Prices			Shares		Weighted Average Remaining Life
Options:
	$	1.01		124,358	10.00
	$	1.454		17,200	9.75
	$	1.47		2,456,226	9.48
	$	2.10		14,286	9.25
	$	2.25		293	8.65
	$	2.42		24,768	8.38
	$	2.80		57,145	9.01
	$	3.75		44,000	8.50
	$	4.125		3,636	8.75
	$	4.1975		7,147	8.72
	$	4.25		3,529	8.25
	$	5.125		3,902	8.69
	$	65.75		190	7.40
	$	73.50		1,157	8.01
	$	77.50		2,323	7.50
	$	80.25		187	7.75
	$	86.25		232	7.25
	$	131.25		81	4.69
	$	148.125		928	5.21
	$	150.00		1,760	4.63
	$	162.50		123	7.01
	$	206.25		121	6.75
	$	248.4375		121	5.54
	$	262.50		130	5.54
	$	281.25		529	5.04
	$	318.75		3	5.35
	$	346.875		72	6.25
	$	431.25		306	6.19
	$	506.25		188	6.00
	$	596.25		42	5.75
Total				2,764,983

	Warrants
		$	1.07	697,946	4.85
		$	2.25	385,000	4.06
		$	4.46	756,999	3.92
		$	93.75	2,255	0.19
		$	123.75	94,084	2.67
		$	150.00	4,114	0.20
		$	225.00	107	0.07
		$	243.75	2,529	1.59
		$	281.25	3,107	0.14
		$	309.375	2,850	1.61
		$	309.50	222	1.85
		$	337.50	178	0.46
		$	371.25	944	0.41
		$	506.25	59	1.12
		$	609.375	862	1.09
Total				1,951,257

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		2,503,152		1.01	-	2.10
2018		836,950		0.91	-	1.35
Total		3,448,885		$0.91	–	$596.25

Warrants:
Year	Shares		Price
2014		6,455		$243.75	–	$609.38
2015		94,151		0.00	–	243.75
2016		252,333			1.00
2017		1,082,946		1.07	-	2.25
2018		1,883,380		1.00	-	1.155
Total		3,319,265		$0.00	–	$609.38

Stock Options:
Year	Shares		Price
2011		173			281.25
2012		1,841		131.25	–	150.00
2013		1,553		148.13	–	596.25
2014		835		162.50	–	431.25
2015		4,088		65.75	–	86.25
2016		144,423		2.25	–	5.13
2017		2,612,070		1.01	–	2.10
Total		2,764,983	$	1.01	–	596.25

Warrants:
Year	Shares		Price
2013		10,705		93.75	–	371.25
2014		6,455		243.75	–	609.38
2015		94,152		0.00	–	243.75
2016		756,999			4.46
2017		1,082,946		1.07	–	2.25
Total		1,951,257	$	0.00	–	609.38