Note 10 - Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	Year Ended December 31,
	2019					2018
	Number of Shares			Weighted- Average Exercise Price Per Share		Number of Shares			Weighted- Average Exercise Price Per Share
Beginning balance		1,726,522		$	29.88		482,873		$	93.70
Warrants granted		444,445		$	0.10		1,512,816		$	4.20
Warrants exercised		(435,264	)	$	0.35		(269,167	)	$	0.10
Warrants expired/canceled		(19,637	)				--
Outstanding		1,716,066		$	25.23		1,726,522		$	29.88
Exercisable		1,646,214		$	22.91		1,656,668		$	27.80

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Year Ended December 31,
	2019		2018
Cost of revenues	$	3,000	$	15,000
Sales and marketing		185,000		63,000
Research and development		98,000		136,000
General and administrative		328,000		438,000
	$	614,000	$	652,000

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

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life		Aggregate Intrinsic Value
Outstanding at January 1, 2019		302,368		$	13.99
Granted		11,450		$	4.38
Forfeited/cancelled		(22,011	)	$	9.42
Outstanding at December 31, 2019		291,807		$	13.96		8.3	$	280,000
Vested and Expected to Vest at December 31, 2019		224,102		$	15.72		8.2	$	203,000
Exercisable at December 31, 2019		147,124		$	19.79		7.9	$	115,000

Non Vested Stock Options Activity [Table Text Block]

	Non-vested Stock Options			Weighted-Average Grant Date Fair Value
Outstanding at January 1, 2019		212,172			$6.39
Granted		11,450			$3.30
Vested		(63,675	)		$6.73
Cancelled/forfeited		(15,264	)		$2.74
Outstanding at December 31, 2019		144,683			$6.38

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31,
	2019			2018
Expected life (years)		5			6
Risk-free interest rate		1.68	%		2.7	%
Expected volatility		103	%		103	%
Dividend yield		0	%		0	%