Note 8 - Summary of Stock Options (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2015

Dec. 31, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Nine Months Ended September 30, 2015
						Weighted
				Weighted		Average		Aggregate
	Number			Average		Remaining		Intrinsic
	of			Exercise		Contractual		Value
	Shares			Price		Term (years)		(in thousands)
Options outstanding, beginning of period		2,291,783		$	1.02		9.32	$	-
Options granted		1,082,000		$	0.61
Options exercised		-		$	-
Options canceled		(21,000	)	$	1.00
Options outstanding, end of period		3,352,783		$	0.89		8.84	$	686,174
Vested and exercisable and expected to vest, end of period		3,122,622		$	0.91		8.81	$	634,288
Vested and exercisable, end of period		864,510		$	1.70		7.72	$	104,545

	Year Ended December 31,
	2014									2013
	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)		Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value (in thousands)
Options outstanding, beginning of year		363,413		$	1.24		8.80				360,531		$	1.24		9.74
Options granted		1,901,476		$	0.60						95,581		$	1.24
Options assumed from PLC		68,238		$	10.24						-		$	-
Options exercised		(160	)	$	0.12						-		$	-
Options canceled		(41,184	)	$	1.83						(92,699	)	$	1.24
Options outstanding, end of year		2,291,783		$	1.02		9.32	$	-		363,413		$	1.24		8.80	$	-
Vested and exercisable and expected to vest, end of year		2,099,687		$	1.06		9.29	$	-		348,865		$	1.24		8.80	$	-
Vested and exercisable, end of year		519,901		$	2.45		7.89	$	-		120,955		$	2.48		8.60	$	-

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

			Options Outstanding						Options Exercisable
							Weighted
			Number		Weighted		Average		Number		Weighted
			Outstanding		Average		Remaining		Exercisable		Average
Range of			as of		Exercise		Contractual		as of		Exercise
Exercise Prices			Sept 30, 2015		Price		Term (Years)		Sept 30, 2015		Price
	$0.33			100,000	$	0.33		9.62		-	$	-
$0.46	-	$0.47		635,000	$	0.47		9.36		-	$	-
	$0.60			1,881,476	$	0.60		9.00		475,203	$	0.60
$0.89	-	$0.99		347,000	$	0.96		9.85		-	$	-
	$1.24			312,373	$	1.24		7.15		312,373	$	1.24
$7.00	-	$9.00		57,603	$	8.64		2.08		57,603	$	8.64
$12.00	-	$18.63		19,081	$	15.29		2.57		19,081	$	15.29
	$37.00			250	$	37.00		1.98		250	$	37.00
				3,352,783	$	0.89		8.84		864,510	$	1.70

			Options Outstanding						Options Exercisable
							Weighted
			Number		Weighted		Average		Number		Weighted
			Outstanding		Average		Remaining		Exercisable		Average
Range of					Exercise		Contractual		as of		Exercise
Exercise Prices				December 31, 2014	Price		Term (Years)		December 31, 2014		Price
	$0.60			1,901,476	$	0.60		9.64		129,594	$	0.60
	$1.24			312,373	$	1.24		7.90		312,373	$	1.24
$7.00	-	$9.00		58,603	$	8.64		7.46		58,603	$	8.64
$12.00	-	$18.63		19,081	$	15.29		6.54		19,081	$	15.29
	$37.00			250	$	37.00		3.47		250	$	37.00
				2,291,783	$	1.02		9.32		519,901	$	2.45

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

	Three Months Ended					Nine Months Ended
	September 30,					September 30,
	2015			2014		2015			2014
Expected term (in years)		5			5		5			5
Average volatility	61%	-	62%		61%	61%	-	62%		61%
Risk-free interest rate	1.50%	-	1.69%		1.80%	1.29%	-	1.69%		1.80%
Dividend yield		0%			0%		0%			0%

	Year Ended
	Decenber 31,
	2014			2013
Expected term (in years)		5			5
Average volatility		61	%		68	%
Risk-free interest rate		1.80	%		0.84	%
Dividend yield		0	%		0	%

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
Research and development	$	5	$	-	$	13	$	1
Selling, general and administrative		50		113		132		143
Total	$	55	$	113	$	145	$	144

	Year Ended
	Year Ended December 31,
	2014		2013
Research and development	$	5	$	-
Selling, general and administrative		179		87
Total	$	184	$	87