Note 9 - Summary of Stock Options (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

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

	Year Ended December 31, 2015									Year Ended December 31, 2014
	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 period		286,501		$	8.16		9.32	$	-		45,427		$	9.92		8.80
Options granted		753,880		$	5.80						237,687		$	4.80
Options assumed from PLC		-		$	-						8,530		$	81.92
Options exercised		-		$	-						(20	)	$	0.96
Options canceled		(18,186	)	$	5.10						(5,123	)	$	14.64
Options outstanding, end of period		1,022,195		$	6.47		9.37	$	1,194,180		286,501		$	8.16		9.15	$	-
Vested and exercisable and expected to vest, end of period		927,286		$	6.54		9.33	$	1,094,069		262,490		$	8.47		9.10	$	-
Vested and exercisable, end of period		121,886		$	12.63		7.20	$	143,458		65,020		$	19.61		7.13	$	-

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

					Options Outstanding				Options Exercisable
Range of Exercise Prices			Number Outstanding as of December 31, 2015		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)		Number Exercisable as of December 31, 2015		Weighted Average Exercise Price
$2.64	-	$4.80		313,002	$	4.45		8.72		73,197	$	4.80
$6.00	-	$9.92		699,554	$	6.32		9.76		39,050	$	9.92
$56.00	-	$96.00		7,393	$	69.76		1.59		7,393	$	69.76
$104.00	-	$296.00		2,246	$	126.98		1.57		2,246	$	126.98
				1,022,195	$	6.47		9.37		121,886	$	12.63

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

	Year Ended December 31,
	2015			2014
Expected term (in years)		5			5
Average volatility		63	%		61	%
Risk-free interest rate		1.70	%		1.80	%
Dividend yield		0	%		0	%

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

	Year Ended December 31,
	2015		2014
Research and development	$	18	$	5
Selling, general and administrative		202		179
Total	$	220	$	184