Note 11 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

Stock Options	Number Outstanding			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at January 1, 201 6		154,581		$	80.44
Granted		60,449		$	18.08
Canceled or expired		(3,817	)	$	135.95
Outstanding at December 31, 201 6		211,213		$	61.59
Granted		535,964		$	2.69
Canceled or expired		(43,735	)	$	164.12
Outstanding at December 31, 2017		703,442		$	10.34		8.9	$	-
Exercisable at December 31, 201 7		405,075		$	14.97		8.6	$	-

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

Restricted Stock	Number Outstanding			Weighted Average Grant Da te Fair Value
Non-vested stock awards outstanding at January 1, 201 6		5,822		$	36.96
Granted		8,000		$	22.82
Vested and issued		(9,037	)	$	24.08
Non-vested stock awards outstanding at December 31, 2016		4,785		$	37.42
Vested and issued		(3,357	)	$	42.20
Forfeited		(1,428	)	$	26.18
Non-vested stock awards outstanding at December 31, 2017		-		$	-

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		Weighted Average Remaining Contractual Term (in years)		Weighted Average Exercise Price		Number		Weighted Average Remaining Contractual Term (in years)		Weighted Average Exercise Price
Up to		$5.00		535,964		9.4	$	2.69		256,720		9.4	$	2.69
5.00	to	35.00		105,674		7.9	$	24.64		88,153		7.9	$	25.12
Above $ 35.00				61,804		6.2	$	52.23		60,202		6.2	$	52.32
				703,442						405,075

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

	Year Ended December 31,
	201 7					2016
Risk-free interest rate		2.21	to	2.32	%		1.55	to	1.87	%
Expected volatility		90.4	-	100.8	%		87.5	-	89.1	%
Expected life (in years)			10					10
Expected forfeiture rate			0		%			5		%
Expected dividend yield			0.0		%			0.0		%