Note 11 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Share-based Payment Arrangement, Cost by Plan [Table Text Block]

	Year Ended December 31,
	201 9		201 8
Stock options and ESPP awards
Research and development	$	—	$	21
Selling, general and administrative		—		48
Restricted stock awards
Research and development		228		85
Selling, general and administrative		993		417
Stock appreciation rights
Research and Development		66		61
Selling, general and administrative		62		51
Total stock-based compensation	$	1,349	$	683

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

						Weighted-
						Average
				Weighted-		Remaining
				Average		Contractual		Aggregate
	Number of			Exercise		Term		Intrinsic
	Options			Price		(years)		Value
Options outstanding at December 31, 2018		2,313		$	2,358.44		6.87	$	—
Granted		—		$	—
Canceled or forfeited		(752	)	$	5,151.80
Exercised		—		$	—
Options outstanding at December 31, 2019		1,561		$	928.79		6.56	$	—
Options exercisable at December 31, 2019		1,511		$	1,043.47		6.53	$	—
Options vested and expected to vest at December 31, 2019		1,561		$	928.79		6.56	$	—

Schedule of Nonvested Share Activity [Table Text Block]

				Weighted-
				Average
	Number of			Grant-Date
	Shares			Fair Value
Non-vested at December 31, 2018		290,300		$	3.45
Granted		1,308,613		$	1.91
Vested		(254,500	)	$	3.45
Canceled or forfeited		(35,800	)	$	3.45
Non-vested at December 31, 2019		1,308,613		$	1.91

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

	December 31, 2018			Grant Date(1)
Risk-free interest rate		2.54	%		2.84	%
Expected dividend yield		—			—
Expected volatility factor		134.17	%		125.03	%
Expected option life (in years)		5.75			5.75
Weighted average value	$	1.65		$	4.53