Note 11 - Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

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

	Three Months Ended September 30,					Nine Months Ended September 30,
	2021			2020		2021		2020
Equity Classified Awards
Stock options
Research and development	$	188		$	—	$	188	$	—
Selling, general and administrative		598			—		598		—
Restricted stock
Research and development		273			142		519		353
Selling, general and administrative		821			500		1,995		1,122
Total equity classified awards		1,880			642		3,300		1,475
Liability Classified Awards
Restricted stock
Selling, general and administrative		2,368			—		2,368		—
Stock appreciation rights
Research and development		(40	)		16		149		(61	)
Selling, general and administrative		(2	)		16		6		(67	)
Total liability classified awards		2,326			32		2,523		(128	)
Total stock-based compensation	$	4,206		$	674	$	5,823	$	1,347

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

					Weighted-
					Average
			Weighted-		Remaining
			Average		Contractual	Aggregate
	Number of		Exercise		Term	Intrinsic
	Options		Price (1)		(years)	Value
Options outstanding at December 31, 2020	1,552		$	556.13	5.6	$	—
Granted	4,670,324		$	4.98
Canceled or forfeited	(1,597	)	$	130.67
Exercised	—		$	—
Options outstanding at September 30, 2021	4,670,279		$	5.12	9.9	$	7,750,148
Options exercisable at September 30, 2021	1,515		$	431.34	4.9	$	—
Options vested and expected to vest at September 30, 2021	4,435,359		$	5.12	9.9	$	7,360,181

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

Period Ended	Total Stock Options Granted	Weighted-Average Exercise Price		Weighted-Average Expected Term	Weighted Average Volatility	Weighted-Average Risk-Free Interest Rate	Expected Dividends		Weighted-Average Grant Date Fair Value
September 30, 2021	4,670,324	$	4.98	5.75 years	144%	0.87%	$	0	$	4.57

Schedule of Nonvested Share Activity [Table Text Block]

			Weighted-
			Average
	Number of		Grant-Date
	Shares		Fair Value
Non-vested at December 31, 2020	4,701,556		$	0.79
Granted	4,807,378		$	5.08
Vested	(2,585,547	)	$	0.99
Canceled or forfeited	(129,149	)	$	0.84
Non-vested at September 30, 2021	6,794,238		$	3.75