Note 12 - Summary of Stock Options (Tables)

6 Months Ended

Jun. 30, 2021

Notes Tables

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

	Six Months Ended June 30, 2021
						Weighted
				Weighted		Average
	Number			Average		Remaining		Aggregate
	of			Exercise		Contractual		Intrinsic
	Shares			Price		Term (years)		Value
Options outstanding, beginning of period		986,399		$	19.10		8.9	$	675
Options granted		2,220,600		$	2.73
Options exercised		-
Options canceled		(18,371	)	$	46.78
Options outstanding, end of period		3,188,628		$	7.54		9.5	$	502,298
Vested and exercisable and expected to vest, end of period		2,888,549		$	7.95		9.5	$	444,100
Vested and exercisable, end of period		348,326		$	34.42		8.3	$	-

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

							Weighted
			Number		Weighted		Average		Number		Weighted
			Outstanding		Average		Remaining		Exercisable		Average
Range of			as of		Exercise		Contractual		as of		Exercise
Exercise Prices			June 30, 2021		Price		Term (Years)		June 30, 2021		Price
$2.73	-	$3.40		2,220,600	$	2.73		10.0		-	$	-
$4.45	-	$6.90		105,300	$	5.30		9.3		2,501	$	6.22
$8.60	-	$8.91		843,788	$	8.69		8.4		334,782	$	8.69
$10.90	-	$13.60		15,500	$	12.64		8.7		8,084	$	12.99
$380.00	-	$580.00		125	$	552.00		7.9		116	$	563.62
$1,000.00	-	$1,970.00		1,882	$	1,433.60		7.4		1,509	$	1,433.29
$2,020.00	-	$2,830.00		66	$	2,559.55		6.4		55	$	2,567.27
$3,110.00	-	$3,580.00		189	$	3,439.26		7.1		159	$	3,449.62
$4,360.00	-	$4,970.00		595	$	4,552.59		5.9		541	$	4,555.21
$5,010.00	-	$5,670.00		294	$	5,373.27		5.8		290	$	5,370.52
$6,000.00	-	$6,000.00		138	$	6,000.00		4.5		138	$	6,000.00
$7,140.00	-	$7,920.00		139	$	7,722.73		5.4		139	$	7,722.73
$9,920.00	-	$9,920.00		12	$	9,920.00		1.6		12	$	9,920.00
Total:				3,188,628	$	7.54		9.5		348,326	$	34.42

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

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2021			2020		2021			2020
Expected term (in years)		6			N/A		6			5
Average volatility		83	%		N/A		83	%		73	%
Risk-free interest rate		0.98	%		N/A		0.98	%		0.45	%
Dividend yield		0	%		N/A		0	%		0	%

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Cost of revenue	$	60	$	61	$	115	$	121
Research and development		102		85		200		171
Selling, general and administrative		705		511		1,362		1,075
Total	$	867	$	657	$	1,677	$	1,367