Note 12 - Summary of Stock Options (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

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

	Number			Average		Remaining		Aggregate
	of			Exercise		Contractual		Intrinsic
	Shares			Price		Term (years)		Value
Options outstanding, beginning of period		986,399		$	19.10		-	$	-
Options granted		2,251,000		$	2.73
Options exercised		-
Options canceled		(41,657	)	$	23.35
Options outstanding, end of period		3,195,742		$	7.52		9.3	$	-
Vested and exercisable and expected to vest, end of period		2,932,744		$	7.88		9.3	$	-
Vested and exercisable, end of period		581,757		$	23.17		8.5	$	-

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			September 30, 2021		Price		Term (Years)		September 30, 2021		Price
$2.28	-	$2.96		2,224,354	$	2.73		9.7		130,533	$	2.73
$3.06	-	$3.40		10,000	$	3.20		9.5		-	$	-
$4.45	-	$4.80		11,900	$	4.72		9.2		1,219	$	4.80
$5.10	-	$5.40		88,000	$	5.28		9.0		50,875	$	5.40
$6.90	-	$6.90		5,400	$	6.90		8.5		2,026	$	6.90
$8.60	-	$8.91		837,150	$	8.69		8.1		384,272	$	8.69
$10.90	-	$13.60		15,500	$	12.64		8.4		9,678	$	12.99
$380.00	-	$9,920.00		3,438	$	2,876.47		6.5		3,154	$	2,968.91
Total:				3,195,742	$	7.52		9.3		581,757	$	23.17

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

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2021			2020			2021			2020
Expected term (in years)		5			5			6			5
Average volatility		84	%		87	%		76	%		81	%
Risk-free interest rate		0.81	%		0.27	%		0.97	%		0.34	%
Dividend yield		0	%		0	%		0	%		0	%

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2021		2020		2021		2020
Cost of revenue	$	76	$	42	$	191	$	163
Research and development		131		78		330		250
Selling, general and administrative		881		522		2,244		1,596
Total	$	1,088	$	642	$	2,765	$	2,009