Note 12 - Summary of Stock Options (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

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

	Nine Months Ended September 30, 2020
						Weighted
				Weighted		Average
	Number			Average		Remaining		Aggregate
	of			Exercise		Contractual		Intrinsic
	Shares			Price		Term (years)		Value
Options outstanding, beginning of period		10,087,678		$	2.22		9.9	$	3,928,715
Options granted		1,018,000		$	0.70
Options exercised		-
Options canceled		(1,350,224	)	$	3.01
Options outstanding, end of period		9,755,454		$	1.96		9.1	$	-
Vested and exercisable and expected to vest, end of period		9,047,744		$	2.03		9.1	$	-
Vested and exercisable, end of period		1,969,073		$	5.19		8.7	$	-

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, 2020		Price		Term (Years)		September 30, 2020		Price
$0.52	-	$0.89		9,563,606	$	0.85		9.1		1,918,010	$	0.87
$1.09	-	$1.36		155,000	$	1.26		9.4		25,000	$	1.36
$38.00	-	$58.00		1,250	$	55.20		8.7		1,115	$	56.99
$100.00	-	$197.00		19,996	$	142.17		8.0		11,956	$	144.84
$202.00	-	$283.00		725	$	250.69		7.3		451	$	253.26
$311.00	-	$358.00		1,875	$	343.99		7.9		1,505	$	346.28
$430.00	-	$497.00		6,443	$	454.44		6.4		4,935	$	455.06
$501.00	-	$567.00		3,139	$	537.25		6.2		2,777	$	536.54
$600.00	-	$661.00		1,379	$	601.64		5.1		1,379	$	601.64
$700.00	-	$792.00		1,937	$	767.72		6.1		1,841	$	767.15
$992.00	-	$992.00		104	$	992.00		2.3		104	$	992.00
Total:				9,755,454	$	1.96		9.1		1,969,073	$	5.19

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Expected term (in years)		5		N/A		5		5
Average volatility		87%		N/A		81%		73%
Risk-free interest rate		0.27%		N/A		0.34%		2.49%
Dividend yield		-		N/A		-		-

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Cost of revenue	$	42	$	25	$	163	$	91
Research and development		78		41		250		134
Selling, general and administrative		522		452		1,596		1,409
Total	$	642	$	518	$	2,009	$	1,634

2017 Employee Stock Purchase Plan [Member]

Notes Tables

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

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Expected term (in years)		0.25		0.25		0.25		0.25
Average volatility		76%		98%		106%		84%
Risk-free interest rate		0.14%		2.21%		0.66%		2.40%
Dividend yield		0%		0%		0%		0%