Note 12 - Summary of Stock Options (Details Textual) - USD ($) $ / shares in Units, Pure in Thousands		1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
	Jan. 01, 2022	Jan. 31, 2021	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	May 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			4,105,706				4,105,706		3,173,103
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)			$ 6.05				$ 6.05		$ 7.51
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)							8 years 6 months		9 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)							959,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate			0.00%			0.00%	0.00%	0.00%
Employees and Nonemployees [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)			4,000			30,400	959,000	2,251,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)			$ 0.43			$ 1.60	$ 0.92	$ 1.75
Restricted Stock Units (RSUs) [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 327,000				$ 327,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)							3 months 18 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)							2 years
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate							0.00%
Dividend, Share-Based Payment Arrangement, Total							$ 0
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total			$ 4,755,788				$ 4,755,788
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)							2 years 4 months 24 days
The 2006 Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			12				12
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)			0				0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)			$ 9,920.00				$ 9,920.00
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)							3 months 18 days
The 2013 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)			4,105,694				4,105,694
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)			244,624				244,624
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)			$ 6.02				$ 6.02
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)							8 years 6 months
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)	1,076,833
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	5,016,969								3,940,136
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			668,000				668,000
The 2013 Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)			226				226
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			0				0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)			6,000			5,000	6,000	11,000
The 2013 Plan [Member] | Restricted Stock Units (RSUs) [Member] | Employees and Board Members [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		690,000
The 2013 Plan [Member] | Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			0			0	0	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)			2			4	2	6
2017 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)			392,859				392,859
Common Stock, Capital Shares Reserved for Future Issuance (in shares)						500,378		500,378		400
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant During Offering Period (in shares)						2,000		2,000		2
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)			33,815	24,505	20,691	10,844
Shares Issued, Price Per Share (in dollars per share)			$ 0.54	$ 0.56	$ 0.90	$ 1.94	$ 0.54	$ 1.94