Note 13 - Summary of Stock Options (Details Textual) - USD ($)		1 Months Ended			3 Months Ended				12 Months Ended
	Aug. 22, 2016	Jan. 31, 2021	Jan. 31, 2020	Aug. 31, 2017	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2021	May 31, 2021	Sep. 30, 2020	Jan. 01, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)					3,173,103				3,173,103	986,399
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)					$ 7.51				$ 7.51	$ 19.10
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)									9 years	8 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)									2,251,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)									(0)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate									0.00%	0.00%
Restricted Stock Units (RSUs) [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total					$ 1,151,000				$ 1,151,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)									1 year 1 month 6 days
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate									0.00%
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total					$ 5,831,000				$ 5,831,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)									2 years 9 months 18 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)									1 year 1 month 6 days
The 2013 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)					3,173,091				3,173,091
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)					94,392				94,392
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)					$ 7.48				$ 7.48
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)									9 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)									10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)									4 years
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum									10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent									110.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized, Percentage Increase of Outstanding Common Stock	4.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)		307,705	263,993
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)		1,758,951			3,940,136				3,940,136	1,451,246	3,940,136			1,451,246
The 2013 Plan [Member] | Employees and Nonemployees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)									2,251,000	146,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)									$ 1.75	$ 4.08
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)									0	0
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)					674,000				674,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)									0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)									16,000
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, Nonvested, Number, Ending Balance (in shares)					228				228
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	18
The 2013 Plan [Member] | Holdings Greater Than 10 Percent of Shares Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)									5 years
2017 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent				85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee (in shares)				200
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)					17,286	10,844	30	32
Shares Issued, Price Per Share (in dollars per share)					$ 0.97	$ 1.94	$ 4.79	$ 5.86	$ 0.97				$ 4.44
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares (in shares)					471,870				471,870				22
Common Stock, Capital Shares Reserved for Future Issuance (in shares)											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