Annual report pursuant to Section 13 and 15(d)

Note 14 - Stockholders' Equity (Details Textual)

Note 14 - Stockholders' Equity (Details Textual)	1 Months Ended											3 Months Ended				12 Months Ended
Note 14 - Stockholders' Equity (Details Textual)	Aug. 31, 2023 USD ($) $ / shares shares	Jul. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Oct. 31, 2022 USD ($) shares	Aug. 31, 2022 USD ($) shares	Jul. 31, 2022 USD ($) shares	Jun. 30, 2022 USD ($) shares	May 31, 2022 USD ($) shares	Apr. 30, 2022 USD ($) shares	Feb. 28, 2022 USD ($) shares	Jan. 31, 2022 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Jun. 30, 2023 USD ($) shares	Mar. 31, 2023 USD ($) shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2019 shares	Dec. 31, 2017 shares	Dec. 31, 2021 shares
Common Stock, Shares Authorized (in shares)			200,000,000									200,000,000				200,000,000	200,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares			$ 0.001									$ 0.001				$ 0.001	$ 0.001
Proceeds from Issuance of Common Stock \| $																$ 3,786,000	$ 6,519,000
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation (in shares)																939,198
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation \| $																$ 1,091,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)																192,707
Stock Issued During Period, Shares, Issued for Class Action Settlement (in shares)																469,366
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)			994,267														994,267			1,026,712
The 2014 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)																			2,127,306
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)																			3 years
The 2014 Stock Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																			10 years
The 2019 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)																		18,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)																		3 years
The 2019 Stock Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																		10 years
Public Offering Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		363,860
Sale of Stock, Warrants, Commission Percent		2.00%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares		$ 1.375
Warrants and Rights Outstanding, Term (Year)		5 years
Warrants and Rights Outstanding \| $		$ 388,000
Public Offering Warrant [Member] \| Measurement Input, Share Price [Member]
Warrants and Rights Outstanding, Measurement Input		1.54
Public Offering Warrant [Member] \| Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input		0.819
Public Offering Warrant [Member] \| Measurement Input, Discount Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0.0381
Public Offering Warrant [Member] \| Measurement Input, Expected Dividend Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0
Yulho SPA Underwriter Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	205,761
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) \| $ / shares	$ 1.25
Warrants and Rights Outstanding, Term (Year)	5 years
Warrants and Rights Outstanding \| $	$ 181,000
Yulho SPA Underwriter Warrant [Member] \| Measurement Input, Share Price [Member]
Warrants and Rights Outstanding, Measurement Input	1.27
Yulho SPA Underwriter Warrant [Member] \| Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input	0.823
Yulho SPA Underwriter Warrant [Member] \| Measurement Input, Discount Rate [Member]
Warrants and Rights Outstanding, Measurement Input	0.0381
Yulho SPA Underwriter Warrant [Member] \| Measurement Input, Expected Dividend Rate [Member]
Warrants and Rights Outstanding, Measurement Input	0
ATM [Member]
Stock Issued During Period, Shares, New Issues (in shares)																3,244,302
Proceeds from Issuance of Common Stock \| $																$ 3.8
July 2023 Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)																18,193,000
Proceeds from Issuance of Common Stock \| $		$ 18,300,000
Yulho Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)	4,545,455
Proceeds from Issuance of Common Stock \| $	$ 4,600,000
Options Granted in Reliance on Nasdaq Rule 5635(c)(4) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)												47				47
Stock Options and Restricted Stock Units [Member]
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount \| $												$ 6,100,000				$ 6,100,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognitio (Year)																2 years 4 months 24 days
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)							3 years		3 years	3 years	3 years	3 years	3 years	12 months	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				28,223	10,537	143,708	12,121	182,293	9,615	47,933	44,780	4,007,972	136,254	204,547	64,149	5,110,852	3,691,202
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $				$ 21,308	$ 10,000	$ 120,000	$ 10,000	$ 175,000	$ 10,000	$ 50,000	$ 50,000	$ 3,422,275	$ 155,000	$ 225,000	$ 70,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period, Number of Installments												6	3	4	3
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested \| $																$ 3,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding \| $												$ 6,600,000				$ 6,600,000
Restricted Stock Units (RSUs) [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)			3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			27,739
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $			$ 20,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period, Number of Installments			3
Restricted Stock Units (RSUs) [Member] \| Share-Based Payment Arrangement, Tranche Two [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)																	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)			3,184,253
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $			$ 2,368,682
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period, Number of Installments																	6
Restricted Stock Units (RSUs) [Member] \| Additional RSU's Vesting in Three Years [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)												3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)												52,632
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $												$ 41,513
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period, Number of Installments												3
Restricted Stock Units (RSUs) [Member] \| RSU's Vesting in Six Months [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)												65,789
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value \| $												$ 51,891
Stock Price Hurdle RSU's [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)												3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)												3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)												475,282				475,282
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)												475,282
Management and Employees [Member]
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)																1,462,814	2,150,467
Management and Employees [Member] \| Reissued Treasury Stock [Member]
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)																510,632
Board Members [Member]
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)																170,692	125,264
Director [Member]
Stock Issued During Period, Shares, Issued for Services (in shares)																104,227	28,223
Former Board Member [Member]
Stock Issued During Period, Shares, Issued for Services (in shares)																15,781	19,176
ATM [Member]
Stock Issued During Period, Shares, New Issues (in shares)																	6,742,069
Proceeds from Issuance of Common Stock \| $																	$ 6,500,000