XML 49 R36.htm IDEA: XBRL DOCUMENT v3.23.1
Note 6 - Equity (Details Textual)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
May 31, 2022
shares
Jun. 30, 2021
USD ($)
$ / shares
shares
Feb. 28, 2021
USD ($)
$ / shares
shares
Jan. 31, 2021
USD ($)
shares
Dec. 31, 2022
USD ($)
$ / shares
shares
Dec. 31, 2021
USD ($)
shares
Oct. 04, 2018
USD ($)
Preferred Stock, Shares Issued, Total (in shares) | shares         0 0  
Proceeds from Issuance of Common Stock | $         $ 0 $ 74,684  
Share Based Compensation Arrangement by Share Based Payment Award, Options, Grants in Period, Aggregate Fair Value | $         1,100 $ 1,700  
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $         $ 1,500    
The 2015 Stock Plan [Member]              
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) | shares 2,000,000            
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares) | shares 3,750,001       752,296    
Share-Based Payment Arrangement, Option [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)         10 years    
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $         $ 2,500    
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)         2 years 4 months 24 days    
Share-Based Payment Arrangement, Option [Member] | Employees [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         4 years    
Share-Based Payment Arrangement, Option [Member] | Director [Member] | Minimum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         1 year    
Share-Based Payment Arrangement, Option [Member] | Director [Member] | Maximum [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         3 years    
Restricted Stock Units (RSUs) [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)         4 years    
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | $         $ 1,100    
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)         2 years 9 months 18 days    
Share Based Compensation Arrangement by Share Based Payment Award, Number of Installment Periods   4     4    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) | shares   150,000     452,334    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares   $ 3.73     $ 1.49    
The 2021 ATM Agreement [Member]              
Stock Issued During Period, Shares, New Issues (in shares) | shares         0 0  
At Market Issuance Sales Agreement, Maximum Aggregate Offering Price | $   $ 50,000          
Underwritten Public Offering [Member]              
Stock Issued During Period, Shares, New Issues (in shares) | shares     14,273,684        
Shares Issued, Price Per Share (in dollars per share) | $ / shares     $ 4.75        
Proceeds from Issuance of Common Stock | $     $ 78,000        
Over-Allotment Option [Member]              
Stock Issued During Period, Shares, New Issues (in shares) | shares     2,141,052        
Lincoln Park Transaction [Member]              
Purchase Agreement, Common Stock, Maximum Aggregate Commitment | $             $ 20,000
Stock Issued During Period, Shares, Commitment Consideration (in shares) | shares   107,788          
Purchase Agreement, Maximum Aggregate Commitment, Number of Additional Shares Issued (in shares) | shares   53,893          
Stock Issued During Period, Value, Additional Commitment Shares | $   $ 400          
The 2020 ATM Agreement [Member]              
Stock Issued During Period, Shares, New Issues (in shares) | shares       468,684      
Proceeds from Issuance of Common Stock | $       $ 2,900