Quarterly report [Sections 13 or 15(d)]

Note 11 - Stockholders' Equity (Details Textual)

v3.26.1
Note 11 - Stockholders' Equity (Details Textual)
 3 Months Ended 6 Months Ended 12 Months Ended
Jul. 22, 2025
shares
May 15, 2025
USD ($)
shares
Jun. 30, 2026
USD ($)
shares
Mar. 31, 2026
USD ($)
shares
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
shares
Jun. 30, 2025
USD ($)
shares
Dec. 31, 2019
shares
Dec. 31, 2025
USD ($)
Oct. 16, 2025
USD ($)
Aug. 22, 2024
USD ($)
Share-Based Payment Arrangement, Expense | $     $ 325,000   $ 345,000 $ 775,000 $ 1,047,000        
Lincoln Park Capital Fund, LLC [Member]                      
Stock Issued During Period, Shares, New Issues (in shares)             22,717        
The 2026 ESPP [Member]                      
Stock Issued During Period, Shares, New Issues (in shares)           131,569          
Proceeds from Issuance of Common Stock | $           $ 621,000          
The 2019 Stock Incentive Plan [Member]                      
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) 400,000             140,000      
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares) 260,000                    
The 2019 Stock Incentive Plan [Member] | Maximum [Member]                      
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)               10 years      
Restricted Stock Units (RSUs) [Member]                      
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)     7,934 53,385              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Fair Value | $     $ 36,000 $ 296,000              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period, Number of Installments     3 6              
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)     3 years 3 years              
Performance Stock Units (PSUs) [Member]                      
Share-Based Payment Arrangement, Expense | $       $ 121,000              
Management and Employees [Member]                      
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)           41,619 5,835        
Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation (in shares)           17,269 2,648        
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation | $           $ 78,000 $ 67,000        
Management and Employees [Member] | Reissued Treasury Stock [Member]                      
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)           18,449 2,942        
Director [Member]                      
Stock Issued During Period, Shares, Restricted Stock Award, Gross (in shares)           8,695 671        
Stock Issued During Period, Shares, Issued for Services (in shares)             4,568        
ATM [Member]                      
Equity Offering, Maximum Amount | $                 $ 50,000,000 $ 30,000,000 $ 30,000,000
Equity Offering, Compensation From Gross Proceeds, Percent                     2.50%
Stock Issued During Period, Shares, New Issues (in shares)           379,772 211,474        
Proceeds from Issuance of Common Stock | $           $ 1,876,000 $ 2,735,000        
Equity Offering, Remaining Availability | $     $ 48,050,000     48,050,000          
ELOC [Member]                      
Equity Offering, Maximum Amount | $   $ 10,000,000                  
Stock Issued During Period, Shares, New Issues (in shares)             12,000        
Proceeds from Issuance of Common Stock | $           $ 0 $ 69,000        
Equity Offering, Period (Month)   24 months                  
Equity Offering, Maximum Shares (in shares)   177,283