Note 8 - Basic and Diluted Loss Per Share (Details Textual) - shares
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Weighted Average Number Diluted Shares Outstanding Adjustment, Total (in shares) 0 0 0
Restricted Stock [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) 1,850,286 1,191,944 616,751
Share-based Payment Arrangement, Option [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) 273,414 32,591 629,866