Note 2 - Significant Accounting Policies - Tax Returns Subject to Examination (Details)
12 Months Ended
Mar. 31, 2022
Domestic Tax Authority [Member]  
Open tax year 2019 2020 2021 2022
State and Local Jurisdiction [Member] | New Jersey Division of Taxation [Member]  
Open tax year 2018 2019 2020 2021 2022