Note 10 - Stock Compensation Plans - Vesting of Non-vested RSU Grants (Details) - Restricted Stock Units (RSUs) [Member]	Sep. 30, 2020 shares
RSUs vesting (in shares)	447,000
Vesting in 2020 [Member]
RSUs vesting (in shares)	106,250
Vesting in 2021 [Member]
RSUs vesting (in shares)	306,750
Vesting in 2022 [Member]
RSUs vesting (in shares)	24,000
Vesting in 2023 [Member]
RSUs vesting (in shares)	10,000