Annual report pursuant to Section 13 and 15(d)

Note 9 - Asset Retirement Obligation (Details Textual)

v3.20.4
Note 9 - Asset Retirement Obligation (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Mar. 31, 2017
Asset Retirement Obligations, Noncurrent, Total $ 0 $ 790,000 $ 700,000
Asset Retirement Obligation, Accretion Expense $ 45,000 $ 46,000