XML 48 R36.htm IDEA: XBRL DOCUMENT v3.22.1
Note 1 - Significant Accounting Policies - Summary of Allowance for Doubtful Accounts (Details) - USD ($)
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Balance $ 7,000 $ 8,000
Additions charged to expense 0 0
Recovery of amounts previously reserved 0 0
Amounts written off 0 1,000
Balance at end of year $ 7,000 $ 7,000