XML 46 R35.htm IDEA: XBRL DOCUMENT v3.20.2
Note 2 - Inventory - Summary of Inventory (Details) - USD ($)
Jun. 30, 2020
Dec. 31, 2019
Furnace parts and supplies $ 834,710 $ 621,991
Raw materials 1,980,305 2,125,921
Work in process 2,124,366 1,624,499
Finished goods and filtration systems 1,084,111 1,492,135
Reserve for obsolescence (666,878) (665,308)
Net Inventory $ 5,356,614 $ 5,199,238