Annual report pursuant to Section 13 and 15(d)

Note 2 - Summary of Significant Accounting Policies (Details Textual)

v3.20.4
Note 2 - Summary of Significant Accounting Policies (Details Textual)
$ in Thousands
2 Months Ended 3 Months Ended 12 Months Ended
Nov. 29, 2019
USD ($)
Feb. 25, 2021
USD ($)
Dec. 31, 2020
USD ($)
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Impairment of Long-Lived Assets Held-for-use     $ 11,741 $ (0) $ (0) $ (0) $ 11,741 $ (0)
Proceeds from Insurance Settlement, Investing Activities             $ 9,838 2,500
Number of Operating Segments             1  
Number of Geographic Segments             1  
Accounts Receivable, after Allowance for Credit Loss, Current, Total     32       $ 32 $ 244
Cost of Goods and Service Benchmark [Member] | Supplier Concentration Risk [Member] | Chemicals [Member]                
Number of Major Suppliers             1  
Cost of Goods and Service Benchmark [Member] | Supplier Concentration Risk [Member] | Lead Acid Batteries [Member]                
Number of Major Suppliers             2  
Trade Accounts Receivable [Member]                
Accounts Receivable, after Allowance for Credit Loss, Current, Total     $ 0       $ 0  
AquaRefining Fire [Member]                
Property, Plant and Equipment, Net Write-off $ 19,900              
Proceeds from Insurance Settlement, Investing Activities             23,400  
AquaRefining Fire [Member] | Subsequent Event [Member]                
Proceeds from Insurance Settlement, Investing Activities   $ 100            
Construction in Progress Not Yet Capitalized [Member]                
Property, Plant and Equipment, Net Write-off             7,700  
Property, Plant and Equipment, Other Types [Member]                
Property, Plant and Equipment, Net Write-off             $ 4,000