Quarterly report pursuant to Section 13 or 15(d)

Schedule of Fair Value of Financial Instruments (Details)

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Schedule of Fair Value of Financial Instruments (Details) - USD ($)
Sep. 30, 2021
Dec. 31, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities $ 14,328,000 $ 1,639,000
Marketable equity securities 214,000
Fair Value, Inputs, Level 1 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 214,000
Marketable equity securities 214,000  
Fair Value, Inputs, Level 2 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 14,114,000 1,639,000
Marketable equity securities  
Fair Value, Inputs, Level 3 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities
Marketable equity securities  
U.S. Government Obligations [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 323,000 1,014,000
U.S. Government Obligations [Member] | Fair Value, Inputs, Level 1 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities
U.S. Government Obligations [Member] | Fair Value, Inputs, Level 2 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 323,000 1,014,000
U.S. Government Obligations [Member] | Fair Value, Inputs, Level 3 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities
Corporate Obligations [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 13,791,000 625,000
Corporate Obligations [Member] | Fair Value, Inputs, Level 1 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities
Corporate Obligations [Member] | Fair Value, Inputs, Level 2 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities 13,791,000 625,000
Corporate Obligations [Member] | Fair Value, Inputs, Level 3 [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Fair value of marketable debt securities