Quarterly report pursuant to Section 13 or 15(d)

Summary of Marketable Securities (Details)

v3.21.2
Summary of Marketable Securities (Details) - USD ($)
$ in Thousands
Sep. 30, 2021
Dec. 31, 2020
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Available-for-sale Securities, Amortized Cost Basis $ 28,909 $ 46,019
Available-for-sale Securities, Gross Unrealized Gain 21 228
Available-for-sale Securities, Gross Unrealized Loss (23)
Available-for-sale Securities 28,907 46,247
U.S. Treasury Bonds [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 3,500 18,293
Available-for-sale Securities, Gross Unrealized Gain 5 136
Available-for-sale Securities, Gross Unrealized Loss
Available-for-sale Securities 3,505 18,429
U.S. Government Notes [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 16,010 22,148
Available-for-sale Securities, Gross Unrealized Gain 16 82
Available-for-sale Securities, Gross Unrealized Loss (16)
Available-for-sale Securities 16,010 22,230
Corporate Debt Securities [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 9,149 4,303
Available-for-sale Securities, Gross Unrealized Gain 3
Available-for-sale Securities, Gross Unrealized Loss (7)
Available-for-sale Securities 9,142 4,306
State and Municipal Bonds [Member]    
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 250 1,275
Available-for-sale Securities, Gross Unrealized Gain 7
Available-for-sale Securities, Gross Unrealized Loss
Available-for-sale Securities $ 250 $ 1,282