Quarterly report pursuant to Section 13 or 15(d)

Cash Equivalents and Investments (Schedule of Estimated Fair Value of Available-for-Sale Securities) (Details)

v3.20.2
Cash Equivalents and Investments (Schedule of Estimated Fair Value of Available-for-Sale Securities) (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Estimated Market Value $ 19,122 $ 18,461
Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Due within one year 5,264  
Amortized Cost, Due after one year through five years 6,676  
Amortized Cost 11,940  
Estimated Market Value, Due within one year 5,265  
Estimated Market Value, Due after one year through five years 6,668  
Estimated Market Value $ 11,933 $ 9,700