Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.2
Cash Equivalents and Investments (Schedule of Cash Equivalents and Available-for-Sale Securities) (Details) - USD ($)
Sep. 30, 2020
Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 19,129,000 $ 18,462,000
Gross Unrealized Gains 2,000
Gross Unrealized Losses (9,000) (1,000)
Fair Value 19,122,000 18,461,000
Cash Equivalents 7,189,000 8,761,000
Short-Term Investments 5,264,774 9,449,650
Long-Term Investments 6,668,000 250,000
Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,189,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 7,189,000 8,761,000
Cash Equivalents 7,189,000 8,761,000
Short-Term Investments
Long-Term Investments
Cash Equivalents [Member] | Money Market Funds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,189,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 7,189,000 8,761,000
Cash Equivalents 7,189,000 8,761,000
Short-Term Investments
Long-Term Investments
Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 11,940,000 9,701,000
Gross Unrealized Gains 2,000
Gross Unrealized Losses (9,000) (1,000)
Fair Value 11,933,000 9,700,000
Cash Equivalents
Short-Term Investments 5,265,000 9,450,000
Long-Term Investments 6,668,000 250,000
Investments [Member] | Commercial Paper [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 3,898,000 8,695,000
Gross Unrealized Gains 2,000
Gross Unrealized Losses (1,000)
Fair Value 3,900,000 8,694,000
Cash Equivalents
Short-Term Investments 3,900,000 8,694,000
Long-Term Investments
Investments [Member] | Corporate Notes/Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,687,000 756,000
Gross Unrealized Gains
Gross Unrealized Losses (9,000)
Fair Value 7,678,000 756,000
Cash Equivalents
Short-Term Investments 1,365,000 756,000
Long-Term Investments 6,313,000
Investments [Member] | Convertible Debt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 355,000 250,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 355,000 250,000
Cash Equivalents
Short-Term Investments
Long-Term Investments $ 355,000 $ 250,000