Annual report pursuant to Section 13 and 15(d)

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

v3.21.1
Cash Equivalents and Investments (Schedule of Cash Equivalents and Available-for-Sale Securities) (Details) - USD ($)
Dec. 31, 2020
Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 18,387,000 $ 18,462,000
Gross Unrealized Gains 7,000
Gross Unrealized Losses (1,000) (1,000)
Fair Value 18,393,000 18,461,000
Cash Equivalents 9,424,000 8,761,000
Short-Term Investments 2,759,024 9,449,650
Long-Term Investments 6,210,000 250,000
Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 9,424,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 9,424,000 8,761,000
Cash Equivalents 9,424,000 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 9,424,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 9,424,000 8,761,000
Cash Equivalents 9,424,000 8,761,000
Short-Term Investments
Long-Term Investments
Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 8,963,000 9,701,000
Gross Unrealized Gains 7,000
Gross Unrealized Losses (1,000) (1,000)
Fair Value 8,969,000 9,700,000
Cash Equivalents
Short-Term Investments 2,759,000 9,450,000
Long-Term Investments 6,210,000 250,000
Investments [Member] | Commercial Paper [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 700,000 8,695,000
Gross Unrealized Gains
Gross Unrealized Losses (1,000)
Fair Value 700,000 8,694,000
Cash Equivalents
Short-Term Investments 700,000 8,694,000
Long-Term Investments
Investments [Member] | Corporate Notes/Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,658,000 756,000
Gross Unrealized Gains 7,000
Gross Unrealized Losses (1,000)
Fair Value 7,664,000 756,000
Cash Equivalents
Short-Term Investments 2,059,000 756,000
Long-Term Investments 5,605,000
Investments [Member] | Convertible Debt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 605,000 250,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 605,000 250,000
Cash Equivalents
Short-Term Investments
Long-Term Investments $ 605,000 $ 250,000