Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Cash Equivalents and Investments (Schedule of Cash Equivalents and Available-for-Sale Securities) (Details) - USD ($)
Mar. 31, 2020
Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 28,584,000 $ 18,462,000
Gross Unrealized Gains 1,000
Gross Unrealized Losses (17,000) (1,000)
Fair Value 28,568,000 18,461,000
Cash Equivalents 16,913,000 8,761,000
Short-Term Investments 11,299,604 9,449,650
Long-Term Investments 355,000 250,000
Cash Equivalents [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 16,913,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 16,913,000 8,761,000
Cash Equivalents 16,913,000 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 16,913,000 8,761,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 16,913,000 8,761,000
Cash Equivalents 16,913,000 8,761,000
Short-Term Investments
Long-Term Investments
Investments [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 11,671,000 9,701,000
Gross Unrealized Gains 1,000
Gross Unrealized Losses (17,000) (1,000)
Fair Value 11,655,000 9,700,000
Cash Equivalents
Short-Term Investments 11,300,000 9,450,000
Long-Term Investments 355,000 250,000
Investments [Member] | Commercial Paper [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 11,316,000 8,695,000
Gross Unrealized Gains 1,000
Gross Unrealized Losses (17,000) (1,000)
Fair Value 11,300,000 8,694,000
Cash Equivalents
Short-Term Investments 11,300,000 8,694,000
Long-Term Investments
Investments [Member] | Corporate Notes/Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 355,000 756,000
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value 355,000 756,000
Cash Equivalents
Short-Term Investments 756,000
Long-Term Investments $ 355,000
Investments [Member] | Convertible Debt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost   250,000
Gross Unrealized Gains  
Gross Unrealized Losses  
Fair Value   250,000
Cash Equivalents  
Short-Term Investments  
Long-Term Investments   $ 250,000