Quarterly report pursuant to Section 13 or 15(d)

Investments - Schedule of Available for Sale Securities Reconciliation (Details)

v3.19.2
Investments - Schedule of Available for Sale Securities Reconciliation (Details)
12 Months Ended
Dec. 31, 2018
USD ($)
Debt Securities, Available-for-sale [Line Items]  
Cost $ 4,572,000
Unrealized Gain 1,000
Unrealized Loss (48,000)
Fair Value 4,525,000
Short-term Investments [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 393,000
Unrealized Gain 1,000
Unrealized Loss
Fair Value 394,000
Short-term Investments [Member] | U.S. Treasury Notes [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 302,000
Unrealized Gain 1,000
Unrealized Loss
Fair Value 303,000
Short-term Investments [Member] | Corporate Bonds and Commercial Paper [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 91,000
Unrealized Gain
Unrealized Loss
Fair Value 91,000
Long-term Investments [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 4,179,000
Unrealized Gain
Unrealized Loss (48,000)
Fair Value 4,131,000
Long-term Investments [Member] | U.S. Treasury Notes [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 1,569,000
Unrealized Gain
Unrealized Loss (2,000)
Fair Value 1,567,000
Long-term Investments [Member] | Government Agency Bonds [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 1,548,000
Unrealized Gain
Unrealized Loss (23,000)
Fair Value 1,525,000
Long-term Investments [Member] | Corporate Bonds [Member]  
Debt Securities, Available-for-sale [Line Items]  
Cost 1,062,000
Unrealized Gain
Unrealized Loss (23,000)
Fair Value $ 1,039,000