Annual report pursuant to Section 13 and 15(d)

INVESTMENTS HELD-TO-MATURITY (Details)

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INVESTMENTS HELD-TO-MATURITY (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]    
Amortized cost   $ 16,900,000
Fair Value   16,900,000
Unrealized Gain (Loss)   0
Investments held-to-maturity $ 0 16,863,000
Interest and investment income $ 253,000 481,000
US Treasury Bills, Maturing April 2018 | Commercial Paper    
Schedule of Held-to-maturity Securities [Line Items]    
Investments held-to-maturity   25,000,000
Commercial Paper, Maturing In 2018 | Commercial Paper    
Schedule of Held-to-maturity Securities [Line Items]    
Investments held-to-maturity   $ 14,600,000