Annual report pursuant to Section 13 and 15(d)

Short-term Investments (Details)

v3.20.1
Short-term Investments (Details) - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost $ 6,494 $ 32,718
Unrealized Gains 15 14
Unrealized Losses (14) (15)
Fair Value 6,495 32,717
Commercial paper    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 998 8,772
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 998 8,772
Overnight repurchase agreement    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 3,500 9,000
Unrealized Gains 0 0
Unrealized Losses 0 0
Fair Value 3,500 9,000
U.S. government securities    
Schedule of Held-to-maturity Securities [Line Items]    
Amortized Cost 1,996 14,946
Unrealized Gains 15 14
Unrealized Losses (14) (15)
Fair Value $ 1,997 $ 14,945