XML 63 R48.htm IDEA: XBRL DOCUMENT v3.19.2
Fair value of financial instruments and marketable securities - Unrealized Loss Positions (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Unrealized losses    
Securities in an unrealized loss position less than 12 months $ (10) $ (8)
Securities in an unrealized loss position greater than 12 months 0 (3)
Total (10) (11)
Fair Value    
Securities in an unrealized loss position less than 12 months 17,684 16,223
Securities in an unrealized loss position greater than 12 months 0 10,087
Total 17,684 26,310
Commercial paper    
Unrealized losses    
Securities in an unrealized loss position less than 12 months 0 (1)
Securities in an unrealized loss position greater than 12 months 0 0
Total 0 (1)
Fair Value    
Securities in an unrealized loss position less than 12 months 0 1,993
Securities in an unrealized loss position greater than 12 months 0 0
Total 0 1,993
Corporate debt securities    
Unrealized losses    
Securities in an unrealized loss position less than 12 months (10) (7)
Securities in an unrealized loss position greater than 12 months 0 (3)
Total (10) (10)
Fair Value    
Securities in an unrealized loss position less than 12 months 17,684 14,230
Securities in an unrealized loss position greater than 12 months 0 10,087
Total 17,684 $ 24,317
Asset-backed securities    
Unrealized losses    
Securities in an unrealized loss position less than 12 months 0  
Securities in an unrealized loss position greater than 12 months 0  
Total 0  
Fair Value    
Securities in an unrealized loss position less than 12 months 0  
Securities in an unrealized loss position greater than 12 months 0  
Total $ 0