Quarterly report pursuant to Section 13 or 15(d)

Cash, Cash Equivalents and Short-Term Investments - Gross Unrealized Gains and Losses (Details)

v3.19.3
Cash, Cash Equivalents and Short-Term Investments - Gross Unrealized Gains and Losses (Details) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Cash equivalents and available-for-sale securities    
Amortized Cost $ 78,894 $ 116,830
Fair Value 78,930 116,805
Gross Unrealized Gains    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) 39 2
Gross Unrealized Losses    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) (3) (27)
U.S. treasury bills    
Cash equivalents and available-for-sale securities    
Amortized Cost 8,040  
Fair Value 8,045  
U.S. treasury bills | Gross Unrealized Gains    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) 5  
Government-sponsored enterprises securities    
Cash equivalents and available-for-sale securities    
Amortized Cost 15,159 7,873
Fair Value 15,165 7,872
Government-sponsored enterprises securities | Gross Unrealized Gains    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) 7  
Government-sponsored enterprises securities | Gross Unrealized Losses    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) (1) (1)
Corporate bonds and commercial paper    
Cash equivalents and available-for-sale securities    
Amortized Cost 55,695 108,957
Fair Value 55,720 108,933
Corporate bonds and commercial paper | Gross Unrealized Gains    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) 27 2
Corporate bonds and commercial paper | Gross Unrealized Losses    
Cash equivalents and available-for-sale securities    
Gross Unrealized Gains (Losses) $ (2) $ (26)