Quarterly report pursuant to Section 13 or 15(d)

Fair Value (Details)

v3.20.2
Fair Value (Details) - USD ($)
$ in Thousands
Jun. 30, 2020
Dec. 31, 2019
Fair Value    
Investments at fair value $ 68,027 $ 87,250
Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 89,869 94,707
U.S. treasury bills    
Fair Value    
Investments at fair value 6,006 12,539
Government-sponsored enterprises securities    
Fair Value    
Investments at fair value 36,127 19,017
Corporate bonds and commercial paper    
Fair Value    
Investments at fair value 25,894 55,694
Fair value inputs Level 1    
Fair Value    
Investments at fair value 21,842 7,457
Fair value inputs Level 2    
Fair Value    
Investments at fair value 68,027 87,250
Fair value measurements recurring | Money market funds | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 21,842 7,457
Fair value measurements recurring | U.S. treasury bills | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 6,006 12,539
Fair value measurements recurring | Government-sponsored enterprises securities | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 36,127 19,017
Fair value measurements recurring | Corporate bonds and commercial paper | Estimate Of Fair Value Fair Value Disclosure    
Fair Value    
Investments at fair value 25,894 55,694
Fair value measurements recurring | Fair value inputs Level 1 | Money market funds    
Fair Value    
Investments at fair value 21,842 7,457
Fair value measurements recurring | Fair value inputs Level 2 | U.S. treasury bills    
Fair Value    
Investments at fair value 6,006 12,539
Fair value measurements recurring | Fair value inputs Level 2 | Government-sponsored enterprises securities    
Fair Value    
Investments at fair value 36,127 19,017
Fair value measurements recurring | Fair value inputs Level 2 | Corporate bonds and commercial paper    
Fair Value    
Investments at fair value $ 25,894 $ 55,694