Quarterly report pursuant to Section 13 or 15(d)

Marketable securities - Available-for-sale debt securities - Unrealized loss position (Details)

v3.22.1
Marketable securities - Available-for-sale debt securities - Unrealized loss position (Details)
Mar. 31, 2022
USD ($)
security
Dec. 31, 2021
USD ($)
security
Marketable securities    
Fair market value of investments in an unrealized loss position $ 188,959,000 $ 176,483,000
Number of investments in an unrealized loss position | security 39 36
Unrealized losses $ (1,538,000) $ (390,000)
Number of available-for-sale securities in an unrealized loss position for more than one year | security 5 1
Corporate debt securities    
Marketable securities    
Fair market value of investments in an unrealized loss position $ 112,253,000 $ 163,258,000
Number of investments in an unrealized loss position 24,000 34,000
Unrealized losses $ (1,105,000) $ (348,000)
Corporate debt securities | Debt Securities    
Marketable securities    
Fair market value of investments in an unrealized loss position $ 29,672,000 $ 8,232,000
Number of investments in an unrealized loss position 5 1
Unrealized losses   $ (35,000)
Unrealized losses $ (275,000)  
U.S. Treasury securities    
Marketable securities    
Fair market value of investments in an unrealized loss position $ 42,144,000  
Number of investments in an unrealized loss position 9  
Unrealized losses $ (48,000)  
Agency bonds    
Marketable securities    
Fair market value of investments in an unrealized loss position $ 4,890,000 $ 4,993,000
Number of investments in an unrealized loss position 1 1
Unrealized losses $ (110,000) $ (7,000)