Quarterly report pursuant to Section 13 or 15(d)

Investments in Marketable Securities - Amortized Cost and Fair Value of Investments in Available for Sale Securities Unrealized Loss Position (Detail)

v3.21.1
Investments in Marketable Securities - Amortized Cost and Fair Value of Investments in Available for Sale Securities Unrealized Loss Position (Detail) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]    
Available for sale securities continuous unrealized loss position for less than 12 months, fair value $ 20,949 $ 72,058
Available for sale securities continuous unrealized loss position for less than 12 months, gross unrealized loss (55) (45)
Available for sale securities continuous unrealized loss position for 12 months or longer, fair value 484 157
Available for sale securities continuous unrealized loss position for 12 months or longer, gross unrealized loss (14) (5)
Available for sale securities continuous unrealized loss position, fair value 21,433 72,215
Available for sale securities continuous unrealized loss position, gross unrealized loss (69) (50)
U.S. Treasuries [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available for sale securities continuous unrealized loss position for less than 12 months, fair value   41,702
Available for sale securities continuous unrealized loss position for less than 12 months, gross unrealized loss   (5)
Available for sale securities continuous unrealized loss position for 12 months or longer, fair value   0
Available for sale securities continuous unrealized loss position for 12 months or longer, gross unrealized loss   0
Available for sale securities continuous unrealized loss position, fair value   41,702
Available for sale securities continuous unrealized loss position, gross unrealized loss   (5)
U.S. Government Sponsored Entities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available for sale securities continuous unrealized loss position for less than 12 months, fair value 139  
Available for sale securities continuous unrealized loss position for less than 12 months, gross unrealized loss (3)  
Available for sale securities continuous unrealized loss position for 12 months or longer, fair value 0  
Available for sale securities continuous unrealized loss position for 12 months or longer, gross unrealized loss 0  
Available for sale securities continuous unrealized loss position, fair value 139  
Available for sale securities continuous unrealized loss position, gross unrealized loss (3)  
Corporate debt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available for sale securities continuous unrealized loss position for less than 12 months, fair value 20,447 29,810
Available for sale securities continuous unrealized loss position for less than 12 months, gross unrealized loss (52) (34)
Available for sale securities continuous unrealized loss position for 12 months or longer, fair value 139 0
Available for sale securities continuous unrealized loss position for 12 months or longer, gross unrealized loss (8) 0
Available for sale securities continuous unrealized loss position, fair value 20,586 29,810
Available for sale securities continuous unrealized loss position, gross unrealized loss (60) (34)
ABS and other [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available for sale securities continuous unrealized loss position for less than 12 months, fair value 363 546
Available for sale securities continuous unrealized loss position for less than 12 months, gross unrealized loss 0 (6)
Available for sale securities continuous unrealized loss position for 12 months or longer, fair value 345 157
Available for sale securities continuous unrealized loss position for 12 months or longer, gross unrealized loss (6) (5)
Available for sale securities continuous unrealized loss position, fair value 708 703
Available for sale securities continuous unrealized loss position, gross unrealized loss $ (6) $ (11)