The fair value of available-for-sale investments by type of security was as follows:
|
|
December 31, 2020 |
|
|
|
Amortized
Cost |
|
|
Unrealized
Gains |
|
|
Unrealized
Losses |
|
|
Fair
Value |
|
Investments: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
U.S treasury bills |
|
$ |
29,997 |
|
|
$ |
21 |
|
|
$ |
— |
|
|
$ |
30,018 |
|
U.S agency securities |
|
|
20,996 |
|
|
5 |
|
|
|
— |
|
|
|
21,001 |
|
Total investments with a maturity of one year or less |
|
|
50,993 |
|
|
|
26 |
|
|
|
— |
|
|
|
51,019 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
U.S treasury bills |
|
|
3,008 |
|
|
|
— |
|
|
|
— |
|
|
|
3,008 |
|
U.S agency securities |
|
|
176,350 |
|
|
38 |
|
|
|
— |
|
|
|
176,388 |
|
Total investments with a maturity of one to two years |
|
|
179,358 |
|
|
|
38 |
|
|
|
— |
|
|
|
179,396 |
|
Total investments |
|
$ |
230,351 |
|
|
$ |
64 |
|
|
$ |
— |
|
|
$ |
230,415 |
|
|
|
December 31, 2019 |
|
|
|
Amortized
Cost |
|
|
Unrealized
Gains |
|
|
Unrealized
Losses |
|
|
Fair
Value |
|
Investments: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
U.S treasury bills |
|
$ |
232,336 |
|
|
$ |
268 |
|
|
$ |
— |
|
|
$ |
232,604 |
|
U.S agency securities |
|
|
81,201 |
|
|
|
57 |
|
|
|
— |
|
|
|
81,258 |
|
Total investments with a maturity of one year or less |
|
$ |
313,537 |
|
|
$ |
325 |
|
|
$ |
— |
|
|
$ |
313,862 |
|
|