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v3.21.1

Investments | 12 Months Ended
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Dec. 31, 2020
Schedule Of Investments [Abstract] |
Investments | 4. Investments 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 |

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- Definition The entire disclosure for investment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -URI http://asc.fasb.org/topic&trid=75115024 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 325 -URI http://asc.fasb.org/topic&trid=2197064 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -URI http://asc.fasb.org/topic&trid=2196965 + Details
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- References No definition available. + Details
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