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Cash Equivalents and Investments | 12 Months Ended
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Dec. 31, 2020
Cash Equivalents And Investments [Abstract] |
Cash Equivalents and Investments | Cash Equivalents and Investments The fair value of cash equivalents and available-for-sale investments at December 31, 2020 and 2019, were as follows (in thousands):
| December 31, 2020
| Amortized Cost |  | Gross Unrealized |  | Estimated Fair Value
|  | Gains |  | Losses |
Money market funds | $ | 59,823 |  |  | $ | — |  |  | $ | — |  |  | $ | 59,823 |
U.S. government securities | 190,663 |  |  | 16 |  |  | (2) |  |  | 190,677 |
Corporate notes | 26,426 |  |  | 2 |  |  | (5) |  |  | 26,423 |
Commercial paper | 29,489 |  |  | — |  |  | — |  |  | 29,489 |
Total available-for-sale marketable debt securities | $ | 306,401 |  |  | $ | 18 |  |  | $ | (7) |  |  | $ | 306,412 |
Classified as: |  |  |  |  |  |  |
Cash equivalents |  |  |  |  |  |  | $ | 59,823 |
Short-term investments |  |  |  |  |  |  | 246,589 |
Long-term investments |  |  |  |  |  |  | — |
Total cash equivalents and available-for-sale investments |  |  |  |  |  |  | $ | 306,412 |
| December 31, 2019
| Amortized Cost |  | Gross Unrealized |  | Estimated Fair Value
|  | Gains |  | Losses |
Money market funds | $ | 13,897 |  |  | $ | — |  |  | $ | — |  |  | $ | 13,897 |
U.S. government securities | 77,329 |  |  | 72 |  |  | (1) |  |  | 77,400 |
Corporate notes | 14,955 |  |  | 11 |  |  | — |  |  | 14,966 |
Commercial paper | 35,753 |  |  | — |  |  | — |  |  | 35,753 |
Total available-for-sale marketable debt securities | $ | 141,934 |  |  | $ | 83 |  |  | $ | (1) |  |  | $ | 142,016 |
Classified as: |  |  |  |  |  |  |
Cash equivalents |  |  |  |  |  |  | $ | 13,897 |
Short-term investments |  |  |  |  |  |  | 120,089 |
Long-term investments |  |  |  |  |  |  | 8,030 |
Total cash equivalents and available-for-sale investments |  |  |  |  |  |  | $ | 142,016 |
The following table summarizes the fair value of the Company's cash equivalents, short-term and long-term marketable securities classified by maturity (in thousands):
| December 31,
| 2020 |  | 2019
Due within one year | $ | 306,412 |  |  | $ | 133,986 |
Due after one year through three years | — |  |  | 8,030 |
Total cash equivalents and available-for-sale investments | $ | 306,412 |  |  | $ | 142,016 |
The following tables present the Company's available-for-sale securities that were in an unrealized loss position as of December 31, 2020 (in thousands):
| December 31, 2020
| Less than 12 months |  | 12 Months or Greater |  | Total
Assets | Fair Value |  | Unrealized Loss |  | Fair Value |  | Unrealized Loss |  | Fair Value |  | Unrealized Loss
U.S. government securities | $ | 28,487 |  |  | $ | (2) |  |  | $ | — |  |  | $ | — |  |  | $ | 28,487 |  |  | $ | (2) |
Corporate notes | 13,883 |  |  | (5) |  |  | — |  |  | — |  |  | 13,883 |  |  | (5) |
Total | $ | 42,370 |  |  | $ | (7) |  |  | $ | — |  |  | $ | — |  |  | $ | 42,370 |  |  | $ | (7) |
Unrealized losses as of December 31, 2020 were not material. Available-for-sale securities held as of December 31, 2020 had a weighted average maturity of 92 days. At December 31, 2020, six investments were in an unrealized loss position and no investments have been in an unrealized loss position for more than one year.

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- Definition Cash Equivalents and Investments. + References No definition available. + Details
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- Definition Cash equivalents and short term and long term Investments. + References No definition available. + Details
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