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Cash Equivalents and Investments | 3 Months Ended
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Mar. 31, 2019
Cash Equivalents And Investments [Abstract] |
Cash Equivalents and Investments | 3. Cash Equivalents and Investments The fair value of securities, not including cash at March 31, 2019 and December 31, 2018, were as follows (in thousands):
|  | March 31, 2019 |
|  | Amortized |  |  | Gross Unrealized |  |  | Estimated |
|  | Cost |  |  | Gains |  |  | Losses |  |  | Fair Value |
Money market funds |  | $ | 23,613 |  |  | $ — |  |  | $ — |  |  | $ | 23,613 |
U.S. government securities |  |  | 3,476 |  |  |  | 1 |  |  | — |  |  |  | 3,477 |
Corporate notes |  |  | 11,284 |  |  |  | 2 |  |  | — |  |  |  | 11,286 |
Commercial paper |  |  | 15,744 |  |  | — |  |  | — |  |  |  | 15,744 |
Total available-for-sale marketable debt securities |  | $ | 54,117 |  |  | $ | 3 |  |  | $ | — |  |  | $ | 54,120 |
Classified as: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash equivalents |  |  |  |  |  |  |  |  |  |  |  |  |  | $ | 23,613 |
Short-term investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30,507 |
Total cash equivalents and investments |  |  |  |  |  |  |  |  |  |  |  |  |  | $ | 54,120 |
|  | December 31, 2018 |
|  | Amortized |  |  | Gross Unrealized |  |  | Estimated |
|  | Cost |  |  | Gains |  |  | Losses |  |  | Fair Value |
Money market funds |  | $ | 10,606 |  |  | $ | — |  |  | $ | — |  |  | $ | 10,606 |
U.S. government securities |  |  | 9,976 |  |  |  | — |  |  |  | (1 | ) |  |  | 9,975 |
Corporate notes |  |  | 16,514 |  |  |  | 3 |  |  |  | (18 | ) |  |  | 16,499 |
Commercial paper |  |  | 36,331 |  |  |  | — |  |  |  | — |  |  |  | 36,331 |
Total available-for-sale marketable debt securities |  | $ | 73,427 |  |  | $ | 3 |  |  | $ | (19 | ) |  | $ | 73,411 |
Classified as: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash equivalents |  |  |  |  |  |  |  |  |  |  |  |  |  | $ | 15,091 |
Short-term investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 58,320 |
Total cash equivalents and investments |  |  |  |  |  |  |  |  |  |  |  |  |  | $ | 73,411 |
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):
|  | March 31, |  |  | December 31, |
|  | 2019 |  |  | 2018 |
Due within one year |  | $ | 54,120 |  |  | $ | 73,411 |
Due after one year through three years |  |  | — |  |  |  | — |
Total available-for-sale marketable debt securities |  | $ | 54,120 |  |  | $ | 73,411 |
The following tables present the Company's available-for-sale securities that were in an unrealized loss position as of March 31, 2019 and December 31, 2018 (in thousands):
|  | As of March 31, 2019 |
|  | Less than 12 months |  |  | 12 Months or Greater |  |  | Total |
Assets |  | Fair Value |  |  | Unrealized Loss |  |  | Fair Value |  |  | Unrealized Loss |  |  | Fair Value |  |  | Unrealized Loss |
Corporate notes |  | $ | 2,498 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 2,498 |  |  | $ | — |
Total |  | $ | 2,498 |  |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 2,498 |  |  | $ | — |
|  | December 31, 2018 |
|  | 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 |  | $ | 5,977 |  |  | $ | (1 | ) |  | $ | — |  |  | $ | — |  |  | $ | 5,977 |  |  | $ | (1 | )
Corporate notes |  |  | 11,521 |  |  |  | (10 | ) |  |  | 2,993 |  |  |  | (8 | ) |  |  | 14,514 |  |  |  | (18 | )
Total |  | $ | 17,498 |  |  | $ | (11 | ) |  | $ | 2,993 |  |  | $ | (8 | ) |  | $ | 20,491 |  |  | $ | (19 | )
Available-for-sale securities held as of March 31, 2019 had a weighted average days to maturity of 30 days. As of March 31, 2019, the Company had one investment in an unrealized loss position, and no investment has been in an unrealized loss position for more than 12 months. There have been no material realized gains or realized losses on available-for-sale securities for the periods presented.

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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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