| Schedule of financial assets and liabilities measured at fair value on a recurring basis |
The components of the Company’s Level 1 and Level 2 assets are as follows: | | | | | | | | | | | | | | | | | | | | | | September 30, 2017 | | Amortized Cost | | Gross Unrealized Gain (Loss) | | Estimated Fair Value | | Cash equivalents | | Short-term investments | | (in thousands) | Level 1: | | | | | | | | | | Money market funds | 9,911 |
| | — |
| | 9,911 |
| | 9,911 |
| | — |
| | $ | 9,911 |
| | $ | — |
| | $ | 9,911 |
| | $ | 9,911 |
| | $ | — |
| Level 2: | | | | | | | | | | U.S. treasuries | 29,974 |
| | (5 | ) | | 29,969 |
| | 5,997 |
| | 23,972 |
| Corporate securities | 11,151 |
| | (4 | ) | | 11,147 |
| | — |
| | 11,147 |
| Commercial paper | 13,945 |
| | — |
| | 13,945 |
| | — |
| | 13,945 |
| | $ | 55,070 |
| | $ | (9 | ) | | $ | 55,061 |
| | $ | 5,997 |
| | $ | 49,064 |
| Total | $ | 64,981 |
| | $ | (9 | ) | | $ | 64,972 |
| | $ | 15,908 |
| | $ | 49,064 |
|
| | | | | | | | | | | | | | | | | | | | | | December 31, 2016 | | Amortized Cost | | Gross Unrealized Gain (Loss) | | Estimated Fair Value | | Cash equivalents | | Short-term investments | | (in thousands) | Level 1: | | | | | | | | | | Money market funds | 25,244 |
| | — |
| | 25,244 |
| | 25,244 |
| | — |
| | $ | 25,244 |
| | $ | — |
| | $ | 25,244 |
| | $ | 25,244 |
| | — |
| Level 2: | | | | | | | | | | U.S. treasuries | 22,516 |
| | (19 | ) | | 22,497 |
| | — |
| | 22,497 |
| Corporate securities | 7,353 |
| | (12 | ) | | 7,341 |
| | — |
| | 7,341 |
| Commercial paper | 12,570 |
| | — |
| | 12,570 |
| | — |
| | 12,570 |
| | $ | 42,439 |
| | $ | (31 | ) | | $ | 42,408 |
| | $ | — |
| | 42,408 |
| Total | $ | 67,683 |
| | $ | (31 | ) | | $ | 67,652 |
| | $ | 25,244 |
| | $ | 42,408 |
|
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