| 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: | | | | | | | | | | | | | | | | | | | | | | 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 |
|
| | | | | | | | | | | | | | | | | | | | | | December 31, 2015 | | Amortized Cost | | Gross Unrealized Gain (Loss) | | Estimated Fair Value | | Cash equivalents | | Short-term investments | | (in thousands) | Level 1: | | | | | | | | | | Money market funds | 33,436 |
| | — |
| | 33,436 |
| | 33,436 |
| | — |
| | $ | 33,436 |
| | $ | — |
| | $ | 33,436 |
| | $ | 33,436 |
| | — |
| Level 2: | | | | | | | | | | U.S. treasuries | 15,988 |
| | (21 | ) | | 15,967 |
| | — |
| | 15,967 |
| Corporate securities | 23,679 |
| | (40 | ) | | 23,639 |
| | — |
| | 23,639 |
| Commercial paper | 6,987 |
| | — |
| | 6,987 |
| | — |
| | 6,987 |
| | $ | 46,654 |
| | $ | (61 | ) | | $ | 46,593 |
| | $ | — |
| | 46,593 |
| Total | $ | 80,090 |
| | $ | (61 | ) | | $ | 80,029 |
| | $ | 33,436 |
| | $ | 46,593 |
|
|