| Marketable Securities |
Marketable Securities At December 31, 2015 and December 31, 2014, respectively, marketable securities consisted of the following (in thousands): | | | | | | | | | | | | | | | | | | Amortized Cost | | Unrealized Gains | | Unrealized Losses | | Fair Value | December 31, 2015 | | | | | | | | U.S. agency obligations | $ | 83,763 |
| | $ | — |
| | $ | (48 | ) | | $ | 83,715 |
| U.S. treasury securities | 33,924 |
| | — |
| | (31 | ) | | 33,893 |
| Money market mutual funds | 1,038 |
| | — |
| | — |
| | 1,038 |
| | 118,725 |
| | — |
| | (79 | ) | | 118,646 |
| Included in cash and cash equivalents | 4,038 |
| | — |
| | (1 | ) | | 4,037 |
| Included in marketable securities | $ | 101,334 |
| | $ | — |
| | $ | (60 | ) | | $ | 101,274 |
| Included in marketable securities, noncurrent | $ | 13,353 |
| | $ | — |
| | $ | (18 | ) | | $ | 13,335 |
|
| | | | | | | | | | | | | | | | | | Amortized Cost | | Unrealized Gains | | Unrealized Losses | | Fair Value | December 31, 2014 | | | | | | | | U.S. agency obligations | $ | 177,297 |
| | $ | 4 |
| | $ | (44 | ) | | $ | 177,257 |
| U.S. treasury securities | 5,580 |
| | 1 |
| | — |
| | 5,581 |
| Money market mutual funds | 1,919 |
| | — |
| | — |
| | 1,919 |
| | 184,796 |
| | 5 |
| | (44 | ) | | 184,757 |
| Included in cash and cash equivalents | 3,480 |
| | — |
| | — |
| | 3,480 |
| Included in marketable securities | $ | 175,093 |
| | $ | 5 |
| | $ | (41 | ) | | $ | 175,057 |
| Included in marketable securities, noncurrent | $ | 6,223 |
| | $ | — |
| | $ | (3 | ) | | $ | 6,220 |
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