Summary of investments |
The following tables summarize our cash and available-for-sale securities by significant category within the fair value hierarchy (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | September 30, 2019 | | | | Amortized Cost | | Gross Unrealized Gain | | Gross Unrealized Loss | | Fair Value | | Cash and Cash Equivalents | | Short-Term Marketable Securities | | Cash- Restricted | Assets: | | | | | | | | | | | | | | Cash-non-restricted | $ | 14,053 |
| | $ | — |
| | $ | — |
| | $ | 14,053 |
| | $ | 14,053 |
| | $ | — |
| | $ | — |
| Cash-restricted | 2,075 |
| | — |
| | — |
| | 2,075 |
| | — |
| | — |
| | 2,075 |
| Total cash | $ | 16,128 |
| | $ | — |
| | $ | — |
| | $ | 16,128 |
| | $ | 14,053 |
| | $ | — |
| | $ | 2,075 |
| Available-for-sale: | | | | | | | | | | | | | | Level I: | | | | | | | | | | | | | | Money market funds | $ | 11,833 |
| | $ | — |
| | $ | — |
| | $ | 11,833 |
| | $ | 11,833 |
| | $ | — |
| | $ | — |
| U.S. treasury securities | 36,825 |
| | 50 |
| | — |
| | 36,875 |
| | — |
| | 36,875 |
| | — |
| Subtotal | $ | 48,658 |
| | $ | 50 |
| | $ | — |
| | $ | 48,708 |
| | $ | 11,833 |
| | $ | 36,875 |
| | $ | — |
| Total | $ | 64,786 |
| | $ | 50 |
| | $ | — |
| | $ | 64,836 |
| | $ | 25,886 |
| | $ | 36,875 |
| | $ | 2,075 |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2018 | | Amortized Cost | | Gross Unrealized Gain | | Gross Unrealized Loss | | Fair Value | | Cash and Cash Equivalents | | Short-Term Marketable Securities | Assets: | | | | | | | | | | | | Cash | $ | 17,685 |
| | $ | — |
| | $ | — |
| | $ | 17,685 |
| | $ | 17,685 |
| | $ | — |
| Available-for-sale: | | | | | | | | | | | | Level I: | | | | | | | | | | | | Money market funds | $ | 77,716 |
| | $ | — |
| | $ | — |
| | $ | 77,716 |
| | $ | 77,716 |
| | $ | — |
| U.S. treasury securities | — |
| | — |
| | — |
| | — |
| | — |
| | — |
| Subtotal | $ | 77,716 |
| | $ | — |
| | $ | — |
| | $ | 77,716 |
| | $ | 77,716 |
| | $ | — |
| Total | $ | 95,401 |
| | $ | — |
| | $ | — |
| | $ | 95,401 |
| | $ | 95,401 |
| | $ | — |
|
|
Schedule of debt |
The carrying values of the components of the 2014 Notes and the 2018 Notes are as follows (in thousands): | | | | | | | | | | September 30, 2019 | | December 31, 2018 | 2.75% 2014 Notes due 2034 | | | | Principal amount | $ | 51,250 |
| | $ | 51,250 |
| Unamortized debt discount | (1,182 | ) | | (1,232 | ) | Unamortized debt issuance cost | (215 | ) | | (224 | ) | | $ | 49,853 |
| | $ | 49,794 |
| 2.75% 2018 Notes due 2034 | | | | Principal amount | $ | — |
| | $ | 149,999 |
| Premium accretion | — |
| | 3,755 |
| Unamortized debt discount | — |
| | (29,558 | ) | Unamortized debt issuance cost | — |
| | (1,932 | ) | | $ | — |
| | $ | 122,264 |
| | $ | 49,853 |
| | $ | 172,058 |
|
The following table summarizes the par value, carrying value and the estimated fair value of the 2014 and 2018 Notes at September 30, 2019 and December 31, 2018, respectively (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | September 30, 2019 | | December 31, 2018 | | Par Value | | Carrying Value | | Fair Value | | Par Value | | Carrying Value | | Fair Value | 2014 Notes | $ | 51,250 |
| | $ | 49,853 |
| | $ | 49,713 |
| | $ | 51,250 |
| | $ | 49,794 |
| | $ | 43,665 |
| 2018 Notes | — |
| | — |
| | — |
| | 149,999 |
| | 122,264 |
| | 171,843 |
| Total | $ | 51,250 |
| | $ | 49,853 |
| | $ | 49,713 |
| | $ | 201,249 |
| | $ | 172,058 |
| | $ | 215,508 |
|
|