The carrying amounts of the Group’s financial instruments carried at amortized cost are not materially different from their fair values as of December 31, 2016 and 2017. Their carrying amounts, fair values and the level of fair values hierarchy are disclosed below:
| Carrying amount as of December 31, 2016 |
Fair value as of December 31, 2016 |
Carrying amount as of December 31, 2017 |
Fair value as of December 31, 2017 |
Fair value measurement as of December 31, 2017 categorized into |
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| Level 1 | Level 2 | Level 3 | ||||||||||||||||||||||||||
|
Non-current portion of long-term bank loans |
4,495 | 4,339 | 3,473 | 3,187 | — | 3,187 | — | |||||||||||||||||||||
|
Non-current portion of promissory notes |
17,906 | 18,031 | — | — | — | — | — | |||||||||||||||||||||
|
Non-current portion of corporate bonds |
17,970 | 17,989 | 17,981 | 17,712 | 17,712 | — | — | |||||||||||||||||||||