Short-term investments (Details) - Fair Value, Measurements, Recurring [Member] $ in Thousands |
Sep. 30, 2018
USD ($)
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| Amortized Cost | $ 4,744 |
| Carrying value | 4,744 |
| Mutual Fund [Member] | Available-for-sale Securities [Member] | |
| Amortized Cost | 3,026 |
| Carrying value | 3,026 |
| Corporate Debt Securities [Member] | Held-to-maturity Securities [Member] | |
| Amortized Cost | 1,718 |
| Carrying value | $ 1,718 |
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- Definition Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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