| Leases - Future Minimum Lease Payments Under Non-cancelable Operating Leases (Details) $ in Thousands | Dec. 31, 2018  USD ($) | 
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| Leases [Abstract] | |
| 2019 | $ 904 | 
| 2020 | 1,020 | 
| 2021 | 1,030 | 
| 2022 | 985 | 
| 2023 | 766 | 
| Thereafter | 2,356 | 
| Total | $ 7,061 | 
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- References No definition available. 
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- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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- Definition Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef 
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