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Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Prepaid Expenses and Other Current Assets |  |
Rio Grande LNG site option | $ 365 | $ 508
Short-term security deposits | 27 | 18
Rio Bravo Pipeline options | 40 | 54
Prepaid insurance | 191 | 233
Prepaid marketing and sponsorships | 782 | 242
Other | 376 | 255
Total prepaid expenses and other current assets | $ 1,781 | $ 1,310

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