Prepaid Expenses and Other Current Assets (Details) $ in Thousands	Sep. 30, 2017 USD ($) Project	Dec. 31, 2016 USD ($)
Prepaid Expenses and Other Current Assets [Abstract]
Inventory	$ 1,159	$ 0
Income tax receivable	268	446
Prepaid expenses	451	422
Other current assets	1,078	1,184
Total prepaid expenses and other current assets	$ 2,956	$ 2,052
Number of projects | Project	3