Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Prepaid Expenses and Other Current Assets.
Prepaid purchase orders	$ 2,634	$ 126
Prepaid insurance	19	69
Prepaid operating expenses	213	114
Other receivables	47	94
Prepaid expenses and other current assets	$ 2,913	$ 403