Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short-term debt:
NAU Promissory Note
Current portion of long-term debt	45	27
Total short-term debt	45	27
Long-term debt:
Capital lease obligations	51	72
Other unsecured promissory notes	132	400
Other promissory notes		5
Total	183	477
Less: current portion of long-term debt	45	27
Total long-term debt	$ 138	$ 450