Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Prepaid Expense And Other Assets Current [Abstract]
Insurance premiums	$ 501	$ 625
Kits for clinical use		162
Other	197	173
Total prepaid expenses and other current assets	$ 698	$ 960