Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Prepaid Expenses And Other Current Assets [Line Items]
Equipment maintenance and services	$ 586	$ 689
Prepaid VAT	553	558
Prepaid insurance	356	455
Deferred costs	5	206
Prepaid taxes	73	105
Interest receivable	29	63
Other	42	22
Total	$ 1,644	$ 2,098