Other Current Assets - Schedule of Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid expenses	$ 1,442	$ 1,519
Advances to vendors	6,738	6,403
Other receivables	124	1,422
Total	$ 8,304	$ 9,344