Other Accrued Expenses and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Liabilities And Other Liabilities Current [Abstract]
Accrued professional fees	$ 1,504	$ 1,065
Customer deposits	1,517
Accrued warranties	316
Other accrued expenses	1,940	955
Total	$ 5,277	$ 2,020