Other Accrued Expenses and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accrued Liabilities And Other Liabilities Current [Abstract]
Accrued professional fees	$ 1,567	$ 1,504
Customer deposits	199	1,517
Accrued warranties	505	316
Other accrued expenses	2,425	1,940
Total	$ 4,696	$ 5,277