Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued salaries, benefits and bonus	$ 7,861	$ 6,474
Accrued professional, consulting and lobbying	2,225	3,673
Accrued warranty expense	719	780	$ 748	$ 314
Accrued income and other taxes	5,082	4,581
Other accrued liabilities	6,544	2,740
Accrued liabilities	$ 22,431	$ 18,248