Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued salaries, benefits and bonus	$ 10,217		$ 8,957
Accrued professional, consulting and lobbying fees	4,046		3,870
Accrued warranty expense	559		644	$ 347	$ 780
Accrued income and other taxes	8,945		2,558
Other accrued liabilities	11,102		7,473
Accrued liabilities	$ 34,869	$ 26,014	$ 23,502