Changes in Initial Product Warranty Accrual and Expenses Under Initial and Extended Warranties (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Movement in Standard Product Warranty Accrual
Initial warranty accrual, beginning balance	$ 2,188	$ 1,449
Provision for estimated warranty cost	61	451
Warranty expenditures	(189)	(233)
Initial warranty accrual, ending balance	2,060	1,667
Less warranty accrual, long-term	973	640	$ 843
Total warranty accrual, current portion	$ 1,087	$ 1,027	$ 1,345