Changes in Initial Product Warranty Accrual and Expenses Under Initial and Extended Warranties (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Accrued Liabilities [Line Items]
Initial warranty accrual, beginning balance	$ 1,096	$ 1,699
Provision for estimated warranty cost	148	337
Warranty expenditures	(219)	(281)
Initial warranty accrual, ending balance	1,025	1,755
Total warranty accrual, long-term
Total warranty accrual, current portion	$ 1,025	$ 1,755	$ 1,096