Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 251	$ 200	$ 200
Charged to Costs and Expenses	86	142	24
Deductions	(15)	(91)	(24)
Balance at End of Period	322	251	200
Warranty Reserve
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	675	955	484
Charged to Costs and Expenses	(62)	396	1,001
Deductions	(299)	(676)	(530)
Balance at End of Period	$ 314	$ 675	$ 955