Schedule II - Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for accounts receivable [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance at beginning of period	$ 617	$ 482	$ 1,382
Valuation Allowances and Reserves, Additions charged to costs and expenses	347	730	1,045
Valuation Allowances and Reserves, Deductions	(362)	(595)	(1,945)
Valuation Allowances and Reserves, Balance at end of period	602	617	482
Allowance for excess and obsolete inventory [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance at beginning of period	301	352	417
Valuation Allowances and Reserves, Additions charged to costs and expenses	124	76	73
Valuation Allowances and Reserves, Deductions	(274)	(127)	(138)
Valuation Allowances and Reserves, Balance at end of period	$ 151	$ 301	$ 352