Accounts Receivable and Sales Concentrations - Summary of Activity in the Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Receivables [Abstract]
Balance at Beginning of Year	$ 445	$ 311	$ 438
Additions	208	177	98
Write- offs	(123)	(47)	(224)
Currency Impacts	(10)	4	(1)
Balance at End of Year	$ 520	$ 445	$ 311