Summary of Significant Accounting Policies - Summary of Adjustments in Allowances for Doubtful Accounts and Sales Adjustments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Balance at beginning of year	$ 1,621	$ 990	$ 1,603
Provisions for losses - accounts receivable	729	961	805
Collection of accounts previously reserved			(142)
Deductions for accounts charged off or credits issued	(1,237)	(330)	(1,276)
Balance at end of year	$ 1,113	$ 1,621	$ 990