Summary of Significant Accounting Policies - Summary of Adjustments in Allowances for Doubtful Accounts and Sales Adjustments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Balance at beginning of year	$ 1,725	$ 1,113	$ 1,621
Provisions for losses - accounts receivable	1,756	1,897	729
Collection of accounts previously written off	153
Deductions for accounts charged off or credits issued	(1,994)	(1,285)	(1,237)
Balance at end of year	$ 1,640	$ 1,725	$ 1,113