Accounts Receivable - Changes in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Balance at beginning of year	$ 150	$ 150	$ 250
Provisions for doubtful accounts	56	47	39
Charge-offs, net of recoveries	(56)	(47)	(139)
Balance at end of year	$ 150	$ 150	$ 150