Certain Balance Sheet Accounts - Summary of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Balance, beginning of year	$ 188	$ 254	$ 404
Provision for doubtful accounts	106	320	189
Write-offs	(141)	(386)	(339)
Balance, end of year	$ 153	$ 188	$ 254