Schedule II-Valuation and Qualifying Accounts (Detail) - Allowance for doubtful accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of the year	$ 161	$ 211	$ 144
Provision	(70)	(38)	88
Recoveries/Write- Offs	(18)	(12)	(21)
Balance at end of the year	$ 73	$ 161	$ 211