Income Taxes - Provisions for Income Taxes and Effective Income Tax Rates (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 13	$ 61	$ 35	$ 200
Effective income tax rate	2.40%	7.30%	0.60%	4.50%