Income Taxes - Total Income Tax Benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal tax benefit, at statutory rate	$ 7,200	$ 5,500	$ 5,000
State tax benefit, net of federal benefit	600	400	400
Nondeductible expenses	(300)	100	(200)
Other	100	(1,100)	(300)
Valuation allowance	(7,700)	(4,900)	(4,900)
Income tax (provision) benefit	$ (50)	$ (38)	$ (23)