Income Taxes - Allocation of Federal and State Income Taxes Between Current and Deferred Portions (Detail) - USD ($) $ in Thousands	3 Months Ended						12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Current tax expense:
State							$ 13	$ 9
Total current tax expense							13	9
Deferred tax expense (benefit):
Federal							(25)	(676)
State							23	29
Total deferred federal and state tax expense (benefit)							(2)	(647)
Change in valuation allowance							2	530
Total deferred tax expense (benefit)								(117)
Total tax expense (benefit)	$ 10	$ 3	$ (103)	$ (1)	$ (1)	$ (3)	$ 13	$ (108)