Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 10	$ (312)
Statutory rate	21.00%	21.00%
Deferred tax assets, net of deferred tax liabilities	$ 14,500
Operating loss and credit carry forward, expiration period	The Company’s federal NOLs generated in 2019 and 2018 have an infinite life, and the Company’s NOLs and credits generated as of December 31, 2017 have a finite life primarily based on the 20-year carry forward of federal net operating losses.
Net operating loss carry forward period	20 years
Domestic deferred tax assets ratable reversal pattern period	12 years
Deferred tax assets, valuation allowance	$ 14,500		$ 14,500
Gross unrecognized tax benefit	$ 700		$ 700