Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Valuation allowance	$ 60,824,000	$ 58,248,000
Corporate federal tax rate	21.00%	34.00%
Net recognized deferred tax asset		$ 0
Decrease in net deferred assets		15,800,000
Decrease of valuation allowance		15,800,000
Net operating losses, carried back term	2 years
Net operating losses, carried forward term	20 years
Maximum offset percentage of indefinite carryforward operating loss	80.00%
Repatriation tax	$ 0
GILTI income	$ 0
Operating loss carryforwards, expiration end year	2038
Liabilities for unrecognized tax benefits	$ 2,800,000	2,800,000
Amount of unrecognized tax benefits, which, if recognized, would affect the tax rate	100,000	100,000
Penalties accrued related to unrecognized tax benefits	1,000	1,000
Interest accrued related to unrecognized tax benefits	1,000	4,000
Recognized total liability for penalties	13,000	14,000
Recognized total liability for interest	33,000	$ 32,000
Federal
Income Taxes [Line Items]
Operating loss carryforwards	117,400,000
State
Income Taxes [Line Items]
Operating loss carryforwards	63,800,000
Foreign
Income Taxes [Line Items]
Operating loss carryforwards	$ 120,700,000
Maximum
Income Taxes [Line Items]
Corporate federal tax rate		35.00%