Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended			23 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2014
Income Tax Disclosure [Line Items]
Net deferred tax asset	$ 14,600			$ 14,600
Federal provision at statutory rate	11,237	$ 4,776	$ 2,392
Deferred tax asset reduction U.S. corporate tax rate	(4,200)	7,200
Repatriation of accumulated untaxed earnings of foreign subsidiaries	4,200	(4,000)		200
Valuation allowance	14,665	15,021		14,665
Net operating loss carryforwards	130,100			130,100
Cash held by foreign subsidiaries	48,700			48,700
Amount planned to repatriate	16,000
Deferred tax liabilities	500			500
Unrecognized tax benefits liability	530	485	$ 628	530	$ 489
Accrued interest and penalties are included in the unrecognized tax benefits	$ 300	$ 300		300
Minimum
Income Tax Disclosure [Line Items]
Federal research and development tax credit carryforward expiration year	2026
Maximum
Income Tax Disclosure [Line Items]
Federal research and development tax credit carryforward expiration year	2038
Research And Development
Income Tax Disclosure [Line Items]
Tax credits carried forward	$ 1,800			1,800
Foreign Tax Authority
Income Tax Disclosure [Line Items]
Release of valuation allowance	900
Net operating loss carryforwards	71,000			71,000
Tax credits carried forward	1,600			1,600
State and Local Jurisdiction
Income Tax Disclosure [Line Items]
Valuation allowance	1,200			1,200
Net operating loss carryforwards	$ 59,100			$ 59,100