Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards, Expire year	2028
Unrecognized tax benefits	$ 428,000	$ 428,000	$ 428,000
Cumulative loss period	5 years
Valuation allowance	$ 49,405,000	50,397,000
Increase (decrease) in valuation allowance of deferred tax assets	(1,000,000.0)	(2,000,000.0)
Interest and penalties	0	0
Cumulative interest and penalties	0	0
Outstanding tax audit	0
Income before provision for income taxes for foreign subsidiaries	112,000	$ (31,000)
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Income related to GILTI	86,000
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 160,500,000
Net operating loss carryforwards, expiry terms	Federal NOL carryforwards will expire from 2024 through 2037
Tax credit carryforwards	$ 2,500,000
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 128,200,000
Net operating loss carryforwards, expiry terms	State NOL carryforwards will expire 2019 through 2039
Tax credit carryforwards	$ 700,000
Federal income tax returns subject to examination description	State income tax returns are subject to examination for a period of three to four years after filing