Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Corporate tax rate			21.00%	35.00%
Current tax expense in connection with transition tax	$ 45,000
Total transition tax on Federal tax return		$ 31,000
Valuation allowance	$ 352,000	33,000	$ 33,000	$ 352,000
Decrease in valuation allowance			320,000	$ 91,000	$ 85,000
NOL carryforwards		200,000	200,000
Unrecognized tax expenses		0	0			$ 184,000
Undistributed earnings, foreign subsidiaries		7,000,000	7,000,000
Foreign Country [Member]
Income Taxes [Line Items]
NOL carryforwards		$ 200,000	$ 200,000