Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized tax benefits, penalties and interest	$ 0	$ 0	$ 0
Unrecognized tax benefits	0	0	0
Valuation allowances for deferred tax assets	(15,394,000)	$ (13,044,000)	$ (12,234,000)	$ (13,179,000)
United States
Operating loss carryforwards, domestic	17,469,000
ITALY
Operating loss carryforwards, foreign	5,681,000
Valuation allowances for deferred tax assets	(1,363,000)
China
Operating loss carryforwards, foreign	$ 12,689,000