Summary of Significant Accounting Policies (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Segment	Dec. 31, 2017 USD ($)
Summary of Significant Accounting Policies (Textual)
Bad debt expense	$ 660	$ 1,223
Land use right, useful life	50 years
Description of provision recorded on inventory	The Company records a provision for slow-moving or obsolete materials and finished goods aged more than two years.
Impairment charges of long lived assets
Inspection charges and selling expenses	1,100	800
Research and development costs	800	1,070
PRC received government subsidies	1,190	2,930
Accumulated other comprehensive income	$ (3,578)	2,585
Assets and liabilities translation rate, description	Assets and liabilities at December 31, 2018 and 2017 were translated at RMB6.88 and RMB6.51 to $1.00 respectively.
Average translation rate applied to income statement accounts and statement of cash flows, description	The average translation rates applied to income statement accounts and statement of cash flows for the years ended December 31, 2018 and 2017 were RMB6.61 and RMB6.76 to $1.00, respectively.
Gains or losses from exchange rate fluctuations	$ 1,200	1,880
Number of segments | Segment	2
Accounts Receivable [Member]
Summary of Significant Accounting Policies (Textual)
Allowance for doubtful accounts	$ 5,900	$ 5,500