Credit Facility (Details) - USD ($)		3 Months Ended	9 Months Ended
	Nov. 07, 2018	Sep. 28, 2018	Sep. 28, 2018	May 09, 2016	Feb. 28, 2012
Revolving line of credit facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under credit facility				$ 45,000,000	$ 20,000,000
Additional borrowing capacity				$ 25,000,000
Maturity date			May 09, 2021
Pledge of capital stock to U.S. subsidiaries			100.00%
Pledge of capital stock to direct foreign subsidiaries			66.00%
Payment of principal		$ 2,000,000	$ 7,500,000
Outstanding balance		$ 11,500,000	$ 11,500,000
Interest rate		3.60%	3.60%
Revolving line of credit facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Margin percentage base rate			1.50%
Revolving line of credit facility [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Margin percentage base rate			0.75%
Revolving line of credit facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Payment of principal	$ 3,000,000
Outstanding balance	$ 8,500,000
Term Loan [Member]
Line of Credit Facility [Line Items]
Borrowing capacity under credit facility					$ 47,000,000
Term of debt			5 years