Debt - Narrative (Details)				1 Months Ended		6 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 20, 2019 USD ($)	Aug. 08, 2018 USD ($)	Sep. 30, 2019 USD ($) repayment tranche	Dec. 31, 2018 USD ($)	Mar. 31, 2020 USD ($) invoice	Sep. 30, 2019 USD ($)	Dec. 17, 2018 USD ($)
Line of Credit Facility [Line Items]
Short-term debt arrangement	$ 15,542,000			$ 15,542,000		$ 17,191,000	$ 15,542,000
Number of customer invoices factored | invoice						1
Foreign subsidiary borrowings
Line of Credit Facility [Line Items]
Receivables pledged as collateral	672,000			$ 672,000		$ 918,000	672,000
Long-term debt, number of tranches with modified repayment schedule | tranche				1
Debt instrument, number of repayments reduced | repayment				2
Debt instrument, repayment reduction per payment, amount				$ 96,000
Debt instrument, loan extension period				6 months
Foreign subsidiary borrowings | Euribor | Minimum
Line of Credit Facility [Line Items]
Euribor variable interest rates						1.00%
Foreign subsidiary borrowings | Euribor | Maximum
Line of Credit Facility [Line Items]
Euribor variable interest rates						4.00%
2018 Credit Agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Fixed charge coverage ratio			1.1
Percent availability under revolving commitment			12.50%
Percentage of stock pledged on credit agreement		66.67%
2018 Credit Agreement | Revolving credit agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity			$ 30,000,000
Accordion feature, increase limit			$ 10,000,000
Weighted average interest rate, revolving credit facility						3.60%
Commitment fee percentage			0.25%
Debt issuance costs incurred						$ 212,000
Revolving line of credit, accumulated amortization of debt issuance costs	$ 106,000			$ 106,000		$ 158,000	$ 106,000
2018 Credit Agreement | Revolving credit agreement | Revolving credit agreement | LIBOR
Line of Credit Facility [Line Items]
Basis spread on LIBOR						2.00%	1.75%
Export Credit Facility | Revolving credit agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity								$ 5,000,000
Accordion feature, increase limit								$ 35,000,000
Weighted average interest rate, revolving credit facility	3.40%			3.40%		3.10%	3.40%
Export Credit Facility | Revolving credit agreement | Revolving credit agreement | LIBOR
Line of Credit Facility [Line Items]
Basis spread on LIBOR						1.50%	1.25%
Third Amendment To Credit Agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Coverage ratio threshold for three or more business days in consecutive thirty day period		12.50%
Fourth Amendment To Credit Agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Fixed charge coverage ratio			1.1
Percent availability under revolving commitment		10.00%
Coverage ratio threshold for three or more business days in consecutive thirty day period	10.00%	10.00%
Line of credit facility, benchmark of collateral threshold		$ 20,000,000
Receivables pledged as collateral	$ 24,000,000			$ 24,000,000		$ 26,000,000	$ 24,000,000
Fourth Amendment To Credit Agreement | Revolving credit agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Revolving credit facility, maximum borrowing capacity	35,000,000			35,000,000		35,000,000	35,000,000
Line of credit facility, covenant terms, floor		2,000,000
Line of credit facility, benchmark of collateral threshold		$ 20,000,000
Line of credit facility, total commitment springs	2,400,000			2,400,000		2,600,000	2,400,000
Remaining borrowing capacity	7,709,000			7,709,000		$ 7,999,000	7,709,000
Short Term Debt Arrangement For Working Capital Purposes
Line of Credit Facility [Line Items]
Debt instrument, term					6 months
Short-term debt arrangement					$ 1,137,000
First And Second Amendment to 2018 Credit Agreement | Revolving credit agreement | Revolving credit agreement
Line of Credit Facility [Line Items]
Debt issuance costs incurred	$ 75,000			$ 75,000			$ 75,000