Leases (Narrative) (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Finance Lease, Weighted Average Discount Rate, Percent	5.56%
Finance Lease, Weighted Average Remaining Lease Term	1 year 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	5.50%
Operating Lease, Weighted Average Remaining Lease Term	3 years 2 months 12 days
Finance Lease, Interest Payment on Liability \| $	$ 27
Operating Lease, Payments \| $	$ 510
Future minimum payments, 2019 \| $		$ 2,417
Future minimum payments, 2020 \| $		2,255
Future minimum payments, 2021 \| $		1,689
Future minimum payments, 2022 \| $		950
Future minimum payments, 2023 \| $		$ 188
Minnesota [Member]
Number of leased facilities	3
Illinois [Member]
Number of leased facilities	1
Singapore [Member]
Number of leased facilities	1
Indonesia [Member]
Number of leased facilities	1
United Kingdom [Member]
Number of leased facilities	1
Germany [Member]
Number of leased facilities	1
Lease Expiration In 2022 [Member] \| Minnesota [Member]
Number of leased facilities	2
Lease Expiration In 2023 [Member] \| Minnesota [Member]
Number of leased facilities	1
Minimum [Member]
Lessee, Operating Lease, Term of Contract	1 year
Maximum [Member]
Lessee, Operating Lease, Term of Contract	5 years

Number Of Leased Facilities

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Amount of interest paid on finance lease liability.

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Weighted average discount rate for finance lease calculated at point in time.

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Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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