Contigencies And Commitments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Selas SAS, Liabilities | $	$ 468
Rent expense | $	$ 1,728	$ 1,498	$ 1,265
Initial term	1 year
Remaining rentals payable, 2017 | $	$ 1,647
Remaining rentals payable, 2018 | $	1,674
Remaining rentals payable, 2019 | $	1,586
Remaining rentals payable, 2020 | $	1,135
Remaining rentals payable, 2021 | $	$ 444
Minnesota [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	2
Minnesota [Member] | Lease Expiration In 2022 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
Illinois [Member] | Lease Expiration In 2021 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
Singapore [Member] | Lease Expiration In 2020 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
Indonesia [Member] | Lease Expiration In 2021 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
GB [Member] | Lease Expiration In 2021 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
Germany 2 [Member] | Lease Expiration In 2022 [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of leased facilities | item	1
Minimum [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Base salary term	11 months
Employment period	1 year
Maximum [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Base salary term	2 years