Derivative Instruments - Gain (Loss) Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) reclassified from accumulated other comprehensive income (loss) into net income	$ 0	$ 41	$ (398)
Accumulated other comprehensive income (loss), net of tax \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recorded in shareholders' equity (effective portion)	0	0	37
Total gains (losses) reclassified from accumulated other comprehensive income (loss) into net income	0	41	(398)
Product Revenue \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	0	30	(438)
Research, development, and engineering expenses \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	0	3	13
Selling, general and administrative expenses \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	0	8	27
Foreign currency gain (loss) \| Not Designated as Hedging Instrument [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Gains (losses) recognized in net income	$ (285)	$ 270	$ (515)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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