| Restructuring - (Schedule of Restructuring and Related Costs) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | |
| Restructuring Cost and Reserve [Line Items] | ||||
| Restructuring charges | $ 24 | $ 42 | $ 64 | $ 83 | 
| 2015 Plan [Member] | ||||
| Restructuring Cost and Reserve [Line Items] | ||||
| Restructuring Reserve, Beginning Balance | 93 | |||
| Restructuring charges | 24 | $ 42 | 64 | $ 83 | 
| Cash payments | (63) | |||
| Restructuring Reserve, Ending Balance | $ 94 | 94 | ||
| Other Restructuring [Member] | 2015 Plan [Member] | ||||
| Restructuring Cost and Reserve [Line Items] | ||||
| Restructuring charges | $ 64 | |||
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- Definition Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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