Intangible Assets - Acquired Assets (Details) - Equipois $ in Thousands  | 
12 Months Ended | 
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 Dec. 31, 2018  
USD ($) 
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| Acquired Indefinite-lived Intangible Assets [Line Items] | |
| Cost | $ 1,610 | 
| Accumulated Amortization | (1,610) | 
| Net | 0 | 
| Developed technology | |
| Acquired Indefinite-lived Intangible Assets [Line Items] | |
| Cost | 1,160 | 
| Accumulated Amortization | (1,160) | 
| Net | $ 0 | 
| Estimated Useful Life | 3 years | 
| Customer relationships | |
| Acquired Indefinite-lived Intangible Assets [Line Items] | |
| Cost | $ 70 | 
| Accumulated Amortization | (70) | 
| Net | $ 0 | 
| Estimated Useful Life | 3 years | 
| Customer trade name | |
| Acquired Indefinite-lived Intangible Assets [Line Items] | |
| Cost | $ 380 | 
| Accumulated Amortization | (380) | 
| Net | $ 0 | 
| Estimated Useful Life | 3 years | 
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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 Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available. 
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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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