Revenue - Schedule of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands  | 
6 Months Ended | |
|---|---|---|
Jun. 30, 2019  | 
Dec. 31, 2018  | 
|
| Account receivables, net of allowance | $ 7,747 | $ 7,735 | 
| Unbilled receivables - current | 6,158 | 3,105 | 
| Deferred revenue | 4,785 | $ 6,595 | 
| Year-to-date Change [Member] | ||
| Account receivables, net of allowance | 12 | |
| Unbilled receivables - current | 3,053 | |
| Deferred revenue | $ (1,810) | |
| Changes in Account receivables, net of allowance, percentage | 0.20% | |
| Changes in Unbilled receivables - current, percentage | 98.30% | |
| Changes in Deferred revenue, percentage | (27.40%) | 
| X | ||||||||||
- Definition Percentage of change in unbilled receivables - current percentage. No definition available. 
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| X | ||||||||||
- Definition Percentage of change in account receivables, net of allowance. No definition available. 
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| X | ||||||||||
- Definition Percentage of change in deferred revenue. No definition available. 
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| X | ||||||||||
- Definition Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable, classified as current. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
- Definition Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer. No definition available. 
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| X | ||||||||||
- Details 
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