Summary of Significant Accounting Policies - Changes in the contract assets and contract liabilities (Details) - USD ($) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Contract with Customer, Liability [Abstract] | ||
| Contract with Customer, Liability, Revenue Recognized | $ 2,686,000 | |
| Deferred Revenue | ||
| Contract with Customer, Liability [Abstract] | ||
| Deferred Revenue | $ (2,686,000) | $ 2,686,000 |
| X | ||||||||||
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Details
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