Summary of Significant Accounting Policies - Contract Balances (Details) - USD ($) |
12 Months Ended | |
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Dec. 31, 2020 |
Dec. 31, 2019 |
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| Summary of Significant Accounting Policies | ||
| Contract liabilities | $ 373,000 | $ 451,000 |
| Revenue included in contract balances | $ 436,000 |
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- References No definition available.
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- 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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- 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
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