Summary of Significant Accounting Policies - Changes in the contract assets and contract liabilities (Details) |
12 Months Ended |
|---|---|
|
Dec. 31, 2020
USD ($)
| |
| Summary of Significant Accounting Policies | |
| Amounts included in contract liability at the beginning of the period | $ 2,686,000 |
| X | ||||||||||
- References No definition available.
|
| 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
|