Accounts Receivable (Schedule of Accounts Receivable) (Details) - USD ($) $ in Thousands |
Dec. 31, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Accounts Receivable [Abstract] | ||
| Accounts receivable | $ 4,627 | $ 5,453 |
| Less allowance for doubtful accounts | (139) | (139) |
| Accounts receivable, net | $ 4,488 | $ 5,314 |