Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - USD ($) $ in Thousands  | 
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2020  | 
Sep. 30, 2019  | 
Sep. 30, 2020  | 
Sep. 30, 2019  | 
|
| Statement of Stockholders' Equity [Abstract] | ||||
| Marketable debt securities, net realized losses | $ 2 | $ 1 | $ 4 | $ 9 | 
| X | ||||||||||
- Definition Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). No definition available. 
  | 
| X | ||||||||||
- References No definition available. 
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