Commitments and Contingencies (Details) - USD ($) $ in Thousands |
Dec. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2014 |
---|---|---|---|
Commitments and Contingencies Disclosure [Abstract] | |||
Nonrecourse liability related to sale of future royalties; long term | $ 19,248 | $ 22,575 | $ 30,000 |