Liability Related to Sale of Future Royalties - Additional Information (Detail) - USD ($) $ in Millions |
Dec. 30, 2020 |
Dec. 16, 2020 |
Feb. 24, 2012 |
|---|---|---|---|
| 2012 Purchase and Sale Agreement | |||
| Liability Related to Sale of Future Royalties [Line Items] | |||
| Proceeds from sale of royalty rights | $ 124.0 | ||
| Transaction costs related to sale of potential future royalties | $ 4.4 | ||
| 2020 Purchase and Sale Agreement | |||
| Liability Related to Sale of Future Royalties [Line Items] | |||
| Proceeds from sale of royalty rights | $ 150.0 | ||
| Transaction costs related to sale of potential future royalties | $ 3.8 | ||
| Payment of transaction related to purchase and sale agreement | $ 210.0 | ||
| Payment of transaction related to purchase and sale agreement if threshold is not achieved | 240.0 | ||
| Minimum transaction royalties payments needed to pay the difference between the 2025 threshold and 2020 transaction royalties | $ 208.0 |