Agreements with Royalty Pharma - Schedule Represents Allocation of Transaction Consideration on a Relative Fair Value Basis to the Liability and the Common Stock (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Mar. 31, 2026 |
Jun. 30, 2025 |
Mar. 31, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| RP Aficamten Liability [Member] | ||||||
| Royalty Liability [Line Items] | ||||||
| Liabilities related to revenue participation right purchase agreements, net beginning balance | $ 339,580 | $ 320,764 | $ 276,636 | $ 262,599 | $ 320,764 | $ 262,599 |
| Interest accretion | 20,177 | 18,816 | 13,140 | 14,037 | ||
| Amortization of issuance costs | 0 | 0 | 0 | 0 | ||
| Royalty payment | (214) | 0 | ||||
| Liabilities related to revenue participation right purchase agreements, net ending balance | 359,543 | 339,580 | 289,776 | 276,636 | 359,543 | 289,776 |
| RPOM Liability [Member] | ||||||
| Royalty Liability [Line Items] | ||||||
| Liabilities related to revenue participation right purchase agreements, net beginning balance | 199,795 | 199,795 | 199,660 | 199,593 | 199,795 | 199,593 |
| Interest accretion | 0 | 0 | 41 | 41 | ||
| Amortization of issuance costs | 0 | 0 | 26 | 26 | ||
| Royalty payment | 0 | 0 | ||||
| Liabilities related to revenue participation right purchase agreements, net ending balance | $ 199,795 | $ 199,795 | $ 199,727 | $ 199,660 | $ 199,795 | $ 199,727 |