Liabilities Measured at Fair Value Using Level 3 Inputs (Detail) - Contingent Payment $ in Thousands |
12 Months Ended |
---|---|
Dec. 31, 2017
USD ($)
| |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Contingent acquisition consideration payable, Beginning balance | $ 161,637 |
Changes in the fair value of other contingent acquisition consideration payable | 14,587 |
Foreign exchange remeasurement of Euro denominated contingent acquisition consideration payable | 20,487 |
Contingent acquisition consideration payable, Ending balance | 188,966 |
Huxley Pharmaceuticals, Inc. | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Milestone payments to former shareholders | (3,500) |
Firdapse | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | |
Reversal of contingent liability related to revised estimate of Firdapse FDA acceptance and approval milestones | $ (4,245) |