Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
$ 302,236
|
$ 500,869
|
| Contingent purchase consideration, fair value |
0
|
24,661
|
| Liabilities at fair value |
|
24,661
|
| Fair Value, Inputs, Level 1 |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
227,182
|
251,037
|
| Fair Value, Inputs, Level 2 |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
75,054
|
249,832
|
| Fair Value, Inputs, Level 3 |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Contingent purchase consideration, fair value |
|
24,661
|
| Liabilities at fair value |
|
24,661
|
| Money Market |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
227,182
|
251,037
|
| Money Market | Fair Value, Inputs, Level 1 |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
227,182
|
251,037
|
| U.S. Treasury Securities |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
75,054
|
249,832
|
| U.S. Treasury Securities | Fair Value, Inputs, Level 2 |
|
|
| Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |
|
|
| Assets at fair value |
$ 75,054
|
$ 249,832
|