Accrued Expenses - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Accrued Expenses [Line Items]
Accrued legal verdict expense, estimate owed	$ 31,536	$ 31,350
Eshelman v. Puma Biotechnology, Inc.
Accrued Expenses [Line Items]
Accrued legal verdict expense, estimate owed	22,400
Minimum | Hsu v. Puma Biotechnology, Inc.
Accrued Expenses [Line Items]
Accrued legal verdict expense, estimate owed	9,100
Maximum | Hsu v. Puma Biotechnology, Inc.
Accrued Expenses [Line Items]
Accrued legal verdict expense, estimate owed	$ 18,100