Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Apr. 01, 2014	Jan. 24, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Liabilities, fair value disclosure		$ 0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Liabilities, fair value disclosure	$ 0
Convertible Senior Subordinated Notes | Early Conversion Payment
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Conversion price of per principal amount (in dollars per share)				$ 83.33
Principal amount of convertible notes, denominator				$ 1,000
Convertible Senior Subordinated Notes | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Estimated fair value Notes	$ 105,900,000	$ 127,100,000
2018 Notes | Convertible Senior Subordinated Notes
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Principal amount of convertible notes, denominator				$ 1,000
2018 Notes | Convertible Senior Subordinated Notes | Early Conversion Payment
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Conversion price of per principal amount (in dollars per share)				$ 83.33
Principal amount of convertible notes, denominator				$ 1,000
2019 Notes | Convertible Senior Subordinated Notes
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Conversion price of per principal amount (in dollars per share)			$ 83.33
Principal amount of convertible notes, denominator			$ 1,000