Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale marketable securities	$ 149,100	$ 0
Prepaid expenses and other current assets	102,551	93,622
Total	150,698	(578)
Foreign exchange derivative assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets	1,021	424
1.25% Notes Embedded Cash Conversion Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	(17,659)	(81,210)
1.25% Call Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	17,080	80,208
Non-marketable Convertible Note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	1,156	0
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale marketable securities	149,100	0
Total	149,100	0
Level 1 [Member] | Foreign exchange derivative assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets	0	0
Level 1 [Member] | 1.25% Notes Embedded Cash Conversion Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	0	0
Level 1 [Member] | 1.25% Call Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	0	0
Level 1 [Member] | Non-marketable Convertible Note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	0	0
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale marketable securities	0	0
Total	1,021	424
Level 2 [Member] | Foreign exchange derivative assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets	1,021	424
Level 2 [Member] | 1.25% Notes Embedded Cash Conversion Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	0	0
Level 2 [Member] | 1.25% Call Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	0	0
Level 2 [Member] | Non-marketable Convertible Note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	0	0
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available for sale marketable securities	0	0
Total	577	(1,002)
Level 3 [Member] | Foreign exchange derivative assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepaid expenses and other current assets	0	0
Level 3 [Member] | 1.25% Notes Embedded Cash Conversion Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	(17,659)	(81,210)
Level 3 [Member] | 1.25% Call Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	17,080	80,208
Level 3 [Member] | Non-marketable Convertible Note [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	$ 1,156	$ 0