Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Commitments And Contingencies [Line Items]
Purchase order commitments	Approximately $33.6 million
Purchase order commitments	$ 33,600,000
Maximum period for purchase order commitments	1 year
Contingent consideration	45,840,000	43,740,000
Minimum [Member]
Commitments And Contingencies [Line Items]
Performance milestone payment term	8 years
Maximum [Member]
Commitments And Contingencies [Line Items]
Performance milestone payment term	10 years
Aggregate milestone payments	$ 320,000,000