Restructuring Charges - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restructuring Cost And Reserve [Line Items]
Employee-related costs	$ 9,211,000us-gaap_SeveranceCosts1	$ 5,736,000us-gaap_SeveranceCosts1	$ 573,000us-gaap_SeveranceCosts1
Stock based compensation expense	7,679,000	5,002,000	3,854,000
Lease termination costs	1,332,000us-gaap_BusinessExitCosts1	5,202,000us-gaap_BusinessExitCosts1	1,887,000us-gaap_BusinessExitCosts1
Employee-Related Restructuring Reserves [Member]
Restructuring Cost And Reserve [Line Items]
Employee-related costs	8,300,000	5,700,000	573,000
Stock based compensation expense	947,000
Lease termination costs	$ 1,300,000	$ 5,200,000	$ 1,900,000

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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