Facility Lease Exit - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Mar. 31, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Facility Lease Exit Disclosure [Line Items]
Notice period to surrender remaining leased space					90 days
Write-off of leasehold improvements					$ 200	$ 7,600	$ 100
3rd Amendment, Lease exit costs associated with 650 E. Kendall.
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred	$ 15,600
Leased space surrendering date					May 29, 2015
3rd Amendment, Lease exit costs associated with 650 E. Kendall. | Leasehold Improvements
Facility Lease Exit Disclosure [Line Items]
Additional charge to depreciation expense due to revision of estimated useful life					$ 2,900
3rd Amendment, Lease exit costs associated with 650 E. Kendall. | Deferred Rent And Leasehold Improvement
Facility Lease Exit Disclosure [Line Items]
Additional charge to depreciation expense due to revision of estimated useful life					3,500
Lease exit costs associated with 650 E. Kendall.
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred		$ 1,900	$ 15,200	$ 15,200	500	17,142
Write-off of leasehold improvements					$ 200	7,600
Lease exit costs associated with 650 E. Kendall. | Deferred rent
Facility Lease Exit Disclosure [Line Items]
Lease exit write-off cost						$ 14,000