Facility Lease Exit - Additional Information (Detail)		1 Months Ended	6 Months Ended	12 Months Ended
	May 09, 2012 USD ($) ft²	Sep. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred				$ 0
Notice period to surrender remaining leased space				90 days
3rd Amendment, Lease exit costs associated with 650 E. Kendall.
Facility Lease Exit Disclosure [Line Items]
Lease exit expense incurred		$ 15,600,000
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			$ 2,900,000		$ 2,900,000
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			$ 3,500,000
BMR-650 E KENDALL B LLC
Facility Lease Exit Disclosure [Line Items]
Lease agreement, square feet of property leased | ft²	126,065
Lease agreement, initial term	12 years 7 months
Operating lease, maximum lease improvements reimbursement amount	$ 14,900,000
Operating lease, rent expense					(9,500,000)	$ 4,300,000
Recognition of deferred rent credits					$ 10,600,000	$ 3,800,000