Commitments and Contingencies (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Future minimum commitments under facility leases commitments with terms of more than one year
2017	$ 87,910
2018	84,886
2019	91,241
2020	92,897
2021	92,097
Thereafter	735,658
Total minimum lease payments	1,184,689
Future minimum sublease income
2017	(15,687)
2018	(5,236)
2019	0
2020	0
2021	0
Thereafter	0
Total minimum lease payments	(20,923)
Rental expense	19,100	$ 18,100	$ 38,900
Fan Pier Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2017	67,206
2018	67,206
2019	72,589
2020	72,589
2021	72,589
Thereafter	535,032
Total minimum lease payments	887,211
San Diego Lease
Future minimum commitments under facility leases commitments with terms of more than one year
2017	3,147
2018	3,245
2019	6,906
2020	9,208
2021	9,208
Thereafter	138,217
Total minimum lease payments	$ 169,931
Kendall Square Lease
Operating lease
Office space used for operation (in square feet) | ft²	120
Future minimum commitments under facility leases commitments with terms of more than one year
2017	$ 20,088
2018	6,696
2019	0
2020	0
2021	0
Thereafter	0
Total minimum lease payments	26,784
Other Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2017	13,156
2018	12,975
2019	11,746
2020	11,100
2021	10,300
Thereafter	62,409
Total minimum lease payments	$ 121,686