Property and Equipment, net - Property and equipment, net (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property and equipment, net
Property and Equipment, gross	$ 281,735	$ 219,489
Less accumulated depreciation and amortization	(62,857)	(51,810)
Property and Equipment, net	218,878	167,679	[1]
Office Equipment
Property and equipment, net
Property and Equipment, gross	10,487	9,243
Laboratory Equipment
Property and equipment, net
Property and Equipment, gross	42,258	37,203
Computer Equipment
Property and equipment, net
Property and Equipment, gross	43,079	38,184
Land
Property and equipment, net
Property and Equipment, gross	5,350	4,125
Building And Leasehold Improvements
Property and equipment, net
Property and Equipment, gross	$ 180,561	$ 130,734

[1] The condensed consolidated balance sheet at December 31, 2016 has been derived from the audited financial statements at that date.