Property and equipment, net - Property and equipment, net (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Property and equipment, net
Property and Equipment, gross	$ 183,006	$ 131,269
Less accumulated depreciation and amortization	(44,493)	(45,263)
Property and Equipment, net	138,513	86,006	[1]
Office Equipment
Property and equipment, net
Property and Equipment, gross	9,131	6,753
Laboratory Equipment
Property and equipment, net
Property and Equipment, gross	34,797	31,296
Computer Equipment
Property and equipment, net
Property and Equipment, gross	30,464	22,491
Land
Property and equipment, net
Property and Equipment, gross	3,825
Building And Leasehold Improvements
Property and equipment, net
Property and Equipment, gross	$ 104,789	$ 70,729

[1] The condensed consolidated balance sheet at December 31, 2015 has been derived from the audited financial statements at that date.