Property and equipment, net - Property and equipment, net (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property and equipment, net
Property and Equipment, gross	$ 538,366	$ 499,437
Less accumulated depreciation and amortization	(128,332)	(121,870)
Property and Equipment, net	410,034	377,567	[1]
Office equipment
Property and equipment, net
Property and Equipment, gross	15,285	15,303
Laboratory equipment
Property and equipment, net
Property and Equipment, gross	72,352	70,510
Computer equipment
Property and equipment, net
Property and Equipment, gross	60,077	59,069
Land
Property and equipment, net
Property and Equipment, gross	10,227	10,203
Building and leasehold improvements
Property and equipment, net
Property and Equipment, gross	208,276	208,293
Operating lease right-of-use assets
Property and equipment, net
Property and Equipment, gross	18,641	19,672
Construction in Progress
Property and equipment, net
Property and Equipment, gross	$ 153,508	$ 116,387

[1] The condensed consolidated balance sheet at December 31, 2019 has been derived from the audited consolidated financial statements at that date.