Variable Interest Entities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) variable_interest_entity	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2013 patent
Variable Interest Entity [Line Items]
Assets	$ 1,464,730		$ 1,612,082
Liabilities	689,134		825,801
Cash and cash equivalents	515,793	$ 503,240	745,491
Patents, net	425,685		436,339
Accounts receivable	25,608		28,272
Other non-currents assets	79,146		76,026
Noncontrolling interests	(1,777)	(1,411)
Chordant
Variable Interest Entity [Line Items]
Noncontrolling interests	300	300
Convida
Variable Interest Entity [Line Items]
Noncontrolling interests	$ 1,500	$ 1,100
Primary Beneficiary
Variable Interest Entity [Line Items]
Number of variable interest entities | variable_interest_entity	3
Assets	$ 65,300		60,600
Liabilities	3,900		5,400
Cash and cash equivalents	23,800		18,500
Accounts receivable and prepaid assets	3,200
Patents, net	$ 38,300		39,300
Accounts receivable			1,700
Other non-currents assets			$ 1,300
Number of patents (more than) | patent				500