Acquisitions of Ownership Interests in Partner Companies and Funds (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments				$ 8,026	$ 28,329
Equity method investments	$ 118,958		$ 154,666	118,958		$ 154,666
Good Start Genetics, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		$ 17,200
Convertible bridge loan	1,800
Cask Data
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		11,000
Convertible bridge loan	600
CloudMine
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		2,000				5,500
InfoBionic
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments						14,500
Convertible bridge loan		4,000
Lumesis, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments						6,200
Convertible bridge loan		200
Novasom, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments						22,000
Convertible bridge loan				1,000
Full Measure
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		2,400	$ 8,600
Aventura
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments						6,200
Equity method investments	0			0
Convertible bridge loan		300
WebLinc
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments				$ 2,000		$ 12,000
Sonobi
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments		5,400
Convertible bridge loan	3,000
Trice Medical, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	2,100	8,000
Aktana, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 1,500	$ 8,200