Active Partner Companies by Segment (Detail)	Aug. 31, 2013 Quantia [Member]	Aug. 31, 2013 Clutch Holdings, LLC [Member]	Feb. 28, 2013 Clutch Holdings, LLC [Member]	Feb. 28, 2013 Pneuron, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] AdvantEdge Healthcare Solutions, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Alverix, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Crescendo Bioscience, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Good Start Genetics, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Medivo, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] NovaSom, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] NuPathe Inc. [Member]		Sep. 30, 2013 Healthcare [Member] PixelOptics, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Putney, Inc. [Member]	Sep. 30, 2013 Healthcare [Member] Quantia [Member]	Sep. 30, 2013 Healthcare [Member] Sotera Wireless, Inc. [Member]	Sep. 30, 2013 Technology [Member] AppFirst, Inc. [Member]	Sep. 30, 2013 Technology [Member] Beyond.com, Inc [Member]	Sep. 30, 2013 Technology [Member] Bridgevine, Inc. [Member]	Sep. 30, 2013 Technology [Member] Clutch Holdings, LLC [Member]	Sep. 30, 2013 Technology [Member] DriveFactor Inc. [Member]	Sep. 30, 2013 Technology [Member] Hoopla Software, Inc. [Member]	Sep. 30, 2013 Technology [Member] Lumesis, Inc. [Member]	Sep. 30, 2013 Technology [Member] MediaMath, Inc. [Member]	Sep. 30, 2013 Technology [Member] Pneuron, Inc. [Member]	Sep. 30, 2013 Technology [Member] Spongecell, Inc. [Member]	Sep. 30, 2013 Technology [Member] ThingWorx, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	34.40%	24.00%		27.60%	40.20%	49.20%		30.00%	34.50%	30.30%			24.60%	27.60%	34.40%		34.50%	38.20%	22.70%	24.00%	40.60%	25.30%	44.20%	22.50%	27.60%	23.00%	39.80%
Ownership interest under cost method, percentage			6.50%				12.60%									7.40%
Ownership interest under fair value method, percentage											16.50%	[1]

[1] The Company’s ownership interest in NuPathe was accounted for as available-for-sale securities following NuPathe’s completion of an initial public offering in August 2010. In October 2012, the Company participated in a private placement of NuPathe preferred stock units, and in conjunction with this financing, the Company placed two persons on NuPathe’s board of directors. As a result, the Company determined that it exercised significant influence over NuPathe which made the equity method of accounting applicable to its ownership interests. Instead, the Company elected the fair value option beginning in October 2012. Prior to August 2010, the Company accounted for NuPathe under the equity method.