Operating Segments - Active Partner Companies by Segment (Detail)	Sep. 30, 2015	Jun. 30, 2015	May. 31, 2015	Apr. 30, 2015	Feb. 28, 2015	Jan. 31, 2015
Aventura [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage						19.90%
meQuilibrium [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage				31.50%
CloudMine [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage					30.10%
Full Measure [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage						25.40%
InsideVault [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage		24.50%
Sonobi [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage			22.60%
Healthcare [Member] | AdvantEdge Healthcare Solutions, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	40.10%
Healthcare [Member] | Aventura [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	19.90%
Healthcare [Member] | Good Start Genetics, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	29.80%
Healthcare [Member] | InfoBionic [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	38.50%
Healthcare [Member] | Medivo, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	34.50%
Healthcare [Member] | meQuilibrium [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	31.50%
Healthcare [Member] | Novasom, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	31.70%
Healthcare [Member] | Propeller [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	24.60%
Healthcare [Member] | Putney, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	28.20%
Healthcare [Member] | Syapse, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	24.40%
Healthcare [Member] | Trice [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	27.70%
Technology [Member] | AppFirst, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	34.20%
Technology [Member] | Apprenda [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	29.50%
Technology [Member] | Beyond.com, Inc [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	38.20%
Technology [Member] | Bridgevine, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under cost method, percentage	17.20%
Technology [Member] | CloudMine [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	30.10%
Technology [Member] | Clutch Holdings, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	39.30%
Technology [Member] | Full Measure [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	25.40%
Technology [Member] | Hoopla Software, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	25.60%
Technology [Member] | InsideVault [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	24.50%
Technology [Member] | Lumesis, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	44.70%
Technology [Member] | MediaMath, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	20.60%
Technology [Member] | Pneuron [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	35.40%
Technology [Member] | Sonobi [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	22.60%
Technology [Member] | Spongecell, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	23.00%
Technology [Member] | Transactis [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	24.50%
Technology [Member] | WebLinc [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest under equity method, percentage	29.20%