Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended				12 Months Ended
	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain on sale of investment		$ 500,000		$ 700,000	$ 492,000	$ 842,000	$ 1,430,000
Level 3 assets	$ 0		$ 0		0	$ 0
Level 3 activity					0
CeloNova BioSciences, Inc. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment loss on investment	$ 1,500,000				1,500,000
ThermopeutiX, Inc. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment loss on investment			$ 1,200,000		$ 1,200,000