Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended						12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Quarterly Financial Data [Line Items]
Gain on sale of strategic investment					$ 500			$ 700	$ 492	$ 842	$ 1,430
Royalty payment				$ 600
Claim settlement	$ 100	$ 300	$ 2,500						2,500
Impairment losses on strategic investments			1,500			$ 1,200			1,500	1,184	158
Contingent royalties			$ 800
Allocated share-based compensation expense									$ 2,381	$ 3,337	$ 2,552
Director [Member]
Quarterly Financial Data [Line Items]
Allocated share-based compensation expense							$ 900