CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (10,965)	$ (5,182)	$ (22,007)	$ (10,627)
Other comprehensive loss
Change in unrealized gains on available-for-sale securities, net of tax	31	23	5	21
Foreign currency translation adjustments	(366)	(1,966)	(1,588)	(4,618)
Total other comprehensive loss	(335)	(1,943)	(1,583)	(4,597)
Total comprehensive loss	$ (11,300)	$ (7,125)	$ (23,590)	$ (15,224)