Summarized Data for Each of the Quarters (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 23,683	$ 14,195	$ 20,558	$ 15,285	$ 16,314	$ 17,678	$ 14,931	$ 13,137	$ 73,721	$ 62,060	$ 84,867
Gross profit (loss)	(9,686)	(5,112)	(2,558)	(3,327)	(5,467)	(2,900)	(4,594)	(6,402)	(20,683)	(19,363)	(11,200)
Loss from operations	(18,178)	(13,774)	(11,060)	(11,311)	(14,816)	(12,015)	(13,987)	(14,692)	(54,323)	(55,510)	(52,555)
Other income (expense), net	231	46	(102)	40	2	(617)	719	73	215	177	2,721
Net loss	$ (19,207)	$ (14,376)	$ (11,503)	$ (11,705)	$ (12,309)	$ (11,654)	$ (10,965)	$ (11,042)	$ (56,791)	$ (45,970)	$ (32,641)
Basic loss per share	$ (1.46)	$ (1.09)	$ (0.88)	$ (0.89)	$ (0.94)	$ (0.89)	$ (0.84)	$ (0.85)	$ (4.32)	$ (3.52)	$ (2.51)
Diluted loss per share	$ (1.46)	$ (1.09)	$ (0.88)	$ (0.89)	$ (0.94)	$ (0.89)	$ (0.84)	$ (0.85)	$ (4.32)	$ (3.52)	$ (2.51)