Summarized Data for Each of the Quarters (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 20,587	$ 21,270	$ 19,247	$ 14,644	$ 23,683	$ 14,195	$ 20,558	$ 15,285	$ 75,748	$ 73,721	$ 62,060
Gross profit (loss)	5,264	4,677	1,999	(968)	(9,686)	(5,112)	(2,558)	(3,327)	10,972	(20,683)	(19,363)
Loss from operations	(780)	(5,136)	(5,222)	(9,605)	(18,178)	(13,774)	(11,060)	(11,311)	(20,743)	(54,323)	(55,510)
Other income (expense), net	610	393	(183)	131	231	46	(102)	40	951	215	177
Net loss	$ (207)	$ (4,796)	$ (4,729)	$ (9,480)	$ (19,207)	$ (14,376)	$ (11,503)	$ (11,705)	$ (19,212)	$ (56,791)	$ (45,970)
Basic loss per share	$ (0.02)	$ (0.36)	$ (0.36)	$ (0.72)	$ (1.46)	$ (1.09)	$ (0.88)	$ (0.89)	$ (1.45)	$ (4.32)	$ (3.52)
Diluted loss per share	$ (0.02)	$ (0.36)	$ (0.36)	$ (0.72)	$ (1.46)	$ (1.09)	$ (0.88)	$ (0.89)	$ (1.45)	$ (4.32)	$ (3.52)