Loss Per Share - Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended						9 Months Ended
		Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Numerator
Net loss		$ (15,331)	$ (14,769)	$ (40,151)	$ (5,311)	$ (19,530)	$ (17,548)	$ (70,251)	$ (42,389)
Preferred dividends — Series B		(800)	$ (800)	$ (931)		$ (800)	$ (800)
Net loss attributable to common stockholders		(16,131)			$ (8,328)			(72,782)	(64,242)
Series A warrant exchange		$ (1,694)						$ (39,311)	$ 0
Denominator
Weighted average basic common shares		217,966,402			45,069,911			210,389,907	21,608,427
Effect of dilutive securities	[1]	0			0			0	0
Weighted average diluted common shares		217,966,402			45,069,911			210,389,907	21,608,427
Basic loss per share		$ (0.07)			$ (0.18)			$ (0.35)	$ (2.97)
Diluted loss per share	[1]	$ (0.07)			$ (0.18)			$ (0.35)	$ (2.97)
Series A Warrant [Member]
Numerator
Series A warrant exchange		$ 0			$ 0			$ 0	$ (3,169)
Series B Preferred Stock [Member]
Numerator
Preferred dividends — Series B		(800)			(810)			(2,531)	(2,410)
Series C Preferred Stock [Member]
Numerator
Preferred stock deemed contributions (dividends) and redemption value adjustment, net		0			884			0	(6,522)
Series D Preferred Stock [Member]
Numerator
Preferred stock deemed dividends and redemption accretion		$ 0			$ (3,091)			$ 0	$ (9,752)

[1] Due to the net loss to common stockholders in each of the periods presented above, diluted loss per share was computed without consideration to potentially dilutive instruments as their inclusion would have been anti-dilutive.