Loss Per Share - Calculation of Basic and Diluted Loss Per Share (Details) - USD ($)			3 Months Ended						9 Months Ended
		May 15, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Numerator
Net loss			$ (5,311,000)			$ (15,881,000)			$ (42,389,000)	$ (33,238,000)
Preferred stock dividends				$ (800,000)	$ (800,000)	(800,000)	$ (800,000)	$ (800,000)
Net loss attributable to common stockholders			$ (8,328,000)			$ (17,620,000)			$ (64,242,000)	$ (44,239,000)
Denominator
Weighted average basic common shares			45,069,911			7,191,457			21,608,427	6,607,687
Effect of dilutive securities	[1]		0			0			0	0
Weighted average diluted common shares			45,069,911			7,191,457			21,608,427	6,607,687
Basic loss per share			$ (0.18)			$ (2.45)			$ (2.97)	$ (6.70)
Diluted loss per share	[1]		$ (0.18)			$ (2.45)			$ (2.97)	$ (6.70)
Series A Warrant [Member]
Numerator
Warrant exchange									$ (3,169,000)
Series B Preferred Stock [Member]
Numerator
Preferred stock dividends		$ 0	$ (810,000)			$ (800,000)			(2,410,000)	$ (2,400,000)
Series C Preferred Stock [Member]
Numerator
Preferred stock deemed contributions (dividends) and redemption value adjustment, net			884,000			(939,000)			(6,522,000)	(8,601,000)
Series D Preferred Stock [Member]
Numerator
Preferred stock deemed dividends and redemption accretion			$ (3,091,000)			$ 0			$ (9,752,000)	$ 0

[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 antidilutive.