Loss Per Share - Calculation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended
		Apr. 30, 2019	Jan. 31, 2019	Apr. 30, 2018	Jan. 31, 2018	Apr. 30, 2019	Apr. 30, 2018
Numerator
Net loss		$ (19,530)		$ (13,174)		$ (37,078)	$ (17,357)
Preferred stock dividends		(800)	$ (800)	(800)	$ (800)
Net loss attributable to common stockholders		$ (22,876)		$ (18,173)		$ (55,914)	$ (26,619)
Denominator
Weighted average basic common shares		11,090,698		6,630,272		9,683,253	6,310,964
Effect of dilutive securities	[1]	0		0		0	0
Weighted average diluted common shares		11,090,698		6,630,272		9,683,253	6,310,964
Basic loss per share		$ (2.06)		$ (2.74)		$ (5.77)	$ (4.22)
Diluted loss per share	[1]	$ (2.06)		$ (2.74)		$ (5.77)	$ (4.22)
Series A Warrant [Member]
Numerator
Warrant exchange		$ (3,169)				$ (3,169)
Series B Preferred Stock [Member]
Numerator
Preferred stock dividends		(800)		$ (800)		(1,600)	$ (1,600)
Series C Preferred Stock [Member]
Numerator
Preferred stock deemed contributions (dividends) and redemption value adjustment, net		1,599		(4,199)		(7,406)	(7,662)
Series D Preferred Stock [Member]
Numerator
Preferred stock deemed dividends and redemption accretion		$ (976)		$ 0		$ (6,661)	$ 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.