Stockholders' Equity - Additional Information (Details) - USD ($)			12 Months Ended
	Jun. 13, 2018	May 03, 2017	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016	Apr. 30, 2018	Dec. 14, 2017
Stockholders' Equity Note
Common stock, shares authorized			225,000,000	125,000,000	75,000,000
Common stock, par value			$ 0.0001	$ 0.0001
Common stock price per share						$ 1.86
Excess percentage of common shares outstanding							19.90%
Series C Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding			11,569,364	11,580,900
Series D Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding				2,584,174
Series A Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 5.83
Class of Warrant or Right, Outstanding			7,680,000
Series B Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 0.0001
Class of Warrant or Right, Outstanding			4,926,000		3,826,000
At Market Issuance Sales Agreement [Member] | B. Riley FBR, Inc and Oppenheimer & Co. Inc. [Member]
Stockholders' Equity Note
Percentage of sales commission	3.00%
At Market Issuance Sales Agreement [Member] | B. Riley FBR, Inc and Oppenheimer & Co. Inc. [Member] | Maximum [Member]
Stockholders' Equity Note
Aggregate offering price	$ 50,000,000
Underwritten Public Offering [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues		12,000,000
Gross proceeds from common stock and warrants		$ 15,400,000
Common stock price per share		$ 1.28
Net proceeds from common stock and warrants		$ 13,900,000
Underwritten Public Offering [Member] | Series C Warrants [Member]
Stockholders' Equity Note
Class of warrants or rights issued		12,000,000
Warrants issued, price per share		$ 1.28
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.60
Class of warrant or right term		5 years
Underwritten Public Offering [Member] | Series D Warrants [Member]
Stockholders' Equity Note
Class of warrants or rights issued		12,000,000
Warrants issued, price per share		$ 1.28
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 1.28
Class of warrant or right term		1 year
Common Stock [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			5,715,180	7,245,430	6,023,372
Stock issued during period on sales agreement				$ 12,600,000	$ 36,100,000
Sale of common stock net of fees				$ 100,000	$ 100,000
Common Stock [Member] | Series C Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			11,536
Net proceeds from common stock and warrants			$ 20,000
Common Stock [Member] | Series D Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			2,584,174
Net proceeds from common stock and warrants			$ 3,300,000
Common Stock [Member] | At Market Issuance Sales Agreement [Member] | B. Riley FBR, Inc and Oppenheimer & Co. Inc. [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			5,700,000
Stock issued during period on sales agreement			$ 8,000,000
Sale of common stock net of fees			$ 900,000