Stockholders' Equity - Additional Information (Details) - USD ($)			3 Months Ended
	Jun. 13, 2018	May 03, 2017	Jan. 31, 2019	Oct. 31, 2018
Series C Warrants [Member]
Stockholders' Equity Note
Class of Warrant or Right, Outstanding			11,569,364	11,569,364
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
Common Stock [Member] | Series C Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			0
Common Stock [Member] | Series D Warrants [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			0
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] | Maximum [Member] | B. Riley FBR, Inc and Oppenheimer & Co. Inc. [Member]
Stockholders' Equity Note
Aggregate offering price	$ 50,000,000
At Market Issuance Sales Agreement [Member] | Common Stock [Member] | B. Riley FBR, Inc and Oppenheimer & Co. Inc. [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues			0
Underwritten Public Offering [Member]
Stockholders' Equity Note
Stock issued during period, shares, new issues		12,000,000
Underwritten Public Offering [Member] | Series C Warrants [Member]
Stockholders' Equity Note
Class of warrants or rights issued		12,000,000
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