Stockholders' Equity - Schedule of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Oct. 31, 2016
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued and outstanding	3,246,042	7,374,454
Preferred stock, net carrying value	$ 111,195	$ 10,153
Preferred stock, aggregate liquidation preference	$ 2,140	$ 4,854
Preferred stock, common shares issuable upon conversion	9,020,287	2,783,000
Series A Convertible Preferred Stock [Member]
Preferred stock, shares authorized	8,830,000	8,830,000
Preferred stock, shares issued and outstanding	3,146,671	7,138,158
Preferred stock, net carrying value	$ 769	$ 1,745
Preferred stock, aggregate liquidation preference	$ 2,140	$ 4,854
Preferred stock, common shares issuable upon conversion	713,245	1,189,693
Series B Convertible Preferred Stock [Member]
Preferred stock, shares authorized	54,250	54,250
Preferred stock, shares issued and outstanding	47,689	54,201
Preferred stock, net carrying value	$ 4,020	$ 4,569
Preferred stock, aggregate liquidation preference
Preferred stock, common shares issuable upon conversion	794,806	903,362
Series C Convertible Preferred Stock [Member]
Preferred stock, shares authorized	26,000	26,000
Preferred stock, shares issued and outstanding	17,965	25,763
Preferred stock, net carrying value	$ 1,401	$ 2,010
Preferred stock, aggregate liquidation preference
Preferred stock, common shares issuable upon conversion	417,791	429,392
Series D Convertible Preferred Stock [Member]
Preferred stock, shares authorized	170,000	170,000
Preferred stock, shares issued and outstanding	26,667	156,332
Preferred stock, net carrying value	$ 312	$ 1,829
Preferred stock, aggregate liquidation preference
Preferred stock, common shares issuable upon conversion	44,445	260,553
Series E Convertible Preferred Stock [Member]
Preferred stock, shares authorized	7,050
Preferred stock, shares issued and outstanding	7,050
Preferred stock, net carrying value	$ 104,693
Preferred stock, aggregate liquidation preference
Preferred stock, common shares issuable upon conversion	7,050,000
Other Authorized, Unissued [Member]
Preferred stock, shares authorized	912,700	919,750
Preferred stock, shares issued and outstanding
Preferred stock, net carrying value
Preferred stock, aggregate liquidation preference
Preferred stock, common shares issuable upon conversion