6. STOCKHOLDERS' EQUITY (Details Narrative) - USD ($)	1 Months Ended	6 Months Ended
	Sep. 08, 2016	Oct. 31, 2016	Oct. 31, 2015
Stock Incentive Plans [Member]
Shares reserved for future issuance		39,525,245
ESPP [Member]
Shares reserved for future issuance		10,520,626
Warrants [Member]
Shares reserved for future issuance		273,280
Common Stock [Member]
Proceeds from issuance of stock		$ 5,966,000
Commissions and other issuance costs		185,000	$ 444,000
Common Stock [Member] | August 2015 AMI Sales Agreement [Member]
Remaining Aggregate Gross Proceeds Available Under Agreement		19,103,000
Proceeds from issuance of stock		$ 3,450,000
Shares issued, new		8,309,357
Commissions and other issuance costs		$ 108,000
Common Stock [Member] | Equity Distribution Agreement [Member]
Remaining Aggregate Gross Proceeds Available Under Agreement		10,515,000
Proceeds from issuance of stock		$ 2,516,000
Shares issued, new		5,637,404
Commissions and other issuance costs		$ 77,000
Series E Preferred Stock [Member]
Shares reserved for future issuance		47,785,040
If converted, Series E Preferred stock holders would receive shares of common stock. Common shares to be issued		13,731,333
Each outstanding share that could be converted into common shares		29
Proceeds from issuance of stock	$ 1,634,000
Commissions and other issuance costs		$ 57,000	$ 1,000
Series E Preferred Stock [Member] | June 2014 Series E AMI Sales Agreement [Member]
Remaining Aggregate Gross Proceeds Available Under Agreement		9,101,000
Gross proceeds from issuance of preferred stock		$ 1,634,000
Shares issued, new		70,320
Commissions and other issuance costs		$ 57,000