Consolidated Statements of Cash Flows - USD ($)
 12 Months Ended
Jul. 31, 2017
Jul. 31, 2016
Operating activities    
Net loss $ (6,263,000) $ (14,371,000)
Adjustments to reconcile net loss to net cash used in operating activities:    
Share-based compensation 1,070,000 1,902,000
Amortization of stock issued for services 144,000 225,000
Fair value of derivative liabilities in excess of proceeds 1,867,000
Impairment of patents 48,000
Depreciation and amortization 276,000 219,000
Inventory write-off 50,000
Change in fair value of derivative liabilities 277,000 5,481,000
Changes in operating assets and liabilities:    
Accounts receivable (34,000) (74,000)
Inventories 27,000 (143,000)
Prepaid expenses (58,000) (8,000)
Accounts payable and accrued liabilities (59,000) (131,000)
Deferred rent 8,000 (6,000)
Net cash used in operating activities (4,562,000) (4,991,000)
Investing activities    
Investment in patents (20,000) (15,000)
Purchases of property, plant and equipment (206,000) (390,000)
Net cash used in investing activities (226,000) (405,000)
Financing activities    
Net proceeds from the sale of common stock 1,049,000 8,000,000
Net proceeds from the exercise of warrants 185,000 1,269,000
Net cash provided by financing activities 1,234,000 9,269,000
Net decrease and increase in cash and cash equivalents (3,554,000) 3,873,000
Cash and cash equivalents at beginning of year 5,194,000 1,321,000
Cash and cash equivalents at end of year 1,640,000 5,194,000
Supplemental disclosure of cash flow information    
Cash paid for taxes 7,000 2,000
Noncash Investing and Financing activities    
Warrant liability removed due to settlements 226,000 13,550,000
Restricted stock unit cancelation 38,000
Fair value of warrant liability at issuance 9,867,000
Common stock issued for prepaid services $ 290,000