Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2017
Cash flows from operating activities:
Net loss	$ (15,881)	$ (17,001)	$ (33,238)	$ (43,924)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation			2,309	3,432
Loss from change in fair value of embedded derivatives			53	94
Depreciation			6,525	6,502
Non-cash interest expense on preferred stock and debt obligations			4,418	4,607
Unrealized foreign exchange (gains) losses			(280)	1,052
Deferred income taxes			(3,035)	0
Project asset impairment			485	0
Other non-cash transactions, net			203	165
Decrease (increase) in operating assets:
Accounts receivable			33,109	(9,296)
Inventories			22,138	(5,460)
Other assets			(2,511)	85
Increase (decrease) in operating liabilities:
Accounts payable			3,563	(8,147)
Accrued liabilities			(4,534)	(7,547)
Deferred revenue			141	616
Net cash provided by (used in) operating activities			29,346	(57,821)
Cash flows from investing activities:
Capital expenditures			(7,625)	(10,469)
Project asset expenditures			(28,411)	(12,796)
Cash acquired from asset acquisition			0	633
Net cash used in investing activities			(36,036)	(22,632)
Cash flows from financing activities:
Repayment of debt			(13,080)	(7,467)
Proceeds from debt			13,091	17,891
Payment of deferred financing costs			(352)	(119)
Payment of preferred dividends and return of capital			(3,134)	(3,102)
Cash received for common stock issued for stock plans			0	86
Proceeds from sale of common stock and warrant exercises, net			10,013	28,455
Net cash provided by financing activities			6,538	35,744
Effects on cash from changes in foreign currency rates			(41)	161
Net decrease in cash, cash equivalents and restricted cash			(193)	(44,548)
Cash, cash equivalents and restricted cash-beginning of period			87,448	118,316	$ 118,316
Cash, cash equivalents and restricted cash-end of period	$ 87,255	$ 73,768	87,255	73,768	$ 87,448
Supplemental cash flow disclosures:
Cash interest paid			1,960	2,022
Noncash financing and investing activity:
Common stock issued for Employee Stock Purchase Plan in settlement of prior year accrued employee contributions			0	50
Net noncash reclass of project assets to inventory			7,756	7,282
Assumption of debt in conjunction with asset acquisition			0	2,289
Acquisition of project assets			0	2,386
Series C preferred share conversions			17,983	0
Accrued purchase of fixed assets, cash paid in subsequent period			798	1,581
Accrued purchase of project assets, cash paid in subsequent period			$ 2,026	$ 2,597