Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 8,266	$ 63,100	$ 4,852
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation, amortization and accretion expense	2,506	2,952	8,518
Stock-based compensation expense	2,086	4,586	4,439
Deferred income taxes	0	24,080	(24,080)
Gain on sale of an investment	0	0	(307)
Provision adjustments related to doubtful accounts	23	556	245
Provision adjustments related to product warranty	376	838	2,114
Provision for losses on inventory purchase commitments	0	0	306
Change in fair value of financial instruments	0	(122)	(34)
Gain from change in estimate on ARO obligation	0	(845)	0
Reclassification of foreign currency translation adjustment	0	(744)	0
Recognition of previously deferred gain on sale of assets from discontinued operations	(3,804)	0
Gain on reduction of product warranty of discontinued operations	(423)	0
Gain on settlement of solar power assets and obligations	(689)	0
Gain on settlement of Newark lease	(310)	0
Net (gain) loss on disposal of equipment	(41)	237	(100)
Settlement of customer related warranty claim	0	(442)	0
Total non-cash adjustments	(276)	(58,408)	(8,899)
Changes in operating assets and liabilities:
Accounts receivable	(1,171)	3,526	(3,290)
Inventory	(10,904)	(3,440)	5,481
Other assets	148	359	2,879
Accounts payable	3,179	(3,231)	3,113
Accrued expenses and other current liabilities	(4,794)	(5,823)	(3,135)
Expiration of specific historical sales allowance	0	(345)	0
Adjustments of unrecognized gross tax benefits	0	(207)	0
Total change in operating assets and liabilities	(13,542)	(8,609)	5,048
Net cash (used in) provided by operating activities	(5,552)	(3,917)	1,001
Cash flows from investing activities:
Cash proceeds from sale of investment	0	0	307
Purchase of equipment	(5,779)	(2,799)	(3,001)
(Increase) decrease in restricted cash	(590)	1,107	(667)
Receipt of escrow funds from sale of assets	1,853	0	0
Proceeds from disposal of property, plant and equipment	100	50	100
Net cash (used in) provided by investing activities	(4,416)	165,276	(3,261)
Cash flows from financing activities:
Net (payments) proceeds from borrowings of credit facilities	0	(26,518)	4,813
Repurchases of common stock	0	(45,650)	0
Payment of special dividend	(39,214)	0	0
Proceeds from stock plans	960	1,902	1,763
Net cash (used in) provided by financing activities	(38,254)	(70,266)	6,576
Effect of exchange rate changes on foreign currency	242	105	267
Net (decrease) increase in cash and cash equivalents	(47,980)	91,198	4,583
Cash and cash equivalents at beginning of period	111,885	20,687	16,104
Cash and cash equivalents at end of period	63,905	111,885	20,687
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	88	194	429
Cash paid during the period for income taxes	124	938	0
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment	282	514	0
Issuance of common stock to Board of Directors	263	413	265
Photovoltaics Business [Member]
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Gain on sale of business	0	(86,958)	0
Cash flows from investing activities:
Proceeds from sale of business	0	149,936	0
Digital Products Business [Member]
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Gain on sale of business	0	(1,994)	0
Cash flows from investing activities:
Proceeds from sale of business	$ 0	$ 16,982	$ 0