Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 63,100	$ 4,852	$ 4,988
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, amortization and accretion expense	2,952	8,518	8,688
Stock-based compensation expense	4,586	4,439	4,209
Deferred income taxes	24,080	(24,080)	0
Gain on sale of an investment	0	(307)	(4,800)
Provision adjustments related to doubtful accounts	556	245	119
Provision adjustments related to product warranty	838	2,114	2,914
Provision for losses on inventory purchase commitments	0	306	0
Change in fair value of financial instruments	(122)	(34)	(515)
Gain from change in estimate on ARO obligation	(845)	0	0
Reclassification of foreign currency translation adjustment	(744)	0	0
Net loss on disposal (gain) of equipment	237	(100)	0
Settlement of customer related warranty claim	(442)	0	0
Expiration of specific historical sales allowance	(345)	0	0
Adjustments of unrecognized gross tax benefits	(207)	0	0
Non-cash insurance proceeds	0	0	(16,134)
Gain on sale of assets	0	0	(338)
Total non-cash adjustments	(58,408)	(8,899)	(5,857)
Changes in operating assets and liabilities:
Accounts receivable	3,526	(3,290)	(4,967)
Inventory	(3,440)	5,481	2,016
Other assets	359	2,879	5,370
Accounts payable	(3,231)	3,113	(14,032)
Accrued expenses and other current liabilities	(5,823)	(3,135)	(9,623)
Total change in operating assets and liabilities	(8,609)	5,048	(21,236)
Net cash (used in) provided by operating activities	(3,917)	1,001	(22,105)
Cash flows from investing activities:
Cash proceeds from sale of investment	0	307	0
Cash proceeds from sale of equity method investment	0	0	4,800
Purchase of equipment	(2,799)	(3,001)	(7,242)
Deposits on equipment orders	0	0	(3)
Flood-related insurance proceeds from equipment	0	0	5,373
Proceeds from sale of assets	0	0	1,150
Decrease (increase) in restricted cash	1,107	(667)	(733)
Proceeds from disposal of property, plant and equipment	50	100	484
Net cash provided by (used in) investing activities	165,276	(3,261)	3,829
Cash flows from financing activities:
Payments on credit facilities	(26,518)	4,813	2,390
Repurchases of common stock	(45,650)	0	0
Proceeds from sale of common stock	0	0	21,189
Proceeds from stock plans	1,902	1,763	1,705
Net cash (used in) provided by financing activities	(70,266)	6,576	25,284
Effect of exchange rate changes on foreign currency	105	267	49
Net increase in cash and cash equivalents	91,198	4,583	7,057
Cash and cash equivalents at beginning of period	20,687	16,104	9,047
Cash and cash equivalents at end of period	111,885	20,687	16,104
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	194	429	704
Cash paid during the period for income taxes	938	0	15
NON-CASH INVESTING AND FINANCING ACTIVITIES
Forgiveness of capital lease and accounts payable	0	0	10,761
Changes in accounts payable related to purchases of equipment	514	0	0
Photovoltaics Business [Member]
Adjustments to reconcile net income to net cash used in operating activities:
Gain on sale of business	(86,958)	0	0
Cash flows from investing activities:
Proceeds from sale of business	149,936	0	0
Digital Products Business [Member]
Adjustments to reconcile net income to net cash used in operating activities:
Gain on sale of business	(1,994)	0	0
Cash flows from investing activities:
Proceeds from sale of business	$ 16,982	$ 0	$ 0