CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Operating Activities:
Net income (loss)	$ (9,486)	$ 15,510	$ 9,439
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	12,400	12,979	13,120
Amortization	355	352	435
Stock-based compensation	2,724	4,883	3,171
Excess tax benefit from stock-based compensation	0	387	191
Bad debt expense/(recovery)	(160)	187	(29)
Deferred income tax expense	100	2,330	10,521
Gain on amended supply agreement	(2,029)	(2,029)	(2,029)
Cash received from amended supply agreement	2,333	2,333	2,333
Changes in operating assets and liabilities:
Accounts receivable	47,983	369	391
Costs and billings in excess of estimates on uncompleted contracts	(3,270)	39,612	(17,430)
Inventories	8,213	6,159	(572)
Income taxes	(6,758)	(195)	(1,647)
Prepaid expenses and other current assets	453	861	4,222
Accounts payable	(2,417)	(11,658)	(4,992)
Accrued liabilities	(11,676)	3,927	(3,373)
Other, net	(1,950)	(1,101)	(833)
Net cash provided by operating activities	36,815	74,906	12,918
Investing Activities:
Purchases of property, plant and equipment	(3,636)	(3,044)	(34,719)
Proceeds from sale of property, plant and equipment	12	187	112
Purchases of short-term investments	(60,018)	0	0
Maturities of short-term investments	33,189	0	0
Changes in restricted cash	(24,851)	0	0
Net cash used in investing activities	(55,304)	(2,857)	(34,607)
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)	(400)
Excess tax benefit from stock-based compensation	0	(387)	(191)
Shares withheld in lieu of employee tax withholding	(398)	(1,000)	(740)
Purchase of treasury shares	0	(3,740)	(21,259)
Dividends paid	(11,875)	(11,845)	(12,358)
Net cash used in financing activities	(12,673)	(17,372)	(34,948)
Net increase (decrease) in cash and cash equivalents	(31,162)	54,677	(56,637)
Effect of exchange rate changes on cash and cash equivalents	1,801	(526)	(2,912)
Cash and cash equivalents, beginning of period	97,720	43,569	103,118
Cash and cash equivalents, end of period	$ 68,359	$ 97,720	$ 43,569