Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities:
Net loss	$ (8,691)	$ (4,343)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	9,494	9,218
Amortization	161	263
Stock-based compensation	2,485	2,304
Bad debt expense (recovery)	110
Bad debt expense (recovery)		(226)
Deferred income tax benefit	(2,840)	(915)
Gain on amended supply agreement	(507)	(1,522)
Cash received from amended supply agreement	0	2,333
Changes in operating assets and liabilities:
Accounts receivable, net	(19,252)	23,847
Costs and billings in excess of estimated earnings on uncompleted contracts	(6,211)	17,861
Inventories	(4,542)	7,519
Income taxes	945	(6,206)
Prepaid expenses and other current assets	924	2,022
Accounts payable	1,288	(9,627)
Accrued liabilities	355	(14,017)
Other, net	224	(1,387)
Net cash provided by (used in) operating activities	(26,057)	27,124
Investing Activities:
Purchases of short-term investments	(20,712)	(60,018)
Maturities of short-term investments	31,444	4,654
Changes in restricted cash	1,264	(25,301)
Purchases of property, plant and equipment	(3,978)	(2,520)
Proceeds from sale of property, plant and equipment	56	11
Net cash provided by (used in) investing activities	8,074	(83,174)
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(578)	(398)
Dividends paid	(8,934)	(8,904)
Net cash used in financing activities	(9,912)	(9,702)
Net decrease in cash and cash equivalents	(27,895)	(65,752)
Effect of exchange rate changes on cash and cash equivalents	(389)	516
Cash and cash equivalents, beginning of period	68,359	97,720
Cash and cash equivalents, end of period	$ 40,075	$ 32,484