Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities:
Net loss	$ (8,992)	$ (1,128)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	6,307	6,138
Amortization	117	176
Stock-based compensation	2,067	1,820
Bad debt expense (recovery)	92	(97)
Deferred income tax benefit	(3,060)	(243)
Gain on amended supply agreement	(507)	(1,015)
Changes in operating assets and liabilities:
Accounts receivable, net	(14,272)	34,084
Costs and billings in excess of estimated earnings on uncompleted contracts	10,251	(2,074)
Inventories	(3,561)	6,088
Income taxes	768	(524)
Prepaid expenses and other current assets	2,156	(1,038)
Accounts payable	1,589	(6,929)
Accrued liabilities	(4,051)	(14,397)
Other, net	489	(1,191)
Net cash provided by (used in) operating activities	(10,607)	19,670
Investing Activities:
Purchases of short-term investments	(20,712)	(14,874)
Maturities of short-term investments	26,019	0
Changes in restricted cash	(5,627)	0
Purchases of property, plant and equipment	(2,815)	(1,702)
Proceeds from sale of property, plant and equipment	55	0
Net cash used in investing activities	(3,080)	(16,576)
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(438)	(398)
Dividends paid	(5,954)	(5,934)
Net cash used in financing activities	(6,792)	(6,732)
Net decrease in cash and cash equivalents	(20,479)	(3,638)
Effect of exchange rate changes on cash and cash equivalents	357	(614)
Cash and cash equivalents, beginning of period	68,359	97,720
Cash and cash equivalents, end of period	$ 48,237	$ 93,468