Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net loss	$ (2,846)	$ (364)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,414	2,630
Stock-based compensation	1,008	894
Bad debt expense (recovery), net	91	(19)
Deferred income taxes	(915)	(82)
Changes in operating assets and liabilities:
Accounts receivable, net	(1,189)	(6,249)
Contract assets and liabilities, net	(6,730)	(4,955)
Inventories	(6,312)	244
Income taxes	(578)	267
Prepaid expenses and other current assets	857	166
Accounts payable	(2,918)	(7,387)
Accrued liabilities	(11,035)	(10,087)
Other, net	320	(234)
Net cash used in operating activities	(27,833)	(25,176)
Investing Activities:
Purchases of short-term investments	(3,937)	(3,924)
Maturities of short-term investments	0	7,847
Purchases of property, plant and equipment, net	(436)	(961)
Net cash provided by (used in) investing activities	(4,373)	2,962
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(660)	(632)
Dividends paid	(3,048)	(3,028)
Net cash used in financing activities	(4,108)	(4,060)
Net decrease in cash and cash equivalents	(36,314)	(26,274)
Effect of exchange rate changes on cash and cash equivalents	(95)	74
Cash and cash equivalents at beginning of period	114,314	160,216
Cash and cash equivalents at end of period	$ 77,905	$ 134,016