Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Activities:
Net loss	$ (1,737)	$ (8,992)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	6,460	6,424
Stock-based compensation	1,890	2,067
Bad debt expense	101	92
Deferred income tax benefit	(346)	(3,060)
Gain on amended supply agreement	0	(507)
Changes in operating assets and liabilities:
Accounts receivable, net	12,716	(14,272)
Contract assets and liabilities, net	19,663	10,251
Inventories	(3,452)	(3,561)
Income taxes	6,198	768
Prepaid expenses and other current assets	61	2,156
Accounts payable	(7,080)	1,589
Accrued liabilities	(7,640)	(4,051)
Other, net	(787)	489
Net cash provided by (used in) operating activities	26,047	(10,607)
Investing Activities:
Purchases of short-term investments	(5,869)	(20,712)
Maturities of short-term investments	13,088	26,019
Purchases of property, plant and equipment, net	(1,963)	(2,760)
Net cash provided by investing activities	5,256	2,547
Financing Activities:
Payments on industrial development revenue bonds	(400)	(400)
Shares withheld in lieu of employee tax withholding	(1,147)	(438)
Dividends paid	(5,988)	(5,954)
Net cash used in financing activities	(7,535)	(6,792)
Net increase (decrease) in cash, cash equivalents and restricted cash	23,768	(14,852)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(491)	357
Cash, cash equivalents and restricted cash, beginning of period	61,725	93,210
Cash, cash equivalents and restricted cash, end of period	$ 85,002	$ 78,715