CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net income (loss)	$ 27,876	$ (88,587)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	13,730	13,849
Gain on settlement of equity method investment	(1,847)	0
Stock-based compensation	6,884	6,568
Amortization of premium on marketable securities and deferred financing costs	28	315
Undistributed earnings of equity method investments	(4,719)	(869)
Deferred income tax provision	334	73,454
Gain on disposal of long-lived assets	(117)	0
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(9,672)	(664)
Inventories	(7,341)	(374)
Prepaid expenses and other current assets	(2,256)	(2,046)
Accounts payable	10,072	(7,073)
Deferred revenue	14,425	15,538
Accrued warranty and retrofit costs	792	(333)
Accrued compensation and tax withholdings	(1,799)	(7,297)
Accrued restructuring costs	(3,799)	5,323
Accrued expenses and other current liabilities	707	(7,433)
Net cash provided by operating activities	43,298	371
Cash flows from investing activities
Purchases of property, plant and equipment	(5,153)	(6,090)
Purchases of marketable securities	0	(12,900)
Sales and maturities of marketable securities	0	139,388
Disbursement for a loan receivable	0	(741)
Acquisitions, net of cash acquired	(5,346)	(125,498)
Purchases of other investments	(170)	(250)
Net cash used in investing activities	(10,669)	(6,091)
Cash flows from financing activities
Proceeds from issuance of common stock	960	948
Payment of deferred financing costs	(27)	0
Common stock dividends paid	(13,945)	(13,738)
Net cash used in financing activities	(13,012)	(12,790)
Effects of exchange rate changes on cash and cash equivalents	(764)	(50)
Net increase (decrease) in cash and cash equivalents	18,853	(18,560)
Cash and cash equivalents, beginning of period	85,086	80,722
Cash and cash equivalents, end of period	103,939	62,162
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	543	835
Fair value of non-cash consideration for the acquisition of Cool Lab, LLC	$ 10,348	$ 0