CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net income	$ 16,486	$ 13,871
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,521	6,752
Gain on settlement of equity method investment		(1,847)
Stock-based compensation	4,809	2,498
Amortization of premium on marketable securities and deferred financing costs	122	79
Earnings of equity method investment	(2,180)	(1,942)
Deferred income tax benefit	(689)	(421)
Other gains on disposals of assets		(109)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(16,157)	(11,137)
Inventories	(5,518)	(2,930)
Prepaid expenses and other current assets	3,285	(3,516)
Accounts payable	4,449	13,040
Deferred revenue	1,376	10,737
Accrued warranty and retrofit costs	87	(4)
Accrued compensation and tax withholdings	(11,145)	(6,884)
Accrued restructuring costs	(592)	(2,538)
Accrued expenses and other current liabilities	362	3,061
Net cash provided by operating activities	3,216	18,710
Cash flows from investing activities
Purchases of property, plant and equipment	(2,700)	(3,768)
Purchases of marketable securities	(26,875)
Sales and maturities of marketable securities	100
Acquisitions, net of cash acquired	(65,074)	(5,346)
Purchases of other investments		(170)
Proceeds from sales of property, plant and equipment	200
Net cash used in investing activities	(94,349)	(9,284)
Cash flows from financing activities
Proceeds from term loan	197,554
Payment of deferred financing costs	(318)	(27)
Common stock dividends paid	(7,057)	(6,966)
Net cash provided by (used in) financing activities	190,179	(6,993)
Effects of exchange rate changes on cash and cash equivalents	1,671	(4,574)
Net increase (decrease) in cash and cash equivalents	100,717	(2,141)
Cash and cash equivalents, beginning of period	101,622	85,086
Cash and cash equivalents, end of period	202,339	82,945
Supplemental disclosure of non-cash investing and financing activities:
Capital Expenditures Incurred but Not yet Paid	865	424
Deferred financing costs included in accounts payable	$ 143
Fair value of non-cash consideration for the acquisition of Cool Lab, LLC		$ 10,348