Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 9,366,000	$ 16,708,000	$ 6,588,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property, equipment and improvements	2,900,000	2,742,000	2,949,000
Amortization of identifiable intangible assets	2,597,000	1,872,000	2,910,000
Stock-based compensation	4,659,000	3,654,000	4,301,000
Excess tax benefits from stock-based compensation	(326,000)	(212,000)	0
Deferred income tax (benefit) provision	(2,108,000)	1,115,000	(769,000)
Gain on insurance settlement related to property and equipment	0	0	(1,375,000)
Gain on sale of business	0	(2,870,000)	0
Change in fair value of contingent consideration	(4,364,000)	(441,000)	0
Bad debt/product return provision	361,000	168,000	357,000
Inventory obsolescence	1,850,000	1,734,000	1,284,000
Restructuring charges, net	2,515,000	747,000	509,000
Other	(9,000)	66,000	87,000
Changes in operating assets and liabilities (net of acquisition):
Accounts receivable	833,000	(1,188,000)	(1,794,000)
Inventories	(4,484,000)	3,993,000	(1,913,000)
Other assets	562,000	597,000	241,000
Income taxes	(3,000)	(1,589,000)	387,000
Accounts payable	(3,536,000)	1,612,000	(3,769,000)
Accrued expenses	(8,338,000)	(1,619,000)	4,081,000
Net cash provided by operating activities	2,475,000	27,089,000	14,074,000
Investing activities:
Purchase of marketable securities	(61,964,000)	(74,759,000)	(54,427,000)
Proceeds from maturities of marketable securities	87,105,000	73,706,000	38,028,000
Proceeds from sale of business	3,000,000	2,849,000	0
Acquisition of businesses, net of cash acquired	(30,111,000)	(2,860,000)	0
Proceeds from insurance settlement related to property and equipment	0	0	1,400,000
Proceeds from sale of property and equipment	0	0	45,000
Proceeds from sale of investment	0	13,000	0
Purchase of property, equipment, improvements and certain other intangible assets	(1,773,000)	(2,729,000)	(4,500,000)
Net cash used in investing activities	(3,743,000)	(3,780,000)	(19,454,000)
Financing activities:
Acquisition earn-out payments	(518,000)	0	0
Excess tax benefits from stock-based compensation	326,000	212,000	0
Proceeds from stock option plan transactions	3,502,000	7,191,000	6,559,000
Proceeds from employee stock purchase plan transactions	685,000	896,000	925,000
Purchase of common stock	(938,000)	(550,000)	(2,339,000)
Net cash provided by financing activities	3,057,000	7,749,000	5,145,000
Effect of exchange rate changes on cash and cash equivalents	706,000	(349,000)	(2,237,000)
Net increase (decrease) in cash and cash equivalents	2,495,000	30,709,000	(2,472,000)
Cash and cash equivalents, beginning of period	75,727,000	45,018,000	47,490,000
Cash and cash equivalents, end of period	78,222,000	75,727,000	45,018,000
Supplemental disclosures of cash flow information:
Interest paid	1,000	9,000	4,000
Income taxes paid, net	2,129,000	3,029,000	1,296,000
Supplemental schedule of non-cash investing and financing activities:
Accrual for capitalized intangible asset	(36,000)	(183,000)	(17,000)
Receivable related to sale of business	0	4,956,000	0
Liability related to acquisition of business	$ (1,310,000)	$ (10,550,000)	$ 0