Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income	$ 17,934	$ 22,943	$ 17,177
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,416	4,324	4,055
Stock-based compensation	2,642	2,349	2,256
Fair value adjustments to contingent consideration obligations	171	(29)	106
Provision for doubtful accounts and allowances	388	264	230
Provision for inventory write-downs	747	671	396
Provision (benefit) for deferred income taxes	824	(2,152)	300
Gain on acquisitions and divestitures		(7,474)
Foreign currency transaction gain	(57)	259	(29)
Changes in operating assets and liabilities:
Accounts receivable	(1,301)	(1,283)	(1,507)
Inventory and other deferred costs	(11,335)	(4,262)	(1,352)
Prepaid expenses and other assets	(654)	(418)	(288)
Accounts payable and other liabilities	(596)	4,314	1,524
Net cash provided by operating activities	14,179	19,506	22,868
Investing activities
Purchases of property and equipment	(3,761)	(3,054)	(6,417)
Payments related to acquisitions	(21,240)	(12,282)
Purchases of short-term marketable securities	(22,699)	(19,619)	(22,541)
Proceeds from sales of marketable securities	23,600	20,500
Proceeds from divestitures		7,400
Net cash used in investing activities	(24,100)	(7,055)	(28,958)
Financing activities
Payment of deferred acquisition consideration	(2,059)	(1,199)	(463)
Proceeds from issuance of common stock	4,856	2,969	5,500
Purchase of treasury stock	(683)	(741)	(778)
Common stock cash dividend paid	(6,736)	(5,445)	(4,179)
Net cash provided by (used in) financing activities	(4,622)	(4,416)	80
Effect of exchange rate changes on cash and cash equivalents	11	(813)	818
Net increase (decrease) in cash and cash equivalents	(14,532)	7,222	(5,192)
Cash and cash equivalents at beginning of year	26,318	19,096	24,288
Cash and cash equivalents at end of year	$ 11,786	$ 26,318	$ 19,096