CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 13,102	$ 29,827
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Amortization of intangibles	774	763
Depreciation	2,363	2,426
Foreign currency exchange (gain) loss	(222)	43
Change in fair value of contingent consideration		603
Share-based compensation	3,836	3,588
Provision for doubtful accounts and inventory valuation	1,003	1,875
Changes in operating assets and liabilities	(11,066)	(29,666)
Net cash and cash equivalents provided by operating activities	9,790	9,459
Cash flows from investing activities:
Purchases of marketable securities	(38,227)	(105,721)
Proceeds from sales of marketable securities	33,186	88,843
Purchases of property, plant and equipment	(2,654)	(2,178)
Net cash and cash equivalents used in investing activities	(7,695)	(19,056)
Cash flows from financing activities:
Purchase of common stock	(744)
Tax payments related to shares withheld for share-based compensation plans	(749)	(977)
Payment of contingent consideration for acquired business	(1,121)	(1,057)
Issuance of shares through share-based compensation plans	160	490
Net cash and cash equivalents used in financing activities	(2,454)	(1,544)
Effect of exchange rate changes on cash and cash equivalents	(71)	(138)
Net decrease in cash and cash equivalents	(430)	(11,279)
Cash and cash equivalents at beginning of period	112,388	67,770
Cash and cash equivalents at end of period	111,958	56,491
Supplemental disclosure of cash flow information:
Income taxes paid	$ 209	$ 52