CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 7,576	$ 15,130
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Amortization of intangibles	387	380
Depreciation	1,254	1,310
Foreign currency exchange (loss) gain	(381)	183
Change in fair value of contingent consideration		318
Share-based compensation	2,163	1,507
Provision for doubtful accounts and inventory valuation	1,028	705
Changes in operating assets and liabilities	(13,593)	(14,894)
Net cash and cash equivalents (used in) provided by operating activities	(1,566)	4,639
Cash flows from investing activities:
Purchases of marketable securities	(22,142)	(57,134)
Proceeds from sales of marketable securities	14,295	54,404
Purchases of property, plant and equipment	(1,320)	(1,442)
Net cash and cash equivalents used in investing activities	(9,167)	(4,172)
Cash flows from financing activities:
Purchase of common stock	(744)
Tax payments related to shares withheld for share-based compensation plans	(598)	(839)
Issuance of shares through share-based compensation plans		122
Net cash and cash equivalents used in financing activities	(1,342)	(717)
Effect of exchange rate changes on cash and cash equivalents	(145)	535
Net increase in cash and cash equivalents	(12,220)	285
Cash and cash equivalents at beginning of period	112,388	67,770
Cash and cash equivalents at end of period	100,168	68,055
Supplemental disclosure of cash flow information:
Income taxes paid	$ 114	$ 249