CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 29,827	$ 16,344
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Amortization of intangibles	763	1,010
Depreciation	2,426	1,880
Foreign currency exchange loss	43	435
Change in fair value of contingent consideration	603	132
Share-based compensation	3,588	2,948
Provision for doubtful accounts and inventory valuation	1,875	2,026
Changes in operating assets and liabilities	(29,666)	5,198
Net cash and cash equivalents provided by operating activities	9,459	29,973
Cash flows from investing activities:
Purchases of marketable securities	(105,721)	(62,527)
Proceeds from sales of marketable securities	88,843	59,491
Purchases of property, plant and equipment	(2,178)	(5,301)
Net cash and cash equivalents used in investing activities	(19,056)	(8,337)
Cash flows from financing activities:
Redemption of stock warrants	0	(1,025)
Tax payments related to shares withheld for share-based compensation plans	(977)	(1,323)
Payment of contingent consideration for acquired business	(1,057)	(358)
Issuance of shares through share-based compensation plans	490	289
Net cash and cash equivalents used in financing activities	(1,544)	(2,417)
Effect of exchange rate changes on cash and cash equivalents	(138)	627
Net (decrease) increase in cash and cash equivalents	(11,279)	19,846
Cash and cash equivalents at beginning of period	67,770	37,859
Cash and cash equivalents at end of period	56,491	57,705
Supplemental disclosure of cash flow information:
Income taxes paid	$ 52	$ 2,246