Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 53,572		$ 39,522
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,351		13,266
Provision for doubtful accounts	0		53
Provision for warranty and returns	(22)		38
Stock compensation	11,464		9,305
Loss (gain) on disposal of property and equipment	40		(1,102)
Bond premium amortization	1,026		1,451
Bargain purchase gain	(1,456)		0
Other	69		0
Cash provided by (used in) changes in operating assets and liabilities
Accounts receivable	4,736		(11,390)
Inventories	(6,635)		(4,867)
Prepaid expenses and other assets	(2,228)		(8,824)
Accounts payable	(1,587)		3,246
Accrued liabilities	(7,314)		6,915
Income taxes, including excess tax benefits and deferred income taxes	2,691		1,017
Net cash provided by operating activities	68,707		48,630
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(15,018)		(7,729)
Proceeds from sale of asset	1		3,592
Business acquisitions, net of cash acquired	2,584		0
Intangible assets additions	(861)		(778)
Purchases of investment securities	(111,575)		(40,217)
Proceeds from sale of investment securities	45,429		70,293
Net cash (used in) provided by investing activities	(84,608)		25,161
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	15,830		10,974
Proceeds from employee stock purchase plan	2,361		2,162
Purchase of treasury stock	(17,155)		(1,523)
Net cash provided by financing activities	1,036		11,613
Effect of exchange rate changes on cash	1,664		(5,848)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(13,201)		79,556
CASH AND CASH EQUIVALENTS, beginning of period	336,164	[1]	275,812
CASH AND CASH EQUIVALENTS, end of period	322,963		355,368
NON-CASH INVESTING ACTIVITIES
Accounts payable for property and equipment	$ 595		$ 1,106

[1] December 31, 2015 balances were derived from audited consolidated financial statements.