Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 34,766		$ 23,256
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	9,648		9,026
Provision for doubtful accounts	0		53
Provision for warranty and returns	(125)		38
Stock compensation	7,674		5,947
Loss (gain) on disposal of property and equipment	31		(33)
Bond premium amortization	121		1,223
Bargain purchase gain	(1,110)		0
Cash provided by (used in) changes in operating assets and liabilities
Accounts receivable	(2,527)		(5,529)
Inventories	(5,479)		(2,267)
Prepaid expenses and other assets	(3,784)		(1,375)
Accounts payable	3,752		1,894
Accrued liabilities	(5,985)		(1,027)
Income taxes, including excess tax benefits and deferred income taxes	4,793		(2,031)
Net cash provided by operating activities	41,775		29,175
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(9,112)		(5,005)
Proceeds from sale of asset	1		34
Business acquisitions, net of cash acquired	2,606		0
Intangible assets additions	(513)		(440)
Purchases of investment securities	(18,106)		(17,092)
Proceeds from sale of investment securities	31,765		49,555
Net cash provided by investing activities	1,429		27,052
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	7,796		5,797
Proceeds from employee stock purchase plan	1,197		1,041
Purchase of treasury stock	(16,911)		(1,435)
Net cash (used in) provided by financing activities	(7,918)		5,403
Effect of exchange rate changes on cash	1,445		(6,350)
NET INCREASE IN CASH AND CASH EQUIVALENTS	36,731		55,280
CASH AND CASH EQUIVALENTS, beginning of period	336,164	[1]	275,812
CASH AND CASH EQUIVALENTS, end of period	372,895		331,092
NON-CASH INVESTING ACTIVITIES
Accrued liabilities for property and equipment	$ 1,574		$ 232

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