Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 39,522	$ 18,963
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,266	14,642
Provision for doubtful accounts	53	3
Provision for warranty and returns	38	(488)
Stock compensation	9,305	6,990
Loss (gain) on disposal of property and equipment	(1,102)	8
Bond premium amortization	1,451	1,599
Cash provided (used) by changes in operating assets and liabilities
Accounts receivable	(11,390)	9,433
Inventories	(4,867)	(4,655)
Prepaid expenses and other assets	(8,824)	2,146
Accounts payable	3,246	681
Accrued liabilities	6,915	2,123
Income taxes, including excess tax benefits and deferred income taxes	(5,177)	(3,098)
Net cash provided by operating activities	42,436	48,347
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(7,729)	(14,924)
Proceeds from sale of asset	3,592	5
Intangible assets additions	(778)	(709)
Purchases of investment securities	(40,217)	(78,993)
Proceeds from sale of investment securities	70,293	69,470
Net cash provided (used) by investing activities	25,161	(25,151)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	10,974	9,105
Proceeds from employee stock purchase plan	2,162	2,485
Tax benefits from exercise of stock options	6,194	2,734
Payments for Repurchase of Common Stock	(1,523)	(5,836)
Net cash provided by financing activities	17,807	8,488
Effect of exchange rate changes on cash	(5,848)	(5,465)
NET INCREASE IN CASH AND CASH EQUIVALENTS	79,556	26,219
CASH AND CASH EQUIVALENTS, beginning of period	275,812	226,022
CASH AND CASH EQUIVALENTS, end of period	355,368
NON-CASH INVESTING ACTIVITIES
Accrued liabilities for property and equipment	$ 1,106	$ 100