Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 35,245	$ 24,492
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	4,779	2,893
Stock-based compensation	13,360	8,839
Deferred income taxes	(1,597)	1,670
Excess tax benefit on stock based-compensation	(6,012)	(10,569)
Amortization of investment premiums	0	487
Changes in operating assets and liabilities:
Accounts receivable	9,144	(16,075)
Inventories	8,099	(10,706)
Prepaid expenses and other current assets	8,878	2,613
Other assets	533	(3,502)
Accounts payable	(16,123)	(1,936)
Accrued liabilities	(14,868)	(12,358)
Deferred revenue	22,412	26,356
Income taxes payable	6,802	8,985
Other liabilities	464	(422)
Net cash provided by operating activities	71,116	20,767
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(51,638)	0
Purchases of property and equipment	(7,962)	(5,136)
Purchases of intangible assets	(670)	(667)
Net cash used in investing activities	(60,270)	(5,803)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments of lease financing obligations	(314)	(255)
Proceeds from issuance of common stock upon exercising options, net of repurchases	1,862	5,322
Proceeds from issuance of common stock under employee stock purchase plan	4,888	4,856
Excess tax benefit on stock-based compensation	6,012	10,569
Issuance costs from initial public offering	0	(261)
Net cash provided by financing activities	12,448	20,231
Effect of exchange rate changes	43	(40)
NET INCREASE IN CASH AND CASH EQUIVALENTS	23,337	35,155
CASH AND CASH EQUIVALENTS—Beginning of period	687,326	240,031
CASH AND CASH EQUIVALENTS—End of period	710,663	275,186
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for income taxes, net of refunds	597	521
Cash paid for interest—lease financing obligation	737	757
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING INFORMATION:
Property and equipment included in accounts payable and accrued liabilities	$ 958	$ 657