CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 21,330	$ 75,917
Adjustments to reconcile net income to net cash provided by operating activities:
Loss on debt repurchase, including write-off of debt issuance costs		3,542
Depreciation and amortization	17,164	16,548
Amortization and accretion of investments	6,230	3,791
Amortization of debt discount and debt issuance costs, excluding write-off of debt issuance costs	8,018	10,379
Deferred income taxes	(12,748)	(7,993)
Stock-based compensation	16,139	12,492
Contingent consideration	4,639	5,523
Payment of contingent consideration		(17,408)
Premium paid for convertible subordinated debt repurchase		(26,945)
Other non-cash	1,058	6,618
Changes in assets and liabilities:
Accounts receivable	(8,142)	(2,326)
Inventory	(10,339)	(6,684)
Prepaid expenses and other current assets	(259)	(182)
Other assets	1,646	5,449
Accounts payable and accrued liabilities	(13,508)	(14,922)
Deferred revenue and other liabilities	(1,387)	3,296
Total adjustments	8,511	(8,822)
Net cash provided by operating activities	29,841	67,095
Cash flows from investing activities:
Purchases of property and equipment	(10,030)	(12,093)
Purchases of investments	(716,455)	(718,738)
Proceeds from maturities of investments	789,971	665,249
Payment for purchase option	(20,000)
Net cash provided by (used in) investing activities	43,486	(65,582)
Cash flows from financing activities:
Payment of contingent consideration		(12,592)
Issuance of common stock, net	19,391	17,348
Excess tax benefit on stock-based awards	8,677	5,482
Repurchase of convertible subordinated debt		(74,704)
Net cash provided by (used in) financing activities	28,068	(64,466)
Net increase (decrease) in cash and cash equivalents	101,395	(62,953)
Cash and cash equivalents at beginning of period	104,041	197,618
Cash and cash equivalents at end of period	$ 205,436	$ 134,665