CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ 7,804	$ (10,402)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation	2,899	4,948
Depreciation	3,481	3,791
Amortization of intangible assets	6,797	7,040
Non-cash interest expense and amortization of convertible debt issuance costs	6,242	4,089
Deferred income taxes	5,967	263
Non-cash restructuring	0	653
Gain from sale of intellectual property	(170)	(1,285)
Change in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(5,565)	469
Prepaid expenses and other assets	(183)	2,965
Accounts payable	749	(2,243)
Accrued salaries and benefits and other accrued liabilities	(6,682)	4,646
Income taxes payable	(4,828)	378
Net cash provided by operating activities	16,511	15,312
Cash flows from investing activities:
Purchases of property, plant and equipment	(3,145)	(3,703)
Acquisition of intangible assets	0	(1,875)
Purchases of marketable securities	(34,050)	(36,699)
Maturities of marketable securities	26,050	33,250
Proceeds from sale of intellectual property	1,250	2,000
Net cash used in investing activities	(9,895)	(7,027)
Cash flows from financing activities:
Proceeds received from issuance of common stock under employee stock plans	1,352	0
Principal payments against lease financing obligation	(60)	(26)
Payments under installment payment arrangement	(28)	(28)
Net cash provided by (used in) financing activities	1,264	(54)
Net increase in cash and cash equivalents	7,880	8,231
Cash and cash equivalents at beginning of period	338,696	148,984
Cash and cash equivalents at end of period	346,576	157,215
Non-cash investing and financing activities during the period:
Property, plant and equipment received and accrued in accounts payable and other accrued liabilities	$ 280	$ 166