Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net loss	$ (8,160)	$ (1,748)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	3,759	3,678
Amortization of debt discount and issuance expenses	2,129	0
Depreciation and amortization	2,846	2,307
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable, trade and other	7,487	(2,489)
Decrease (increase) in inventories	(733)	611
Increase in prepaid expenses and other assets	(34)	(638)
Increase (decrease) in accounts payable and accrued expenses	2,429	(1,198)
Increase (decrease) in deferred revenue	(7,860)	7,999
Increase (decrease) in deferred rent	3,204	(284)
Net cash provided by operating activities	5,067	8,238
Cash flows from investing activities:
Purchases of short-term investments	(51,107)	(41,384)
Purchases of property and equipment	(6,680)	(1,439)
Redemptions of short-term investments	40,594	50,553
Sales and redemptions of long-term investments	1,600	100
Net cash provided by (used in) investing activities	(15,593)	7,830
Cash flows from financing activities:
Proceeds from issuance of convertible debt, net of issuance costs	338,921	0
Purchase of convertible note hedge	(70,000)	0
Proceeds from sale of warrants	41,475	0
Proceeds from exercise of common stock options	22	1,201
Employee Stock Purchase Plan purchases	0	795
Purchases of treasury stock	(125)	(77)
Proceeds from Board of Directors stock purchases	17	39
Net cash provided by financing activities	310,310	1,958
Effect of exchange rate changes on cash	(49)	14
Increase in cash and cash equivalents	299,735	18,040
Cash and cash equivalents, beginning of period	35,857	37,535
Cash and cash equivalents, end of period	$ 335,592	$ 55,575