Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net loss	$ (77,069)	$ (81,153)	$ (93,351)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,536	2,405	1,913
Non-cash equity-based compensation expense	10,038	14,523	15,421
Non-cash income tax benefit	(1,170)	(481)	(1,089)
Amortization of premium/discount on purchased securities	3,639	1,679	490
Fair value adjustment of settlement rights		788	778
Losses (gains) on investments, net	193	(408)	(942)
Changes in operating assets and liabilities:
Accounts receivable, net	(147)	21,565	(26,942)
Inventories	1,506	(6,675)	(9,063)
Receivable from collaboration	13	(441)
Prepaid and other current assets	1,661	(2,477)	(762)
Accounts payable and accrued expenses	1,698	2,745	13,215
Deferred revenues	(6,353)	46,697	9,682
Other long-term liabilities	(349)	(294)	(68)
Total adjustments	13,265	79,626	2,633
Net cash used in operating activities	(63,804)	(1,527)	(90,718)
Cash flows from investing activities:
Proceeds from sales or maturities of available-for-sale investments	141,095	160,079	74,543
Purchase of available-for-sale investments	(126,585)	(262,597)	(310)
Capital expenditures	(507)	(1,223)	(2,835)
Change in restricted cash			61
Net cash provided by (used in) investing activities	14,003	(103,741)	71,459
Cash flows from financing activities:
Proceeds from the exercise of stock options	121	1,337	4,047
Proceeds from the issuance of common stock, net of underwriting discounts and other expenses		165,559
Proceeds from the issuance of common stock under ESPP	508	892	1,156
Net cash provided by financing activities	629	167,788	5,203
Net(decrease) increase in cash and cash equivalents	(49,172)	62,520	(14,056)
Cash and cash equivalents at beginning of the year	112,646	50,126	64,182
Cash and cash equivalents at end of the year	63,474	112,646	50,126
Non-cash investing activities:
Accrued construction in process			$ 272