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 loss	$ (7,102)	$ (3,895)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	162	650
Amortization of premium/discount on purchased securities	664	681
Write-down of inventory to net realizable value	1,437
Non-cash equity-based compensation expense	1,930	2,283
Amortization of debt discount and debt issuance costs	851
Gains on sale of assets	(100)	(299)
Gains on investments, net		(6)
Change in fair value of contingent consideration	789
Changes in operating assets and liabilities:
Accounts receivable, net	(3,273)	(2,109)
Inventories	(2,521)	1,834
Receivable from collaboration	76	155
Prepaid and other current assets	(1,014)	(6)
Other long-term assets	885
Accounts payable and accrued expenses	(1,101)	(7,074)
Deferred revenues	(3,075)	(1,816)
Other long-term liabilities	318	(111)
Total adjustments	(3,972)	(5,818)
Net cash used in operating activities	(11,074)	(9,713)
Cash flows from investing activities:
Proceeds from sales or maturities of investments	26,706	30,663
Purchase of investments	(25,046)	(33,906)
Proceeds from sale of assets	100	368
Capital expenditures	(124)	(23)
Change in restricted cash	2,883
Net cash provided by (used in) investing activities	4,519	(2,898)
Cash flows from financing activities:
Payment of contingent consideration	(31)
Proceeds from issuance of convertible debt	200,000
Payment of debt issuance costs	(6,361)
Proceeds from issuance of warrants	25,620
Purchase of convertible bond hedges	(39,760)
Proceeds from the exercise of stock options	1,017	163
Net cash provided by financing activities	180,485	163
Net increase (decrease) in cash and cash equivalents	173,930	(12,448)
Cash and cash equivalents at beginning of the period	26,986	46,293
Cash and cash equivalents at end of the period	$ 200,916	$ 33,845