Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities
Net (loss) income	$ (46,284)	$ 53,815	$ (38,463)
Income from discontinued operations		(77,040)	(612)
Loss from continuing operations	(46,284)	(23,225)	(39,075)
Adjustments to reconcile (loss) income from continuing operations to net cash used in operating activities:
Gain on sale of property and equipment		(25)	(54)
Change in fair value of warrant liability	710	85
Unrealized loss (gain) on marketable securities	(57)	1	(2)
Depreciation and amortization	871	879	1,188
Income tax benefit	0	(16,245)	(399)
Amortization of deferred financing costs and debt discount	330	218
Stock-based compensation expense	443	(82)	297
Changes in operating assets and liabilities:
Accounts receivable	(11)	44	284
Interest receivable	(664)	114	220
Inventory	(1,152)
Prepaid expenses and other assets	(516)	(247)	74
Accounts payable, accrued expenses, and supplemental executive retirement plan	(1,098)	(959)	5,211
Deferred revenue	120	697
Other non-current liabilities	109	539	64
Net cash used in operating activities from continuing operations	(47,199)	(38,206)	(32,192)
Net cash (used in) provided by operating activities from discontinued operations		2,021	(352)
Net cash used in operating activities	(47,199)	(36,185)	(32,544)
Cash flows from investing activities
Purchases of marketable securities	(97,674)	(17,890)	(32,781)
Sales and maturities of marketable securities	49,468	26,870	58,898
Purchases of property and equipment, net	(753)	(685)	(294)
Net cash provided by (used in) investing activities from continuing operations	(48,959)	8,295	25,823
Net cash provided by disposal/sale of discontinued operations		25,607
Net cash provided by (used in) investing activities	(48,959)	33,902	25,823
Cash flows from financing activities
Proceeds from issuance of common stock	100,735	29	4
Proceeds from issuance of secured notes payable		30,000
Repayments of secured notes payable	(6,775)
Financing costs and underwriters discounts	(6,044)	(975)	(1,345)
Net cash (used in) provided by financing activities from continuing operations	87,916	29,054	(1,341)
Net cash provided by (used in) financing activities from discontinued operations		(1,967)	397
Net cash (used in) provided by financing activities	87,916	27,087	(944)
Net change in cash and cash equivalents	(8,242)	24,804	(7,665)
Cash and cash equivalents at beginning of year	48,544	23,740	31,405
Cash and cash equivalents at end of year	40,302	48,544	23,740
Supplemental cash flow information:
Cash paid for interest-Continuing operations	2,938	1,412
Noncash financial activity:
Conversion of preferred stock	49
Issuance of warrants		612
Exercise of warrants	$ 1,156