Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities
Net loss	$ (45,771)	$ (19,288)
Adjustments to reconcile loss to net cash used in operating activities:
Loss on extinguishment of debt	1,162
Change in fair value of derivative liabilities	8,540	472
Unrealized (loss) gain on marketable securities	(178)	6
Depreciation and amortization	326	438
Amortization of deferred financing costs and debt discount	887	164
Stock-based compensation expense	769	105
Changes in operating assets and liabilities :
Accounts receivable	(537)
Interest receivable	(127)
Inventory	(3,163)
Prepaid expenses and other assets	(918)	(544)
Accounts payable and accrued expenses	1,341	(994)
Deferred product revenue, net	3,967
Deferred licensing revenue	246	(149)
Other non-current liabilities	478	33
Net cash used in operating activities	(32,978)	(19,757)
Cash flows from investing activities
Purchases of marketable securities	(61,004)	(36,824)
Sales and maturities of marketable securities	24,413	7,674
Purchases of property and equipment, net	(1,037)	(160)
Net cash used in investing activities	(37,628)	(29,310)
Cash flows from financing activities
Proceeds from issuance of common stock	2,153	52,408
Proceeds from convertible debt issuances	90,000
Repayment of secured notes payable	(24,344)	(1,771)
Financing costs and underwriters discounts	(3,598)	(2,872)
Net cash used in financing activities	64,211	47,765
Net change in cash and cash equivalents	(6,395)	(1,302)
Cash and cash equivalents at beginning of period	40,302	48,544
Cash and cash equivalents at end of period	33,907	47,242
Supplemental cash flow information:
Cash paid for interest	975	1,488
Noncash financial activity:
Conversion of preferred stock		49
Initial value of interest make-whole derivatives
Issued in connection with the convertible debt	$ 9,270