Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended		99 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Cash flows from operating activities
Net loss	$ (20,866)	$ (11,433)	$ (84,654)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	47	104	933
Amortization and accretion costs related to notes payable-related parties	2,377		3,774
Gain on conversion of notes payable			(821)
Stock-based compensation	1,531	292	2,561
Interest payable-related parties	488		1,625
Change in fair value measurements	3,850	441	3,851
Changes in operating assets and liabilities
Prepaid, current and other assets	(18)	39	(179)
Accounts payable and other current liabilities	1,025	(1,395)	2,481
Net cash used in operating activities	(11,566)	(11,952)	(70,429)
Cash flows from investing activities
Purchase of furniture, fixtures and equipment	(28)	(51)	(1,047)
Net cash provided by (used in) investing activities	(28)	(51)	(1,047)
Cash flows from financing activities
Proceeds from sale of preferred stock			45,000
Payments of stock issuance costs			(1,216)
Proceeds from notes payable to related parties	15,000		34,778
Dividends paid			(130)
Payments of debt issuance costs			(115)
Proceeds from sale of common stock			3
Proceeds from exercise of stock options	1	6	16
Payments of long-term debt			(528)
Payments of initial public offering costs	(1,713)		(1,713)
Net cash provided by financing activities	13,288	6	76,095
Net change in cash and cash equivalents	1,694	(11,997)	4,619
Beginning of period	2,925	15,068
End of period	4,619	3,071	4,619
Noncash financing activities
Conversion of long-term debt into preferred stock			17,364
Debt discount attributable to warrants	5,275		7,724
Accretion from conversion of note payable to related parties	220	219	755
Accretion of stock issuance costs	193	193	722
Deferred offering costs	$ 617		$ 617