Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows From Operating Activities:
Net Loss	$ (16,842)	$ (25,981)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,959	1,413
Stock issued for milestone payments	0	1,350
Change in fair value of warrant liabilities	(3,015)	8,047
Depreciation	57	19
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	3,745	(5,407)
Deposits and other assets	(11)	(12)
Accounts payable	143	7,690
Accrued expenses	1,543	317
Accrued employee benefits	897	(144)
Deferred rent	(10)	0
Net Cash Used In Operating Activities	(11,534)	(12,708)
Cash Flows From Investing Activities:
Purchases of property and equipment	(45)	(61)
Net Cash Used In Investing Activities	(45)	(61)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock for stock option exercises	810	1
Net Cash Provided By Financing Activities	810	1
Net decrease in cash	(10,769)	(12,768)
Cash at beginning of period	20,818	17,525
Cash at end of period	10,049	4,757
Supplemental disclosures of cash flow information:
Cash paid for interest	0	0
Cash paid for taxes	$ 0	$ 0