Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net loss	$ (30,079)	$ (14,464)
Adjustments to reconcile net loss to net cash used for operating activities:
Share-based compensation expense	9,330	6,595
Third party share-based compensation expense	1,013	0
Depreciation expense	209	10
Changes in operating assets and liabilities:
Restricted Cash	(200)	0
Prepaid clinical expenses	1,168	0
Prepaid expenses and other current assets	(347)	(110)
Other assets	(57)	0
Accounts payable	1,837	(151)
Accrued expenses	219	713
Accrued payroll and related expenses	205	(68)
Net cash used for operating activities	(16,702)	(7,475)
Investing activities
Purchase of property and equipment	(1,681)	(86)
Net cash used for investing activities	(1,681)	(86)
Financing activities
Net proceeds from the issuance of common stock	104,596	53,063
Net proceeds from the exercise of stock options for common stock	287	0
Net cash provided by financing activities	104,883	53,063
Net increase in cash and cash equivalents	86,500	45,502
Cash and cash equivalents at beginning of period	48,555	8,629
Cash, cash equivalents at end of period	135,055	54,131
Series C-1 Convertible Preferred Stock [Member]
Non-cash investing and financing activity:
Conversion of stock	11	0
Series F Convertible Preferred Stock [Member]
Non-cash investing and financing activity:
Conversion of stock	61	452
Series C-1 and D-1 Convertible Preferred Stock [Member]
Non-cash investing and financing activity:
Conversion of stock	$ 0	$ 3,099