Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities
Net loss	$ (19,605)	$ (9,412)
Adjustments to reconcile net loss to net cash used for operating activities:
Share-based compensation expense	6,504	4,827
Third party share-based compensation expense	778	0
Issuance of common stock for services	0	25
Depreciation expense	95	5
Changes in operating assets and liabilities:
Prepaid clinical expenses	1,070	0
Prepaid expenses and other current assets	(485)	(105)
Other assets	(57)	0
Accounts payable	1,113	83
Accrued expenses	(641)	(129)
Accrued payroll and related expenses	(14)	21
Net cash used for operating activities	(11,242)	(4,685)
Investing activities
Purchase of property and equipment	(1,325)	(56)
Net cash used for investing activities	(1,325)	(56)
Financing activities
Net proceeds from the exercise of stock options for common stock	57	0
Net cash provided by financing activities	57	0
Net decrease in cash and cash equivalents	(12,510)	(4,741)
Cash and cash equivalents at beginning of period	48,555	8,629
Cash, cash equivalents at end of period	36,045
Conversion of Series C-1 and D-1 Preferred Stock into Common Stock [Member]
Non-cash investing and financing activity
Conversion of stock	0	3,099
Conversion of Series F Preferred Stock into Common Stock [Member]
Non-cash investing and financing activity
Conversion of stock	$ 61	$ 452