Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (32,047)	$ (19,605)
Adjustments to reconcile net loss to net cash used for operating activities:
Share-based compensation expense	6,960	6,504
Third party share-based compensation expense	86	778
Depreciation expense	310	95
Loss on disposal of equipment	75	0
Changes in operating assets and liabilities:
Restricted cash	37	0
Prepaid clinical expenses	36	1,070
Prepaid expenses and other current assets	(738)	(485)
Other assets	(147)	(57)
Accounts payable	(250)	1,113
Accrued expenses	888	(641)
Accrued payroll and related expenses	(295)	(14)
Net cash used for operating activities	(25,085)	(11,242)
Investing activities
Purchase of property and equipment	(910)	(1,325)
Net cash used for investing activities	(910)	(1,325)
Financing activities
Net proceeds from the exercise of stock options for common stock	85	57
Net cash provided by financing activities	85	57
Net decrease in cash and cash equivalents	(25,910)	(12,510)
Cash and cash equivalents at beginning of period	126,467	48,555
Cash, cash equivalents at end of period	100,557	36,045
Series F Convertible Preferred Stock [Member]
Non-cash investing and financing activity:
Conversion of stock	$ 0	$ 61