Condensed Consolidated Statements of Operations (unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenues	$ 0	$ 0	$ 0	$ 0
Expenses:
Research and development	10,353,601	4,433,222	15,039,321	9,170,797
General and administrative	988,266	1,049,815	1,781,444	2,149,647
Total expenses	11,341,867	5,483,037	16,820,765	11,320,444
Loss before other income (expense) and taxes	(11,341,867)	(5,483,037)	(16,820,765)	(11,320,444)
Interest income	381	6,397	4,175	8,911
Interest expense	(430,024)	(281,996)	(882,683)	(546,823)
Financing expense	0	(16,595)	0	(31,231)
Change in fair value of warrant liability	442,922	445,660	545,698	926,671
Derecognition of CIRM liability	7,719,440	0	7,719,440	0
Loss before provision for income taxes	(3,609,148)	(5,329,571)	(9,434,135)	(10,962,916)
Provision for income taxes	0	0	0	0
Net loss	$ (3,609,148)	$ (5,329,571)	$ (9,434,135)	$ (10,962,916)
Net loss per share (in USD per share)	$ (1.02)	$ (2.30)	$ (2.66)	$ (4.76)
Weighted average number of shares basic and diluted (in shares)	3,551,575	2,321,957	3,550,550	2,301,802