STATEMENT OF STOCKHOLDERS' EQUITY - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital Common Stock	Accumulated Deficit
Balance (in shares) at Dec. 31, 2014		104,452,105
Balance at Dec. 31, 2014	$ 33,841	$ 104	$ 406,349	$ (372,612)
Stock-based compensation	$ 6,054		6,054
Exercise of employee stock options (in shares)	2,938,161	2,208,268
Exercise of employee stock options	$ 3,366	$ 2	3,364
Restricted stock awards (in shares)		1,054,186
Restricted stock awards		$ 1	(1)
Repurchase of common stock (Shares)		(3,711)
Repurchase of common stock	(34)		(34)
Repurchase of restricted common stock and stock option (in shares)		(45,110)
Repurchase of restricted common stock and stock option	(379)		(379)
Issuance of common stock in public offering (in shares)		11,500,000
Issuance of common stock in public offering	94,320	$ 12	94,308
Issuance of common stock in licensing agreement (in shares)		11,722,163
Issuance of common stock in licensing agreement	67,285	$ 12	67,273
Net loss	(110,612)			(110,612)
Balance (in shares) at Sep. 30, 2015		130,887,901
Balance at Sep. 30, 2015	$ 93,841	$ 131	$ 576,934	$ (483,224)