Quarterly Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Data (unaudited)

Schedule of quarterly results of operations

	Three Months Ended
	March 31, 2012			June 30, 2012			September 30, 2012			December 31, 2012
	(in thousands, except shares and per share data)
Revenues:
License and milestone revenue	$	—		$	—		$	—		$	—
Cost sharing reimbursements, net		—			—			—			—
Total collaboration revenues		—			—			—			—
Grant revenue		147			—			—			—
Total revenues		147			—			—			—
Operating expenses:
Research and development		12,066			11,252			11,743			14,351
General and administrative		2,646			2,882			2,796			3,352
Total operating expenses		14,712			14,134			14,539			17,703
Loss from operations		(14,565	)		(14,134	)		(14,539	)		(17,703	)
Interest expense, net		(486	)		(486	)		(457	)		(420	)
Net loss	$	(15,051	)	$	(14,620	)	$	(14,996	)	$	(18,123	)
Basic and diluted net loss per common share	$	(0.27	)	$	(0.25	)	$	(0.25	)	$	(0.29	)
Basic and diluted weighted average number of common shares outstanding		56,366,992			57,650,412			60,661,720			62,914,546

	Three Months Ended
	March 31, 2011			June 30, 2011			September 30, 2011			December 31, 2011
	(in thousands, except shares and per share data)
Revenues:
License and milestone revenue	$	1,143		$	1,143		$	1,143		$	3,302
Cost sharing reimbursements, net		—			—			—			—
Total collaboration revenues		1,143			1,143			1,143			3,302
Grant revenue		—			211			521			121
Total revenues		1,143			1,354			1,664			3,423
Operating expenses:
Research and development		9,436			10,417			10,751			10,859
General and administrative		2,673			2,946			3,131			2,803
Total operating expenses		12,109			13,363			13,882			13,662
Loss from operations		(10,966	)		(12,009	)		(12,218	)		(10,239	)
Interest expense, net		(435	)		(493	)		(516	)		(504	)
Net loss	$	(11,401	)	$	(12,502	)	$	(12,734	)	$	(10,743	)
Basic and diluted net loss per common share	$	(0.27	)	$	(0.26	)	$	(0.26	)	$	(0.22	)
Basic and diluted weighted average number of common shares outstanding		42,008,818			47,845,315			49,403,589			49,426,806