FINANCIAL INFORMATION BY QUARTER (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Financial Information by Quarter

	2015 for Quarter Ended
	December 31			September 30			June 30			March 31
	(in thousands)
Revenue from research contracts and other grants	$	1,253		$	—		$	—		$	—
Operating expenses:
Research and development		41,376			36,673			29,180			39,165
General and administrative		24,329			15,090			12,927			22,697
Total operating expenses		65,705			51,763			42,107			61,862
Operating loss		(64,452	)		(51,763	)		(42,107	)		(61,862	)
Other income (loss):
Interest income and other, net		(229	)		(176	)		256			303
Total other income (loss)		(229	)		(176	)		256			303
Net loss	$	(64,681	)	$	(51,939	)	$	(41,851	)	$	(61,559	)
Net loss per share—basic and diluted	$	(1.44	)	$	(1.25	)	$	(1.01	)	$	(1.49	)
Shares used in per share calculations—basic and diluted		44,882			41,565			41,357			41,324
	2014 for Quarter Ended
	December 31			September 30			June 30			March 31
	(in thousands)
Revenue from research contracts and other grants	$	27		$	1,059		$	2,583		$	6,088
Operating expenses:
Research and development		30,832			21,852			20,641			20,906
General and administrative		13,917			12,882			12,213			10,303
Total operating expenses		44,749			34,734			32,854			31,209
Operating loss		(44,722	)		(33,675	)		(30,271	)		(25,121	)
Other income (loss):
Interest income and other, net		306			193			181			99
Gain (loss) on change in warrant valuation		—			4,256			(3,784	)		(3,251	)
Total other income (loss)		306			4,449			(3,603	)		(3,152	)
Net loss	$	(44,416	)	$	(29,226	)	$	(33,874	)	$	(28,273	)
Net loss per share—basic and diluted	$	(1.08	)	$	(0.71	)	$	(0.85	)	$	(0.75	)
Shares used in per share calculations—basic and diluted		41,304			41,066			39,862			37,821