Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
License revenue	$ 6,555	$ 2,245	$ 7,010	$ 2,573
Reagent sales		107		166
Grant revenue	7	23	7	29
Total revenues	6,562	2,375	7,017	2,768
Costs of revenues
Licensing costs	1,311	449	1,402	515
Costs of reagent sales	6	49	6	79
Research and development	13,917	10,680	30,536	16,863
General and administrative	6,355	6,169	12,977	11,648
Other operating expenses (income)	29	(20)	74	(134)
Total operating expenses	21,618	17,327	44,995	28,971
Loss from operations	(15,056)	(14,952)	(37,978)	(26,203)
Other Income
Investment income	583	515	1,512	998
Total other income	583	515	1,512	998
Net loss	(14,473)	(14,437)	(36,466)	(25,205)
Other Comprehensive Income (Loss)
Unrealized gain (loss) on available-for-sale securities,net of reclassifications of $480 for the six months ended June 30, 2017	(74)	246	(613)	1,240
Total other comprehensive income (loss)	(74)	246	(613)	1,240
Comprehensive loss	(14,547)	(14,191)	(37,079)	(23,965)
Net loss applicable to common stockholders	$ (14,473)	$ (14,437)	$ (36,466)	$ (25,205)
Basic and diluted net loss per common share	$ (0.47)	$ (0.55)	$ (1.27)	$ (0.96)
Weighted-average basic and diluted common shares	30,662	26,362	28,678	26,344