Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue
Collaborations, licenses and milestones	$ 66,007	$ 1,014	$ 73,259	$ 2,505
Operating expenses
Research and development	14,408	7,476	24,443	12,681
General and administrative	3,043	2,524	6,993	5,288
Total operating expenses	17,451	10,000	31,436	17,969
Income (loss) from operations	48,556	(8,986)	41,823	(15,464)
Other income (expenses)
Interest income	368	290	726	391
Interest expense	(10)	(4)	(37)	(8)
Other income		(168)	4	(231)
Total other income, net	358	118	693	152
Income (loss) before income tax	48,914	(8,868)	42,516	(15,312)
Provision for income tax	1,749		1,749
Net income (loss)	47,165	(8,868)	40,767	(15,312)
Other comprehensive income (loss), net of tax
Net unrealized gain (loss) on marketable securities	113	(55)	732	(90)
Comprehensive income (loss)	$ 47,278	$ (8,923)	$ 41,499	$ (15,402)
Net income (loss) per share attributable to common shareholders:
Basic (in dollars per share)	$ 1.16	$ (0.22)	$ 1.00	$ (0.41)
Diluted (in dollars per share)	$ 1.13	$ (0.22)	$ 0.98	$ (0.41)
Weighted average shares used to compute net income (loss) per share attributable to common stockholders:
Basic (in shares)	40,800,586	40,389,648	40,703,688	37,518,271
Diluted (in shares)	41,738,460	40,389,648	41,701,262	37,518,271