Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Collaboration revenue	$ 14,984	$ 0	$ 47,080	$ 0
Revenue—related party	137	167	275	338
Total revenue	15,121	167	47,355	338
Operating expenses:
Research and development	8,615	8,147	17,957	14,104
General and administrative	4,937	3,212	9,810	6,393
Total operating expenses	13,552	11,359	27,767	20,497
Income (loss) from operations	1,569	(11,192)	19,588	(20,159)
Other income (expense):
Interest income	16	14	35	36
Other income (expense), net	1	0	(34)	0
Total other income (expense)	17	14	1	36
Income (loss) before income taxes	1,586	(11,178)	19,589	(20,123)
Provision for income taxes	296	124	447	130
Net income (loss)	$ 1,290	$ (11,302)	$ 19,142	$ (20,253)
Net income (loss) per share attributable to holders of ordinary shares
Basic (in dollars per share)	$ 0.06	$ (0.64)	$ 0.87	$ (1.15)
Diluted (in dollars per share)	$ 0.06	$ (0.64)	$ 0.83	$ (1.15)
Shares used to compute net income (loss) per share attributable to holders of ordinary shares
Basic (in shares)	21,959	17,679	21,922	17,679
Diluted (in shares)	22,898	17,679	22,927	17,679