Collaborative Arrangements and Licensing Agreements, Research, Development and Commercialization Partners - Roche (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Apr. 30, 2013	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaborative Arrangement and Licensing Agreement [Abstract]
Revenue earned		$ 160,349	$ 110,927	$ 38,470	$ 36,874	$ 51,571	$ 49,121	$ 120,428	$ 62,583	$ 346,620	$ 283,703	$ 214,161
Roche [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront payment recorded as deferred revenue	$ 30,000
Payment receivable due for updated development activities		3,000								3,000
Maximum amount of payments receivable for license fee and substantive milestones		365,000								365,000
Maximum amount of payments receivable for development milestones		70,000								70,000
Maximum amount of payments receivable for regulatory milestones		170,000								170,000
Maximum amount of payments receivable for commercialization milestones		80,000								80,000
Maximum amount of payment receivable for each additional drug developed		136,500								136,500
Cumulative payments received		53,600								53,600
Next prospective milestone		10,000								10,000
Revenue earned										7,100	31,200	$ 8,700
Deferred revenue		$ 1,700				$ 8,800				$ 1,700	$ 8,800
Roche [Member] | Revenue [Member] | Strategic Partner [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Concentration percentage										2.00%	11.00%	4.00%